Receiving device and power supply device

Abstract

To use an industrial product metal portion as an antenna to receive electric field energy of a radio wave or a quasi-electrostatic field (near field) in a space and convert it into energy.SOLUTION: An antenna device includes an antenna unit including: a rectifier circuit that receives electric field energy of a radio wave or a quasi-electrostatic field (near field) in a space and rectifies an AC signal into a direct current; a first antenna element that is a conductor to be in contact with or connected to an industrial product metal portion; and a second antenna element that is a conductor different from the first antenna element and provided not to be electrically connected to the industrial product metal portion. An input line output from the first antenna element to a rectifier circuit unit of the AC signal output from the antenna unit is connected to the rectifier circuit.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] This technology relates to a power supply device having an energy harvesting function. Receiving device and

Background Art

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

[0003] Non-Patent Document 1 describes that by using a high-impedance antenna to receive the 470-600 MHz band of terrestrial digital broadcast and increasing the excitation voltage of the rectifier, the rectenna can be made more efficient.

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

Prior Art Documents

Non-Patent Documents

[0005]

Non-Patent Document 1

Non-Patent Document 2

[0006] Both Non-Patent Documents 1 and 2 mentioned above focus solely on the electromagnetic energy of radio waves propagating through the air, designing antennas matched to specific frequencies and incorporating matching sections to achieve impedance matching. However, such configurations have the problem that reception is limited to matched frequencies, resulting in significantly reduced power output. In particular, separate antennas are required for each receiving frequency, and to receive broadcast waves, a size of approximately half the wavelength is necessary. Minimizing the size reduces reception efficiency, severely limiting the range of applications. In other words, to receive signals across a wide frequency range, multiple antennas of sizes matched to the receivable frequencies are required, and these antennas must be installed separately.

[0007] Therefore, the objective of this technology is to obtain greater received power by incorporating the electric field energy of a quasi-electrostatic field (near-field) in addition to the widely present radio waves, using a configuration different from conventional methods that convert radio wave energy into power using a receiving antenna. Receiving device and The objective is to provide a power supply device. [Means for solving the problem]

[0008] This technology is Multiple instances are provided of at least one of the first antenna element and the second antenna element. It consists of a first antenna element and a second antenna element, Receiving the electric field energy of radio waves and quasi-electrostatic fields (near-fields) in space. The antenna unit converts the electric field energy into electricity, It has multiple rectifier circuits that rectify the AC signal from the antenna section. The first antenna element is a conductor that is in contact with or connected to the metal part of an industrial product, and the metal part of the industrial product is used as an antenna. The second antenna element is a separate conductor from the first antenna element, is provided so as not to be electrically connected to the metal parts of the industrial product, and is grounded to the earth via capacitive coupling or grounded to the earth via a cable, thereby forming an electric field. Input lines from the first antenna element of the antenna section to the rectifier circuit are provided and connected to the rectifier circuit, respectively. It is a receiving device. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a block diagram of one embodiment of a receiving device based on this technology. [Figure 2] Figures 2A, 2B, and 2C are plan and cross-sectional views of an example of an antenna device included in a receiving device. [Figure 3] Figures 3A and 3B are plan and cross-sectional views, respectively, of other examples of antenna devices included in a receiving device. [Figure 4] Figure 4 is a schematic diagram illustrating a specific example of an antenna device. [Figure 5] Figure 5 is a schematic diagram illustrating a first example of an antenna device including a circuit board. [Figure 6] Figure 6 is a schematic diagram illustrating a modified example of the first example. [Figure 7] Figure 7 is a schematic diagram illustrating a second example of an antenna device including a circuit board. [Figure 8] Figure 8 is a schematic diagram illustrating a modified version of the second example. [Figure 9] Figure 9 is a schematic diagram illustrating a third example of an antenna device including a circuit board. [Figure 10] Figure 10 is a connection diagram illustrating a modified example of the antenna device. [Figure 11] Figure 11 is a connection diagram illustrating a modified example of the antenna device. [Figure 12] Figures 12A, 12B, and 12C are schematic diagrams showing specific examples of the second antenna element, respectively. [Figure 13]FIG. 13 is a schematic diagram for explaining the operation of the antenna device. [Figure 14] FIG. 14 is a schematic diagram used for explaining an embodiment in which the present technology is applied to a metal rack. [Figure 15] FIG. 15 is a schematic diagram used for explaining an example of an embodiment. [Figure 16] FIG. 16 is a schematic diagram used for explaining a modification example of an embodiment. [Figure 17] FIGS. 17A and 17B are schematic diagrams used for explaining an example applied to a microwave oven. [Figure 18] FIG. 18 is a connection diagram showing the configuration of an example of a rectifier circuit. [Figure 19] FIG. 19 is a connection diagram showing the configuration of another example of a rectifier circuit. [Figure 20] FIG. 20 is a graph for explaining the characteristics of a diode in a rectifier circuit. [Figure 21] FIG. 21 is a block diagram of a modification example of a circuit configuration. [Figure 22] FIG. 22 is a connection diagram showing an example of the configuration of an antenna device using another example of a rectifier circuit. [Figure 23] FIG. 23 is a connection diagram showing another example of the configuration of an antenna device using another example of a rectifier circuit. [Figure 24] FIG. 24 is a connection diagram showing yet another example of the configuration of an antenna device using another example of a rectifier circuit. [Figure 25] FIG. 25 is a connection diagram used for explaining an application example of the antenna device. [Figure 26] FIG. 26 is a graph used for explaining an application example of the antenna device. [Figure 27] FIGS. 27A and 27B are schematic diagrams used for explaining other embodiments in which the present technology is applied to a vehicle. [Figure 28] FIG. 28 is a perspective view showing an enlarged partial cross-section of a tire. [Figure 29] FIG. 29 is a block diagram showing the configuration of another application example of the present technology. [Figure 30]Figures 30A and 30B are block diagrams showing typical configurations for increasing output. [Figure 31] Figure 31 is a block diagram of an example of a configuration in which antenna devices are connected in series. [Figure 32] Figure 32 is a connection diagram showing an example of the circuit connection in Figure 31. [Figure 33] Figure 33 is a block diagram of another example of a configuration in which antenna devices are connected in series. [Figure 34] Figure 34 is a connection diagram showing an example of the circuit connection in Figure 33. [Figure 35] Figure 35 is a block diagram of an example of a configuration in which antenna devices are connected in parallel. [Figure 36] Figure 36 is a connection diagram showing an example of the circuit connection shown in Figure 35. [Figure 37] Figure 37 is a block diagram of another example of a configuration in which antenna devices are connected in parallel. [Figure 38] Figure 38 is a connection diagram showing an example of the circuit connection shown in Figure 37. [Figure 39] Figure 39 is a schematic diagram used to explain the case of increasing the number of antennas. [Figure 40] Figures 40A and 40B are connection diagrams used to explain how to increase the number of antennas. [Modes for carrying out the invention]

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

[0011] This technology utilizes metal parts (iron, aluminum, copper, metal alloys, etc.) that induce electric field energy, such as those found in everyday industrial products like cars, vending machines, refrigerators, microwave ovens, metal racks, guardrails, mailboxes, and traffic lights. These metal parts act as antennas, receiving electric field energy from radio waves and quasi-electrostatic fields (near-field fields) in the surrounding space. In other words, if a metal exists floating in space, various alternating currents flow across its surface. This technology treats the metal as an antenna and efficiently converts these currents into energy.

[0012] For example, electric field energy is induced in the metal parts (iron, aluminum, copper, metal alloys, etc.) of everyday industrial products such as cars, vending machines, refrigerators, microwave ovens, metal racks, guardrails, mailboxes, and traffic lights. This technology uses the metal parts of such industrial products as antennas to receive electric field energy from radio waves and quasi-electrostatic fields (near-field fields) in space. In other words, if metal exists while floating in space, various alternating currents flow through the metal surface, and this technology treats the metal as an antenna to efficiently convert this power into energy. Note that the metal parts of industrial products referred to are metal parts other than those of industrial products that are specifically designed as antennas.

[0013] For the input terminal section, which is in contact with or connected to the metal part of an industrial product and uses the metal part itself as an antenna, a high impedance is desirable for reception when connecting to the subsequent rectifier circuit. In particular, instead of providing a matching circuit that matches the frequency, it is connected in series and rectified with a diode that has a very small reverse current relative to the forward current. As a result, in addition to conventional radio waves, it is possible to efficiently receive power from quasi-electrostatic fields (near-field fields), which are not radio waves such as 50 / 60Hz leaking from power supplies, at very low frequencies.

[0014] Thus, the antenna shape does not need to be considered between the input terminal connected to the metal part of the industrial product and the rectifier circuit, and a matching circuit is unnecessary. As a result, in the first method, the ground of the antenna device is capacitively coupled to the ground of the earth or to the ground by a cable, etc., and a structure is made to create an electric field, making it possible to capture electric field energy in quasi-electrostatic fields other than radio waves. In the second method, a separate antenna element, different from the ground of the antenna device, is capacitively coupled to the ground of the earth or to the ground by a cable, etc., and a structure is made to create an electric field, making it possible to capture electric field energy in quasi-electrostatic fields other than radio waves. In other words, it is possible to receive power and noise leaking from power cords and inverters and convert them into energy. This technology can increase the received power by being able to receive electric field energy over a wide range. A quasi-electrostatic field is a voltage phenomenon that does not propagate like a radiated electromagnetic field, so-called radio waves, but is distributed around people, vehicles, and materials like electrostatic charging. While an electrostatic field is considered to have zero time variation, a quasi-electrostatic field has frequency components and is accompanied by time variation.

[0015] Figure 1 shows one embodiment of an antenna device equipped with an energy harvesting function according to this technology. The antenna section 1a, consisting of a first antenna element and a second antenna element, receives electric field energy, and the output of the antenna section 1a is supplied to the rectifier circuit 2. The antenna device 1 is composed of the antenna section 1a and the rectifier circuit 2.

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

[0017] Antenna device 1 is composed of a first antenna element and a second antenna element that are in contact with metal. An example of antenna device 1 is described with reference to Figures 2A (plan view), 2B (cross-sectional view), 2C (cross-sectional view), 3A (plan view), and 3B (cross-sectional view), as well as a circuit board diagram on which the rectifier circuit 2 (explained later) is mounted (see Figures 5 and 6). As shown in Figures 2A, 2B, 2C, 3A, and 3B, the first antenna element 11 that contacts or connects to the metal part of the industrial product is configured in a plate shape (patch shape). The antenna element 11 is a plate 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 to match the shape of the metal part of the industrial product, such as linear, pin, hemispherical, or convex / concave. The metal part of the industrial product and the antenna element 11 are contacted or connected by methods such as welding, mechanical bonding (such as crimping), bonding with conductive adhesive, or attachment to iron material using magnets or other magnetic materials. Furthermore, the antenna element 11 may be made of a conductive resin or conductive rubber, for example, a material containing carbon or metal. Using a conductive resin makes it easy to form electrodes of various shapes. Using conductive rubber makes it possible to construct electrodes that can be elastically deformed or electrodes with high adhesion. Furthermore, the material of the antenna element 11 is not limited; the materials described above may be used individually, or the electrodes may be constructed by combining the materials.

[0018] Furthermore, it is sufficient if the antenna element 11 can capacitively couple with the metal even with space or an insulator in between. Figure 4 shows a desk lamp 6 equipped with a fluorescent lamp 7. The antenna device 1 is attached to the main body 8, for example, housed in a resin case.

[0019] The circuit board 9, housed within the resin case of the main unit 8, has the inverter and other circuit components mounted on it. The inverter converts the 50Hz or 60Hz commercial power supply into DC, and then further converts it into a high-frequency signal of 20-50kHz to light the fluorescent lamp 7. This lighting method does not produce the flicker characteristic of fluorescent lamps compared to lighting using the frequency of the commercial power supply. As indicated by the arrows, spatial noise is generated from the circuit components. The antenna device 1 is spatially coupled to the circuit board on which the inverter and other circuit components are mounted, and can induce a voltage due to the spatial noise. For example, experiments have confirmed that a voltage of approximately 4.4V is induced when the fluorescent lamp is turned ON.

[0020] In Figures 2B and 2C, for example, a plate-shaped (patch-shaped) antenna element 11 and a device substrate (circuit board) 12 are arranged opposite each other, with a dielectric plate 13 interposed between the antenna element 11 and the device substrate 12. Alternatively, the dielectric plate 13 may be omitted, leaving a space between the antenna element 11 and the device substrate 12.

[0021] To electrically connect the antenna element 11 and the equipment board 12, one end of the antenna element 11 and a conductive pin 14 are electrically connected, and the other end of the conductive pin 14 penetrates the equipment board 12 and is soldered to the signal path electrode on the back surface of the equipment board 12. The antenna section 1a is formed by the antenna element 11 and the ground formed by the copper foil pattern of the equipment board 12. The ground is a second antenna element. This antenna section 1a has the structure of a T-type antenna with a flat plate as the antenna element. The connection point between the signal path electrode of the equipment board 12 and the conductive pin 14 becomes the feed point 15 of the antenna. A circuit section 16 is provided, for example, on the back surface of the equipment board 12.

[0022] The antenna device with the above configuration is housed in case 17. All contact surfaces of case 17 except for the antenna element 11 are made of insulating material such as resin. Furthermore, the sides of the case and the opposite side of the case, other than the contact surface with the metal from which energy is intended to be absorbed, are also made of insulating material.

[0023] Figure 2C shows that the case 17 consists of a non-metallic case 17A made of resin or the like and a metal case 17B. It is also possible to configure the case 17B to be electrically connected to the ground 19 on either the upper or lower surface of the equipment circuit board 12. That is, the insulating material case 17A on which the antenna element 11 is provided and the metal material case 17B on the opposite side may be connected by a connector 22 such as a screw, and the case 17B and the ground 19 of the equipment circuit board 12 may be connected by a wire 23.

[0024] Furthermore, as shown in Figures 3A and 3B, an insulated coated cable 24 may be connected to the ground 19 formed by the copper foil pattern of the equipment substrate 12 using solder or the like to connect it to the ground. In this embodiment, the antenna element 11 is constructed in a plate shape and is configured to contact or connect to the metal part of the industrial product. However, the connection between the antenna element 11 and the feed point 15 can also be made by directly connecting them using an insulated coated cable or the like to the metal part of the industrial product.

[0025] As shown in Figure 5, a ground 19 formed by a copper foil pattern is formed on the circuit board 12, and the antenna section 1a is composed of the antenna element 11 and the ground 19 formed by the copper foil pattern of the equipment board 12. The ground 19 is the second antenna element. Furthermore, as a measure against static electricity, an electrostatic discharge protection component, such as a varistor 18, is inserted between the antenna element 11, which is in contact with or connected to metal, and the ground formed by the copper foil pattern of the receiving equipment. The varistor 18 may also be connected between the output terminal 34a and the ground 19.

[0026] The circuit section 16 includes a rectifier circuit 2. The rectifier circuit 2 is configured so as not to overlap with the ground 19 formed by the copper foil pattern on the equipment board 12. The input line output from the antenna element 11 to the rectifier circuit 2 is connected in series with the rectifier circuit without going through a matching circuit. The circuit section 16 may include a charger 3 and an energy storage element 4 (not shown), or they may exist as separate components.

[0027] Figure 6 shows the configuration of the equipment board 12 corresponding to Figures 3A and 3B. The ground 19 (shown as a shaded area) formed by the copper foil pattern of the equipment board 12 is grounded to the earth ground via an insulated covered cable 24. The earth ground may include the ground itself, or it may function as a low-potential ground such as a wide conductive plate. The varistor 18 may be connected between the output terminal 34a and the ground 19.

[0028] Next, a separate second antenna element 20 (shown as a shaded area) formed from a copper foil pattern may be constructed on the above substrate, as shown in Figure 7. In this case, the separate second antenna element 20 must not come into contact with or connect to the metal part of the industrial product from which energy is to be captured. Alternatively, as shown in Figure 8, an insulated coated cable 25a may be connected to the ground 19 (shown as a shaded area) formed from the copper foil pattern of the equipment substrate 12 to connect it to the ground. In addition, although it is created on a separate substrate in Figures 7 and 8, it may also be formed on a metal part such as a housing that is configured not to come into contact with metal, on the opposite side of the metal contact surface of the receiver. In this case as well, an electrostatic discharge protection component, such as a varistor 21, can be inserted between the antenna element 11 that comes into contact with metal and the ground of the receiving equipment as an electrostatic discharge protection measure. The varistor 21 may also be connected between the output terminal 34a and the ground 19.

[0029] Furthermore, as shown in Figure 9, an electrostatic discharge (ESD) protection component, such as a varistor 21, may be inserted between the antenna element 11, which is in contact with metal, and the antenna element 20, and an insulated cable 25b may be connected to the antenna element 20 to ground it to the earth. In this case, the antenna element 20 can draw power much larger than the electric field created between it and the earth through capacitive coupling. When considering drawing power from metal products such as microwave ovens and refrigerators in a room, grounding is required as an ESD protection measure, and when drawing power from the metal parts of such products, it is necessary to connect them with an insulated cable or the like, as described above. The varistor 21 may also be connected between the output terminal 34a and the ground 19.

[0030] Figures 10 and 11 show modified examples of Figures 5 and 7. Specifically, in cases where the metal part of an industrial product is directly grounded to the ground using an insulated wire, the wire is grounded via an electrostatic protection component such as a varistor 18. The above configuration is used for existing electrical products that require a separate ground connection.

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

[0032] A great deal of electric field energy exists around us, but it can be divided into low-frequency and high-frequency components. For example, leakage electric fields from household AC power supplies (50Hz / 60Hz) and noise near personal computers are low-frequency components. These are called quasi-electrostatic fields (near-field). On the other hand, radio broadcasts (AM / FM), television broadcasts, and mobile phone radio waves are high-frequency components. These are called radio waves (far-field).

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

[0034] In the antenna device 1, it is preferable that the antenna element 11 is directly connected to the metal part of the industrial product, but in this example, the basic principle is to make contact over a surface to increase capacitance. As long as it is in contact with or connected to the metal part, in the case of contact, it may be a pin structure, hemispherical, or interlocking structure other than a flat surface, and in the case of connection, it may be connected directly by screwing, soldering, welding, etc., or via an insulator such as an insulated cable or conductive rubber (or air). The antenna section 1a, which is composed of the antenna element 11 in contact with the metal and the ground electrode 19 of the equipment circuit board 12, or a separate second antenna element 20, can receive electric field energy and generate power.

[0035] As shown in Figure 14, for example, the metal rack 91 exists electrically floating on the carpet, which is an insulating material, and when the antenna device 1 (shaded portion) including the antenna section 1a is attached, the circuit configurations shown in Figures 5 and 7 can be adopted. In this case, it can be considered that the ground 19 of the equipment board 12 (not shown here), or a separate second antenna element 20 (not shown here), is capacitively coupled to the ground (GND1) to form a large antenna section. This antenna section can receive low-frequency quasi-electrostatic fields.

[0036] Figure 15 shows that when the circuit configuration is as shown in Figure 10, the effect of capturing energy from space is further enhanced. In other words, this can be achieved by connecting a separate second antenna element 20 to the ground (GND) of, for example, an earthed outlet via an insulated cable 25c.

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

[0038] Next, Figures 17A and 17B show configuration examples of the embodiments of Figures 10 and 11. When the earth cable 82 attached to the microwave oven 81 is grounded, an electrostatic protection component 83 is provided between it and the earth terminal of the power outlet. The electrostatic protection component 83 has a screw portion 85 for connecting the earth cable 82 and a varistor 84 for electrostatic protection provided on a circuit board, and the earth cable 82 is soldered to the circuit board.

[0039] Thus, the antenna device 1 is capable of receiving electric field energy over a wide frequency range. Therefore, with this antenna device based on this technology, a wide range of electric field energy can be easily captured simply by making contact with metal. Furthermore, if a larger amount of energy capture is desired, connection by soldering to the metal part of an industrial product is preferable. In addition, if the metal rack is made of iron, the connection may be maintained with a magnet.

[0040] An example of rectifier circuit 2 is shown in Figure 18. When dealing with small voltages such as those used in energy harvesting, it is possible to rectify them with a normal rectifier circuit, but a certain voltage is required to store energy quickly. Therefore, it is necessary to boost the voltage and rectify it, like in a voltage doubler circuit. Thus, by inserting a capacitor of the desired voltage boost level before the diode and rectifying, the voltage equivalent to that of the capacitor is added, making it possible to boost the voltage. Accordingly, a full-wave quadruple voltage doubler rectifier circuit was constructed consisting of input capacitors 26 and 27 connected to the antenna section 1a, diodes 28, 29, 30 and 31, and capacitors 32 and 33. DC is output from both ends of the series connection of capacitors 32 and 33 to the output terminals 34a and 34b. In this configuration, capacitors 32 and 33 not only boost the voltage but also store current, so it is desirable to have a large capacitance and low leakage current in this section.

[0041] This example uses a full-wave 4x voltage multiplier rectifier circuit, but a standard 1x half-wave rectifier circuit, a full-wave rectifier circuit, a voltage doubler rectifier circuit, or a Cockcroft-Walton circuit can also be used. Furthermore, the full-wave rectifier circuit is more efficient because it can increase the voltage of the AC signal and capture all of it. Therefore, even considering the diode losses, the full-wave rectifier circuit yielded better results with the diodes used in this example. This is a two-stage 4x full-wave rectifier, but the number of stages can be increased further if a higher voltage output is desired.

[0042] Examples of values ​​for each component are shown below: Capacitors 26, 27: 0.22μF, 32, 33: 47μF; Diodes 28, 29, 30, 31: 1N60 (silicon)

[0043] In the case of the 4x voltage rectifier circuit described above, it is important that the leakage current of the diodes during reverse bias is very small. If there is leakage current, a full-wave rectifier circuit is suitable. Another example of rectifier circuit 2 (full-wave rectifier circuit) is shown in Figure 19. As shown in Figure 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 varistor 66 for electrostatic discharge protection and a Zener diode 67 for IC protection (for example, with a Zener voltage of 6.5V) are connected in parallel between output terminals 34a and 34b.

[0044] Although discrete diodes were used, a dedicated IC could also be used. Figure 20 and Table 1 show the results of measuring the forward voltage Vf and reverse current Is of the diodes used in rectifier circuit 4. For diode part number 1N60, silicon and germanium diodes were measured, while for other part number ISS108, germanium diodes from different manufacturers were used for evaluation. In Figure 20, curve 42 represents the characteristics of 1N60 (silicon), curve 41 represents the characteristics of 1N60 (germanium), and curve 43 represents the characteristics of ISS108 (germanium).

[0045] [Table 1]

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

[0047] When the output of the antenna section 1a described above is rectified, it was found that the diode 1N60 (silicon), which does not allow current to flow in the reverse direction, can capture more power than the diode with a lower voltage at which current begins to flow in the forward direction. Since the input being rectified is AC, the reverse current Is when the forward voltage Vf of the diode is applied in the reverse direction can be calculated from the data in Table 1 for 10V. When the same voltage as Vf is applied in the reverse direction, the reverse current Is is 0.036 μA for 1N60 (silicon), 0.21 μA for 1N60 (germanium), and 0.5 μA for ISS108 (germanium). Therefore, the ratio of the reverse current Is at forward current (1 mA) / forward voltage Vf is calculated to be 1 / 27778 for 1N60 (silicon), 1 / 4762 for 1N60 (germanium), and 1 / 2000 for ISS108 (germanium). In other words, the diode used in rectifier circuit 2 needs to have a ratio greater than approximately 4700 times, and preferably, a ratio of 10000 or more. As a result, among the three diodes given as examples, 1N60 (silicon) has the most suitable characteristics.

[0048] Furthermore, considering the characteristics of the diode, a smaller reverse current Is is preferable when current is applied in the reverse direction. Using 10V data, the reverse resistance values ​​are calculated to be 100MΩ for 1N60 (silicon), 1.43MΩ for 1N60 (germanium), and 0.38MΩ for ISS108 (germanium). In other words, a higher resistance value is preferable to prevent current from flowing in the reverse direction. For the diode used in rectifier circuit 2, the aforementioned resistance value must be greater than 1.43MΩ, preferably 10MΩ or more. As a result, among the three diodes given as examples, 1N60 (silicon) has the most suitable characteristics.

[0049] Taking into account the differences in diode characteristics, as shown in Figure 21, it is also possible to provide two rectifier circuits 2a and 2b and split the output of the antenna section 1a into two frequency components using a diplexer 7. The lower frequency component, below a predetermined frequency, for example, below 1 MHz, separated by the diplexer 7, is supplied to one rectifier circuit 2a and rectified. The higher frequency component, above the predetermined frequency, for example, above 1 MHz, is supplied to the other rectifier circuit 2b and rectified. The outputs of these rectifier circuits 2a and 2b are added together by an adder circuit 8 and output.

[0050] The rectifier diodes constituting the rectifier circuit 2a have characteristics suitable for rectifying electrical signals generated from quasi-electrostatic fields with low frequency components, for example, a low reverse current Is at a forward voltage Vf. The rectifier diodes constituting the rectifier circuit 2b have characteristics suitable for rectifying electrical signals generated from radio waves of radiated electromagnetic fields with high frequency components, for example, a low forward voltage. The diplexer 7 that frequency-separates the output signal of the antenna section 1a is constructed to minimize losses as much as possible. Note that the predetermined frequency of 1 MHz is just an example, and the frequency division may be set to different frequencies depending on the diode frequency characteristics, or the frequency division may be set to three or more divisions.

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

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

[0053] As shown in Figure 25, a full-wave rectifier circuit (consisting of diodes 61-64 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 high-resistance sensor (2 MΩ or more, preferably 10 MΩ), such as a voltmeter 95. In addition, the output of the full-wave rectifier circuit charges the battery 96 via the reverse current blocking diode 65, and the output of the battery 96 is used as the power source for the voltmeter 95.

[0054] By using high-resistance sensors, it becomes possible to measure the voltage induced in metal. Analyzing the acquired data allows for obtaining information on the operating status of the equipment's motors, inverters, etc. This enables monitoring of the equipment's condition and allows for alerts to be issued before a malfunction occurs.

[0055] As an example, an experiment was conducted by attaching an antenna device to the side of a refrigerator. Using the generated power of 4.4V, a step-down DC-DC converter was used to step down the voltage from 3.7V to 2.5V to charge the battery. The results of checking the charging voltage and input voltage at regular intervals are shown in the graph in Figure 26. From this graph, it can be seen that the battery was being charged and that the timing of turning the inverter OFF could be detected.

[0056] Other embodiments of this technology will be described with reference to Figures 27A, 27B, and 28. The other embodiments apply this technology to a vehicle (particularly the vehicle body). As shown in Figure 27A, when the antenna device 1 (shaded portion) is attached to the vehicle 71, it can be considered that, in the configuration of Figures 5 and 7, the ground of the equipment board 12, or the relationship between the separate second antenna element 20 and the ground, is capacitively coupled to form a large antenna device 1. This antenna device 1 is capable of capturing the energy of quasi-electrostatic fields and radio waves generated in space, including the reception of low-frequency quasi-electrostatic fields.

[0057] Generally, cars (car bodies) are made of metal, so they are prone to generating static electricity. Recently, to improve tire wear resistance, silica has been added instead of conventional carbon. Since silica does not conduct electricity, measures are taken to dissipate static electricity, such as adding conductive slits 74 (shown with diagonal lines) to a portion of the tire 73, as shown in the enlarged cross-section in Figure 28. The conductive slits 74 create a structure that dissipates the generated static electricity. However, because the contact area of ​​the conductive slits 74 with the ground is limited, the tire has a resistance of approximately 10 MΩ. In other words, it is a circuit configuration grounded by a resistance as shown in Figure 27B. Therefore, from the perspective of the energy of the quasi-electrostatic field and radio waves generated in the space under consideration, it is in a state of floating in space. Furthermore, even if it is not completely insulated from the ground, although Figure 19B shows an example of resistance, the connection between the metal part (e.g., car body) 72 and the ground may be coupled by an inductance component instead of resistance.

[0058] By using the large metal parts of a car as antennas in this way, it becomes possible to capture more energy from quasi-electrostatic fields and radio waves generated in the surrounding space. If the captured energy is rectified and stored in energy storage elements such as secondary batteries, it will eliminate the need to recharge car key position detection sensors and other devices that are currently required for cars.

[0059] This technology utilizes metal objects such as cars, vending machines, refrigerators, microwave ovens, metal racks, guardrails, mailboxes, and traffic lights as antennas. Furthermore, by creating an antenna that connects to the receiving device's ground or a separate antenna, the receivable frequency range is not limited by the antenna's shape. Additionally, by creating a structure where the receiving device's ground is capacitively coupled to the ground, it becomes possible to capture electric field energy in quasi-electrostatic fields other than radio waves. In other words, it makes it possible to convert power and noise leaking from power cords and inverters into energy. Thus, the metal of the product is treated as a single antenna element, and the power induced in the metal itself can be captured between the product and the receiving device's ground, acting as an antenna.

[0060] For indoor appliances such as microwave ovens and refrigerators, when considering drawing power from metal products that need to be grounded as a measure against static electricity, static electricity countermeasures can be implemented by inserting an electrostatic protection component, such as a varistor 21, between the antenna element 11 and the appliance, and connecting insulated cables 24, 25a, and 25b to the ground via the appliance's ground 19 or the antenna element 20, thereby grounding to the earth.

[0061] Furthermore, in the example shown in Figure 9, the antenna element 20 is connected to the ground via an insulated cable, making it possible to extract significantly more power than with capacitive coupling. When extracting power from the metal parts of such a product, it is necessary to connect them with an insulated cable or the like, as described above.

[0062] Although embodiments of this technology have been described in detail above, the technology is not limited to the embodiments described above, and various modifications are possible based on the technical concept of this technology. Furthermore, one or more of the modifications can be arbitrarily selected and combined as appropriate. In addition, the configuration, methods, processes, shapes, materials, and numerical values ​​of the embodiments described above can be combined with each other as long as they do not deviate from the spirit of this technology. For example, this technology can be used in combination with power generation using natural energy, such as solar power generation, or with thermoelectric conversion elements to store energy.

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

[0064] Figure 29 is a block diagram showing an application example of this technology applied to a power supply for IoT (Internet of Things) for environmental monitoring or detection of the condition of equipment. It includes an illuminance sensor 51, temperature, humidity and atmospheric pressure sensors 52, BLE (Bluetooth® Low Energy) and an MCU (Microcontroller unit) 53, and these blocks (ICs) are connected by an I2C bus 54. An antenna device 1 (configured as an antenna unit 1a and a rectifier circuit 2, as shown in Figure 6) based on this technology is applied as a power supply for such IoT.

[0065] Furthermore, if rectifier circuit 2 uses a capacitor, for example, a voltage doubler rectifier circuit, it is important that the diode leakage current during reverse bias is very small. If there is leakage current, a full-wave rectifier circuit is suitable. In terms of diode characteristics, it is good to have one that can supply a large current from a very small Vf voltage. In order to obtain a high voltage, it is desirable that the leakage current of the reverse voltage application substrate is very small. When using circuits such as a 4x voltage doubler, the leakage current at this time should be about 0.001 μA when a reverse voltage of 5 V is applied.

[0066] Furthermore, if rectifier circuit 2 is a voltage doubler rectifier circuit or higher that uses a capacitor, it is important that the diode leakage current during reverse bias is very small. If there is leakage current, a full-wave rectifier circuit is suitable. In terms of diode characteristics, it is good to have one that can supply a large current from a very small Vf voltage. In order to obtain a high voltage, it is desirable that the leakage current of the reverse voltage application board is very small. When using circuits such as a 4x voltage doubler, the leakage current at this time should be about 0.001 μA when a reverse voltage of 5 V is applied.

[0067] BLE is an extension of Bluetooth®, enabling communication with extremely low power consumption. Using BLE and the MCU 53, detection data from the illuminance sensor 51 and the temperature, humidity, and atmospheric pressure sensors 52 can be wirelessly transmitted to mobile devices such as smartphones and tablets.

[0068] The output terminals 34a and 34b of the rectifier circuit 2 are connected to a DC-DC converter 55 acting as a charger. The output of the DC-DC converter 55 charges an energy storage element, such as 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 supplies power to the illuminance sensor 51, temperature, humidity, and atmospheric pressure sensors 52, the BLE, and the MCU 53. Additionally, the output of the LDO 58 supplies power to the BLE and the MCU 53. The LDO is a linear regulator that operates even with a low input / output potential difference. This low potential difference operation minimizes energy loss and allows for a design that suppresses heat generation. The LDO is supplied to the AD conversion inputs of the BLE and the MCU 53, and the output voltage of the secondary battery 56 is monitored by the BLE and the MCU 53.

[0070] For external communication such as BLE, a dipole antenna is preferable, as it is an antenna configuration that does not use the circuit board's ground and is less susceptible to energy harvesting.

[0071] By applying the above-described energy storage circuit, it becomes possible to charge the batteries of devices that require charging.

[0072] Furthermore, when used outdoors and exposed to wind and rain, waterproofing, drip-proofing, and weather resistance against ultraviolet rays are required. In the configuration shown in Figures 2 and 3, the weather resistance of the antenna device 1 can be improved by coating the surface of the antenna element 11 and the case 17, or the cases 17A, 17B and the joint 22 when the case is separated (Figure 2C), with a water-resistant and light-resistant resin.

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

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

[0075] Figure 31 shows a first embodiment for increasing the output voltage of an antenna device. A first antenna element 11 that contacts metal is provided, and two second antenna elements 20A and 20B are provided in relation to the antenna element 11. Antenna elements 20A and 20B are, for example, separate independent substrates, housings, etc. A rectifier circuit 2A is provided to rectify the output of the antenna section consisting of antenna elements 11 and 20A, and a rectifier circuit 2B is provided to rectify the output of the antenna section consisting of antenna elements 11 and 20B. Rectifier circuits 2A and 2B are connected in series, and an output line is derived from the series connection.

[0076] Figure 32 shows the circuit connection of the first embodiment. This is an example in which full-wave rectifier circuits are used as the rectifier circuits 2A and 2B connected in series. Zener diodes 66 and 67 are common elements for the two rectifier circuits 2A and 2B.

[0077] According to this first embodiment, if an output voltage of, for example, 4V can be obtained with a single antenna device, an output voltage of 8V can be obtained. A larger output voltage can be obtained by connecting two or more rectifier circuits in series. The first embodiment is suitable for cases where the frequency of voltage-inducing power supply noise, etc., is low, as there is no need to consider the distance between antennas.

[0078] The second embodiment, as shown in Figures 33 and 34, provides independent antenna elements 11A and 11B as the first antenna elements that come into contact with the metal. The antenna elements 11A and 11B come into contact with different parts of the metal.

[0079] Figure 34 shows the circuit configuration of the second embodiment. This is an example in which full-wave rectifier circuits are used as the rectifier circuits 2A and 2B connected in series. Zener diodes 66 and 67 are common elements for the two rectifier circuits 2A and 2B.

[0080] A third embodiment for increasing the output current of the antenna device is shown in Figures 35 and 36. A first antenna element 11 that contacts metal is provided, and two second antenna elements 20A and 20B are provided in relation to the antenna element 11. The antenna elements 20A and 20B are, for example, separate independent substrates, housings, etc. A rectifier circuit 2A is provided to rectify the output of the antenna section consisting of antenna elements 11 and 20A, and a rectifier circuit 2B is provided to rectify the output of the antenna section consisting of antenna elements 11 and 20B. The rectifier circuits 2A and 2B are connected in parallel, and an output line is derived from the parallel connection.

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

[0082] The fourth embodiment, as shown in Figures 37 and 38, provides independent antenna elements 11A and 11B as the first antenna elements that come into contact with the metal. The antenna elements 11A and 11B come into contact with different parts of the metal.

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

[0084] The antenna elements 11, 11A, and 11B that contact the metal, as described above, are connected to the connection points of diodes 61a and 64a and diodes 61b and 64b, respectively, in order to ensure they are in phase. Furthermore, the connection points of the full-wave rectifier circuit are the same. The antenna element connected to the metal element is positioned so that the phases of the rectifier circuit are added together in order to ensure that they are in phase.

[0085] Figures 39A, 39B, 40A, and 40B show examples of increasing the number of antennas in this technology. When increasing the number of antennas of the same length, the voltage will decrease slightly, but if you want to increase the current, you can increase the number of antenna elements. As shown in Figures 39A and 40A, the current can be increased by creating and connecting an antenna element 200 at the base of antenna element 20. If you want to increase both the voltage and the current, the length of the antenna elements should be set so that (length of antenna element 20 < length of antenna element 200). Alternatively, as shown in Figures 39B and 40B, the antenna element 20 may be created on a substrate on which a rectifier circuit is mounted, and the antenna element 200 may be created separately, for example, on a substrate, housing, rod antenna, etc.

[0086] As mentioned above, if a single antenna device can produce an output current of, for example, 4 μA, it can obtain an output current of 8 μA by connecting them in parallel. Furthermore, if you want to increase the voltage, for example, from a 4V output to an 8V output, this can be achieved by using a series connection. In this way, by combining the above series and parallel circuits, it becomes possible to supply the necessary power to the subsequent stages.

[0087] In the circuit configuration described above, a capacitor is used to smooth the voltage after rectification. It may also be connected in parallel with the Zener diode. [Explanation of Symbols]

[0088] 1... Antenna device, 2, 2a, 2b... Rectifier circuit, 4... Energy storage element, 7... Diplexer, 11... Antenna element, 12... Equipment circuit board, 15... Feed point, 91... Metal rack, 71... Car

Claims

1. A plurality of first antenna elements and second antenna elements are provided, An antenna unit comprising the first antenna element and the second antenna element, which receives electric field energy of radio waves and quasi-electrostatic fields (near-fields) in space and converts said electric field energy into power, It has multiple rectifier circuits that rectify the AC signal from the antenna section, The first antenna element is a conductor that is in contact with or connected to a metal part of an industrial product, and the metal part of the industrial product is used as an antenna. The second antenna element is a separate conductor 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 grounded to the ground by a cable, thereby forming an electric field. Input lines from the first antenna element of the antenna section to the rectifier circuit are provided and connected to the rectifier circuit, respectively. Receiving device.

2. The receiving device according to claim 1, wherein a plurality of second antenna elements and a plurality of rectifier circuits are provided with respect to the first antenna element, the plurality of rectifier circuits are connected in series, and an output line is derived from the series connection.

3. The receiving device according to claim 1, wherein a plurality of first antenna elements are provided, each of the first antenna elements is separately contacted or connected to a metal part of an industrial product, the rectifier circuit is connected in series, and an output line is derived from the series connection.

4. The receiving device according to claim 1, wherein a plurality of second antenna elements and a plurality of rectifier circuits are provided with respect to the first antenna element, the plurality of rectifier circuits are connected in parallel, and an output line is derived from the parallel connection.

5. A plurality of the first antenna elements and the second antenna elements are provided, and each of the first antenna elements is separately in contact with or connected to a metal part of an industrial product. The receiving device according to claim 1, wherein the pair of the first antenna element and the second antenna element are connected in phase with respect to the rectifier circuit, the rectifier circuit is connected in parallel, and an output line is derived from the parallel connection.

6. The receiving device according to claim 1, wherein at least one of the rectifier circuits has a diode for rectification, and the ratio of the forward current when the diode is at its forward voltage to the reverse current when that voltage is applied in the reverse direction is at least 4700 times or more, or the resistance value obtained using the reverse current when 10V is applied in the reverse direction to the diode for rectification is 1.4 MΩ or more.

7. The receiving device according to claim 6, wherein the diode is made of silicon.

8. The receiving device according to claim 1, wherein the electric field energy of the quasi-electrostatic field is power or noise leaking from the power cord or inverter.

9. The receiving device according to claim 1, wherein the contact surface of the first antenna element with the metal part of the industrial product is made of a conductive electrode consisting of one or a combination of gold, silver, aluminum, copper, iron, nickel, or an alloy.

10. The receiving 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 crimping, pressure welding, or a combination thereof.

11. The receiving device according to claim 9, wherein the conductive electrode is resin-coated.

12. The receiving device according to claim 1, wherein the connection portion of the first antenna element to the metal part of the industrial product is made of a conductive electrode consisting of one or a combination of gold, silver, aluminum, copper, iron, nickel, or an alloy.

13. The receiving device according to claim 12, characterized in that the connection portion is connected by one or a combination of screws, soldering, welding, conductive resin, conductive tape, conductive rubber, or magnets.

14. The receiving device according to claim 9, wherein the conductive electrode is one of the following: pin, linear, hemispherical, convex, or planar, or a combination thereof.

15. The receiving device according to claim 1, wherein the second antenna element is composed of one or a combination of the following: the ground of the circuit board of the receiver, a pattern on the board separate from the ground, the metal of the receiver housing which is not electrically connected to the metal part of the industrial product, or a conductive cable.

16. The receiving device according to claim 1, characterized in that the second antenna element and the ground are directly or indirectly grounded using an insulated cable.

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

18. The receiving device according to claim 1, wherein at least one of the rectifier circuits has a high-resistance sensor of 2 MΩ or more for measuring the output.

19. The receiving device according to claim 18, which analyzes data measured by the high-resistance sensor and obtains the state of the industrial product.

20. An antenna section comprising the first antenna element and the second antenna element, wherein at least one of the first antenna element and the second antenna element is provided in multiple quantities, and which receives noise generated by an electronic circuit and present in space, It comprises multiple rectifier circuits connected in series or parallel, which rectify the AC signal from the antenna section to generate an output, The first antenna element is a conductor that is in contact with or connected to a metal part of an industrial product via an insulator, and capacitively coupled with the metal part of the industrial product. The second antenna element is a separate conductor 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 grounded to the ground by a cable, thereby forming an electric field. Input lines from the first antenna element of the antenna section to the rectifier circuit are provided and connected to the rectifier circuit, respectively. Receiving device.

21. The receiving device according to any one of Claims 1 to 20, A charger to which the output of the rectifier circuit is supplied, A power supply device equipped with an energy storage element connected to the aforementioned charger.

22. The power supply device according to claim 21, further comprising a load that operates using the power stored in the energy storage element.

23. The power supply device according to claim 22, wherein the load comprises at least one of a microcomputer, a wireless communication unit, and a sensor.

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