Ultrasound-based piezoelectric element-stacked power reception apparatus and system

Abstract

The present invention relates to an ultrasound-based stacked power reception apparatus and system. The ultrasound-based piezoelectric element-stacked power reception apparatus, according to an embodiment of the present invention, may be configured such that: a first intermediate layer receives ultrasound transmitted from an ultrasound transmission apparatus through a medium and controls an acoustic impedance difference between the medium and a first piezoelectric element; the first piezoelectric element generates first electrical energy on the basis of the ultrasound that has passed through the first intermediate layer and transmits backward ultrasound; a second intermediate layer receives and passes the backward ultrasound; and a second piezoelectric element generates second electrical energy on the basis of the backward ultrasound that has passed through the second intermediate layer.

Description

Ultrasonic-based piezoelectric element stacked power receiving device and system

[0001] The present invention relates to an ultrasound-based stacked power receiving device and system, and more specifically, to a technology that improves the performance of wireless power transmission and reception by stacking a plurality of intermediate layers and a plurality of piezoelectric elements to integrate energy generated from a plurality of piezoelectric elements based on ultrasound and rear ultrasound.

[0002] Ultrasonic-based wireless power transmission technology is a technology that generates energy from a receiver by applying ultrasound generated from a transmitter to a receiver.

[0003] Receivers include triboelectric receivers using the triboelectric method and piezoelectric receivers using piezoelectric materials.

[0004] This describes a method for designing a piezoelectric receiver by considering the sound field of transmitted ultrasound in conventional technology.

[0005] When the side lobes of the transmitted ultrasonic sound field are applied to the surface of the receiver, they cause a phase mismatch. The phase mismatch reduces the energy generated at the receiver.

[0006] Therefore, to increase the efficiency of ultrasound-based wireless power transmission, the size of the main lobe of the transmitted ultrasonic sound field at the transmission focus point must be matched with the size of the receiving source, i.e., the piezoelectric receiver.

[0007] Since the output of a piezoelectric receiver is proportional to its size, a rectangular focused transmitter is used to increase the size of the transmitted sound field at the transmission focus point, and the piezoelectric receiver is also manufactured in a rectangular shape.

[0008] In wireless power transmission technology using ultrasound, energy may be wasted because the ultrasonic energy generated backward is not taken into account due to the characteristics of the piezoelectric receiver.

[0009] In addition, because there is a large difference in acoustic impedance between the medium through which the transmitted ultrasound travels and the piezoelectric receiver, a problem may occur in which the intensity of the ultrasound applied to the piezoelectric receiver decreases.

[0010] Wireless power technology has great potential for use in many fields.

[0011] Wireless power technology using ultrasound is widely used for medical purposes, particularly for charging batteries of implant devices inserted into the human body.

[0012] Implantable devices carry the risk of requiring surgery for battery replacement; however, if the power efficiency of ultrasound-based wireless power technology increases, the frequency of such surgeries can be reduced, which will lead to increased demand in the medical industry.

[0013] The present invention aims to improve the performance of wireless power transmission and reception by stacking a plurality of intermediate layers and a plurality of piezoelectric elements and integrating the energy generated from a plurality of piezoelectric elements based on ultrasound and rear ultrasound.

[0014] The present invention aims to improve wireless power reception performance by preventing a reduction in the magnitude of received ultrasound by reducing the acoustic impedance difference between the medium through which ultrasound propagates and the piezoelectric element based on a plurality of intermediate layers.

[0015] The present invention aims to increase wireless power reception efficiency by stacking a plurality of piezoelectric elements to generate additional energy for rearward ultrasonic waves generated backward.

[0016] The present invention aims to increase energy reception efficiency by integrating energy output from a plurality of piezoelectric elements in parallel.

[0017] The present invention aims to reduce the risk associated with surgery for battery replacement in an implant device by charging the battery using ultrasound, and to reduce the frequency of surgery for battery replacement by increasing battery charging efficiency.

[0018] An ultrasonic-based piezoelectric element stacked power receiving device according to an embodiment of the present invention comprises a first intermediate layer, a first piezoelectric element stacked on the first intermediate layer, a second intermediate layer stacked on the first piezoelectric element, and a second piezoelectric element stacked on the second intermediate layer. The first intermediate layer receives ultrasonic waves transmitted through a medium from an ultrasonic transmitting device and controls the acoustic impedance difference between the medium and the first piezoelectric element. The first piezoelectric element transmits a rear ultrasonic wave while generating a first electric energy based on the ultrasonic waves passing through the first intermediate layer. The second intermediate layer receives and transmits the rear ultrasonic waves, and the second piezoelectric element can generate a second electric energy based on the rear ultrasonic waves passing through the second intermediate layer.

[0019] The acoustic impedance of the first intermediate layer is determined by the power of the combination of the acoustic impedance of the first piezoelectric element and the acoustic impedance of the medium, and the acoustic impedance of the second intermediate layer can be determined by the power of the combination of the acoustic impedance of the second piezoelectric element and the acoustic impedance of the medium through which the rear ultrasound passes.

[0020] The first intermediate layer and the second intermediate layer may be formed from at least one material among polymer, glass, ceramic, and metal, as a material having an acoustic impedance of 6 Mrayl to 10 Mrayl.

[0021] The thickness of the first intermediate layer and the second intermediate layer can be determined to be any one of 1 / 8λ to 1 / 4λ.

[0022] The first piezoelectric element outputs the first electrical energy, the second piezoelectric element outputs the second electrical energy, and is connected in parallel with the first piezoelectric element, and the output first electrical energy and the output second electrical energy can be combined in parallel.

[0023] An ultrasonic-based piezoelectric element stacked power receiving system according to an embodiment of the present invention comprises a piezoelectric element stacked power receiver including a first intermediate layer, a first piezoelectric element stacked on the first intermediate layer, a second intermediate layer stacked on the first piezoelectric element, and a second piezoelectric element stacked on the second intermediate layer, a first rectifier connected to the first piezoelectric element to rectify the first energy into a first DC signal, and a second rectifier connected to the second piezoelectric element to rectify the second energy into a second DC signal, wherein the first intermediate layer receives ultrasonic waves transmitted through a medium from an ultrasonic transmitting device and controls the acoustic impedance difference between the medium and the first piezoelectric element, wherein the first piezoelectric element transmits a rear ultrasonic wave while generating a first electric energy based on the ultrasonic waves passing through the first intermediate layer, the second intermediate layer receives and transmits the rear ultrasonic waves, and the second piezoelectric element can generate a second electric energy based on the rear ultrasonic waves passing through the second intermediate layer.

[0024] The output terminals of the first rectifier and the second rectifier are connected in parallel so that the first DC signal and the second DC signal can be integrated to output an integrated DC signal.

[0025] An ultrasonic-based piezoelectric element stacked power receiving system according to one embodiment of the present invention may further include a DC converter that controls the voltage for the integrated DC signal to a preset size voltage, a power management circuit that controls and supplies the controlled voltage to a preset current, and a battery that stores the supplied current.

[0026] The first intermediate layer and the second intermediate layer may be formed from at least one material among polymer, glass, ceramic, and metal, as a material having an acoustic impedance of 6 Mrayl to 10 Mrayl.

[0027] The thickness of the first intermediate layer and the second intermediate layer can be determined to be any one of 1 / 8λ to 1 / 4λ.

[0028] The present invention can improve the performance of wireless power transmission and reception by stacking a plurality of intermediate layers and a plurality of piezoelectric elements to integrate energy generated from a plurality of piezoelectric elements based on ultrasound and rear ultrasound.

[0029] The present invention can improve wireless power reception performance by preventing a reduction in the magnitude of received ultrasound through a reduction in the acoustic impedance difference between the medium through which ultrasound propagates and the piezoelectric element based on a plurality of intermediate layers.

[0030] The present invention can increase wireless power reception efficiency by stacking a plurality of piezoelectric elements to generate additional energy for rearward ultrasonic waves generated backward.

[0031] The present invention can increase energy reception efficiency by integrating energy output from a plurality of piezoelectric elements in parallel.

[0032] The present invention reduces the risk of surgery for battery replacement in an implant device by charging the battery using ultrasound, and reduces the frequency of surgery for battery replacement by increasing battery charging efficiency.

[0033] FIG. 1 is a drawing illustrating an ultrasonic-based piezoelectric element stacked power receiving device according to an embodiment of the present invention.

[0034] FIG. 2 is a diagram illustrating the rear ultrasound used by an ultrasound-based piezoelectric element stacked power receiving device according to an embodiment of the present invention.

[0035] FIGS. 3a and 3b are drawings illustrating the output voltage according to the presence or absence of an intermediate layer of an ultrasonic-based piezoelectric element stacked power receiving device according to an embodiment of the present invention.

[0036] FIG. 4 is a diagram illustrating the output voltage according to the thickness of the intermediate layer of an ultrasonic-based piezoelectric element stacked power receiving device according to an embodiment of the present invention.

[0037] FIGS. 5a to 6b are drawings illustrating the output voltage according to the stacked structure of an ultrasonic-based piezoelectric element stacked power receiving device according to an embodiment of the present invention.

[0038] FIGS. 7a to 8b are drawings illustrating the application of a rectifier to an ultrasonic-based piezoelectric element stacked power receiving device according to an embodiment of the present invention.

[0039] FIG. 9 is a diagram illustrating the output voltage according to the connection of an ultrasonic-based piezoelectric element stacked power receiving device and a rectifier according to an embodiment of the present invention.

[0040] FIGS. 10a and FIGS. 10b are drawings illustrating battery charging using an ultrasonic-based piezoelectric element stacked power receiving device according to an embodiment of the present invention.

[0041] FIGS. 11a to 11c are drawings illustrating energy harvesting performance using an ultrasonic-based piezoelectric element stacked power receiving device according to an embodiment of the present invention.

[0042] Specific structural or functional descriptions of embodiments according to the concept of the present invention disclosed herein are provided merely for the purpose of explaining embodiments according to the concept of the present invention, and embodiments according to the concept of the present invention may be implemented in various forms and are not limited to the embodiments described herein.

[0043] Embodiments according to the concept of the present invention may be subject to various modifications and may take various forms; therefore, embodiments are illustrated in the drawings and described in detail in this specification. However, this is not intended to limit the embodiments according to the concept of the present invention to specific disclosed forms, and includes modifications, equivalents, or substitutions that fall within the spirit and scope of the present invention.

[0044] Terms such as "first" or "second" may be used to describe various components, but said components should not be limited by said terms. For the sole purpose of distinguishing one component from another, for example, without departing from the scope of rights according to the concept of the present invention, the first component may be named the second component, and similarly, the second component may be named the first component.

[0045] When it is stated that one component is "connected" or "connected" to another component, it should be understood that while it may be directly connected or connected to that other component, there may also be other components in between. Conversely, when it is stated that one component is "directly connected" or "directly connected" to another component, it should be understood that there are no other components in between. Expressions describing the relationships between components, such as "between," "exactly between," or "directly adjacent to," should be interpreted in the same way.

[0046] The terms used herein are merely for describing specific embodiments and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, terms such as “comprising” or “having” are intended to specify the existence of the described features, numbers, stages, actions, components, parts, or combinations thereof, and should be understood as not precluding the existence or addition of one or more other features, numbers, stages, actions, components, parts, or combinations thereof.

[0047] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which the present invention pertains. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in this specification.

[0048] Hereinafter, embodiments will be described in detail with reference to the attached drawings. However, the scope of the patent application is not limited or restricted by these embodiments. Identical reference numerals in each drawing indicate identical components.

[0049] FIG. 1 is a drawing illustrating an ultrasonic-based piezoelectric element stacked power receiving device according to an embodiment of the present invention.

[0050] FIG. 1 illustrates the three-dimensional structure of an ultrasonic-based piezoelectric element stacked power receiving device according to an embodiment of the present invention.

[0051] Referring to FIG. 1, an ultrasonic-based piezoelectric element stacked power receiving device (100) according to one embodiment of the present invention includes a first intermediate layer (110), a first piezoelectric element (120) stacked on the first intermediate layer (110), a second intermediate layer (130) stacked on the first piezoelectric element (120), and a second piezoelectric element (140) stacked on the second intermediate layer (130).

[0052] For example, an ultrasonic-based piezoelectric element stacked power receiving device (100) receives ultrasonic waves through a medium via an ultrasonic transmitting device and generates electrical energy for wireless power charging.

[0053] A first intermediate layer (110) according to one embodiment of the present invention can receive ultrasonic waves transmitted through a medium from an ultrasonic transmitting device and control the acoustic impedance difference between the medium and the first piezoelectric element (120).

[0054] For example, the first piezoelectric element (120) transmits rear ultrasound while generating first electrical energy based on ultrasound passing through the first intermediate layer (110).

[0055] Here, the rear ultrasound may be the remaining ultrasound that passes through the first intermediate layer (120), in which the first piezoelectric element (120) generates first electrical energy, and passes through the first piezoelectric element (120) and is transmitted to the second intermediate layer (130).

[0056] A second intermediate layer (130) according to one embodiment of the present invention receives and passes rear ultrasound.

[0057] For example, the second piezoelectric element (140) can generate second electrical energy based on the rear ultrasound that has passed through the second intermediate layer (130).

[0058] For example, the acoustic impedance of the first intermediate layer (110) is determined by the power of the combination of the acoustic impedance of the first piezoelectric element (120) and the acoustic impedance of the medium.

[0059] Additionally, the acoustic impedance of the second intermediate layer (130) can be determined as the square root of the combination of the acoustic impedance of the second piezoelectric element (140) and the acoustic impedance of the medium through which the rear ultrasound passes.

[0060] A more specific explanation regarding the acoustic impedance control of the intermediate layer is provided using Figures 3a and 3b.

[0061] The first intermediate layer (110) and the second intermediate layer (130) may be formed from at least one material among polymer, glass, ceramic, and metal, as a material having an acoustic impedance of 6 Mrayl to 10 Mrayl.

[0062] The thickness of the first intermediate layer (110) and the second intermediate layer (130) can be determined to be any one of 1 / 8λ to 1 / 4λ.

[0063] For example, the first piezoelectric element (120) outputs first electrical energy, and the second piezoelectric element (140) outputs second electrical energy and is connected in parallel with the first piezoelectric element, and the output first electrical energy and the output second electrical energy can be combined in parallel.

[0064] Accordingly, the present invention can improve the performance of wireless power transmission and reception by stacking a plurality of intermediate layers and a plurality of piezoelectric elements to integrate energy generated from a plurality of piezoelectric elements based on ultrasound and rear ultrasound.

[0065] FIG. 2 is a diagram illustrating the rear ultrasound used by an ultrasound-based piezoelectric element stacked power receiving device according to an embodiment of the present invention.

[0066] FIG. 2 illustrates rear ultrasound generated from a piezoelectric element through an ultra-high-speed camera in relation to rear ultrasound used by an ultrasound-based piezoelectric element stacked power receiving device according to an embodiment of the present invention.

[0067] Referring to FIG. 2, image (200) shows the piezoelectric element (201) before receiving ultrasound through a medium, and image (210) shows the piezoelectric element (211) receiving ultrasound through a medium and showing the rear ultrasound (212).

[0068] That is, image (200) is the result when the transmitting ultrasound is not applied, and when the transmitting ultrasound is applied, and image (210) shows the ultrasound traveling to the rear of the piezoelectric element (211).

[0069] In other words, it can be confirmed that when a piezoelectric element receives ultrasound, it generates additional ultrasound backward in response to some of the ultrasound.

[0070] FIGS. 3a and 3b are drawings illustrating the output voltage according to the presence or absence of an intermediate layer of an ultrasonic-based piezoelectric element stacked power receiving device according to an embodiment of the present invention.

[0071] Referring to FIG. 3a, the wireless power transmission and reception structure (300) does not have an intermediate layer on the receiving device side, and the wireless power transmission and reception structure (301) has an intermediate layer on the receiving device side.

[0072] Referring to FIG. 3b, the graph (310) shows the wireless power transmission and reception structure (300) as non-matching with respect to power measurement and the wireless power transmission and reception structure (301) as matching.

[0073] The graph (311) shows the wireless power transmission and reception structure (300) as non-matching with respect to the normalized value for power, and the wireless power transmission and reception structure (301) as matching.

[0074] According to graphs (310) and (311), the efficiency of attaching an intermediate layer to increase the energy generated in the piezoelectric element can be increased.

[0075] The intermediate layer is configured to reduce the difference between the acoustic impedance of the medium through which the ultrasound propagates and the acoustic impedance of the piezoelectric material to which the ultrasound is applied, and can be determined based on the following mathematical formula 1.

[0076] [Mathematical Formula 1]

[0077]

[0078] In mathematical formula 1, Z m Z1 can represent the acoustic impedance of the intermediate layer, Z1 can represent the acoustic impedance of the piezoelectric material, and Z2 can represent the acoustic impedance of the medium through which the ultrasound propagates.

[0079] The acoustic impedance of the piezoelectric material forming the piezoelectric element is 30 Mrayl or higher (the acoustic impedance of PZT5-H is 31.5 Mrayl), and the medium through which the ultrasound propagates is water or the human body, which has an acoustic impedance of 1.5 Mrayl to 2.0 Mrayl.

[0080] Accordingly, an intermediate layer according to one embodiment of the present invention may be formed of a material having an acoustic impedance of 6 Mrayl to 10 Mrayl.

[0081] That is, regarding the piezoelectric material constituting the plurality of piezoelectric elements, the plurality of intermediate layers may be formed from at least one material among polymer, glass, ceramic, and metal, as a material having an acoustic impedance of 6 Mrayl to 10 Mrayl. For example, the plurality of intermediate layers may include a first intermediate layer and a second intermediate layer.

[0082] For example, polymers, glass, ceramics, metals, etc., are used as the material for the intermediate layer. In the laminated structure of the present invention, a non-conductive intermediate layer material may be used or an intermediate layer may not be formed; if a conductive material is used, an insulating material must be added to prevent mutual conductivity between the first piezoelectric element and the second piezoelectric element.

[0083]

[0084] FIG. 4 is a diagram illustrating the output voltage according to the thickness of the intermediate layer of an ultrasonic-based piezoelectric element stacked power receiving device according to an embodiment of the present invention.

[0085] Referring to FIG. 4, the graph (400) shows a comparison of the output of an ultrasonic-based piezoelectric element stacked power receiver according to the thickness of the intermediate layer.

[0086] Looking at the range (401) of the graph (400), it shows the result of determining the magnitude of the voltage according to wireless power reception.

[0087] It indicates that the efficiency is excellent in the range (401) where the thickness of the intermediate layer is 1 / 8λ to 1 / 4λ.

[0088] That is, the thickness of the intermediate layer can be determined as one-quarter of the wavelength of the ultrasound.

[0089] Accordingly, the thickness of the first intermediate layer and the second intermediate layer constituting the ultrasonic-based piezoelectric element stacked power receiving device according to one embodiment of the present invention can be determined to be any one of the thicknesses of 1 / 8λ to 1 / 4λ.

[0090] Accordingly, the present invention can improve wireless power reception performance by preventing a reduction in the magnitude of the received ultrasound by reducing the acoustic impedance difference between the medium through which the ultrasound propagates and the piezoelectric element based on a plurality of intermediate layers.

[0091] FIGS. 5a to 6b are drawings illustrating the output voltage according to the stacked structure of an ultrasonic-based piezoelectric element stacked power receiving device according to an embodiment of the present invention.

[0092] Referring to FIG. 5a, the stacked structure of an ultrasonic-based piezoelectric element stacked power receiving device according to one embodiment of the present invention shows a structure in which an intermediate layer is added to the first piezoelectric element and the second piezoelectric element.

[0093] An ultrasonic-based piezoelectric element stacked power receiving device (500) according to one embodiment of the present invention includes a first intermediate layer (501), a first piezoelectric element (502), a second intermediate layer (503), and a second piezoelectric element (504).

[0094] Through the first intermediate layer (501), the first piezoelectric element (502) receives ultrasound and transmits rear ultrasound, and through the second intermediate layer (503), the second piezoelectric element (504) receives rear ultrasound.

[0095] Referring to FIG. 5b, the simulation results for an ultrasonic-based piezoelectric element stacked power receiving device according to an embodiment of the present invention are shown as graphs (510) and (511).

[0096] Graph (510) shows the voltage measurement results, and graph (511) shows the measurement results for the normalized values.

[0097] Graphs (510) and (511) show that the voltage generated in the first piezoelectric element with the first intermediate layer receiving transmitted ultrasound is measured to be about 48% higher than the voltage generated in the second piezoelectric element receiving rear ultrasound transmitted through the second intermediate layer.

[0098] That is, regarding the ultrasonic-based piezoelectric element stacked power receiving device according to one embodiment of the present invention, voltage generation efficiency can be increased by additionally stacking an intermediate layer and a piezoelectric element.

[0099] FIG. 6a shows an image of a stacked power receiving device actually fabricated in relation to an ultrasound-based piezoelectric element stacked power receiving device according to an embodiment of the present invention.

[0100] Referring to FIG. 6a, image (600) illustrates the measurement results for the horizontal side, and image (601) illustrates the measurement results for the vertical side.

[0101] For example, the size of an ultrasonic-based piezoelectric stacked power receiver can be manufactured to be 6 mm X 23 mm.

[0102] Referring to FIG. 6b, regarding the simulation results of an ultrasonic-based piezoelectric element stacked power receiving device according to one embodiment of the present invention, the voltage measurement results are shown as a graph (610), and the current measurement results are shown as a graph (611).

[0103] In graphs (610) and (611), the operating frequency is 1 MHz and the transmission power is 690 mW / cm² 2 When applied, the voltage generated at the first and second piezoelectric receivers is 110 V pp Wow 59V pp and the current is 365 mA pp and 283 mA pp It can be confirmed that it is.

[0104] Accordingly, the present invention can increase wireless power reception efficiency by stacking a plurality of piezoelectric elements to generate additional energy for rearward ultrasonic waves generated backward.

[0105] FIGS. 7a to 8b are drawings illustrating the application of a rectifier to an ultrasonic-based piezoelectric element stacked power receiving device according to an embodiment of the present invention.

[0106] FIG. 7a illustrates a series connection structure in relation to the application of a rectifier to an ultrasonic-based piezoelectric element stacked power receiving device according to an embodiment of the present invention.

[0107] FIG. 7b illustrates a parallel connection structure in relation to the application of a rectifier to an ultrasonic-based piezoelectric element stacked power receiving device according to an embodiment of the present invention.

[0108] Referring to FIG. 7a, an ultrasonic-based piezoelectric element stacked power receiving device (700) according to one embodiment of the present invention is shown, comprising a rectifier (701) and a load measuring device (702), and a circuit (710).

[0109] Referring to FIG. 7b, a circuit (730) is shown, which is composed of an ultrasonic-based piezoelectric element stacked power receiving device (720), a rectifier (721), and a load measuring device (722) according to one embodiment of the present invention.

[0110] The output of the load resistance for the series connection can be measured through the load measuring device (702).

[0111] In addition, the output of the load resistance for the parallel connection can be measured through the load measuring device (722).

[0112] FIG. 8a illustrates a comparison of the output voltages of a series connection structure and a parallel connection structure of a rectifier for an ultrasonic-based piezoelectric element stacked power receiving device according to an embodiment of the present invention.

[0113] FIG. 8b illustrates a comparison of the impedance change of a series connection structure and a parallel connection structure of a rectifier for an ultrasonic-based piezoelectric element stacked power receiving device according to an embodiment of the present invention.

[0114] Referring to FIG. 8a, graphs (800), (801), and (802) show the measurement results of the change in output voltage with respect to impedance based on the circuit structure exemplified in FIG. 7a and 7b.

[0115] Referring to FIG. 8b, graphs (810), (811), and (812) show the degree of efficiency increase through frequency change with respect to load change for simulation results of measurements based on the circuit structure exemplified in FIG. 7a and FIG. 7b.

[0116] For graphs (800) and (801), it is assumed that the voltage output from the second piezoelectric element is 50% of the voltage output from the first piezoelectric element, and that the impedances of the two piezoelectric elements are the same.

[0117] When the impedance of the first piezoelectric element and the second piezoelectric element is 50 ohms or more, the output decreases when connected in series, and the output increases when connected in parallel.

[0118] Graph (803) is the result of comparing efficiency according to impedance.

[0119] As shown in the results of graphs (800) and (801), the overall voltage decreases as the impedance of the piezoelectric element increases, but graph (802) shows that when multiple piezoelectric elements are stacked and connected in parallel rather than a single piezoelectric element, the efficiency of the output voltage increases.

[0120] When the electrical impedance of the ultrasonic-based piezoelectric element stacked power receiver was measured in graph (802), the impedance of the first piezoelectric receiver was measured to be 250 ohms at 1 MHz, and the impedance of the second piezoelectric receiver was measured to be 730 ohms. When comparing the output voltage of a parallel-connected circuit with the voltage output from a single piezoelectric element, a result of approximately 11% increase can be confirmed.

[0121] For example, a single piezoelectric element can be determined as a piezoelectric power receiving device, and if multiple piezoelectric elements are stacked, it can be viewed as a piezoelectric stacked power receiving device.

[0122] Graphs (810), (811), and (812) show that voltage output and energy generation efficiency are increased when the outputs of multiple piezoelectric elements are connected in parallel.

[0123] FIG. 9 is a diagram illustrating the output voltage according to the connection of an ultrasonic-based piezoelectric element stacked power receiving device and a rectifier according to an embodiment of the present invention.

[0124] Referring to FIG. 9, graphs (900) to (903) are the results of comparing the output of a fabricated piezoelectric element stacked power receiver according to the intensity of the transmitted ultrasound by actually configuring the rectifier circuit in series and in parallel.

[0125] In graphs (900) to (903), the load resistance of each circuit may be 50 ohms.

[0126] In graphs (900) and (901), the output voltage and current of the circuits connected in series show a decreasing result.

[0127] In graphs (902) and (903), the output voltage and current of the parallel-connected circuits both show increasing results.

[0128] Therefore, the rectifier circuit of a piezoelectric stacked power receiver can increase efficiency when connected in parallel.

[0129] FIGS. 10a and FIGS. 10b are drawings illustrating battery charging using an ultrasonic-based piezoelectric element stacked power receiving device according to an embodiment of the present invention.

[0130] FIGS. 10a and 10b illustrate an ultrasonic-based piezoelectric element stacked power receiving system in relation to battery charging using an ultrasonic-based piezoelectric element stacked power receiving device according to an embodiment of the present invention.

[0131] Referring to FIG. 10a, an ultrasonic-based piezoelectric element stacked power receiving system (1000) according to one embodiment of the present invention is composed of an ultrasonic-based piezoelectric element stacked power receiving device, a piezoelectric element stacked power receiver (1001), a rectifier (1002), a DC / DC converter (1003), a power management circuit (1004), and a battery (1005).

[0132] The rectifier (1002) includes a first rectifier and a second rectifier, and the number of rectifiers may correspond to the number of piezoelectric elements stacked in the piezoelectric element stacked power receiver (1001).

[0133] The first rectifier is connected to the first piezoelectric element and rectifies the first energy into a first DC signal.

[0134] The second rectifier is connected to the second piezoelectric element and can rectify the second energy into a second DC signal.

[0135] The first rectifier and the second rectifier have their output terminals connected in parallel so that the first DC signal and the second DC signal can be integrated to output an integrated DC signal.

[0136] The DC / DC converter (1003) may be a DC converter.

[0137] The DC / DC converter (1003) can control the voltage for the integrated DC signal to a preset size voltage.

[0138] The power management circuit (1004) controls the controlled voltage, which is the output of the DC / DC converter (1003), into a preset current and supplies it to the battery (1005).

[0139] The power management circuit (1004) can supply a constant current to the battery (1005) to prevent overcharging and discharging.

[0140] The battery (1005) stores current supplied from the power management circuit (1004).

[0141] Referring to FIG. 10b, graph (1010) shows the battery charging time according to the number of piezoelectric elements, and graph (1011) shows the battery charging time according to the charging capacity.

[0142] Graph (1010) shows that when a commercial battery with a capacity of 150 mAh is charged with a receiver composed of a single piezoelectric element, it is not fully charged due to insufficient power, but when charged with a piezoelectric element stacked power receiver according to an embodiment of the present invention, it takes 1.3 hours to fully charge.

[0143] Graph (1011) shows that when a small capacity battery (80 mAh) is charged, it takes 0.32 hours to reach a constant current and 1.1 hours to fully charge.

[0144] A stacked piezoelectric power receiving device is exemplified by a structure in which two piezoelectric elements are stacked, but energy efficiency can be improved by additionally stacking piezoelectric elements.

[0145] In addition, the piezoelectric stacked power receiving device rectifies and integrates the energy generated from each piezoelectric element into a DC signal, and if the rectifiers are connected in parallel, the efficiency of the integrated energy can be increased.

[0146] Therefore, the present invention can increase energy reception efficiency by integrating the energy output from a plurality of piezoelectric elements in parallel.

[0147] In addition, the present invention reduces the risk of surgery for battery replacement in an implant device by charging the battery using ultrasound, and can reduce the frequency of surgery for battery replacement by increasing battery charging efficiency.

[0148] FIGS. 11a to 11c are drawings illustrating energy harvesting performance using an ultrasonic-based piezoelectric element stacked power receiving device according to an embodiment of the present invention.

[0149] Here, energy harvesting performance can represent charging performance as the efficiency with which energy is received through pig tissue, which has a structure similar to human tissue, by a piezoelectric stacked power receiving device.

[0150] FIG. 11a illustrates an in vitro experiment scene related to energy harvesting performance using an ultrasound-based piezoelectric element stacked power receiving device according to an embodiment of the present invention.

[0151] Referring to FIG. 11a, the configuration of the in vitro experiment scene involves immersing a sample of pig tissue (1102) with a thickness of 30 mm in a container filled with water, placing an ultrasound-based piezoelectric element stacked power receiver (1100) on the bottom of the tissue, and placing a transmitter (1101) on the sample (1102).

[0152] The ultrasound-based piezoelectric element stacked power receiving device (1100) may be composed of piezoelectric elements that are front and rear piezoelectric ultrasound harvesters (PUSHs).

[0153] In other words, an ultrasonic-based piezoelectric element stacked power receiving device (1100) can be configured with a front PUSH corresponding to a first piezoelectric element and a rear PUSH corresponding to a second piezoelectric element.

[0154] The in vitro experiment scene represents a performance evaluation in a biological environment to evaluate whether the ultrasound-based piezoelectric element stacked power receiving device (1100) according to one embodiment of the present invention can charge a battery.

[0155] Unlike water, biological tissues significantly attenuate transmitted ultrasound due to absorption and scattering.

[0156] Therefore, it is very important to understand the effect of biological tissue on the output performance of the ultrasound-based piezoelectric element stacked power receiver (1100) and to optimize energy harvesting efficiency in actual applications.

[0157] In the presence of various types of tissue, the depth of focus may shift slightly from the intended position due to changes in the speed of sound.

[0158] However, in reality, these changes in depth of focus have almost no impact on overall performance.

[0159] In an in vitro experiment to investigate these effects, the output was investigated on pig tissue with a thickness of 30 mm, and the thickness can be changed according to user settings.

[0160] FIG. 11b illustrates voltage measurement results in relation to energy harvesting performance using an ultrasonic-based piezoelectric element stacked power receiving device according to an embodiment of the present invention.

[0161] Referring to FIG. 11b, the graph (1110) can represent the measured output voltage generated by front and rear pushes in an ultrasound-based piezoelectric stacked power receiving device under the sample tissue.

[0162] Graph (1111) can show an enlarged view of the output voltage waveform for a 0.01 ms time frame.

[0163] According to graphs (1110) and (1111), the output voltage from the experiment in FIG. 11a is 38.3V pp Wow, 19.5V pp It is measured as.

[0164] Graph (1112) shows the results of a comparison of the normalized output voltages of the front and back PUSH measured in water and through the sample tissue.

[0165] When comparing the measurement results in water and in the sample tissue, the voltage of the front and back PUSH decreases by 61% and 62%, respectively, when the sample tissue is present compared to when it is in water.

[0166] This decrease can be confirmed to be due to the reduction in the influence of standing wave amplification on ultrasound intensity as well as ultrasound attenuation within the sample tissue.

[0167] Despite this attenuation, it can be confirmed that the back PUSH of the ultrasonic-based piezoelectric stacked power receiver contributes to generating additional voltage that would have been lost in the absence of it.

[0168] In other words, when passing through a sample tissue, the charging voltage decreases due to a reduction in ultrasonic intensity; however, by using a rear push to compensate for the voltage lost when only a front push is used, the voltage lost within the sample tissue can be replenished.

[0169] FIG. 11c illustrates current measurement results in relation to energy harvesting performance using an ultrasonic-based piezoelectric element stacked power receiving device according to an embodiment of the present invention.

[0170] The graph (1120) can show the measured output current generated by front and rear pushes in an ultrasonic-based piezoelectric stacked power receiving device.

[0171] Graph (1121) can show an enlarged view of the output current waveform for a 0.01 ms time frame.

[0172] According to graphs (1120) and (1121), the output current from the experiment in FIG. 11a is 260.0 mA pp and 149.1mA pp It is measured as.

[0173] The graph (1122) can show the results of a comparison of normalized output currents measured in water and through sample tissues.

[0174] When comparing the measurement results in water and in the sample tissue, the front and back PUSH currents are reduced by 32% and 39%, respectively, when the sample tissue is present compared to water.

[0175] This decrease can be confirmed to be due to the reduction in the influence of standing wave amplification on ultrasound intensity as well as ultrasound attenuation within the sample tissue.

[0176] Despite this attenuation, it can be confirmed that the back PUSH of the ultrasonic-based piezoelectric stacked power receiver contributes to generating additional current that would have been lost in the absence of it.

[0177] In other words, when passing through a sample tissue, the charging current decreases due to a reduction in ultrasonic intensity; however, the current lost when using only the front push can be compensated for by using the rear push to replenish the current lost within the sample tissue.

[0178] It can be seen that the ultrasonic-based piezoelectric element stacked power receiving device according to one embodiment of the present invention has excellent advantages in energy harvesting applications. The device described above may be implemented as a hardware component, a software component, and / or a combination of a hardware component and a software component. For example, the device and components described in the embodiments may be implemented using one or more general-purpose or special-purpose computers, such as, for example, a processor, a controller, an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable array (FPA), a programmable logic unit (PLU), a microprocessor, or any other device capable of executing and responding to instructions. The processing unit may execute an operating system (OS) and one or more software applications executed on said operating system. Additionally, the processing unit may access, store, manipulate, process, and generate data in response to the execution of the software. For ease of understanding, the processing unit may be described as being used as a single unit, but a person of ordinary skill in the art will understand that the processing unit may include multiple processing elements and / or multiple types of processing elements. For example, the processing unit may include multiple processors or one processor and one controller. In addition, other processing configurations, such as parallel processors, are also possible.

[0179] Software may include computer programs, code, instructions, or a combination of one or more of these, and may configure a processing unit to operate as desired or command the processing unit independently or collectively. Software and / or data may be permanently or temporarily embodied in any type of machine, component, physical device, virtual equipment, computer storage medium or device, or transmitted signal wave so as to be interpreted by the processing unit or to provide instructions or data to the processing unit. Software may be distributed over networked computer systems and may be stored or executed in a distributed manner. Software and data may be stored on one or more computer-readable recording media.

[0180] Although the embodiments have been described above with reference to the limited drawings, those skilled in the art can make various modifications and variations from the description above. For example, suitable results can be achieved even if the described techniques are performed in a different order than described, and / or the components of the described system, structure, device, circuit, etc. are combined or assembled in a form different from described, or replaced or substituted by other components or equivalents.

[0181] Therefore, other implementations, other embodiments, and equivalents to the claims also fall within the scope of the claims set forth below.

Claims

1. First intermediate layer; A first piezoelectric element stacked on the first intermediate layer; A second intermediate layer stacked on the first piezoelectric element; and It includes a second piezoelectric element stacked on the second intermediate layer, and The first intermediate layer receives ultrasound transmitted through a medium from an ultrasonic transmitting device and controls the acoustic impedance difference between the medium and the first piezoelectric element, and The first piezoelectric element generates first electrical energy based on the ultrasound that has passed through the first intermediate layer and transmits rear ultrasound, and The second intermediate layer receives and passes the rear ultrasound, The second piezoelectric element is characterized by generating second electrical energy based on rear ultrasound that has passed through the second intermediate layer. Ultrasonic-based piezoelectric stacked power receiver.

2. In Paragraph 1, The acoustic impedance of the first intermediate layer is determined by the square root of the combination of the acoustic impedance of the first piezoelectric element and the acoustic impedance of the medium, and The second intermediate layer is characterized in that the acoustic impedance of the second intermediate layer is determined by the square root of the combination of the acoustic impedance of the second piezoelectric element and the acoustic impedance of the medium through which the rear ultrasound passes. Ultrasonic-based piezoelectric stacked power receiver.

3. In Paragraph 1, The first intermediate layer and the second intermediate layer are characterized by being formed of at least one material selected from polymer, glass, ceramic, and metal, having an acoustic impedance of 6 Mrayl to 10 Mrayl. Ultrasonic-based piezoelectric stacked power receiver.

4. In Paragraph 1, The thickness of the first intermediate layer and the second intermediate layer is determined to be any one of 1 / 8λ to 1 / 4λ, characterized in that Ultrasonic-based piezoelectric stacked power receiver.

5. In Paragraph 1, The first piezoelectric element outputs the first electrical energy, and The second piezoelectric element outputs the second electrical energy and is connected in parallel with the first piezoelectric element, The output first electrical energy and the output second electrical energy are characterized by being combined in parallel. Ultrasonic-based piezoelectric stacked power receiver.

6. A piezoelectric element stacked power receiver comprising a first intermediate layer, a first piezoelectric element stacked on the first intermediate layer, a second intermediate layer stacked on the first piezoelectric element, and a second piezoelectric element stacked on the second intermediate layer; A first rectifier connected to the first piezoelectric element to rectify the first energy into a first DC signal; and It includes a second rectifier connected to the second piezoelectric element to rectify the second energy into a second DC signal, The first intermediate layer receives ultrasound transmitted through a medium from an ultrasonic transmitting device and controls the acoustic impedance difference between the medium and the first piezoelectric element, and The first piezoelectric element generates first electrical energy based on the ultrasound that has passed through the first intermediate layer and transmits rear ultrasound, and The second intermediate layer receives and passes the rear ultrasound, The second piezoelectric element is characterized by generating second electrical energy based on rear ultrasound that has passed through the second intermediate layer. Ultrasonic-based piezoelectric stacked power receiving system.

7. In Paragraph 6, The first rectifier and the second rectifier are characterized by having their output terminals connected in parallel so that the first DC signal and the second DC signal are integrated to output an integrated DC signal. Ultrasonic-based piezoelectric stacked power receiving system.

8. In Paragraph 7, A DC converter that controls the voltage for the integrated DC signal with a preset size voltage; A power management circuit that controls and supplies the above-mentioned controlled voltage to a preset current; and Characterized by further including a battery that stores the supplied current. Ultrasonic-based piezoelectric stacked power receiving system.

9. In Paragraph 6, The first intermediate layer and the second intermediate layer are characterized by being formed of at least one material selected from polymer, glass, ceramic, and metal, having an acoustic impedance of 6 Mrayl to 10 Mrayl. Ultrasonic-based piezoelectric stacked power receiving system.

10. In Paragraph 6, The thickness of the first intermediate layer and the second intermediate layer is determined to be any one of 1 / 8λ to 1 / 4λ, characterized in that Ultrasonic-based piezoelectric stacked power receiving system.

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