WO2023053590A1 - Dispositif de génération d'ondes ultrasonores - Google Patents

Dispositif de génération d'ondes ultrasonores Download PDF

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Publication number
WO2023053590A1
WO2023053590A1 PCT/JP2022/023692 JP2022023692W WO2023053590A1 WO 2023053590 A1 WO2023053590 A1 WO 2023053590A1 JP 2022023692 W JP2022023692 W JP 2022023692W WO 2023053590 A1 WO2023053590 A1 WO 2023053590A1
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Prior art keywords
ultrasonic generator
coil
metal foil
pulse current
capacitor
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PCT/JP2022/023692
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English (en)
Japanese (ja)
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正人 安達
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株式会社村田製作所
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Publication of WO2023053590A1 publication Critical patent/WO2023053590A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R23/00—Transducers other than those covered by groups H04R9/00 - H04R21/00
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R3/00—Circuits for transducers, loudspeakers or microphones

Definitions

  • the present invention relates to an ultrasonic generator that has high conversion efficiency and is capable of varying the frequency of generated ultrasonic waves.
  • Ultrasonic generators are widely used for distance detection.
  • a certain type of ultrasonic generator also serves as an ultrasonic detector, transmits ultrasonic waves toward an object, receives the ultrasonic waves that are reflected back from the object, and receives the ultrasonic waves from transmission to reception. Detect the distance to the object by the length of time.
  • Another ultrasonic wave generator is used in combination with an ultrasonic detector, transmits ultrasonic waves, receives the ultrasonic waves with the ultrasonic detector, and determines the length of time from transmission to reception. Detects the distance to the sonic detector.
  • Patent Document 1 Japanese Utility Model Publication No. 4-27280 discloses a conventional ultrasonic generator (ultrasonic transmitter/receiver).
  • the ultrasonic generator disclosed in Patent Document 1 has a structure in which an additional resonator (horn) is attached to a unimorph transducer in which a piezoelectric plate and a metal disc are bonded together.
  • ultrasonic waves are transmitted from the additional resonator by driving the unimorph transducer.
  • the ultrasonic generator of Patent Document 1 Because the ultrasonic generator of Patent Document 1 has a high Qm value (mechanical quality factor), it generates ultrasonic waves with high efficiency at a specific driving frequency. When the driving frequency is changed, the ultrasonic generator of Patent Literature 1 is considered to be used at a specific driving frequency to generate ultrasonic waves of a specific frequency, because it is thought that the conversion efficiency drops sharply. Therefore, the ultrasonic generator of Patent Document 1 has a problem that interference occurs when a plurality of devices are used in close proximity at the same time.
  • Qm value mechanical quality factor
  • Non-Patent Document 1 (“Overview of Airborne Ultrasonic Transducer”) discloses an ultrasonic generator that solves this problem and allows the frequency of the ultrasonic waves to be generated to be variable.
  • the ultrasonic generator disclosed in Non-Patent Document 1 is called a thermophone, and has a structure in which a metal film is provided on a heat-dissipating substrate with a thin heat-insulating layer interposed therebetween.
  • the ultrasonic generator of Non-Patent Document 1 when an electric current is applied to the metal film, the metal film generates heat, and the air in contact with the metal film is warmed to generate ultrasonic waves.
  • the ultrasonic generator of Non-Patent Document 1 can change the frequency of the ultrasonic waves to be generated by changing the frequency of the current applied to the metal film.
  • the ultrasonic generator of Non-Patent Document 1 converts energy in the order of electricity, heat, and ultrasonic waves, there are problems of large loss and low conversion efficiency, and it is difficult to obtain ultrasonic waves with a large sound pressure. There was a problem.
  • Patent Document 2 Japanese Unexamined Patent Application Publication No. 7-328539 discloses another ultrasonic wave generator (electromagnetic acoustic transducer).
  • the ultrasonic generator disclosed in Patent Document 2 generates ultrasonic waves by electromagnetic repulsion.
  • the ultrasonic wave generator of Patent Document 2 is disclosed in FIG. 5 of Patent Document 2 and the like as conventional technology.
  • FIG. 11 of the present application shows an ultrasonic generator 1000 of Patent Document 2. As shown in FIG.
  • the ultrasonic generator 1000 of Patent Document 2 includes a spiral coil 50, a disk-shaped conductive vibration radiator 52 arranged at a certain distance from the spiral coil 50, and a pulse current applied to the spiral coil 50. is provided with a pulse generator 51 for supplying The pulse generator 51 is composed of a DC power supply 511 , a capacitor 512 and a switch 513 .
  • the changeover switch 513 can switch the destination to which the capacitor 512 is connected to either the DC power supply 511 or the spiral coil 50 .
  • the ultrasonic generator 1000 of Patent Document 2 first switches the selector switch 513 to the DC power supply 511 side, and accumulates power supplied from the DC power supply 511 in the capacitor 512 . Next, the selector switch 513 is switched to the spiral coil 50 side, and a large current is instantaneously supplied from the capacitor 512 to the spiral coil 50 .
  • the current When a large current is momentarily supplied from the capacitor 512 to the spiral coil 50 , the current generates a magnetic field due to electromagnetic induction in the direction from the spiral coil 50 to the conductive vibration radiator 52 .
  • the magnetic field induces an eddy current in the conductive vibration radiator 52 , and the eddy current generates a magnetic field by electromagnetic induction in the direction from the conductive vibration radiator 52 to the spiral coil 50 .
  • the ultrasonic generator 1000 of Patent Document 2 can change the frequency of the generated ultrasonic waves by changing the energization time of the current supplied from the capacitor 512 to the spiral coil 50 .
  • the ultrasonic generator of Patent Document 2 is considered to be used for a specific energizing time and generate ultrasonic waves of a specific frequency, because it is thought that the conversion efficiency drops sharply when the energizing time is changed.
  • the ultrasonic generator 1000 of Patent Document 2 is described in paragraph [0004] of Patent Document 2 as follows: "As described above, the conventional electromagnetic acoustic transducer that excites the disk-shaped vibration radiator 52 6(a) and bending vibration shown in FIG. 6(b) are simultaneously excited, and bending-extension vibration combining the two, that is, vibration due to Poisson coupling, is obtained.” , the conductive vibration radiator 52 is made of a metal plate having a certain thickness.
  • the conductive vibration radiator 52 is preferably thin and light. This is because if the conductive vibration radiator 52 is thick and heavy, the initial speed will be slow.
  • the ultrasonic generator 1000 of Patent Document 2 has a problem that the conversion efficiency is low because the conductive vibration radiator 52 is made of a metal plate having a large thickness.
  • Patent Document 2 the application invention of Patent Document 2 (the invention disclosed in FIG. 1 of Patent Document 2, etc.) has a conductive vibration radiator formed into a hemispherical shell shape (bowl shape) while maintaining its shape.
  • a conductive vibration radiator formed into a hemispherical shell shape (bowl shape) while maintaining its shape.
  • An attempt is being made to improve the conversion efficiency by reducing the thickness and weight of the vibration radiator.
  • the conductive vibration radiator is made into a hemispherical shell shape, the central part of the hemisphere is close to the spiral coil, so a large repulsive force can be obtained, but the peripheral part of the hemisphere is far from the spiral coil, so a large repulsive force can be obtained. Therefore, it is considered that the invention of Patent Document 2 does not improve the conversion efficiency so much as a whole.
  • the ultrasonic generator 1000 of Patent Document 2 has the problem that the conversion efficiency is low because the conductive vibration radiator 52 is made of a thick metal plate. Further, in the ultrasonic generator 1000 of Patent Document 2, the conductive vibration radiator 52 is made of a metal plate having a large thickness. Therefore, it has been difficult to widen the area from which ultrasonic waves are radiated.
  • a coil a metal foil placed on at least one side of the first main surface and the second main surface under tension, and a pulse current generating circuit for applying a pulse current to the coil.
  • the ultrasonic generator according to one embodiment of the present invention uses a tensioned metal foil as a medium for generating an eddy current and a repelling magnetic field, so the conversion efficiency is extremely high. That is, the ultrasonic generator according to one embodiment of the present invention uses a thin and light metal foil as a medium, so the conversion efficiency is extremely high. Further, in the ultrasonic generator according to one embodiment of the present invention, since the metal foil is used as the vibration radiator for generating the ultrasonic waves, the area of the main surface of the metal foil is increased to radiate the ultrasonic waves. It is easy to widen the area. Further, the ultrasonic generator according to one embodiment of the present invention can change the frequency of the generated ultrasonic waves by changing the duration of the pulse current applied to the coil.
  • FIG. 1A is a front view of the ultrasonic generator 100 according to the first embodiment.
  • FIG. 1B is a plan view of the ultrasonic generator 100.
  • FIG. 2A and 2B are cross-sectional views of the ultrasonic generator 100, respectively.
  • FIG. 3A is an explanatory diagram of the ultrasonic generator 100 viewed from the front.
  • FIG. 3B is an explanatory diagram of the ultrasonic generator 100 viewed from the plane.
  • 4A and 4B are cross-sectional views of the ultrasonic generator 200 according to the second embodiment, respectively.
  • FIG. 5 is a cross-sectional view of an ultrasonic generator 300 according to the third embodiment.
  • FIG. 6A is an explanatory diagram of an ultrasonic generator 400 according to the fourth embodiment.
  • FIG. 6B is a graph showing the characteristics of the ultrasonic waves generated by the ultrasonic generator 400.
  • FIG. 7A is an explanatory diagram of an ultrasonic generator 500 according to the fifth embodiment.
  • FIG. 7B is a graph showing characteristics of ultrasonic waves generated by the ultrasonic generator 500.
  • FIG. 8 is a graph showing characteristics of ultrasonic waves generated by each ultrasonic generator according to the sixth embodiment.
  • FIG. 9 is an explanatory diagram of an ultrasonic generator 700 according to the seventh embodiment.
  • FIG. 10 is an exploded perspective view of essential parts of an ultrasonic generator 800 according to the eighth embodiment.
  • FIG. 11 is an explanatory diagram of a conventional ultrasonic generator 1000. As shown in FIG.
  • each embodiment exemplifies the embodiment of the present invention, and the present invention is not limited to the content of the embodiment. Moreover, it is also possible to combine the contents described in different embodiments, and the contents of the implementation in that case are also included in the present invention.
  • the drawings are intended to aid understanding of the specification, and may be schematically drawn, and the drawn components or the dimensional ratios between the components may not be the same as those described in the specification. The proportions of those dimensions may not match.
  • constituent elements described in the specification are omitted in the drawings, or where the number of constituent elements is omitted.
  • FIG. 1A is a front view of the ultrasonic generator 100.
  • FIG. 1B is a plan view of the ultrasonic generator 100.
  • FIG. 2A and 2B are cross-sectional views of the ultrasonic generator 100, respectively.
  • FIG. 3A is an explanatory diagram of the ultrasonic generator 100 viewed from the front.
  • FIG. 3B is an explanatory diagram of the ultrasonic generator 100 viewed from the plane. Note that FIG. 2(A) shows the dashed-dotted line YY portion of FIG. 2(B), and FIG. 2(B) shows the dashed-dotted line XX portion of FIG. 2(A). 1A, 1B, 2A and 2B, illustration of the pulse current generating circuit 4 is omitted.
  • the ultrasonic generator 100 includes a frame 1.
  • the frame 1 has a hollow portion 1a and a pair of outlet holes 1b and 1c.
  • the lead-out holes 1b and 1c are for leading out a pair of ends 2c and 2d of the coil 2, which will be described later, to the outside.
  • the material of the frame 1 is arbitrary, for example, resin, ceramic, metal, wood, glass, etc. can be used.
  • the shape of the frame 1 is arbitrary, but in this embodiment, it is rectangular when viewed from the plane direction.
  • the frame 1 is not an essential component, and other structures may be used or omitted.
  • the ultrasonic generator 100 includes a coil 2.
  • the coil 2 may be of any material, shape, etc., but in the present embodiment, a copper wire, which is a conductive wire with an insulating coating (not shown) formed on the outer surface, is spirally wound into a single layer. used.
  • the coil 2 has a first main surface 2a and a second main surface 2b facing each other.
  • the coil 2 has a pair of ends 2c, 2d.
  • the material and diameter of the conductor wire of the coil 2 are arbitrary, and instead of the copper wire, Ag wire, Ni wire, Al wire, Mg wire, W wire, Mo wire, Au wire, nickel-chromium alloy wire, etc. may be used. may be used. Any material can be used for the insulating coating formed on the outer surface of the conductor, and for example, enamel can be used. In the present invention, the insulating coating on the outer surface of the conductor wire of the coil 2 is not an essential component, and can be omitted. Also, instead of the coil 2 wound with conductive wire, a coil made of patterned electrodes or the like printed on a substrate or the like may be used. In this case, the insulating coating may or may not be formed on the pattern electrodes.
  • the coil 2 is accommodated in the hollow portion 1a of the frame 1. An end portion 2c of the coil 2 is led out from the lead-out hole 1b of the frame 1, and an end portion 2d of the coil 2 is led out from the lead-out hole 1c of the frame 1 to the outside.
  • the ultrasonic wave generator 100 is equipped with one sheet of metal foil 3 .
  • the metal foil 3 may be made of any material, but preferably has high electrical conductivity, is light in weight, has high strength, and is inexpensive.
  • aluminum foil, SUS foil, copper foil, nickel foil, iron foil, etc. can be used.
  • SUS foil When aluminum foil is used, it is possible to obtain a metal foil 3 with high electrical conductivity, light weight, and low cost.
  • SUS foil a metal foil 3 with high strength can be obtained.
  • the thickness of the metal foil 3 is preferably 3 ⁇ m or more and 100 ⁇ m or less in the case of aluminum foil, for example. This is because if the thickness of the metal foil 3 is less than 3 ⁇ m, the strength of the metal foil 3 may be insufficient. This is because if the thickness of the metal foil 3 exceeds 100 ⁇ m, the conversion efficiency of the ultrasonic wave generator 100 may be lowered, or it may become impossible to generate ultrasonic waves with a large sound pressure. Note that the thickness of the metal foil 3 will be discussed later in the sixth embodiment.
  • At least a part of the outer periphery of the metal foil 3 is fixed to the frame 1 under tension.
  • the metal foil 3 closes the opening on one side of the hollow portion 1a of the frame 1 (the side of the first main surface 2a of the coil 2), and extends to the opposite side via the side surface of the frame 1. It turns around and closes the opening on the other side of the hollow portion 1a of the frame 1 (on the side of the second main surface 2b of the coil 2).
  • Any method can be used to fix the metal foil 3 to the frame 1.
  • the metal foil 3 can be fixed with an adhesive.
  • the frame 1 is not an essential component in the present invention, and other structures may be used or omitted.
  • the ultrasonic generator 100 of this embodiment has a structure in which the openings on both sides of the hollow portion 1a of the frame 1 are closed with one sheet of metal foil 3, it is easy to manufacture and has high productivity. .
  • the metal foil that closes the opening on one side of the hollow portion 1a of the frame 1 and the metal foil that closes the opening on the other side of the hollow portion 1a of the frame 1 Two foils may be separately prepared and the openings may be closed separately.
  • a gap S is provided between the first main surface 2a of the coil 2 and the metal foil 3 and between the second main surface 2b of the coil 2 and the metal foil 3. formed.
  • the spiral portion and the portion extending from the spiral portion to the one end 2c inevitably intersect, and these gaps S are formed to enable this intersection. is.
  • these gaps S may be omitted and the coil 2 and the metal foil 3 may be brought into contact with each other.
  • the ultrasonic generator 100 includes a pulse current generating circuit 4, as shown in FIGS. 3(A) and 3(B).
  • the pulse current generating circuit 4 has a pair of output terminals 4a and 4b, as shown in FIG. 3(B). Output terminal 4 a is connected to one end 2 c of coil 2 , and output terminal 4 b is connected to the other end 2 d of coil 2 .
  • the pulse current generation circuit 4 further includes a DC power supply 4c, a capacitor 4d, and a switch 4e, as shown in FIG. 3(B).
  • the type of the capacitor 4d is arbitrary, but for example, a laminated ceramic capacitor, a film capacitor, an electrolytic capacitor, etc. can be used. However, if a laminated ceramic capacitor or a film capacitor is used, the equivalent series resistance (ESR) is low. Therefore, it is preferable.
  • ESR equivalent series resistance
  • the output terminal 4a of the pulse current generation circuit 4 is connected to one switching terminal of the changeover switch 4e.
  • the other switching terminal of the changeover switch 4e is connected to the positive side terminal of the DC power supply 4c.
  • a fixed terminal of the switch 4e is connected to one terminal of the capacitor 4d.
  • the negative side terminal of the DC power supply 4c and the other terminal of the capacitor 4d are each connected to the output terminal 4b.
  • the pulse current generation circuit 4 can switch the destination to which the capacitor 4d is connected to either the DC power supply 4c or the coil 2 by switching the selector switch 4e.
  • the selector switch 4e is switched to the DC power supply 4c side, and the power supplied from the DC power supply 4c is stored in the capacitor 4d.
  • the selector switch 4e is switched to the coil 2 side, and a large current is instantaneously supplied to the coil 2 from the capacitor 4d. That is, the capacitor 4d is discharged.
  • the current causes the coil 2 to move in the direction of the metal foils 3 arranged on both sides of the first main surface 2a and the second main surface 2b of the coil 2.
  • Each generates a magnetic field due to electromagnetic induction.
  • the magnetic field generated by the coil 2 induces eddy currents in the metal foil 3 on the first main surface 2a side and the metal foil 3 on the second main surface 2b side.
  • Due to the eddy current generated in the metal foil 3 a magnetic field due to electromagnetic induction is generated in the direction of the coil 2 from the metal foil 3 on the first main surface 2a side and the metal foil 3 on the second main surface 2b side. Occur.
  • the ultrasonic generator 100 can generate pulsed ultrasonic waves by repeating the above operation at a predetermined cycle.
  • the ultrasonic generator 100 discharges all the accumulated electric charges
  • the conduction time of the pulse current applied from the capacitor 4d to the coil 2 is changed. , can change the frequency of the generated ultrasound.
  • the amount of charge stored in the capacitor 4d can be changed by changing the voltage of the DC power supply 4c that supplies power to the capacitor 4d or by changing the capacity of the capacitor 4d.
  • the voltage of the DC power supply 4c that supplies power to the capacitor 4d may be changed, and the capacity of the capacitor 4d may be changed. Details will be described later in a fourth embodiment and a fifth embodiment.
  • the pulse current generation circuit 74 is provided with a semiconductor switching element 74e in place of the changeover switch 4e.
  • the energization time (discharge time) of the pulse current applied to the coil 2 may be changed. Also in this case, the frequency of the generated ultrasonic waves can be changed.
  • the ultrasonic generator 100 of the first embodiment uses the metal foil 3 under tension as the medium that generates eddy currents and repulsive magnetic fields. Vibration-free, single-mode, and extremely high conversion efficiency. Further, according to the ultrasonic generator 100, it is possible to generate an ultrasonic wave having a single frequency and a good waveform. The fact that the generated ultrasonic waves are of a single frequency also contributes to the improvement of the conversion efficiency. Further, the ultrasonic wave generator 100 can change the frequency of the generated ultrasonic waves by changing the charge amount accumulated in the capacitor 4 d of the pulse current generating circuit 4 . Moreover, by increasing the area of the main surface of the metal foil 3, the ultrasonic generator 100 can easily widen the area from which the ultrasonic waves are radiated.
  • FIGS. 4A and 4B respectively show an ultrasonic generator 200 according to the second embodiment.
  • 4A and 4B are cross-sectional views of the ultrasonic generator 200, respectively.
  • FIG. 4(A) shows the dashed-dotted line YY portion of FIG. 4(B)
  • FIG. 4(B) shows the dashed-dotted line XX portion of FIG. 4(A).
  • illustration of the pulse current generating circuit 4 is omitted.
  • the ultrasonic generator 200 of the second embodiment has partially changed the configuration of the ultrasonic generator 100 of the first embodiment.
  • the thickness of the frame 21 is made smaller than the thickness of the frame 1 of the ultrasonic generator 100 .
  • the thickness of the frame 21 is the same as the diameter of the conductive wire (copper wire) of the coil 2 .
  • the thickness of the hollow portion 21a of the frame 21 is also reduced.
  • the frame 21 of the ultrasonic wave generator 200 is provided with lead-out holes 21b and 21c like the lead-out holes 1b and 1c of the ultrasonic wave generator 100 .
  • each wire in Z was scaled to 50% of the thickness of the wires in the other regions, respectively.
  • each conductive wire is rolled in the region Z to have a thickness of 50% of the thickness of the conductive wire in the other regions.
  • the total thickness of the two conductors vertically intersecting in the region Z is equal to the thickness of the conductors in the other regions.
  • the coil 2 is in contact with the metal foil 3 on both sides of the first main surface 2a and the second main surface 2b.
  • the ultrasonic generator 200 of the second embodiment since the coil 2 is in close proximity (contact) with the metal foil 3 on both sides of the first main surface 2a and the second main surface 2b, the ultrasonic wave generated from the coil 2 The magnetic field generated by the metal foil 3 and the magnetic field generated by the metal foil 3 repel each other with a greater force than the ultrasonic generator 100 of the first embodiment. Therefore, the ultrasonic generator 200 has a higher conversion efficiency than the ultrasonic generator 100 . In addition, the ultrasonic wave generator 200 generates a higher sound pressure of ultrasonic waves than the ultrasonic wave generator 100 does.
  • FIG. 5 shows an ultrasonic generator 300 according to the third embodiment.
  • FIG. 5 is a cross-sectional view of the ultrasonic generator 300 . 5, illustration of the pulse current generating circuit 4 is omitted.
  • the ultrasonic generator 300 of the third embodiment is the ultrasonic generator 100 of the first embodiment fixed to a newly provided pedestal 35 . Specifically, one main surface (first main surface 2 a ) of the ultrasonic generator 100 was fixed to the base 35 .
  • the material of the pedestal 35 is arbitrary, but for example, resin, ceramic, metal, or the like can be used. Also, the method of fixing the ultrasonic generator 100 to the base 35 is arbitrary. A method such as bonding with an adhesive can be used.
  • the ultrasonic generator 300 when a large current is instantaneously supplied from the capacitor 4d to the coil 2, the magnetic field generated from the coil 2, the magnetic field generated from the metal foil 3 on the first main surface 2a side of the coil 2, and The magnetic field generated from the metal foil 3 on the second main surface 2b side of the coil 2 repels each other.
  • the metal foil 3 on the first main surface 2a side of the coil 2 is fixed to the base 35, only the metal foil 3 on the second main surface 2b side of the coil 2 is separated from the coil 2. move away. As a result, air is pushed out by the metal foil 3 on the side of the second main surface 2b of the coil 2, and ultrasonic waves are generated.
  • the ultrasonic generator 300 of the third embodiment only the metal foil 3 on the second main surface 2b side of the coil 2 moves, so compared to the ultrasonic generator 100, a larger repulsive force can be generated. Ultrasonic waves with a higher sound pressure can be generated. Theoretically, the ultrasonic generator 300 can generate ultrasonic waves with twice the sound pressure of the ultrasonic generator 100 .
  • FIG. 6A shows an ultrasonic generator 400 according to the fourth embodiment.
  • FIG. 6A is an explanatory diagram of the ultrasonic generator 400.
  • FIG. 6A is an explanatory diagram of the ultrasonic generator 400.
  • the ultrasonic generator 400 of the fourth embodiment has partially changed the configuration of the ultrasonic generator 100 of the first embodiment.
  • the DC power supply 4c of the pulse current generating circuit 4 was a fixed voltage power supply, but the ultrasonic generator 400 changes this to a DC power supply of the pulse current generating circuit 44.
  • 44c used a voltage variable power supply.
  • the DC power supply 44c can switch the voltage to be supplied to 30V, 50V, 75V, and 100V, for example.
  • the capacitance of the capacitor 4d of the pulse current generating circuit 4 was set to 22 ⁇ F.
  • the ultrasonic generator 400 changes the amount of charge accumulated in the capacitor 4d, so that the frequency of the generated ultrasonic waves can be changed.
  • FIG. 6(B) shows the waveforms of ultrasonic waves generated when the voltage supplied by the DC power supply 44c is switched to 30V, 50V, 75V, and 100V.
  • the Y-axis indicates the output voltage of the ultrasonic detection device (microphone) that detected the generated ultrasonic waves.
  • the ultrasonic wave generator 400 can change the frequency of the generated ultrasonic waves by changing the voltage of the DC power supply 44c. Specifically, as the voltage (charging voltage) supplied to the capacitor 4d increases, the sound pressure of the ultrasonic waves increases and the frequency of the ultrasonic waves decreases.
  • FIG. 7A shows an ultrasonic generator 500 according to the fifth embodiment.
  • FIG. 7A is an explanatory diagram of the ultrasonic generator 500 .
  • the ultrasonic generator 500 of the fifth embodiment has partially changed the configuration of the ultrasonic generator 100 of the first embodiment.
  • the capacitor 4d of the pulse current generating circuit 4 is a fixed capacitor, but in the ultrasonic generator 500, this is changed so that the capacitor 54d of the pulse current generating circuit 54 is A variable capacitor was used.
  • Capacitor (variable capacitor) 54d can switch the capacitance to, for example, 2.2 ⁇ F, 22 ⁇ F, and 220 ⁇ F.
  • the voltage of the power supplied to the capacitor 54d by the DC power supply 4c of the pulse current generating circuit 4 was set to 100V.
  • the ultrasonic generator 500 changes the amount of charge accumulated in the capacitor 54d, so that the frequency of the generated ultrasonic waves can be changed.
  • FIG. 7(B) shows the waveforms of ultrasonic waves generated when the capacitance of the capacitor 54d is switched to 2.2 ⁇ F, 22 ⁇ F, and 220 ⁇ F.
  • the ultrasonic wave generator 500 can change the frequency of the generated ultrasonic waves by changing the capacitance of the capacitor 54d. Specifically, as the capacitance of the capacitor 54d is increased, the frequency of the ultrasonic wave is decreased.
  • the ultrasonic generator 100 of the first embodiment shown in FIGS. 1A, 1B, 2A, 2B, 3A, and 3B In terms of structure, four ultrasonic generators (not shown) were manufactured by changing the thickness of the metal foil 3 to 10 ⁇ m, 30 ⁇ m, 50 ⁇ m, and 100 ⁇ m. Aluminum foil was used for each of the metal foils 3 .
  • FIG. 8 shows the waveform of ultrasonic waves generated from each ultrasonic generator. As can be seen from FIG. 8, as the thickness of the metal foil 3 increases, the sound pressure decreases and the frequency decreases. Considering the conversion efficiency, it is preferable that the thickness of the metal foil 3 is thin.
  • FIG. 9 shows an ultrasonic generator 700 according to the seventh embodiment. However, FIG. 9 is an explanatory diagram of the ultrasonic generator 700 .
  • the ultrasonic generator 700 of the seventh embodiment has partially changed the configuration of the ultrasonic generator 100 of the first embodiment.
  • the pulse current generating circuit 4 includes the changeover switch 4e, but in the ultrasonic generator 700, the changeover switch 4e is omitted, and a semiconductor switching element 74e is provided instead.
  • a general transistor is used as the semiconductor switching element 74e, but the type of the semiconductor switching element 74e is arbitrary, and for example, an FET (Field Effect Transistor) or the like may be used.
  • the ultrasonic generator 700 can change the energization time (discharge time) of the pulse current applied from the capacitor 4d to the coil 2, thereby changing the frequency of the ultrasonic waves to be generated. can be done.
  • FIG. 10 shows an ultrasonic generator 800 according to the eighth embodiment.
  • FIG. 8 is an exploded perspective view of the main part of the ultrasonic generator 800.
  • FIG. 10 shows an ultrasonic generator 800 according to the eighth embodiment.
  • FIG. 8 is an exploded perspective view of the main part of the ultrasonic generator 800.
  • the ultrasonic generator 800 of the eighth embodiment has partially changed the configuration of the ultrasonic generator 100 of the first embodiment.
  • the ultrasonic generator 100 uses the coil 2 spirally wound in a single layer.
  • a coil 82 commonly referred to as an alpha winding, was used.
  • the coil 82 of this embodiment is composed of two layers, a lower layer 82a and an upper layer 82b. Although the lower layer 82a and the upper layer 82b are depicted in FIG. 10 in a separated state, the lower layer 82a and the upper layer 82b are actually in contact or close to each other.
  • the coil 82 causes the metal foil 3 to generate a magnetic field by electromagnetic induction.
  • the conductor wire of the coil 82 has a flat cross section, but the conductor wire of the coil 82 may have a circular cross section as in the other embodiments.
  • a conductive wire having a flat cross section like the coil 82 may be used as the coil 2 of another embodiment.
  • the coil 2 is formed by winding a conductor wire in a single layer, but instead of this, a conductor wire wound in multiple layers may be used. Also, the insulating coating of the coil 2 may be omitted if there is a gap between the coil 2 and the metal foil 3 .
  • the coil 2 is formed by spirally winding a conductive wire, but the coil is not limited to this form. may be used.
  • the shape of the metal foil 3 is rectangular when viewed in the planar direction, but the shape of the metal foil 3 is arbitrary, and may be circular instead of rectangular, for example.
  • the ultrasonic generator according to one embodiment of the present invention is as described in the "Means for Solving the Problems" column.
  • ultrasonic generator it is also preferred that metal foils are arranged on both sides of the first main surface and the second main surface of the coil, respectively. In this case, ultrasonic waves can be generated on both sides of the ultrasonic generator.
  • the metal foil arranged on the side of the first main surface and the metal foil arranged on the side of the second main surface wrap the coil from both sides of the first main surface and the second main surface. It is also preferable that In this case, fabrication of the ultrasonic generator is facilitated, and productivity is improved.
  • a frame having a hollow portion is provided, the coil is housed in the hollow portion of the frame, and the metal foil is fixed to the frame with at least a part of the outer circumference being under tension.
  • the conversion efficiency of the ultrasonic generator increases.
  • the ultrasonic generator can be manufactured easily, and the productivity is improved.
  • the coil is coated with insulation and that the coil and the metal foil are in contact.
  • the magnetic field generated by the coil and the magnetic field generated by the metal foil repel each other with great force. Therefore, the conversion efficiency of the ultrasonic generator is increased.
  • the metal foil is an aluminum foil. In this case, a metal foil with high electrical conductivity, light weight, and low cost can be obtained.
  • the thickness of the metal foil is preferably 3 ⁇ m or more and 100 ⁇ m or less when the metal foil is aluminum foil, for example. This is because if the thickness is less than 3 ⁇ m, the strength of the metal foil may be insufficient. This is because if the thickness exceeds 100 ⁇ m, there is a risk that the conversion efficiency will decrease, or that it will be impossible to generate ultrasonic waves with a large sound pressure.
  • the coil may be a conductor wound in a spiral in a single layer.
  • the coil may be a conductive wire wound in multiple layers spirally.
  • the pulse current generating circuit includes a power supply, a capacitor, and a changeover switch.
  • a pulse current can be supplied to the coil with a simple configuration.
  • the amount of electric charge stored in the capacitor is variable, and the energization time of the pulse current applied to the coil from the pulse current generation circuit is also variable.
  • the frequency of ultrasonic waves generated by the ultrasonic generator can be made variable.
  • the amount of charge stored in the capacitor is variable, and the energization time of the pulse current applied to the coil from the pulse current generation circuit is also variable.
  • the frequency of ultrasonic waves generated by the ultrasonic generator can be made variable.
  • the pulse current generation circuit includes a power supply, a capacitor, and a semiconductor switching element, and that the semiconductor switching element is controlled so that the energization time of the pulse current applied from the pulse current generation circuit to the coil is variable.
  • the frequency of ultrasonic waves generated by the ultrasonic generator can be made variable.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Apparatuses For Generation Of Mechanical Vibrations (AREA)

Abstract

L'invention concerne un dispositif de génération d'ondes ultrasonores qui a une efficacité de conversion élevée.　Le dispositif de génération d'ondes ultrasonores comprend : une bobine (2) qui comprend une première surface principale (2a) et une seconde surface principale (2b) qui sont sur des côtés avant/arrière opposés ; une feuille métallique qui est disposée dans un état dans lequel une tension est appliquée sur celle-ci, sur le côté de la première surface principale et/ou sur le côté de la seconde surface principale ; et un circuit de génération de courant pulsé (4) qui applique un courant pulsé à la bobine (2).
PCT/JP2022/023692 2021-09-28 2022-06-13 Dispositif de génération d'ondes ultrasonores WO2023053590A1 (fr)

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JP2021158549 2021-09-28

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6044814A (ja) * 1983-08-22 1985-03-11 Oki Electric Ind Co Ltd 超音波信号発生装置
JPS62281699A (ja) * 1986-05-30 1987-12-07 Fujitsu Ltd 電磁誘導型音源装置
JPH07328539A (ja) * 1994-06-14 1995-12-19 Yukio Kagawa 電磁音響変換器

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6044814A (ja) * 1983-08-22 1985-03-11 Oki Electric Ind Co Ltd 超音波信号発生装置
JPS62281699A (ja) * 1986-05-30 1987-12-07 Fujitsu Ltd 電磁誘導型音源装置
JPH07328539A (ja) * 1994-06-14 1995-12-19 Yukio Kagawa 電磁音響変換器

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