Ultrasonic transducer and ultrasonic treatment device provided with same

Abstract

The ultrasonic vibrator is provided with a vibrator main body (11) and a vibrator cover (12), the radiating surface of the vibrator main body (11) is in a curved surface shape, the vibrator main body (11) generates ultrasonic waves, and the vibrator cover (12) covers the radiating surface of the vibrator main body (11) and serves as a sound matching layer. The oscillator cover (12) is formed so as to extend along the radiating surface (11a) of the oscillator body (11). As a result, provided is an ultrasonic transducer which has high durability and is capable of more stably transmitting sound waves to a deep part.

Description

Technical Field

[0001] The present invention relates to an ultrasonic oscillator and an ultrasonic treatment device having the ultrasonic oscillator, and a radiation surface of the ultrasonic oscillator that generates ultrasonic waves is covered with an oscillator cover. Background Art

[0002] Conventionally, a device for treating dementia has been known, which includes: a plurality of ultrasonic probes; an ultrasonic oscillator disposed on the ultrasonic probe and transmitting non-focused ultrasonic energy to the brain; and an ultrasonic generating device connected to the ultrasonic probe (for example, refer to Patent Document 1).

[0003] This device is configured such that by irradiating a diseased part such as the brain or the heart with LIPUS (Low-Intensity Pulsed Ultrasound), the expression of endothelial nitric oxide synthase (hereinafter referred to as eNOS) and vascular endothelial growth factor (hereinafter referred to as VEGF) is enhanced, and angiogenesis and neurogenesis can be promoted.

[0004] Prior Art Documents Patent Documents Patent Document 1: International Publication No. 2018 / 181991 Summary of the Invention

[0005] -Technical Problem to be Solved by the Invention- However, although the conventional ultrasonic oscillator can irradiate the entire target brain and heart with a single or multiple oscillators, the sound waves irradiated from its radiation surface are difficult to reach deep parts with a constant pressure due to the vibration mode and interference of the sound waves.

[0006] The conventional ultrasonic oscillator has the following problems: Since the radiation surface has a special shape, the impact resistance is poor, and a protective film for waterproofing adhered to the surface is easily peeled off due to heat and impact.

[0007] The present invention has been completed in view of the above problems, and an object thereof is to provide an ultrasonic oscillator having high durability and capable of transmitting sound waves to deep parts more stably.

[0008] -Technical Solution for Solving the Technical Problem- To achieve the above object, in the present invention, a radiation surface of the oscillator body is covered with a cover that extends along the curved surface shape of the oscillator body.

[0009] Specifically, in the invention of the first aspect, it includes an oscillator body and an oscillator cover. The radiation surface of the oscillator body is a curved surface shape, and the oscillator body generates ultrasonic waves.

[0010] The oscillator cover covers the radiation surface of the oscillator body and serves as an acoustic matching layer. The oscillator cover has a shape extending along the radiation surface of the oscillator body.

[0011] According to the above-described configuration, since the radiation surface of the oscillator body is a curved surface shape, the irradiated waveform advances while spreading. And the expansion of the sound in the oscillator cover is determined by Snell's law. However, since the material of the oscillator cover is usually composed of a solid such as a resin molding, the sound speed is faster than that of water and living bodies, so the refractive index becomes larger. As a result, in terms of the range irradiated from the oscillator cover, compared with the case without the oscillator cover, it irradiates from a larger surface. Thus, more uniform irradiation can be performed. Moreover, since the distance from the oscillator body, which is a heat source, to the living body can be maintained by the oscillator cover, the problem of surface temperature rise can also be alleviated.

[0012] The invention of the second aspect is based on the invention of the first aspect, and the shape of the radiation surface of the oscillator body is a convex spherical surface.

[0013] It is generally considered that the waves irradiated from the radiation surface of the oscillator body are a set of point sources based on the radiation surface. If the radiation surface is a convex spherical surface, there will be parts where the sounds from the point sources interfere with each other and weaken or strengthen each other, and ultimately it will not become a uniform sound field. However, according to the above-described configuration, by covering the radiation surface with the oscillator cover, more uniform irradiation can be performed from a larger surface.

[0014] The invention of the third aspect is based on the invention of the first aspect, and the thickness of the oscillator cover is constant.

[0015] According to the above-described configuration, it is not necessary to finely adjust the thickness of the cover, and it is easy to manufacture.

[0016] The invention of the fourth aspect is based on the invention of the third aspect. When the wavelength of the material of the oscillator cover is λ, the thickness of the oscillator cover is λ / 8 or more and 3λ or less, excluding the ranges of λ / 8 ± λ / 40, λ / 4 ± λ / 40, and λ / 2 ± λ / 40.

[0017] According to the above-described configuration method, a resonant structure is formed. By deliberately deviating from the thickness near the thicknesses that can achieve maximum transmission (λ / 8, λ / 4, and λ / 2), an oscillator cover that serves as an acoustic matching layer with a small irradiation deviation and is an ultrasonic oscillator can be obtained. This is because if the thickness is slightly deviated from the thickness at which the amplitude becomes maximum, the problem of a sharp change in irradiation energy can be avoided. If the thickness of the oscillator cover is too thin, the diffusion effect caused by refraction becomes small. In addition, considering not only the acoustic performance but also the manufacturability and the durability of the oscillator cover, the thickness of the oscillator cover is preferably thicker than λ / 8. If the thickness is greater than 3λ, the attenuation becomes too large and it is difficult to use in practice.

[0018] The invention of the fifth aspect is based on the invention of the first aspect, and the thickness of the oscillator cover is not constant but variable.

[0019] According to the above-described configuration method, by making the thickness of the oscillator cover not constant but variable, an appropriate expansion can be controlled.

[0020] In the invention of the sixth aspect, the oscillator cover is formed of a material having an elastic modulus of 2000 MPa or more and 10000 MPa or less and an intrinsic acoustic impedance of 1.5 MPa·s / m or more and 10 MPa·s / m or less.

[0021] According to the above-described configuration method, the elastic modulus of the material of the oscillator cover is maintained at an appropriate level, the sound speed is faster than the sound speed of water and living bodies, so the refractive index becomes larger, and the irradiation range from the oscillator cover becomes larger.

[0022] The ultrasonic treatment device of the invention of the seventh aspect includes the ultrasonic oscillator according to any one of the inventions of the first to sixth aspects, and a system that supplies energy for ultrasonic vibration to the ultrasonic oscillator.

[0023] According to the above-described configuration method, for example, in an ultrasonic treatment device capable of treating angina or dementia by enhancing the expression of eNOS and VEGF, a constant sound pressure can reach a deeper position, and the durability of the ultrasonic oscillator can be improved.

[0024] - Effects of the Invention - As described above, according to the present invention, by covering the radiation surface with a curved surface shape of the oscillator body with an oscillator cover having a shape extending along the radiation surface and serving as an acoustic matching layer, an ultrasonic oscillator with high durability and capable of more stably transmitting sound waves to the deep part can be obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a block diagram showing an overview of an ultrasonic treatment device having an ultrasonic oscillator according to an embodiment of the present invention.

[0026] Figure 2 is an enlarged cross-sectional view of an ultrasonic oscillator.

[0027] Figure 3 is a cross-sectional view of the oscillator body and the oscillator cover, Figure 3 where (a) shows the case where the thickness of the oscillator cover is constant, Figure 3 where (b) shows the case where the thickness at the center of the oscillator cover is thinner, Figure 3 where (c) shows the case where the thickness at the center of the oscillator cover is thicker.

[0028] Figure 4 is a diagram showing the simulation results of the sound pressure level in the case without a cover.

[0029] Figure 5 Among them, Figure 5 where (a) to (c) are diagrams showing the simulation results of the sound pressure levels respectively corresponding to Figure 3 where (a) to (c) are diagrams showing the simulation results of the sound pressure levels respectively corresponding to

[0030] Figure 6 Among them, Figure 6 where (a) shows the simulation result without a cover, Figure 6 where (b) shows the simulation result when the wavelength of the cover material is λ / 8, Figure 6 where (c) shows the simulation result when the wavelength of the cover material is λ / 3.4, assuming the wavelength of the cover material is λ.

[0031] Figure 7 Among them, Figure 7 where (a) and (b) are diagrams showing the simulation results when covers with thicknesses of λ / 4 and λ / 3.4 are installed respectively. Detailed implementation mode

[0032] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0033] Figure 1 shows a general view of an ultrasonic treatment device 20 having an ultrasonic oscillator 10 according to an embodiment of the present invention. The use of the ultrasonic oscillator 10 is not limited to the following ultrasonic treatment device 20, and the ultrasonic treatment device 20 is configured to irradiate the heart and brain with LIPUS by transmitting a frequency within the ultrasonic frequency range, so as to enhance the expression of eNOS and VEGF, thereby enabling the treatment of angina pectoris, heart failure with preserved ejection fraction (HFpEF) or dementia.

[0034] A general description of the ultrasonic treatment device 20 will be given. In the ultrasonic treatment device 20, the control unit 4 of the program management system in the ultrasonic treatment device 20 transmits the treatment information input by the operator 1, such as the treatment site 2 and the patient information 3, as signals. The transmission waveform is controlled in the transmission condition control unit 5, and the treatment program is controlled in the treatment program control unit 6. Then, it is transmitted from the transmission unit 7 and irradiated onto the brain through the ultrasonic transducer 10 via the treatment site 2 (such as the head). The control unit 4, the transmission condition control unit 5, and the treatment program control unit 6 are constituted by, for example, one or more microcomputers built in the ultrasonic treatment device 20.

[0035] When there are two or more ultrasonic transducers 10, it is configured such that the ultrasonic transducers 10 branch into multiple at the transmission unit 7 for irradiation of each ultrasonic transducer 10. For example, when the ultrasonic transducer 10 is used for a headset, a pair of left and right ultrasonic transducers 10 is required.

[0036] The information of the ultrasonic treatment device 20 is displayed to the operator 1 through the display 8. The input to the ultrasonic treatment device 20 is performed by methods such as external input using a keyboard, mouse, etc., touch operation input when the display 8 is a touch display, or insertion of a USB memory.

[0037] As Figure 2 As magnified in the figure, the ultrasonic transducer 10 used includes a transducer body 11, and the transducer body 11 is a diffused transducer whose radiation surface 11a is curved. Since the radiation surface 11a of the transducer body 11 is curved, the irradiated waveform advances while diffusing.

[0038] As a result, the entire treatment site 2 as the object can be irradiated. For example, when the object is the brain, it is preferable that the irradiation range expands at an angle of 77 degrees or more.

[0039] The ultrasonic transducer 10 has a transducer cover 12, which is used to ensure biological safety and protect the transducer body 11 from scars caused by impacts. On the back side of the transducer cover 12, there is a transducer housing 13 that covers the transducer body 11 and a transducer cable 14 for supplying power to the transducer body 11. The transducer housing 13 can be integrated with the transducer cover 12 or can be separate from the transducer cover 12.

[0040] As the oscillator body 11, for example, a piezoelectric (PZT) element, a piezoelectric element made of a homopolymer (PVDF) of vinylidene fluoride (VdF), which is one of fluororesins, barium titanate (BaTiO3), a relaxor-based piezoelectric single crystal (PIN-PmN-PT), etc., an element called a capacitive micromachined ultrasonic transducer (CMUT), a piezoelectric micromachined ultrasonic transducer (PMUT), which is manufactured using semiconductor processes, etc. can be used.

[0041] The frequency (number of cycles) of the ultrasonic wave applied to the oscillator body 11 corresponds to the frequency of the oscillator body 11. Its wave number is 1 cycle or more and 64 cycles or less, preferably 24 cycles or more and 40 cycles or less. The average intensity (Ispta, Spatial Peak Temporal Average Intensity) within the pulse width is not particularly limited and is 720 mW / cm 2 Hereinafter, it is preferably 150 mW / cm 2 Hereinafter.

[0042] The frequency of the oscillator body 11 (the frequency near the resonance point or anti-resonance point) is, for example, 100 kHz or more and 10 MHz or less. The shape of the oscillator body 11 is a convex spherical shape. For example, Figure 2 the radius R of the shown spherical surface is 10 mm or more and 30 mm or less, and the opening diameter D is 10 mm or more and 50 mm or less. And, a backing formed of air, oil, or a solid is provided on the back side of the oscillator body 11. It should be noted that the backing refers to a component that is arranged on the back of the oscillator body 11, suppresses the propagation of ultrasonic waves backward, and helps to shorten the pulse width.

[0043] As the material of the oscillator cover 12, a material having an elastic modulus of 2000 MPa or more and 10000 MPa or less and an intrinsic acoustic impedance of 1.5 MPa·s / m or more and 10 MPa·s / m or less is preferably used.

[0044] Moreover, if the wavelength of the material of the oscillator cover 12 is set to λ, the oscillator cover 12 preferably has a thickness of λ / 8 or more and 3λ or less, excluding the ranges of λ / 8 ± λ / 40, λ / 4 ± λ / 40, and λ / 2 ± λ / 40.

[0045] The shape of the oscillator cover 12 is preferably a shape that extends along the radiation surface of the oscillator body 11.

[0046] As materials for the oscillator cover 12, there are, for example, synthetic resin materials such as PPE (polyphenylene ether), PBT (polybutylene terephthalate), ABS (acrylonitrile-butadiene-styrene), LDPE (low density polyethylene), PS (polystyrene), NORYL (registered trademark, modified polyphenylene ether), Valox (Valox), Pebax (polyether block polyamide), etc.; composite materials of carbon, graphite, metal, etc. and resin, etc.

[0047] The adhesive used to bond the back surface of the oscillator cover 12 to the radiation surface 11a of the oscillator body 11 is preferably, for example, an epoxy adhesive, a silicone adhesive, etc.

[0048] The waterproof property of the oscillator cover 12 can be achieved by the material of the oscillator cover 12 itself, or can be achieved by coating a thin waterproof coating such as Parylene (a series of polymers obtained from p-xylene) within the range that does not affect acoustics.

[0049] Regarding insulation, insulation is required for the part of the oscillator cover 12 that comes into contact with the patient. For example, since the oscillator body 11 has a GND (ground) layer on its surface, when the thickness of the oscillator cover 12 is less than 0.4 mm, or when the withstand voltage is less than 1500 V, an additional insulation layer needs to be provided. Examples of the insulation layer include a polyvinyl chloride coating (PVC), a fluorine coating (ETFE), a polyethylene coating, a nylon coating, an epoxy coating, a polyphenylene sulfide (PPS) / polyether ether ketone (PEEK) coating, etc.

[0050] - Example - Under normal circumstances, the waves irradiated from the radiation surface 11a of the oscillator body 11 are considered to be a set of point light sources based on the radiation surface 11a. In the spherical convex surface shape of the oscillator body 11, there will be parts where the sounds from the point light sources are weakened or enhanced due to interference caused by this shape, and ultimately a constant sound field will not be formed.

[0051] In this embodiment, to solve this problem, the oscillator cover 12 is mounted on the radiation surface 11a of the oscillator body 11.

[0052] Utilizing the effect of the oscillator cover 12, irradiation with a constant sound pressure level can be performed over a larger range. The expansion of the sound within the oscillator cover 12 is determined by Snell's law (the law of refraction), but the sound speed of the material of the oscillator cover 12, i.e., the resin, is generally faster than the sound speed of water and living bodies (the sound speed of water at 20°C is 1480 m / s), so the refractive index becomes larger. As a result, in terms of the irradiation range from the oscillator cover 12, compared with the case without the oscillator cover 12, irradiation is performed from a larger surface. Thus, more constant irradiation can be achieved.

[0053] Figure 3An example of the shape of the oscillator body 11 and the oscillator cover 12 is shown. Figure 3 The oscillator cover 12 in (a) has a uniform and constant thickness; Figure 3 The central part of the oscillator cover 12' in (b) is thinner; Figure 3 The central part of the oscillator cover 12'' in (c) is thicker.

[0054] Here, when the wavelength of the material of the oscillator cover 12 is set to λ, Figure 3 The thickness of the oscillator cover 12 in (a) is t = λ / 3.4; Figure 3 The thickness at the center of the oscillator cover 12' in (b) is t = λ / 4, and the thickness at both ends is λ / 2; Figure 3 The thickness at the center of the oscillator cover 12'' in (c) is t = λ×3 / 4, and the thickness at both ends is λ / 2.

[0055] Next, the results of the acoustic analysis are shown. The acoustic analysis was performed at an overall size of 80 mm and a frequency of 500 kHz, and the sound pressure level dB was color-coded with a linear scale.

[0056] Figure 4 The simulation results of the sound pressure level without a cover are shown, Figure 5 (a) to (c) show the Figure 3 simulation results of the sound pressure level corresponding to (a) to (c) respectively. It can be seen that compared with the case Figure 4 without the oscillator cover 12, in the case Figure 5 of having the oscillator covers 12, 12', 12'' in (a) to (c), the sound pressure further spreads deeper and spreads uniformly over a larger range.

[0057] In order to perform constant irradiation, the thickness of the oscillator cover 12 needs to be above a constant value. This is because: if it is too thin, the diffusion effect caused by refraction becomes smaller.

[0058] As a result of the acoustic analysis, when the wavelength of the material of the oscillator cover 12 is λ, Figure 6 (a) shows the case without a cover; Figure 6 (b) shows the case where the wavelength of the cover material is λ / 8; Figure 6 (c) shows the case where the wavelength of the cover material is λ / 3.4. It can be seen that although affected by the attenuation caused by the oscillator cover 12, in the case of having the oscillator cover 12, the sound pressure is uniform to a deeper position. It can also be seen that when using a Figure 6 thicker Figure 6 λ / 3.4 than λ / 8 in (b), a higher-level sound pressure can be applied to a deeper position. From this, it can be known that the thickness of the cover is preferably at least thicker than λ / 8.

[0059] If the speed of sound is set to 2200 m / s and the transmitted frequency is set to 500 kHz, then λ / 8 = 0.55 mm. Considering not only the acoustic performance but also the manufacturability and the durability of the oscillator cover 12, the thickness of the oscillator cover 12 is preferably thicker than λ / 8.

[0060] It can also be considered that in addition to expanding the sound pressure by using the difference in the speed of sound, the oscillator cover 12 also functions as an acoustic matching layer. If the material used for the oscillator cover 12 is a piezoelectric element, the impedance is about 30 MPa·s / m. If the speed of sound of the oscillator cover 12 is set to 2200 m / s and the density of the resin material is set to 1.2 g / cm 3 , then the impedance is 2.6 MPa·s / m. In contrast, the impedance of water is 1.44 MPa·s / m, and a value between PZT and water is to be taken. It can be considered that by using the oscillator cover 12 to reduce the reflection and unnecessary vibration modes at the interface, irradiation can be performed more efficiently. As a result, it contributes to constant irradiation.

[0061] In the case of a general ultrasonic oscillator having an acoustic matching layer, in order to improve its efficiency, it is designed with a thickness obtained by dividing the wavelength λ by 2×n (n is an integer) (for example, λ / 2, λ / 4, λ / 8, etc.). This is because by designing the general ultrasonic oscillator with this thickness, the radiation surface of the matching layer becomes an open end and the amplitude reaches the maximum.

[0062] However, if slightly deviated from this thickness, there will be a problem that the irradiation energy changes sharply. This indicates that if the thickness, frequency, the speed of sound of the cover, etc. change due to manufacturing deviations, deviations as a device will occur.

[0063] In the present embodiment, by deliberately deviating from the thickness at which maximum transmission can be performed, the oscillator cover 12 is set as an oscillator cover with small irradiation deviation for the ultrasonic oscillator 10 and serving as an acoustic matching layer.

[0064] The method is to install the oscillator cover 12 having the following thickness, which is a value deviated by λ / 40 or more from the value obtained by dividing the wavelength λ of the material of the oscillator cover 12 by 2×n (n is an integer), for example, from the thicknesses of λ / 2, λ / 4, λ / 8.

[0065] As an example, Figure 7 (a)and Figure 7(b) The simulation results are shown respectively when caps with thicknesses of λ / 4 and λ / 3.4 are installed. It can be seen that the difference in thickness is small, approximately λ / 23, but there is a large difference in the sound pressure level. This means that since λ / 4 becomes a resonant structure, energy can be irradiated with very high efficiency at this thickness, but it also means that the sound pressure level changes sharply due to the thickness variation. In addition, compared with the case where the thickness is λ / 4, when the thickness is λ / 3.4, there is a characteristic that the local sound pressure difference is smaller.

[0066] Also, the heat generation of the ultrasonic oscillator 10 during the transmission of ultrasonic waves is also a problem. Since the ultrasonic oscillator 10 is in contact with the patient, there is a possibility of causing obstacles such as burns due to this heat generation. Although the upper limit of the surface temperature rise is determined according to regulations, since the distance from the heating body (oscillator main body 11) to the living body can be maintained by the oscillator cap 12, the problem of surface temperature rise can also be alleviated.

[0067] Moreover, by making the thickness of the oscillator cap 12 change rather than being constant, it is possible to control it to an appropriate expansion.

[0068] By deliberately making its thickness deviate from the design guidelines of the usual acoustic matching layer, namely the thicknesses of 1 / 2 wavelength, 1 / 4 wavelength, and 1 / 8 wavelength, it is possible to minimize the influence caused by the thickness difference generated in the manufacturing process.

[0069] Although the oscillator main body 11 has characteristics such as being easily damaged when impacted due to its shape, by pasting the oscillator caps 12, 12', 12" made of a resin material with a high elastic modulus and having a thickness, the impact resistance characteristics can also be improved.

[0070] The ultrasonic treatment device 20 of the present invention is a device capable of outputting ultrasonic waves over a relatively large range of an object site. By irradiating a prescribed transmission waveform to the brain and the heart, it is possible to enhance the expression of eNOS and VEGF, promote angiogenesis and neurogenesis, and perform the treatment of angina pectoris and heart failure with preserved ejection fraction (HFpEF) or dementia. The ultrasonic oscillator 10 with a convex curved surface has a problem that the pressure is not constant at a deeper position due to the vibration mode and the interference of sound waves due to its special shape. However, the shape of the oscillator cap 12 in this embodiment extends along the shape of the radiation surface 11a, and a resin that can be used as an acoustic matching layer is pasted on the radiation surface 11a, thereby being able to suppress unnecessary vibration modes and alleviate the influence caused by interference, and even with the same output, it can be constantly irradiated to a deeper position.

[0071] (Other embodiments) The above embodiments of the present invention may also adopt the following structures.

[0072] That is to say, in the above-described embodiment, an example of using the ultrasonic oscillator 10 in the ultrasonic treatment device 20 is shown, but the ultrasonic oscillator 10 can also be used in ultrasonic cleaners, ultrasonic humidifiers, ultrasonic dispersion and emulsification machines, etc. The ultrasonic oscillator 10 can also be used in fish finders, ultrasonic diagnostic devices, ultrasonic flow meters, ultrasonic levels, etc.

[0073] In the above-described embodiment, the shape of the radiation surface 11a is a convex spherical surface that is substantially circular when viewed from above, but it can also be a convex curved surface that is elliptical, oblong, rectangular with rounded corners, square with rounded corners, etc. when viewed from above.

[0074] It should be noted that the above embodiments are only essentially preferred examples and are not intended to limit the present invention, its application objects, or its scope of use.

[0075] -Symbol Explanation- 1 Operator 2 Treatment Site 3 Patient Information 4 Control Unit 5 Transmission Condition Control Unit 6 Treatment Plan Control Unit 7 Transmission Unit 8 Display 10 Ultrasonic Oscillator 11 Oscillator Body 11a Radiation Surface 12, 12’, 12” Oscillator Cover 13 Oscillator Housing 14 Oscillator Cable 20 Ultrasonic Treatment Device.

Claims

1. An ultrasonic oscillator, characterized in that, It includes an oscillator body and an oscillator cover. The radiation surface of the oscillator body is in a curved surface shape, and the oscillator body generates ultrasonic waves. The oscillator cover covers the radiation surface of the oscillator body and serves as an acoustic matching layer. The oscillator cover has a shape extending along the radiation surface of the oscillator body.

2. The ultrasonic oscillator according to claim 1, wherein the shape of the radiation surface of the oscillator body is a convex spherical surface.

3. The ultrasonic oscillator according to claim 1, wherein the thickness of the oscillator cover is constant.

4. The ultrasonic oscillator according to claim 3, wherein when the wavelength of the material of the oscillator cover is λ, the thickness of the oscillator cover is not less than λ / 8 and not more than 3λ, excluding the ranges of λ / 8 ± λ / 40, λ / 4 ± λ / 40, and λ / 2 ± λ / 40.

5. The ultrasonic oscillator according to claim 1, wherein the thickness of the oscillator cover is not constant but variable.

6. The ultrasonic oscillator according to claim 1, wherein the oscillator cover is formed of a material having a Young's modulus of not less than 2000 MPa and not more than 10000 MPa and an intrinsic acoustic impedance of not less than 1.5 MPa·s / m and not more than 10 MPa·s / m.

7. An ultrasonic treatment device, characterized in that, It has the ultrasonic oscillator according to any one of claims 1 to 6, and a system for supplying energy for ultrasonic vibration to the ultrasonic oscillator.

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