Ultrasonic wave generation device

Abstract

An ultrasonic wave generation device (10) comprises an ultrasonic wave generation source (11), an ultrasonic wave convergence unit (12), and a waveguide (13). The ultrasonic wave convergence unit (12) includes a reflection unit (21) that has a reflection surface (23) which reflects ultrasonic waves generated by the ultrasonic wave generation source (11) and a connection unit (22) that connects the reflection unit (21) to the waveguide (13). The ultrasonic wave generation source (11) generates longitudinal ultrasonic waves. The ultrasonic wave generation device (10) is configured such that longitudinal ultrasonic waves generated by the ultrasonic wave generation source (11) are transformed into transverse waves upon reflection on the reflection surface (23) and are converged toward the connection unit (22).

Description

ultrasonic generator

[0001] The present invention relates to an ultrasonic generator.

[0002] Patent Document 1 discloses an ultrasonic irradiator. This ultrasonic irradiator includes an ultrasonic transducer and an acoustic propagation body that propagates ultrasonic waves from the ultrasonic transducer. The acoustic propagation body includes a main body and a shaft extending forward from the front surface of the main body. The front surface of the main body functions as a concave primary reflecting surface that reflects ultrasonic waves from the ultrasonic transducer. The main body has a flat rear surface to which the ultrasonic transducer is joined. The main body has a well connected to the rear surface. The bottom surface of the well functions as a concave secondary reflecting surface that reflects the primary reflected wave from the primary reflecting surface. The secondary reflected wave from the secondary reflecting surface propagates through the shaft and is irradiated forward from the tip surface of the shaft.

[0003] Patent No. 6774697

[0004] In the technology of Patent Document 1, longitudinal waves and transverse waves are generated when the primary reflecting surface (first reflecting surface) reflects ultrasonic waves from the ultrasonic transducer. However, Patent Document 1 does not consider utilizing the transverse waves generated at the primary reflecting surface (first reflecting surface).

[0005] An object of the present invention is to provide a technique that makes it possible to introduce longitudinal ultrasonic waves into a waveguide by utilizing transverse waves generated at a reflecting surface.

[0006] The ultrasonic generator of the present disclosure is an ultrasonic generator comprising: an ultrasonic generating source that generates ultrasonic waves; an ultrasonic focusing unit that focuses the ultrasonic waves generated from the ultrasonic generating source; and a waveguide that transmits the ultrasonic waves focused by the ultrasonic focusing unit, wherein the ultrasonic focusing unit has a reflecting unit including a reflecting surface that reflects the ultrasonic waves generated by the ultrasonic generating source; and a connecting unit that connects the reflecting unit and the waveguide, wherein the ultrasonic generating source generates the ultrasonic waves in the form of longitudinal waves, and the ultrasonic generator is configured such that the ultrasonic waves in the form of longitudinal waves generated from the ultrasonic generating source are converted into transverse waves when reflected by the reflecting surface and are focused toward the connecting unit.

[0007] According to the present disclosure, longitudinal ultrasonic waves can be introduced into a waveguide by utilizing transverse waves generated at a reflecting surface.

[0008] FIG. 1 is a cross-sectional view of an ultrasonic generator according to a first embodiment. FIG. 2 is a plan view of the ultrasonic generator according to the first embodiment. FIG. 3 is an explanatory diagram conceptually illustrating how ultrasonic waves are propagated. FIG. 4 is a graph showing the relationship between the angle of incidence and the energy conversion rate from longitudinal waves to shear waves. FIG. 5 is an explanatory diagram conceptually illustrating how ultrasonic waves of shear waves that have passed through a connection portion are reflected by the other-side generating portion and the other-side reflecting surface in that order, and then return to the connection portion. FIG. 6 is an explanatory diagram conceptually illustrating how ultrasonic waves of shear waves that have passed through a connection portion are reflected by the other-side reflecting surface and the other-side generating portion in that order, and then return to the connection portion. FIG. 7 is a perspective view of an ultrasonic generator according to a second embodiment.

[0009] [Description of Embodiments of the Present Disclosure] In the following, embodiments of the present disclosure are listed and illustrated.

[0010] [1] An ultrasonic generator comprising: an ultrasonic generating source that generates ultrasonic waves; an ultrasonic focusing unit that focuses the ultrasonic waves generated from the ultrasonic generating source; and a waveguide that transmits the ultrasonic waves focused by the ultrasonic focusing unit, wherein the ultrasonic focusing unit has a reflecting unit including a reflecting surface that reflects the ultrasonic waves generated by the ultrasonic generating source; and a connecting unit that connects the reflecting unit and the waveguide, wherein the ultrasonic generating source generates the ultrasonic waves in the form of longitudinal waves, and the ultrasonic generator is configured such that the ultrasonic waves in the form of longitudinal waves generated from the ultrasonic generating source are converted into transverse waves when reflected by the reflecting surface and are focused toward the connecting unit.

[0011] In the ultrasonic generator, longitudinal ultrasonic waves generated from the ultrasonic source are converted into shear waves when reflected by the reflecting surface and focused toward the connection. With this configuration, part of the shear waves focused on the connection propagates in the direction of the waveguide as longitudinal waves, and these longitudinal waves are propagated into the waveguide. In other words, the ultrasonic generator can introduce longitudinal ultrasonic waves into the waveguide by using the shear waves generated by the reflecting surface.

[0012] [2] The ultrasonic wave generating source has a one-side generating section arranged on one side of the waveguide and a other-side generating section arranged on the other side of the waveguide in a first direction perpendicular to the direction in which the ultrasonic wave generating source generates the ultrasonic waves, the reflecting surface has a one-side reflecting surface arranged on one side of the waveguide and a other-side reflecting surface arranged on the other side of the waveguide in the first direction, the reflecting section has a one-side reflecting section including the one-side reflecting surface and a other-side reflecting section including the other-side reflecting surface, the connecting section connects the one-side reflecting section and the other-side reflecting section, and the waveguide has a shape extending from the connecting section in a direction perpendicular to the arrangement direction of the one-side reflecting section and the other-side reflecting section, The ultrasonic generator is configured such that the ultrasonic waves of longitudinal waves generated from the one-side generating unit are converted into shear waves when reflected by the one-side reflecting surface and are focused toward the connection portion, and the ultrasonic waves of longitudinal waves generated from the other-side generating unit are converted into shear waves when reflected by the other-side reflecting surface and are focused toward the connection portion. The ultrasonic generator described in [1].

[0013] The ultrasonic generator can more efficiently introduce longitudinal ultrasonic waves into the waveguide by converging transverse waves generated on both sides in the first direction toward the connection portion.

[0014] [3] The ultrasonic generator described in [2] is configured such that at least a portion of the ultrasonic waves converted into transverse waves at the one-side reflecting surface passes through the connecting portion, is reflected by the other-side generating unit and the other-side reflecting surface, and is directed back toward the connecting portion, and at least a portion of the ultrasonic waves converted into transverse waves at the other-side reflecting surface passes through the connecting portion, is reflected by the one-side generating unit and the one-side reflecting surface, and is directed back toward the connecting portion.

[0015] In the ultrasonic generator, a transverse wave that has passed through the connection part once travels back to the connection part. A part of the transverse wave that travels back to the connection part travels as a longitudinal wave in the direction of the waveguide, and this longitudinal wave is propagated to the waveguide. In other words, the ultrasonic generator allows a transverse wave that has passed through the connection part once to propagate back to the connection part, thereby efficiently introducing longitudinal ultrasonic waves into the waveguide.

[0016] [4] The ultrasonic generator described in [3], wherein the one-side reflecting surface and the other-side reflecting surface have a shape that follows the same ellipse on a cross section cut along the direction in which the ultrasonic generating source generates the ultrasonic waves and the first direction.

[0017] A simple configuration in which the one-side reflecting surface and the other-side reflecting surface are shaped along the same ellipse can realize a configuration in which a transverse wave that has once passed through the connecting portion is propagated to the connecting portion again.

[0018] [5] The ultrasonic generating device described in any one of [2] to [4], wherein the ultrasonic generating source, the ultrasonic focusing unit, and the waveguide are shaped to extend in a second direction perpendicular to the first direction among directions perpendicular to the direction in which the ultrasonic generating source generates the ultrasonic waves.

[0019] The ultrasonic generator can introduce ultrasonic waves into the waveguide over a wide range in the second direction by utilizing the transverse waves generated at the first reflecting surface.

[0020] [6] The ultrasonic generator according to any one of [1] to [5], wherein the focal point of the reflecting surface is located at the connection portion, and the ultrasonic generator is configured such that the ultrasonic waves of the longitudinal waves generated from the ultrasonic generating source are converted into transverse waves when reflected by the reflecting surface and directed toward the focal point.

[0021] The ultrasonic generator can focus the transverse waves directed toward the connection part at a focal point.

[0022] [Details of the embodiment of the present disclosure] The ultrasonic generator of the present disclosure is used in, for example, an ultrasonic diagnostic device, an ultrasonic treatment device, a cavitation generator, a dental scaler, a blood coagulation cutting device (e.g., an ultrasonic scalpel), an ultrasonic processing machine, an ultrasonic cleaning machine (e.g., an ultrasonic cleaner), etc.

[0023] 1 and 2 , an ultrasonic generator 10 includes an ultrasonic source 11, an ultrasonic focusing unit 12, and a waveguide 13. The ultrasonic source 11, the ultrasonic focusing unit 12, and the waveguide 13 are symmetrical about an axis C. The axis C is the front-rear direction of the ultrasonic generator 10.

[0024] The ultrasonic wave generating source 11 generates ultrasonic waves. The ultrasonic wave generating source 11 is composed of, for example, a piezoelectric element. The piezoelectric element has a piezoelectric body made of piezoelectric ceramics and electrodes arranged on both sides of the piezoelectric body. The ultrasonic wave generating source 11 is plate-shaped. The ultrasonic wave generating source 11 has a thickness. The thickness direction of the ultrasonic wave generating source 11 is the stacking direction of the piezoelectric body and the electrodes. The ultrasonic wave generating source 11 generates ultrasonic waves when an AC voltage based on a power source P is applied. The ultrasonic wave generating source 11 generates ultrasonic waves at a frequency of, for example, 30 kHz or more and 10 MHz or less. The ultrasonic wave generating source 11 generates ultrasonic waves in its thickness direction. The ultrasonic wave generating source 11 generates ultrasonic waves forward. The ultrasonic wave generating source 11 is bonded to the rear surface of the ultrasonic focusing unit 12.

[0025] The ultrasonic focusing unit 12 focuses the ultrasonic waves generated by the ultrasonic generating source 11. The ultrasonic focusing unit 12 is formed of, for example, a metal (e.g., duralumin). The ultrasonic focusing unit 12 has a reflecting unit 21 and a connecting unit 22. The reflecting unit 21 includes a reflecting surface 23 that reflects the ultrasonic waves generated by the ultrasonic generating source 11. The reflecting surface 23 is disposed forward of the ultrasonic generating source 11. The connecting unit 22 connects the reflecting unit 21 and the waveguide 13. The connecting unit 22 is connected to the base end (specifically, the rear end) of the waveguide 13.

[0026] The waveguide 13 transmits the ultrasonic waves focused by the ultrasonic focusing unit 12. The waveguide 13 has a columnar (e.g., cylindrical) shape extending forward from the front end of the connection unit 22. The waveguide 13 extends along the axis C. In this embodiment, the waveguide 13 is parallel to the axis C, but it does not have to be parallel. For example, the waveguide 13 may be slightly inclined with respect to the axis C, or may be bent midway.

[0027] The waveguide 13 may be a separate member from the ultrasonic focusing unit 12, or may be the same member as the ultrasonic focusing unit 12. The waveguide 13 is preferably formed from a material with high ultrasonic propagation properties, such as an aluminum alloy or metallic glass. The waveguide 13 may also be formed from a shape memory alloy, such as an alloy of titanium and nickel. The waveguide 13 is elastically deformable.

[0028] As shown in FIG. 3 , the ultrasonic wave source 11 generates longitudinal ultrasonic waves. These longitudinal waves are incident on the reflecting surface 23. When the longitudinal waves generated by the ultrasonic wave source 11 are reflected by the reflecting surface 23, longitudinal waves and shear waves are generated. FIG. 3 shows the path of the shear waves generated by the reflecting surface 23. The reflection angle of the longitudinal waves generated by the reflecting surface 23 is the same as the incident angle of the longitudinal waves incident on the reflecting surface 23. The reflection angle θ2 of the shear waves generated by the reflecting surface 23 is smaller than the incident angle θ1 of the longitudinal waves incident on the reflecting surface 23. This relationship follows Snell's law. In other words, because the propagation velocity of shear waves is smaller than the propagation velocity of longitudinal waves, the reflection angle of the shear waves generated by the reflecting surface 23 is smaller than the incident angle of the longitudinal waves incident on the reflecting surface 23.

[0029] 4, the energy conversion rate from longitudinal waves to shear waves at the reflecting surface 23 varies depending on the Poisson's ratio of the material constituting the reflecting surface 23 and the angle of incidence of the longitudinal waves. The reflecting surface 23 includes reflection points where the energy conversion rate from longitudinal waves to shear waves is 50% or more. For example, at reflection points (e.g., reflection points 25A and 25B) where the Poisson's ratio of the material constituting the reflecting surface 23 is 0.17 or more and 0.34 or less and the angle of incidence of the longitudinal waves is 40° or more and 85° or less, the energy conversion rate from longitudinal waves to shear waves is generally 50% or more.

[0030] The reflecting surface 23 reflects the ultrasonic waves generated by the ultrasonic wave generating source 11 so as to be focused toward the connection portion 22 (specifically, the focal point F located at the connection portion 22). The reflecting surface 23 is curved so that the transverse waves generated at the reflecting surface 23 are focused at the connection portion 22 (specifically, the focal point F). For example, the reflecting surface 23 has a shape along an ellipse, and the ratio of the major axis to the minor axis of the ellipse satisfies the condition of the following formula (1). Major axis: minor axis = CDA: √(CDA ２ -CTA ２ ) ...Equation (1) where CDA is the propagation velocity of the longitudinal wave incident on the reflecting surface 23. CTA is the propagation velocity of the transverse wave generated at the reflecting surface 23. With this configuration, the transverse wave generated at the reflecting surface 23 is focused at the focal point F.

[0031] In this way, the ultrasonic source 11 generates longitudinal ultrasonic waves. The ultrasonic generator 10 is configured so that when longitudinal ultrasonic waves generated from the ultrasonic source 11 are reflected by the reflecting surface 23, they are converted into shear waves and focused toward the connection portion 22 (specifically, the focal point F). With this configuration, when longitudinal ultrasonic waves generated from the ultrasonic source 11 are reflected by the reflecting surface 23, they are converted into shear waves and focused toward the connection portion 22 (specifically, the focal point F). A portion of the shear waves focused at the connection portion 22 are transmitted in the direction of the waveguide 13 as longitudinal waves, and these longitudinal waves are propagated to the waveguide 13. In other words, the ultrasonic generator 10 can introduce longitudinal ultrasonic waves into the waveguide 13 by utilizing the shear waves generated at the reflecting surface 23.

[0032] 3, the ultrasonic wave generating source 11 further includes a one-side generating unit 11A disposed on one side of the waveguide 13 in a first direction, and a other-side generating unit 11B disposed on the other side of the waveguide 13. The first direction is a direction perpendicular to the direction in which the ultrasonic wave generating source 11 generates ultrasonic waves. In this embodiment, the one-side generating unit 11A and the other-side generating unit 11B are formed of the same member, but may be formed of different members.

[0033] The reflecting surface 23 has a one-side reflecting surface 23A arranged on one side of the waveguide 13 in the first direction, and a other-side reflecting surface 23B arranged on the other side of the waveguide 13. The reflecting portion 21 has a one-side reflecting portion 21A including the one-side reflecting surface 23A, and a other-side reflecting portion 21B including the other-side reflecting surface 23B. The connecting portion 22 is arranged between the one-side reflecting portion 21A and the other-side reflecting portion 21B, and connects the one-side reflecting portion 21A and the other-side reflecting portion 21B.

[0034] The length L1 of the connecting portion 22 in the front-rear direction is shorter than the length L2 of the one-side reflecting surface 23A in the front-rear direction and shorter than the length L3 of the other-side reflecting surface 23B in the front-rear direction.

[0035] The waveguide 13 has a shape extending from the connection portion 22 in a direction perpendicular to the arrangement direction of the one-side reflecting portion 21A and the other-side reflecting portion 21B. The direction perpendicular to the arrangement direction of the one-side reflecting portion 21A and the other-side reflecting portion 21B is, specifically, a direction perpendicular to the first direction, i.e., the front-to-rear direction. The waveguide 13 is disposed between the one-side reflecting portion 21A and the other-side reflecting portion 21B. The waveguide 13 is disposed with a gap between the one-side reflecting portion 21A and the other-side reflecting portion 21B. The waveguide 13 has a shape extending forward beyond the front ends of the one-side reflecting portion 21A and the other-side reflecting portion 21B.

[0036] The one-side generating unit 11A generates longitudinal ultrasonic waves. These longitudinal waves are incident on the one-side reflecting surface 23A. When the longitudinal waves generated by the one-side generating unit 11A are reflected by the one-side reflecting surface 23A, longitudinal waves and transverse waves are generated. The one-side reflecting surface 23A is curved so that the transverse waves generated by the one-side reflecting surface 23A are focused on the connecting portion 22 (specifically, the focal point F).

[0037] The other-side generating unit 11B generates longitudinal ultrasonic waves. These longitudinal waves are incident on the other-side reflecting surface 23B. When the longitudinal waves generated by the other-side generating unit 11B are reflected by the other-side reflecting surface 23B, longitudinal waves and transverse waves are generated. The other-side reflecting surface 23B is curved so that the transverse waves generated by the other-side reflecting surface 23B are focused on the connecting portion 22 (specifically, the focal point F).

[0038] In this way, the ultrasonic generator 10 is configured so that longitudinal ultrasonic waves generated from the one-side generating unit 11A are converted into shear waves when reflected by the one-side reflecting surface 23A and are focused toward the connecting portion 22, and so that longitudinal ultrasonic waves generated from the other-side generating unit 11B are converted into shear waves when reflected by the other-side reflecting surface 23B and are focused toward the connecting portion 22. With this configuration, by focusing the shear waves generated on both sides in the first direction toward the connecting portion 22, longitudinal ultrasonic waves can be more efficiently introduced into the waveguide 13. Furthermore, the shear ultrasonic waves heading toward the connecting portion 22 from both sides in the first direction collide with each other and are converted into longitudinal ultrasonic waves heading in the direction along the axis C. The longitudinal ultrasonic waves converted in this way are introduced into the waveguide 13 and transmitted by the waveguide 13.

[0039] 5 and 6, the ultrasonic generator 10 is configured so that at least a portion of the ultrasonic waves converted into shear waves by the one-side reflecting surface 23A passes through the connecting portion 22, is reflected as shear waves by the other-side generating unit 11B and the other-side reflecting surface 23B, and is directed back toward the connecting portion 22. Similarly, the ultrasonic generator 10 is configured so that at least a portion of the ultrasonic waves converted into shear waves by the other-side reflecting surface 23B passes through the connecting portion 22, is reflected as shear waves by the one-side generating unit 11A and the one-side reflecting surface 23A, and is directed back toward the connecting portion 22. For example, the one-side reflecting surface 23A and the other-side reflecting surface 23B have a shape that follows the same ellipse in a cross section cut along the direction in which the ultrasonic source 11 generates ultrasonic waves and the first direction. The ratio of the major axis to the minor axis of the ellipse satisfies, for example, the condition of the above-mentioned formula (1).

[0040] According to this configuration, the shear waves that have once passed through the connection portion 22 are directed back toward the connection portion 22. A portion of the shear waves that are directed back toward the connection portion 22 are transmitted as longitudinal waves in the direction of the waveguide 13, and these longitudinal waves are propagated to the waveguide 13. In other words, the ultrasonic generator 10 can efficiently introduce longitudinal ultrasonic waves into the waveguide 13 by propagating the shear waves that have once passed through the connection portion 22 back to the connection portion 22. Furthermore, with a simple configuration in which the one-side reflecting surface 23A and the other-side reflecting surface 23B have shapes that follow the same ellipse, a configuration can be realized in which the shear waves that have once passed through the connection portion 22 are propagated back to the connection portion 22.

[0041] The shear ultrasonic waves reflected by the one-side generating unit 11A and the one-side reflecting surface 23A and directed again toward the connecting portion 22 pass through the connecting portion 22, are reflected by the other-side generating unit 11B and the other-side reflecting surface 23B, and are directed again toward the connecting portion 22. In other words, the shear ultrasonic waves are alternately reflected by the one-side reflecting unit 21A and the other-side reflecting unit 21B, and repeatedly pass through the connecting portion 22. Each time the shear ultrasonic waves pass through the connecting portion 22, a portion of the shear waves is transmitted in the direction of the waveguide 13 as longitudinal waves, and these longitudinal waves are propagated to the waveguide 13. In this way, the ultrasonic generator 10 repeatedly focuses the shear ultrasonic waves on the connecting portion 22 to generate longitudinal ultrasonic waves, and is therefore suitable for continuous driving in which the ultrasonic generating source 11 is continuously driven.

[0042] 2. Second Embodiment In the first embodiment, an example in which the ultrasonic generator is axially symmetrical has been described, whereas in the second embodiment, an example in which the ultrasonic generator is plane symmetrical will be described.

[0043] As shown in Fig. 7, an ultrasonic generator 210 of the second embodiment includes an ultrasonic wave generating source 211, an ultrasonic wave focusing unit 212, and a waveguide 213. The cross-sectional views of the ultrasonic wave generating source 211, the ultrasonic wave focusing unit 212, and the waveguide 213 are the same as the cross-sectional view shown in Fig. 1. The ultrasonic wave generating source 211, the ultrasonic wave focusing unit 212, and the waveguide 213 have shapes obtained by extending the cross-sectional shape shown in Fig. 1 in a second direction perpendicular to the cross section shown in Fig. 1. In other words, the ultrasonic wave generating source 211, the ultrasonic wave focusing unit 212, and the waveguide 213 have shapes extending in the second direction.

[0044] The ultrasonic generator 210 can introduce ultrasonic waves into the waveguide 213 over a wide range in the second direction by using transverse waves generated on the reflecting surface 223 of the ultrasonic focusing section 212 .

[0045] <Other Embodiments> The present invention is not limited to the embodiments described above and illustrated in the drawings, and the following embodiments are also included within the technical scope of the present invention. Furthermore, various features of the above-mentioned embodiments and the embodiments to be described later may be combined in any manner as long as they are not contradictory.

[0046] (1) In the second embodiment, the ultrasonic generating source, the ultrasonic focusing unit, and the waveguide are configured to be continuously arranged in the second direction. In contrast, the ultrasonic generating source may be composed of a plurality of members and be arranged intermittently in the second direction. The ultrasonic focusing unit may be composed of a plurality of members and be arranged intermittently in the second direction. The waveguide may be composed of a plurality of members and be arranged intermittently in the second direction.

[0047] (2) The ultrasonic wave generators of the above embodiments can also be used as receivers that receive reflected waves that are incident on the tip of the waveguide.

[0048] (3) In each of the above embodiments, the ultrasonic wave generating source, the first reflecting surface, and the second reflecting surface are configured to be provided on both sides of the first direction, but they may also be configured to be provided on only one side of the first direction.

[0049] (4) In each of the above embodiments, a configuration is described in which a longitudinal wave propagates through the waveguide. However, a configuration in which a portion of the wave propagating through the waveguide propagates as a transverse wave may also be used, or the main component of the wave propagating through the waveguide may be a transverse wave component.

[0050] It should be noted that the embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is not limited to the embodiments disclosed herein, and is intended to include all modifications within the scope indicated by the claims or within the scope equivalent to the claims.

[0051] DESCRIPTION OF SYMBOLS 10...ultrasonic wave generator 11...ultrasonic wave generating source 11A...one-side generating section 11B...other-side generating section 12...ultrasonic wave focusing section 13...waveguide 21...reflecting section 21A...one-side reflecting section 21B...other-side reflecting section 22...connecting section 23...reflecting surface 23A...one-side reflecting surface 23B...other-side reflecting surface 25A...reflecting point 25B...reflecting point 210...ultrasonic wave generator 211...ultrasonic wave generating source 212...ultrasonic wave focusing section 213...waveguide 223...reflecting surface θ1...angle of incidence of longitudinal wave incident on reflecting surface θ2...reflection angle of transverse wave generated at reflecting surface C...axis F...focus P...power supply

Claims

1. An ultrasonic generator comprising: an ultrasonic source that generates ultrasonic waves; an ultrasonic focusing unit that focuses the ultrasonic waves generated from the ultrasonic source; and a waveguide that transmits the ultrasonic waves focused by the ultrasonic focusing unit, wherein the ultrasonic focusing unit has a reflecting unit including a reflecting surface that reflects the ultrasonic waves generated by the ultrasonic source; and a connecting unit that connects the reflecting unit and the waveguide, wherein the ultrasonic source generates the ultrasonic waves in the form of longitudinal waves, and the ultrasonic generator is configured such that the longitudinal ultrasonic waves generated from the ultrasonic source are converted into transverse waves when reflected by the reflecting surface and are focused toward the connecting unit.

2. The ultrasonic wave generating source has a one-side generating section arranged on one side of the waveguide and a other-side generating section arranged on the other side of the waveguide in a first direction perpendicular to the direction in which the ultrasonic wave generating source generates the ultrasonic waves, the reflecting surface has a one-side reflecting surface arranged on one side of the waveguide and a other-side reflecting surface arranged on the other side of the waveguide in the first direction, the reflecting section has a one-side reflecting section including the one-side reflecting surface and a other-side reflecting section including the other-side reflecting surface, the connecting section connects the one-side reflecting section and the other-side reflecting section, and the waveguide has a shape extending from the connecting section in a direction perpendicular to the arrangement direction of the one-side reflecting section and the other-side reflecting section, 2. The ultrasonic generator according to claim 1, wherein the ultrasonic waves generated from the one-side generating unit are converted into shear waves when reflected by the one-side reflecting surface and are focused toward the connecting portion, and the ultrasonic waves generated from the other-side generating unit are converted into shear waves when reflected by the other-side reflecting surface and are focused toward the connecting portion.

3. The ultrasonic generator according to claim 2, wherein at least a portion of the ultrasonic waves converted into transverse waves at the one-side reflecting surface passes through the connecting portion, is reflected by the other-side generating portion and the other-side reflecting surface, and is directed back toward the connecting portion, and at least a portion of the ultrasonic waves converted into transverse waves at the other-side reflecting surface passes through the connecting portion, is reflected by the one-side generating portion and the one-side reflecting surface, and is directed back toward the connecting portion.

4. The ultrasonic generator according to claim 3, wherein the one-side reflecting surface and the other-side reflecting surface have a shape that follows the same ellipse on a cross section cut along the direction in which the ultrasonic source generates the ultrasonic waves and the first direction.

5. An ultrasonic generator according to any one of claims 2 to 4, wherein the ultrasonic generating source, the ultrasonic focusing section and the waveguide are shaped to extend in a second direction perpendicular to the first direction among directions perpendicular to the direction in which the ultrasonic generating source generates the ultrasonic waves.

6. An ultrasonic generator according to any one of claims 1 to 4, wherein the focal point of the reflecting surface is located at the connection portion, and the ultrasonic generator is configured such that the ultrasonic waves of the longitudinal waves generated from the ultrasonic generation source are converted into transverse waves when reflected by the reflecting surface and directed toward the focal point.

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