JP2015047599A - Focused ultrasonic wave generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a focused ultrasonic wave generator capable of generating a strong ultrasonic wave in the air even with a simple configuration.SOLUTION: A first reflector plate 8 includes a curved reflection surface 11 which is arranged so as to be opposite to the principal surface of a diaphragm 5 and faces an inner space K formed between the diaphragm 5 and itself, and reflects ultrasonic waves P in a direction from the principal surface of the diaphragm 5 to the curved reflection surface 11 toward a focusing position F of the ultrasonic waves P linearly focused from the curved reflection surface 11. A second reflector plate 9 includes a flat reflection surface 12 which is arranged so as to partition the inner space K between the principal surface of the diaphragm 5 and the curved reflection surface 11 and faces the inner space K, and reflects the ultrasonic waves P from the principal surface of the diaphragm 5 to the flat reflection surface 12 toward the inner space K from the flat reflection surface 12.

Description

  The present invention relates to a focused ultrasonic generator that focuses ultrasonic waves in a linear shape.

  Generally, when ultrasonic waves are generated in the air (in the air), it is difficult to generate strong ultrasonic waves in the air because energy efficiency is extremely low. Therefore, in order to generate powerful ultrasonic waves in the air, a technique for focusing the ultrasonic waves radiated in the air to a specific range by some method is required.

  As such a technique, a line focusing type ultrasonic generator using a rectangular flexible diaphragm excited in a striped mode has been developed (see, for example, Patent Documents 1 to 3). In this focused ultrasonic generator, since the ultrasonic wave radiated from the diaphragm to the space is reflected by the reflector and converged linearly, it is possible to generate strong ultrasonic waves in the air.

Japanese Patent Laid-Open No. 9-327656 Japanese Patent Laid-Open No. 11-90330 JP 2009-69027 A

  However, the conventional focused ultrasonic generator has a practical problem such that the structure is complicated and the manufacturing cost is high and the maintenance is difficult.

  One aspect of the present invention has been proposed in view of such conventional circumstances, and provides a focused ultrasonic generator that can generate powerful ultrasonic waves in the air while having a simple structure. One of the purposes is to do.

In order to achieve the above object, the present invention provides the following means.
(1) A focused ultrasonic generator according to an aspect of the present invention includes a vibrator and a diaphragm, and ultrasonic waves generated when the vibrator vibrates the diaphragm from the diaphragm to the space. The ultrasonic wave radiating part, the first reflecting plate, and the second reflecting plate are reflected by the first reflecting plate and the second reflecting plate. And an ultrasonic wave reflecting portion for focusing in a linear shape. The first reflecting plate is disposed to face the main surface of the diaphragm and has a curved reflecting surface facing an inner space formed between the first and second diaphragms. The ultrasonic wave in the direction from the surface toward the curved reflecting surface is reflected toward the focusing position of the ultrasonic wave focused in the linear shape from the curved reflecting surface. The second reflecting plate is disposed so as to partition the inner space between a main surface of the diaphragm and the curved reflecting surface, and has a plane reflecting surface facing the inner space, and the vibration Ultrasonic waves in a direction from the main surface of the plate toward the planar reflecting surface are reflected from the planar reflecting surface toward the inner space.

(2) In the focused ultrasonic generator according to (1), the vibrator excites the diaphragm in a striped mode, and the vibrator is adapted to a position of an antinode of a flexural vibration generated in the diaphragm. The structure by which the 2nd reflecting plate is arrange | positioned may be sufficient.

(3) In the focused ultrasonic wave generating device according to (1) or (2), the curved reflection surface has a convex reflection surface and a concave reflection surface in accordance with a position of a flexural vibration node generated on the diaphragm. And a phase of an ultrasonic wave reflected from the convex reflecting surface toward the focusing position, and reflected from the concave reflecting surface toward the focusing position. The distance from the main surface of the diaphragm to the convex reflecting surface and the distance from the main surface of the diaphragm to the concave reflecting surface are set so that the phases of the ultrasonic waves are in phase with each other It may be a configuration.

(4) In the focused ultrasonic wave generating apparatus according to any one of (1) to (3), the ultrasonic wave reflection unit may be configured to focus the ultrasonic wave in a curved shape.

(5) In the focused ultrasonic generator according to any one of (1) to (4), the first reflector is configured on both sides of the diaphragm. Also good.

(6) In the focused ultrasonic generator according to any one of (1) to (5), the second reflector is configured to be disposed on both sides of the inner space. Also good.

(7) In the focused ultrasonic wave generating apparatus according to any one of (1) to (6), the ultrasonic wave reflection unit includes a third reflection plate disposed outside the inner space, The third reflecting plate may be configured to reflect the ultrasonic wave reflected by the curved reflecting surface toward a focusing position different from the focusing position.

  As described above, according to one embodiment of the present invention, it is possible to provide a focused ultrasound generator that can generate powerful ultrasound in the air while having a simple structure.

It is a perspective view which shows an example of the focused ultrasound generator which concerns on embodiment of this invention. It is a perspective view which shows the structure of the ultrasonic generation part with which a focused ultrasonic generator is provided. It is a schematic diagram for demonstrating the diaphragm excited by the striped mode. It is sectional drawing which shows the structure of the ultrasonic reflection part with which a focused ultrasound generator is provided. It is a schematic diagram for demonstrating the reflection path | route of an ultrasonic wave. It is a graph which shows the sound pressure distribution of the ultrasonic wave which a focused ultrasonic generator emits. It is a schematic diagram for demonstrating the converging position focused on the curve shape of the ultrasonic wave. It is a perspective view which shows the modification of a focused ultrasound generator.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
In addition, this invention is not limited to the following embodiment, In the range which does not change the summary, it can change suitably and can implement. Moreover, in the following description, in order to make each component easy to see, the dimensional scale may be changed depending on the component in the drawings.

[Focusing ultrasonic generator]
First, for example, a focused ultrasonic generator 1 shown in FIG. 1 will be described as an embodiment of the present invention.
FIG. 1 is a perspective view showing the external appearance of the focused ultrasonic wave generating apparatus 1. Further, the x axis shown in FIG. 1 indicates the width direction of the focused ultrasound generator 1, the y axis shown in FIG. 1 indicates the depth direction of the focused ultrasound generator 1, and z shown in FIG. The axis indicates the height direction of the focused ultrasound generator 1.

  As shown in FIG. 1, the focused ultrasound generator 1 includes an ultrasound generator 2 that generates the ultrasound P, and an ultrasound that reflects the ultrasound P and focuses it to a linear focusing position (focusing line) F. And a sound wave reflection unit 3.

  Ultrasound generally refers to high-frequency sound that cannot be heard by humans, but may also refer to sound waves that are not intended to be heard even in the human audible range (about 20 Hz to 20 kHz). .

(Ultrasonic generator)
Next, the configuration of the ultrasonic generator 2 will be described with reference to FIGS. 1 and 2.
FIG. 2 is a perspective view showing the configuration of the ultrasonic wave generator 2.

  As shown in FIGS. 1 and 2, the ultrasonic generator 2 includes a vibrator 4 and a diaphragm 5. In the ultrasonic wave generation unit 2, the ultrasonic wave P generated when the vibrator 4 vibrates the vibration plate 5 is radiated from the vibration plate 5 to the space.

  Specifically, the vibrator 4 is composed of an electromechanical conversion element such as a piezoelectric element, a magnetostrictive element, or an electrostrictive element. Among these, as the vibrator 4 that generates the powerful ultrasonic wave P, a bolt-clamped Langevin type transducer (BLT) can be suitably used. The vibrator 4 is driven by electric power supplied from a power supply circuit (power supply) (not shown).

  The vibrator 4 is connected to the diaphragm 5 via an exponential horn 6 and a vibration transmission rod 7. The exponential horn 6 is attached to the vibrator 4 and amplifies the vibration by the vibrator 4 (increases the amplitude). The vibration transmission rod 7 connects the exponential horn 6 and the diaphragm 5, and transmits the vibration amplified by the exponential horn 6 to the diaphragm 5. The distance from the vibrator 4 to the diaphragm 5 is set to be an integral multiple of ½ wavelength (λ / 2) in order to excite the diaphragm 5 in a striped mode described later.

  The vibration plate 5 is a rectangular flat plate (band-like) flexible vibration plate, and is attached perpendicularly to the vibration transmission rod 7 by attaching the tip of the vibration transmission rod 7 to the central portion in the plane. The material of the diaphragm 5 is not particularly limited as long as it vibrates in a striped mode, which will be described later. For example, a metal plate such as titanium or duralumin can be used.

(Principle of ultrasonic generation)
In the ultrasonic generator 2, as shown in FIGS. 3A to 3C, the diaphragm 5 is excited in a striped mode.

  3A to 3C are schematic diagrams for explaining the diaphragm 5 excited in a striped mode, and FIG. 3A is a diagram when the diaphragm 5 is resonated. FIG. 3B shows a state in one phase (referred to as a plus (+) phase), and FIG. 3B shows a phase opposite to that in FIG. 3A when the diaphragm 5 is resonated (minus (−)). 3 (c) shows the states at the (+) and (−) phases when the diaphragm 5 is resonated.

  In the ultrasonic generator 2, when the diaphragm 5 is excited (resonated) in a striped mode, striped flexural vibrations are generated on both sides of the diaphragm 5 across the vibration transmission rod 7. That is, the striped mode is a mode in which the nodes of flexural vibration generated in the diaphragm 5 are arranged in a striped manner in the width direction of the diaphragm 5. In this striped mode, the distance d between the nodes is ½ of the wavelength λp of the flexural vibration, and the flexural vibrations having antiphases (+) and (−) are generated between the nodes. Thereby, in the ultrasonic wave generation part 2, the ultrasonic wave P can be efficiently radiated from the diaphragm 5 to the space.

  Here, the ultrasonic wave P radiated to the upper and lower spaces sandwiching the diaphragm 5 propagates in the direction of a predetermined angle θ symmetrically with respect to the center normal (z axis) of the diaphragm 5. The angle θ is an angle formed with respect to the z axis of the ultrasonic wave P. In FIG. 3C, the upward direction of the z axis is the + z direction, the downward direction of the z axis is the −z direction, the clockwise direction with respect to the z axis of the angle θ is the + θ direction, and the counterclockwise direction with respect to the z axis of the angle θ is This is expressed as the -θ direction.

  The ultrasonic waves P radiated to the upper and lower spaces across the diaphragm 5 interfere with each other while the ultrasonic waves P in the + θ direction and the ultrasonic waves P in the −θ direction emitted from between the nodes overlap each other. Thus, a sound field that propagates in the z-axis direction as a whole is formed. Therefore, it can be considered that the ultrasonic wave P is emitted in the vertical direction (z-axis direction) from both sides of the diaphragm 5. However, the wavelength λz of the ultrasonic wave P propagating in the z-axis direction is λz = λa / cos θ, which is different from the original wavelength Pa of the ultrasonic wave P determined from the sound wave propagation speed and frequency.

(Ultrasonic reflector)
Next, the configuration of the ultrasonic reflection unit 3 will be described with reference to FIGS. 1 and 4.
FIG. 4 is a cross-sectional view showing the configuration of the ultrasonic reflection unit 3.

  As shown in FIGS. 1 and 4, the ultrasonic reflection unit 3 includes a first reflection plate 8 and a second reflection plate 9. In the ultrasonic reflection unit 3, the ultrasonic wave P radiated from the diaphragm 5 is reflected by the first reflection plate 8 and the second reflection plate 9 and converged linearly toward the convergence position F.

  Specifically, two first reflecting plates 8 are disposed on both upper and lower sides (z-axis direction) across the diaphragm 5 so as to face the main surface of the diaphragm 5. The second reflecting plate 9 is formed between the vibrating plate 5 and the first reflecting plate 8 on both the left and right sides (x-axis direction) sandwiching the vibrating plate 5 and the upper and lower first reflecting plates 8. Four inner spaces K are arranged so as to partition.

  The material of the first reflecting plate 8 and the second reflecting plate 9 is not particularly limited as long as it reflects the ultrasonic wave P. For example, a resin plate such as an acrylic resin can be used. .

  In the ultrasonic reflector 3, a radiation port 3 a in which one surface in the depth direction (y direction) of the inner space K surrounded by the diaphragm 5, the first reflector 8, and the second reflector 9 is opened. Is provided. The ultrasonic wave P is radiated to the outside of the inner space K from the radiation port 3a.

  The ultrasonic reflection unit 3 has a function as a radiation direction converter that converts the radiation direction of the ultrasonic wave P radiated from the diaphragm 5. Then, the ultrasonic wave P whose radiation direction has been converted by the radiation direction converter (ultrasonic reflector 3) forms a linearly focused sound field at the focusing position F.

  Here, the ultrasonic reflector 3 has a configuration in which the first reflector 8 and the second reflector 9 are arranged symmetrically with the diaphragm 5 interposed therebetween. On the other hand, the first reflector 8 disposed below the diaphragm 5 is provided with a through-hole 10 through which the vibration transmission rod 7 penetrates. Other configurations of the first reflecting plate 8 and the second reflecting plate 9 are the same on both the upper and lower sides with the diaphragm 5 interposed therebetween. Therefore, in the following description, the first reflecting plate 8 and the second reflecting plate 9 disposed above the diaphragm 5 will be described as an example.

  The first reflector 8 has substantially the same width as the diaphragm 5, and the end edge on the side opposite to the radiation port 3 a (base end side) is close to the diaphragm 5 (non-contact state). And the edge on the radiation port 3a (tip end) side is arranged in a state of being separated from the diaphragm 5.

  A curved reflecting surface 11 is provided on the surface (inner surface) facing the inner space K of the first reflecting plate 8. The curved reflecting surface 11 includes a convex reflecting surface 11a and a concave reflecting surface 11b. The convex reflection surface 11 a and the concave reflection surface 11 b are alternately arranged in accordance with the position of the flexural vibration node generated in the diaphragm 5. Further, the convex reflection surface 11a and the concave reflection surface 11b are formed so as to draw a parabola from the respective base end portions toward the tip end portions in the cross section along the y-axis direction.

  In the curved reflecting surface 11, the phase of the ultrasonic wave reflected from the convex reflecting surface 11a toward the converging position F and the phase of the ultrasonic wave reflected from the concave reflecting surface 11b toward the converging position F are the same. A distance y1 from the main surface of the diaphragm 5 to the convex reflecting surface 11a and a distance y2 from the main surface of the diaphragm 5 to the concave reflecting surface 11b are set so as to be in phase.

  That is, as described above, the vibration plate 5 generates flexural vibrations having opposite phases (+) and (−) between the nodes. For this reason, the phase of the ultrasonic wave P1 (indicated by a broken line in FIG. 4) from the diaphragm 5 toward the convex reflecting surface 11a and the ultrasonic wave P2 (indicated by the solid line in FIG. 4) from the vibrating plate 5 toward the concave reflecting surface 11b. The phases of these are opposite to each other.

  Therefore, in order for the ultrasonic wave P1 reflected by the convex reflecting surface 11a and the ultrasonic wave P2 reflected by the concave reflecting surface 11b to enter the converging position F in the same phase, the convex reflecting surface 11a and the concave shape It is desirable to provide a step h (= y2-y1) between the reflecting surface 11b.

(Ultrasonic reflection principle)
Here, the reflection paths of the ultrasonic waves P1 and P2 reflected by the first reflecting plate 8 will be described with reference to FIG.
FIG. 5 is a schematic diagram for explaining the reflection paths of the ultrasonic waves P1 and P2. In FIG. 5, the reflection path of the ultrasonic wave P1 is indicated by a broken line, and the reflection path of the ultrasonic wave P2 is indicated by a solid line.

  As shown in FIG. 5, in the ultrasonic reflection unit 3, the first reflection plate 8 causes the first reflection plate 8 to move in the direction from the main surface of the vibration plate 5 to the curved reflection surface 11 (the convex reflection surface 11 a and the concave reflection surface 11 b). The sound waves P1 and P2 can be reflected (focused) from the curved reflecting surface 11 toward the focusing position F, respectively. Further, a step h corresponding to ¼ of the wavelength λz is provided on the z-axis between the convex reflecting surface 11a and the concave reflecting surface 11b. At this time, a difference corresponding to ½ of the wavelength λz is generated between the ultrasonic wave P1 and the ultrasonic wave P2 in the propagation path length from the diaphragm 5 to the focusing position F. Thereby, the ultrasonic wave P1 reflected by the convex reflecting surface 11a and the ultrasonic wave P2 reflected by the concave reflecting surface 11b can be incident on the focusing position F in the same phase relationship.

  As shown in FIGS. 1 and 4, the second reflecting plate 9 is disposed so as to cover both the left and right sides of the diaphragm 5 and the first reflecting plate 8 with the inner space K interposed therebetween. The second reflecting plate 9 is arranged in a state where the end edge along the vibrating plate 5 is close to the vibrating plate 5 (non-contact state), and further along the first reflecting plate 8. The end edge portion is disposed in contact with the first reflecting plate 8.

  That is, in the ultrasonic reflection unit 3, the first reflection plate 8 and the second reflection plate 9 are arranged so that the flexural vibration from the vibration plate 5 is not transmitted to the first reflection plate 8 and the second reflection plate 9. The diaphragm 5 is disposed in a non-contact state. On the other hand, in the ultrasonic reflection part 3, the 1st reflecting plate 8 and the 2nd reflecting plate 9 can be formed integrally. Note that the ultrasonic generator 2 and the ultrasonic reflector 3 are fixed to a frame or the like (not shown) so that their positional relationship is maintained.

  The second reflecting plate 9 is arranged according to the position of the antinode of the flexural vibration generated in the diaphragm 5. That is, the second reflecting plate 9 is provided so as to extend in a direction perpendicular to the main surface of the diaphragm 5 from the central position of the antinode of the flexural vibration generated in the diaphragm 5.

  Further, a plane reflecting surface 12 is provided on the surface (inner surface) facing the inner space K of the second reflecting plate 9. The planar reflecting surface 12 is a surface perpendicular to the main surface of the diaphragm 5 and the curved reflecting surface 11 of the second reflecting plate 9.

  By the way, the ultrasonic wave P radiated from the main surface of the diaphragm 5 described above has a predetermined angle θ symmetrically with respect to the center normal (z axis) of the diaphragm 5 as shown in FIG. Propagate in the direction of. Therefore, the ultrasonic wave P is caused by the + θ direction ultrasonic wave P and the −θ direction ultrasonic wave P radiated from between the nodes and interfering with each other while overlapping each other. Direction), a sound field having a non-uniform sound pressure distribution is formed.

  In a conventional focused ultrasonic generator, in order to make the sound pressure distribution of such an ultrasonic wave uniform in the width direction of the diaphragm, a plurality of partition plates are provided in accordance with the positions of the flexural vibration nodes generated on the diaphragm. It is the structure arrange | positioned between each clause (refer the said patent documents 1-3). In this configuration, the sound pressure distribution of the ultrasonic waves is made uniform in the width direction of the diaphragm by reflecting the ultrasonic waves radiated from between the nodes between the partition plates. However, in this configuration, since the structure is complicated, the manufacturing cost is high and maintenance is difficult.

  On the other hand, in the focused ultrasonic wave generating apparatus 1 of the present embodiment, as shown in FIG. 4, the second reflection plate 9 causes ultrasonic waves in an oblique direction from the main surface of the diaphragm 5 to the plane reflection surface 12. P3 is reflected from the plane reflecting surface 12 toward the inner space K. In the case of this configuration, the ultrasonic wave P3 reflected by the plane reflecting surface 12 and the ultrasonic wave P3 directed toward the plane reflecting surface 12 interfere with each other while overlapping with each other, so that the ultrasonic wave radiated from the main surface of the diaphragm 5 is obtained. It is possible to make the sound pressure distribution of P uniform in the width direction of the diaphragm 5.

Here, FIG. 6 shows the result of measuring the sound pressure distribution in the xz plane of the ultrasonic wave P emitted from the focused ultrasonic wave generating apparatus 1 of the present embodiment.
In this measurement, the driving frequency of the vibrator 4 was set to 50.8 kHz, and a rectangular plate made of duralumin having a dimension of 86.5 × 167.5 × 2 (unit: mm) was used as the diaphragm 5. In this case, the number of nodes of the flexural vibration generated in the diaphragm 5 was 18, and the distance d between the nodes was 9.57 mm.

  As shown in FIG. 6, the ultrasonic waves P1 and P2 having opposite phases are radiated from the diaphragm 5 in accordance with the position of the flexural vibration generated in the diaphragm 5, but the focusing of this embodiment is performed. In the ultrasonic generator 1, the second reflector 9 is arranged in accordance with the position of the antinode of the flexural vibration generated in the diaphragm 5, thereby making the sound pressure distribution of the adjacent ultrasonic waves P <b> 1 and P <b> 2 uniform. Is possible.

  Therefore, in the focused ultrasonic generator 1 of the present embodiment, the ultrasonic waves P1 and P2 having such a uniform sound pressure distribution are reflected by the first reflecting plate 8 and are linearly focused at the focus position F. By this, it is possible to generate a powerful ultrasonic wave P in the air.

  Moreover, in the focused ultrasonic generator 1 of this embodiment, the structure can be simplified by eliminating the need for a plurality of partition plates arranged between the nodes of the striped mode as in the prior art. Maintenance is also easy.

  In the measurement of the sound pressure distribution in the xz plane of the ultrasonic wave P described above, the sound pressure value near the both ends of the inner space K as the second reflector 9 is shifted in the width direction from the center position of the antinode of the flexural vibration. There was a phenomenon that gradually decreased. At the same time, the sound pressure value increased at other positions in the inner space K. Therefore, the second reflector 9 is most preferably arranged in accordance with the center position of the antinode of the flexural vibration in order to make the sound pressure distribution of the ultrasonic wave P uniform in the width direction of the diaphragm 5.

  In addition, this invention is not necessarily limited to the thing of the said embodiment, A various change can be added in the range which does not deviate from the meaning of this invention.

  For example, in the present embodiment, as shown in FIG. 7, it is possible to focus the ultrasonic wave P in a curved shape toward the focusing position F ′. FIG. 7 is a schematic diagram showing a converging position F ′ converged in a curved shape of the ultrasonic wave P. FIG. 7 also shows a linear focusing position F as a reference.

  When the ultrasonic wave P is focused in a curved shape, the convex reflection is performed while changing the shapes of the convex reflection surface 11a and the concave reflection surface 11b constituting the curved reflection surface 11 in the width direction of the first reflection plate 8. The converging position F1 where the ultrasonic wave P1 reflected by the surface 11a is focused and the converging position F2 where the ultrasonic wave P2 reflected by the concave reflecting surface 11b is converged are gradually shifted. Thereby, the ultrasonic wave P as a whole can be focused on the curved focusing position F ′.

  Moreover, in this embodiment, as shown in FIG. 8, a change can be added to the structure of the said focused ultrasound generator 1. FIG. FIG. 8 is a perspective view showing a modified example of the focused ultrasound generator 1 shown in FIG.

  The focused ultrasonic generator 1 shown in FIG. 8 has a configuration in which the ultrasonic reflector 3 includes a third reflector 13 in addition to the first reflector 8 and the second reflector 9. The third reflector 13 is disposed outside the inner space K, and reflects the ultrasonic wave P emitted from the radiation port 3a toward a convergence position F ″ different from the convergence position F.

  In the focused ultrasonic generator 1, the focus position F ″ at which the ultrasonic wave P is focused can be changed by arranging the third reflecting plate 13 as described above. The third reflecting plate 13 may be formed integrally with the first reflecting plate 8 or may be formed separately from the first reflecting plate 8.

  In the present embodiment, although not shown, a plurality of vibrators 4 may be connected to one diaphragm 5 via an exponential horn 6 and a vibration transmission rod 7. . Also in this case, the second reflecting plate 9 may be arranged in accordance with the position of the antinode of the flexural vibration generated in the diaphragm 5.

  Moreover, in this embodiment, it is also possible to set it as the structure which arranged the some ultrasonic generation part 2 side by side. In this case, a configuration in which a plurality of ultrasonic reflection units 3 are arranged for each of the plurality of ultrasonic generation units 2 or a configuration in which a plurality of ultrasonic reflection units 3 are integrated with the plurality of ultrasonic generation units 2 is arranged. It is possible to have a configuration as described above. Furthermore, in this embodiment, it is also possible to adopt a configuration in which a plurality of focused ultrasound generators 1 are arranged side by side.

  As described above, the focused ultrasonic generator 1 of the present embodiment is extremely useful as a powerful line-focusing type ultrasonic sound source. In addition, the focused ultrasonic generator 1 of the present embodiment can be suitably used particularly in a case where it is incorporated in a production line, such as removal of deposits by non-contact method, defoaming, and drying.

  DESCRIPTION OF SYMBOLS 1 ... Focusing ultrasonic generator 2 ... Ultrasonic generator 3 ... Ultrasonic reflector 3a ... Radiation port 4 ... Vibrator 5 ... Diaphragm 6 ... Exponential horn 7 ... Vibration transmission rod 8 ... First reflector 9 DESCRIPTION OF SYMBOLS ... 2nd reflecting plate 10 ... Through-hole 11 ... Curved reflecting surface 11a ... Convex reflecting surface 11b ... Concave reflecting surface 12 ... Planar reflecting surface K ... Inner space F ... Focus position P ... Ultrasonic wave

Claims (7)

An ultrasonic generator that includes a vibrator and a diaphragm, and radiates ultrasonic waves generated by the vibrator vibrating the diaphragm from the diaphragm to the space;
An ultrasonic wave including a first reflecting plate and a second reflecting plate, the ultrasonic wave radiated from the vibrating plate is reflected by the first reflecting plate and the second reflecting plate and focused linearly. With a reflective part,
The first reflecting plate is disposed to face the main surface of the diaphragm and has a curved reflecting surface facing an inner space formed between the first and second diaphragms. Reflecting the ultrasonic wave in the direction from the surface toward the curved reflecting surface toward the focusing position of the ultrasonic wave that is focused linearly from the curved reflecting surface,
The second reflecting plate is disposed so as to partition the inner space between a main surface of the diaphragm and the curved reflecting surface, and has a plane reflecting surface facing the inner space, and the vibration An apparatus for generating focused ultrasonic waves, wherein ultrasonic waves in a direction from a main surface of a plate toward the planar reflecting surface are reflected from the planar reflecting surface toward the inner space.   2. The vibrator according to claim 1, wherein the vibrator excites the diaphragm in a striped mode, and the second reflector is arranged in accordance with a position of an antinode of a flexural vibration generated in the diaphragm. 2. The focused ultrasonic generator according to 1. The curved reflection surface has a configuration in which convex reflection surfaces and concave reflection surfaces are alternately arranged in accordance with the position of a flexural vibration node generated in the diaphragm,
The phase of the ultrasonic wave reflected from the convex reflecting surface toward the focusing position and the phase of the ultrasonic wave reflected from the concave reflecting surface toward the focusing position are in phase with each other. 3. The focusing according to claim 1, wherein a distance from a main surface of the diaphragm to the convex reflecting surface and a distance from the main surface of the diaphragm to the concave reflecting surface are set. Ultrasonic generator.   The focused ultrasonic wave generating apparatus according to claim 1, wherein the ultrasonic wave reflecting unit focuses the ultrasonic wave in a curved shape.   5. The focused ultrasonic wave generating apparatus according to claim 1, wherein the first reflector is disposed on both sides of the diaphragm. 6.   The focused ultrasonic generator according to claim 1, wherein the second reflecting plate is disposed on both sides of the inner space. The ultrasonic reflection unit includes a third reflection plate disposed outside the inner space,
The said 3rd reflecting plate reflects the ultrasonic wave reflected by the said curved-surface reflective surface toward the condensing position different from the said converging position, The Claim 1 characterized by the above-mentioned. Focused ultrasound generator.