JPH0760189A - Focusing ultrasonic generator - Google Patents

Abstract

PURPOSE:To realize a high-performance ultrasonic cleaner and fine processing device, etc., by providing the focusing ultrasonic generator which focuses the ultrasonic sound waves generated from a higher mode circular deflective vibration diaphragm as single peak sound waves and focused and concentrated sound waves by a small-sized and simple structure. CONSTITUTION:The sound wave radiated in the central region of the deflective vibration diaphragm 1 vibrated in a higher mode are reflected back and forth by a circular reflection plate 2 oppositely arranged at a prescribed spacing therefrom. The ultrasonic waves propagated to lateral periphery by the forward and backward reflection and the ultrasonic waves directly radiated from the deflective vibration diaphragm 1 are reflected by a cylindrical reflection plate 3; further, the sound waves reflected from the cylindrical reflection plate 3 are reflected by the peripheral surface of a circular conical reflection plate 4, by which the parallel sound wave fluxes focused in a normal Z direction are obtd. The peripheral surface of the circular conical reflection plate 4 is formed as a paraboloid of revolution. The powerful focused and concentrated sound field is obtd. by forming the inside surface of the cylindrical reflection plate 3 as the paraboloid of revolution without using the circular conical reflection plate 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a focused ultrasonic wave generator, which is applied to, for example, an ultrasonic cleaner or a microfabrication apparatus, and which can generate a small and simple ultrasonic wave generated from a high-order mode circular flexible diaphragm. The present invention relates to a device for focusing as a monomodal sound wave or a focused sound wave depending on the structure.

[0002]

2. Description of the Related Art Recently, in the fields of cleaning the surface of an object and microfabrication for various materials, methods for utilizing the strong sound field of focused ultrasonic waves have been studied and developed. And
The inventors of the present application, as related papers, include "Removal of droplets on the surface of a material by a strong sound field" (Ito, Kawamura, Acoustical Society of Japan: P597-598, March 1983) and "High-power airborne ultrasonic waves". Of water droplets on the plate surface "(Ito, Kawamura, Proceedings of the Acoustical Society of Japan: P755 ~ 756, March 1987)," Total emission ultrasonic waves from a fringe mode diaphragm was applied to both sides of the diaphragm. Report on a method of atomizing and removing water adhering to a glass plate surface with a relatively large area by using a strong sound field that is linearly focused and reflected by a focusing direction changer arranged in Is going. Further, there has been previously proposed an “ultrasonic cleaning method” utilizing the above method (Japanese Patent Application No. 5-80080).
issue).

On the other hand, the ultrasonic wave generation source is not limited to a rectangular plate like the above-mentioned striped mode diaphragm, but it is conceivable to use a higher order mode circular flexible diaphragm whose nodal circles are at substantially equal intervals. In that case, as shown in FIG. 12, when the vibration driving source 102 is attached to the center of the flexible diaphragm 101 with free periphery and high-frequency vibration is performed, the aerial ultrasonic waves 103 radiated from the flexible diaphragm 101 have a mortar-shaped pattern. , Naturally, a strong sound field cannot be formed as it is. Therefore, conventionally, as shown in FIG. 13, by providing a conical reflection plate 104 that is open in the ultrasonic wave propagation direction around the flexural vibration plate 101 and reflecting the emitted ultrasonic waves on the inner surface of the conical reflection plate 104, A method of obtaining a parallel sound flux 105 propagating in a single direction is adopted.

[0004]

By the way, in the case of aiming to obtain a strong sound field by focusing ultrasonic waves, the ultrasonic waves are focused in the inventions of the above-mentioned published papers and patent applications. , Only a focused sound field on a straight line can be obtained,
Since the fringe mode diaphragm is used, the shapes of the reflecting surfaces arranged on both sides of the diaphragm are complicated, and there is a problem that processing of the focusing direction changer is difficult. In addition, there is a disadvantage that a through hole must be formed in one reflecting surface in order to connect the vibration drive source and the striped mode diaphragm.

On the other hand, regarding the configuration in which the flexural vibration plate 101 and the conical reflection plate 104 are combined as shown in FIG. 13, the entire structure is enlarged to provide the conical reflection plate 104, and the parallel sound flux 105 is also As shown in FIG. 13, since the central region 106 corresponding to the planar shape of the flexural diaphragm 101 is a donut-shaped sound field, a strong sound field cannot be obtained despite the large structure, and local cleaning and It is inconvenient to use for fine processing.

Therefore, according to the present invention, the radiated sound waves of the high-order mode circular flexural diaphragm are efficiently focused as unimodal sound waves or focus concentrated sound waves to obtain a powerful sound field with a small size and a simple structure. It was created for the purpose of providing a focused ultrasonic generator capable of

[0007]

According to a first aspect of the present invention, in a focused ultrasonic wave generator, a high-order mode circular flexural vibration plate having a vibration driving source attached to the center thereof is used as the ultrasonic wave generation source. With the normal line passing through the center as the common central axis,
If the radiation angle of the ultrasonic wave generated from the flexible diaphragm is θ and the wavelength of the ultrasonic wave is λa, the reflection of the flexible diaphragm has a circular / planar reflecting surface with a diameter smaller than that of the flexible diaphragm. A first reflecting portion whose surface is arranged in parallel and opposed to the flexible diaphragm with a distance of [m · λa / 2cosθ] (where m is an integer), and the first reflective portion from the peripheral portion of the flexible diaphragm. A second reflecting portion having a cylindrical reflecting surface that surrounds the space on the arrangement side and a conical reflecting surface having an apex angle of θ, and the apex angle side is directed toward the ultrasonic output direction, Placed in the space where the ultrasonic waves reflected by the cylindrical reflecting surface of the section propagate
The present invention relates to a focused ultrasonic wave generator having a reflecting portion fixedly provided.

The second invention is similar to the first invention in the structure of the flexible diaphragm, the first reflecting portion and the second reflecting portion, but instead of the third reflecting portion in the first invention, The present invention relates to a focused ultrasonic wave generating device provided with a fourth reflecting portion as described above. That is, the fourth reflecting portion has a conical reflecting surface composed of a paraboloid of revolution that reflects the ultrasonic wave reflected by the second reflecting portion and focuses it on a normal point. It is arranged in a space in which the ultrasonic waves reflected by the cylindrical reflecting surface of the second reflecting section propagate with the corner side facing the ultrasonic wave output direction.

The third invention is similar to the first and second inventions with respect to the structures of the flexible diaphragm and the first reflecting portion, but the third reflecting portion and the fourth reflecting portion are not provided, and A reflecting portion corresponding to two reflecting portions, covering the space on the arrangement side of the first reflecting portion from the peripheral portion of the flexible diaphragm, and the ultrasonic wave directly incident from the flexible diaphragm and the reflecting surface of the first reflecting portion; A focused ultrasonic wave generating device as a fifth reflecting section having a rotary parabolic reflecting surface for reflecting an ultrasonic wave that is reflected back and forth on the surface of the flexible diaphragm and focused on a point on the normal line. Pertain.

[0010]

[Action]

Regarding the first invention; Of the sound waves emitted from the flexible diaphragm, the ultrasonic waves emitted from the central region of the flexible diaphragm are reciprocally reflected between the flexible diaphragm and the reflecting surface of the first reflecting portion, and then the second reflecting portion has a cylindrical shape. The ultrasonic waves that enter the reflecting surface and are radiated from the outer peripheral region of the flexible diaphragm directly enter the cylindrical reflecting surface of the second reflecting portion. In this case, the radiation angle of the sound wave emitted from the flexible diaphragm is θ,
Radiation from the flexural diaphragm because the wavelength of the radiated sound wave is λa and the distance between the flexural diaphragm and the reflecting surface of the first reflection part is given by [m · λa / 2cosθ] (where m is an integer). The sound wave and the sound wave reflected from the reflecting surface of the first reflecting portion always have the same phase relationship on the surface of the flexural diaphragm, and the sound wave energy is not attenuated by mutual interference.

Further, the incident angle of the ultrasonic wave incident on the cylindrical reflecting surface of the second reflecting portion is [(π / 2) -θ], and naturally the reflecting angle is also the same, but of the third reflecting portion. If the apex angle of the conical reflecting surface is set to θ, the ultrasonic waves reflected by the cylindrical reflecting surface of the second reflecting portion will be reflected by the conical reflecting surface of the third reflecting portion based on the geometrical relationship, The sound flux is parallel to the line. Therefore, a strong ultrasonic sound flux having a diameter corresponding to the shape of the bottom surface of the third reflecting portion is obtained, and the sound flux does not have a hollow portion.

Regarding the second invention; In this invention, the propagation path of the ultrasonic wave emitted from the flexible diaphragm and reflected by the second reflecting section is the same as that of the first invention, but the rotation of the fourth reflecting section is performed. By being reflected by the parabolic surface, it is focused on a normal point (focus point) in front of the fourth reflecting portion, and a strong sound field is formed at the same focal point.

Regarding the third invention; In this invention as well, the propagation path of the ultrasonic wave emitted from the flexible diaphragm and reflected by the second reflecting portion is the same as in the first invention. However, in this invention, the third reflecting portion and the second reflecting portion in the first invention are used.
There is no reflecting portion having a conical reflecting surface like the fourth reflecting portion in the invention described above, and instead, a space on the arrangement side of the first reflecting portion is rotated from the peripheral portion of the flexible diaphragm to a paraboloid of revolution. A fifth reflecting portion that covers the reflecting surface is provided.

The ultrasonic waves reciprocally reflected between the flexible diaphragm and the reflecting surface of the first reflecting portion and the ultrasonic waves emitted from the outer peripheral area of the flexible diaphragm are formed on the inner surface side of the fifth reflecting portion. It is reflected by the rotating parabolic reflection surface and is focused on a normal point (focus point) in front of the fifth reflecting portion,
A strong sound field is formed at the same focal point.

In each of the above inventions, the interval [m · λa / 2cosθ] between the flexible diaphragm and the reflecting surface of the first reflecting portion is a distance equal to an integer multiple of the normal component of the wavelength λa of the radiated sound wave.
Although it is equivalent to / 2, it does not have to be the exact value, and it suffices if it substantially satisfies the condition in consideration of errors due to various factors.

[0016]

Embodiments of the focused ultrasonic wave generator of the present invention will be described in detail below with reference to FIGS. 1 to 11. << Embodiment 1 >> The device of this embodiment corresponds to the invention of claim 1, and the basic structure thereof is shown in FIG. In the figure, 1 is a high-order mode circular flexural vibration plate, 2 is a circular reflection plate, 3 is a cylindrical reflection plate, 4 is a conical reflection plate, and these are normals Z passing through the center of the flexure vibration plate 1. Is arranged as a common central axis. The tip of the exponential horn 5 is attached to the center of the flexible diaphragm 1, and the flexible diaphragm is provided by mechanical vibration from the Langevin type vibrator 6 to the rear end surface of the horn 5. It is designed to vibrate 1. still,
Although the fixing mode of each element is not shown in FIG. 1, the rear end portion of the vibration source unit including the Langevin type vibrator 6 and the cylindrical reflection plate 3 are fixed to the external fixing surface, and the circular reflection plate 2
And the conical reflection plate 4 are integrally configured, and the rigid support plate (circumferential circumference) is provided between the conical surface of the conical reflection plate 3 and the inner peripheral surface of the cylindrical reflection plate 3. Fixed by a thin plate).

FIG. 2 is a cross-sectional view for explaining the above-mentioned structure and the propagation direction of ultrasonic waves in detail. The flexural vibration plate 1 and the circular reflection plate 2 are arranged to face each other in parallel. d is set to approximately [m · λa / 2cosθ] (where m is an integer), where θ is the radiation angle of the ultrasonic wave generated from the flexible diaphragm 1 and λa is the wavelength of the ultrasonic wave. . Further, in the present embodiment, when the diameter of the flexible diaphragm 1 is D1, the diameter D2 of the circular reflector 2 is approximately [D1-2dt.
an θ]. On the other hand, the inner diameter of the cylindrical reflector 3 is configured to be slightly larger than the outer diameter of the flexible diaphragm 1, and a circumferential gap is formed between the peripheral edge of the flexible diaphragm 1 and the inner peripheral surface of the cylindrical reflector 3. Exists, and the peripheral portion of the flexible diaphragm 1 is naturally a free end. The height H3 of the cylindrical reflector 3 is designed to be slightly larger than {d + [(D1-D2) / 2 tan [theta]]}.

The apex angle of the conical reflector 4 is θ.
A conical reflector.
Since the opening on the lower side of 4 is fitted to the peripheral edge of the circular reflector 2, its height H4 is [D2 / 2tanθ]. In this embodiment, the circular reflector 2 and the conical reflector 4 are separate members, but they may be solid cones.

In the above structure, when an alternating voltage is applied to the Langevin type vibrator 6, the flexural diaphragm 1 vibrates in a higher mode, and ultrasonic waves are generated from the entire surface in a steady state in which the nodal circles are at substantially equal intervals. Let In that state, as described with reference to FIG. 11, ultrasonic waves are radiated from the flexible diaphragm 1 in a mortar-shaped pattern having a constant radiation angle θ. Circular reflector 2 in a mode
Since the cylindrical reflector 3 and the conical reflector 4 are provided, the ultrasonic wave propagates through the paths shown by the dotted lines with arrows in FIG. Specifically, the ultrasonic waves radiated and emitted from the central region of the flexible diaphragm 1 are reflected back and forth between the flexible diaphragm 1 and the circular reflecting plate 2 such as point a → point b → point c. The ultrasonic waves incident on the peripheral cylindrical reflector 3 and radiated from the outer peripheral region of the flexible diaphragm 1 are directly incident on the cylindrical reflector 3. Then, the ultrasonic wave incident on the cylindrical reflection plate 3 is reflected on the inner peripheral surface thereof, and the reflected wave is further reflected on the outer peripheral surface of the conical reflection plate 4, and the normal line Z
It is output as a parallel sound flux.

Here, the propagation path of the ultrasonic wave is modeled and shown in FIG. 3, and a detailed explanation will be added. As is clear from the figure, if the radiation angle of the ultrasonic wave is θ and the wavelength of the ultrasonic wave is λa, the component of the wavelength λa in the normal line Z direction is [λa
/ Cosθ], and since the round-trip distance between the flexible diaphragm 1 and the circular reflector 2 is 2d, 2d = m · λa / cosθ
When the relationship of is satisfied, the radiated sound wave from the flexural diaphragm 1 and the reflected sound wave from the circular reflecting plate 2 are
The phase of the ultrasonic wave is always in the same phase, and the ultrasonic energy is incident on the cylindrical reflector 3 without being attenuated between the flexural diaphragm 1 and the circular reflector 2. Further, the ultrasonic waves radiated from the outer peripheral area of the flexural vibration plate 1 are incident on the cylindrical reflection plate 3 regardless of the circular reflection plate 2, but the radiation direction and the phase of the wavefront thereof are the same as those of the above-mentioned reciprocating reflected ultrasonic waves. become.

Next, the ultrasonic wave which is incident on and reflected by the cylindrical reflector 3 is incident on the surface of the conical reflector 4. Now, assuming that the incident angle on the conical reflector 4 is [(π / 2) −ψ], the conical reflector 4 will have a relationship of θ = 2ψ from the geometrical relationship shown in FIG. The propagation direction of the reflected ultrasonic waves becomes parallel to the normal line Z, and as described above, the apex angle of the conical reflector 4 is set to θ to convert the reflected ultrasonic waves into a parallel sound flux. Will be possible.

Based on the above principle, the condition of the flexible diaphragm 1 is set to [vibration frequency: 20.34 kHz, diameter D1: 18.4.
3 cm, thickness: 0.15 cm, knot circle number: 8], and the center of the flexural vibration plate 1 in the case of only the flexural vibration plate 1 and in the case where each reflection plate 2, 3, 4 is sequentially added An experiment was conducted to measure the microphone output voltage in an angle range of 180 ° centered on the normal Z in a plane including the normal Z at a distance of 2 m from. In addition, the input power to the sound source (Langevin type vibrator 6) was constant at 1.2 to 1.4W. The experimental results are shown in FIGS. 4 to 7.

<< Case of Flexible Vibration Plate 1 (FIG. 4) >> FIG. 4 shows the angular dependence of the radiated sound wave when the flexible vibration plate 1 is placed in a free space. As is clear from FIG. 4, the microphone output voltage has the main pole in the direction of an angle of about 40 °, and the radiation angle θ of the flexible diaphragm 1 is about 40 °.
It is understood that That is, in this case, a mortar-shaped radiated sound wave is formed as shown in FIG. 11, and a relatively high sound field is obtained at an angle corresponding to the radiation angle θ, but it is dispersed at other angles as well. The microphone output voltage is less than ⅓ at angles other than the main pole, and is almost averaged.

<< Combination of the flexural vibration plate 1 and the circular reflection plate 2 (FIG. 5) >> In FIGS. 5A, 5B and 5C, the diameter D2 of the circular reflection plate 2 is 14.8 cm. , 14.4 cm, 13.8 cm, and correspondingly, the microphone output voltage was measured when the distance d between the flexible diaphragm 1 and the circular reflector 2 was 2.2 cm, 2.4 cm, 2.7 cm. It is a thing. Now, at a temperature of 15 ° C, the sound velocity is 3436.1 cm, and the radiated sound wave of the flexible diaphragm 1 is 2
At 0.34 kHz, the wavelength λa becomes 0.169 cm, [2
d = m · λa / cos θ] (θ = 40 °), when d is 2.2 cm, 2.4 cm, 2.7 cm, and m is calculated, m = 19.94, 21.8, 24.4, respectively. Becomes Therefore, the microphone output voltage varies depending on the distance between the flexible diaphragm 1 and the circular reflector 2, especially when m is close to an integer [see FIG.
In the case of (a) and (b)], it is understood that a large output is obtained.

<< Combination of Circular Reflector 2 and Cylindrical Reflector 3 with Flexible Vibration Plate 1 (FIG. 6) >> In the case of FIG. 5 (a) [diameter D2 of circular reflector 2: 14.8 cm,
When the distance d between the flexible diaphragm 1 and the circular reflector 2 is 2.2 cm], the cylindrical reflector 3 [inner diameter: 20 cm,
This is a measurement of the microphone output voltage when the height H3: 6 cm] is combined. As is clear from FIG. 6, the characteristics are almost the same as those in FIG. 5A, and no increase in the microphone output voltage is seen.

<< Combination of Circular Reflector 2, Cylindrical Reflector 3 and Conical Reflector 4 with Flexible Vibration Plate 1 (Fig. 7) >> Under the above conditions, the conical reflector 4 [height: 15c
m, bottom diameter: 11 cm, busbar length: 16 cm] was added to measure the microphone output voltage. However, in this case, the diameter D2 of the circular reflector 2 is 14.8 cm, and the diameter of the bottom surface is smaller than that, but the apex of the conical reflector is as shown in FIG. The position in the normal line Z direction is adjusted so that the distance H4 is from the reflecting surface. In this case, the main pole, which is significantly larger in the normal Z direction, appears (the output voltage of the microphone is about three times the main pole of ~),
It is understood that the sound waves radiated from the flexural diaphragm 1 are completely focused into a sound flux in a single direction.

Therefore, from the above experimental results, the focused ultrasonic wave generator having the structure of this embodiment has the single-peaked main pole on the normal line Z of the ultrasonic wave emitted from the flexible diaphragm 1. It can be converted into focused ultrasonic waves, the energy of ultrasonic waves can be concentrated in a local area or a narrow area on the normal line Z, and cleaning and fine processing can be performed by utilizing the strong sound field. .

<< Embodiment 2 >> The apparatus of this embodiment corresponds to the invention of claim 2, and the basic structure thereof is shown in FIG. This figure corresponds to FIG. 2 in the above-described first embodiment, in which the flexible diaphragm 1, the circular reflector 2 and the cylindrical reflector are used.
The structure related to 3 and their positional relationship are the same. The feature of the apparatus of this embodiment is that, instead of the conical reflector 4 of the first embodiment, one point on the normal line Z is the ultrasonic wave reflected by the cylindrical reflector 3.
The point is that a conical reflecting plate 4a having a concave paraboloid of revolution S4 for focusing at (focus F1) is provided.

As is apparent from the figure, as in the case of the first embodiment, the ultrasonic waves emitted from the central region of the flexible diaphragm 1 are reflected back and forth between the flexible diaphragm 1 and the circular reflector 2. Ultrasonic waves incident on the cylindrical reflector 3 on the side circumference and emitted from the outer peripheral region of the flexible diaphragm 1 directly enter the cylindrical reflector 3, but the ultrasonic waves reflected by the cylindrical reflector 3 Is incident on the paraboloid of revolution S4 of the conical reflector 4a, and all the ultrasonic waves reflected by the paraboloid of revolution S4 of the cone are focused on the focal point F1.

Therefore, since all the sound waves emitted from the flexible diaphragm 1 are focused on the focal point F1 at a relatively short distance,
A far stronger sound field can be obtained as compared with the case where the parallel sound flux is converted as in the first embodiment, and an extremely large energy is obtained by scanning the focus F1 on the surface to be cleaned or the finely processed surface. The ultrasonic vibration of can be given.

<< Embodiment 3 >> The apparatus of this embodiment corresponds to the invention of claim 3, and the basic structure thereof is shown in FIG. This figure also corresponds to FIG. 2 in the above-described first embodiment, and although the structures related to the flexural vibration plate 1 and the circular reflection plate 2 and their arrangement relationships are the same, the conical reflection plate 4 in the first embodiment is used. Is not present, and instead of the cylindrical reflecting plate 3, a converging reflecting plate 7 having an inner surface formed as a paraboloid of revolution S7 is provided.

Then, the paraboloid of revolution S7 of the focusing reflector 7
Is the ultrasonic wave radiated from the central area of the flexible diaphragm 1 that is reflected back and forth between the flexible diaphragm 1 and the circular reflector 2 and radiated to the side circumference, and directly from the outer peripheral area of the flexible diaphragm 1. A point on the normal line Z (focal point F2) that reflects the emitted ultrasonic wave
It is formed so as to focus on. That is, in the apparatus of this embodiment, the focusing reflector 7 directly focuses the ultrasonic wave on the focal point F2, and a strong sound field can be obtained at a position extremely close to the flexural diaphragm 1. Further, unlike the above-described embodiments, since the conical reflector is not used, there is no protrusion in the direction of the normal line Z, and a compact and lightweight focused ultrasonic wave generator can be configured.

<Application Example> The focused ultrasonic wave generator according to each of the above-described embodiments may be applied to a cleaning device (spot remover) as shown in, for example, FIG. 10 (side view) and FIG. 11 (plan view). You can In each figure, 51 is an object to be cleaned (clothes, etc.) with stains, 52 is a cleaning mesh table on which the object to be cleaned is developed and placed, and 53 is an ultrasonic unit incorporating the ultrasonic generator. , 54 is a tank storing the cleaning agent,
55 is a tank that stores water, 56 and 57 are nozzles, 58 and 59 are solenoid valves, 60 is a vacuum part, 61 is the upper side of the cleaning mesh table 52, and the ultrasonic unit 53 and nozzles 56 and 57 are mounted and the lower side A carriage supporting the vacuum unit 60 by 62, and 62 an exhaust water blower. Here, the entire carriage 61 can be laterally moved by being guided by rails 52a provided on both sides of the cleaning mesh table 52, and the ultrasonic wave generation unit 53 and each nozzle can be moved by the rails 61a attached to the carriage 61 itself. Five
It is designed to move the 6,57 together in the vertical direction.
The tip of each nozzle 56, 57 is directed to the ultrasonic focusing portion of the ultrasonic unit 53, and the cleaning agent and water in each tank 54, 55 are sprayed to that area by opening the solenoid valves 58, 59. .

When cleaning, first, the carriage 61 and the mounting units 53, 56, 57 are moved to move the ultrasonic unit 53.
The ultrasonic focusing part of is set to the spot adhesion area on the object to be cleaned 51. And the flexible diaphragm 1 of the ultrasonic unit 53
When the ultrasonic waves are focused on the spot adhesion area of the object to be cleaned 51, the solenoid valves 58 and 59 are opened to spray the cleaning agent and water to the area, and the exhaust water blower 62 is also started. Causes the vacuum unit 60 to enter the intake state. In that state, a strong sound field due to focused ultrasonic waves is formed in the spot adhesion area, and the supplied cleaning agent and water vibrate violently, causing dirt particles impregnated in the object to be cleaned 51 to be ejected. Then, they are ejected from the vacuum unit 60 through the cleaning mesh table 52 in the atomized state. Further, since the mounting units 53, 56, 57 can be moved vertically and horizontally based on the above-mentioned mechanism, it is possible to scan each stain adhering area on the article to be cleaned 51 to remove the stains.

According to this cleaning device, intense ultrasonic vibration is applied to the inside of the object to be cleaned 51 by the focused ultrasonic waves, and at the same time, the cleaning agent and water are vibrated by strong energy, so that extremely efficient cleaning is possible. Further, since the non-contact type physical cleaning method is used, there is an advantage that the cloth is not damaged when the object to be cleaned 51 is clothes or the like. The ultrasonic wave generation unit 53 and each nozzle 5
The movement of 6,57 and the vacuum unit 60 may be performed manually, but a control device for the carriage 61 and solenoid valves 58,59 is provided, and the location of the dirt is designated in advance and automatically moved. If scanning is performed, the cleaning process can be completely automated.

[0036]

EFFECTS OF THE INVENTION The focused ultrasonic wave generating device of the present invention has the following effects due to the above-mentioned structure. According to the invention of claim 1, the ultrasonic wave radiated from the high-order mode circular flexural vibration plate has a simple structure including three reflecting portions (first reflecting portion, second reflecting portion, and third reflecting portion).
It is possible to obtain a strong sound field which can be efficiently focused as a parallel sound flux having no hollow area and a small area, and which can be easily used in a cleaning device, a fine processing device and the like. In the invention of claim 2, the reflecting surface of the third reflecting portion of the invention of claim 1 is a paraboloid of revolution, so that the ultrasonic waves emitted from the high-order mode circular flexural diaphragm are focused on one focal point. Allows you to get an extremely strong sound field. According to the invention of claim 3, the ultrasonic wave radiated from the high-order mode circular flexural diaphragm is generated from the flexural diaphragm only by providing the first reflecting portion (circular reflecting plate) and the fifth reflecting portion (focusing reflecting plate). Focusing on one focal point at a close distance makes it possible to obtain an extremely strong sound field. Further, in this invention, since the conical reflecting portion used in each of the above inventions is unnecessary,
It has the advantage that the entire device can be made smaller and lighter.

[Brief description of drawings]

FIG. 1 is a perspective view showing a basic structure of a focused ultrasonic wave generating device according to a first embodiment (corresponding to claim 1).

FIG. 2 is a cross-sectional view showing the structure of a focused ultrasonic wave generator and the propagation direction of ultrasonic waves.

FIG. 3 is a diagram showing the geometrical relationship and the like by modeling the position of each reflector and the propagation path of ultrasonic waves.

FIG. 4 is a graph showing the angle dependence of a radiated sound wave when a flexible diaphragm is placed in a free space (at a distance of 2 m from the center of the flexible diaphragm, the normal Z in the plane including the normal Z). (Measure the microphone output voltage in the angle range of 180 ° around

5 is a graph showing the microphone output voltage when a flexible diaphragm and a circular reflector are combined by the same measurement method as in FIG. 4 (however, (a), (b), (c)). Is measured in a state in which the diameter D2 of the flexible diaphragm and the distance d between the flexible diaphragm and the circular reflector are changed, respectively.

FIG. 6 is a graph showing the microphone output voltage when a flexible diaphragm is combined with a circular reflector and a cylindrical reflector by the same measurement method as in FIG.

FIG. 7 is a graph showing the microphone output voltage when a flexible diaphragm is combined with a circular reflector, a cylindrical reflector, and a conical reflector by the same measurement method as in FIG.

FIG. 8 is a cross-sectional view showing a structure of a focused ultrasonic wave generator of Example 2 (corresponding to claim 2) and an ultrasonic wave propagation direction.

FIG. 9 is a cross-sectional view showing the structure of a focused ultrasonic wave generator of Example 3 (corresponding to claim 3) and the propagation direction of ultrasonic waves.

FIG. 10 is a schematic side view of a cleaning device according to an application example.

FIG. 11 is a schematic plan view of a cleaning device according to an application example.

FIG. 12 is a perspective view showing a radiation pattern of airborne ultrasonic waves generated by a flexible diaphragm.

FIG. 13 is a perspective view showing a conventional ultrasonic focusing method and a focused ultrasonic pattern in that case.

[Explanation of symbols]

1 ... Flexible diaphragm, 2 ... Circular reflector (first reflector), 3 ... Cylindrical reflector (second reflector), 4, 4a ... Cone reflector (3rd reflector, 4th reflector) , 5 ... Exponential horn, 6 ...
Langevin type transducer, 7 ... Focusing reflector (5th reflector), 5
1 ... Object to be cleaned, 52 ... Washing mesh stand, 52a, 61a ... Rail,
53 ... An ultrasonic unit incorporating an ultrasonic generator, 54 ... A tank storing a cleaning agent, 55 ... A tank storing water, 56, 5
7 ... Nozzle, 58, 59 ... Solenoid valve, 60 ... Vacuum part, 61 ... Carriage, 62 ... Exhaust water blower, 101 ... Flexible diaphragm, 102
… Vibration drive source, 103… Mortar-shaped aerial ultrasound, 1
04 ... Conical reflector, 105 ... Donut-shaped parallel sound flux, d ... Distance between flexible diaphragm and circular reflector, D1 ... Diameter of flexible diaphragm, D2 ... Diameter of circular reflector, F1, F2 ... Focus, H3 …
Height of cylindrical reflector, H4 ... Height of conical reflector, S4, S7
… Rotary paraboloid, Z… normal, θ… radiation angle.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoichi Ito 3-6-5 Matsugaoka, Tsurugashima City, Saitama Prefecture (72) Inventor Saburo Aonuma 6-4-5 Higashiooi, Shinagawa-ku, Tokyo Sataco Engineering Co., Ltd.

Claims (3)

[Claims] 1. In a focused ultrasonic wave generator, a high-order mode circular flexural vibration plate having a vibration drive source attached to the center is used as the ultrasonic wave generation source, and a normal line passing through the center of the flexural vibration plate is a common central axis. As, having a circular planar reflection surface having a diameter smaller than the diameter of the flexible diaphragm, when the radiation angle of the ultrasonic wave generated from the flexible diaphragm is θ, the wavelength of the ultrasonic wave is λa, A first reflecting portion whose reflection surface is arranged in parallel and opposed to the flexible diaphragm at a distance of [m · λa / 2cosθ] (where m is an integer), and a peripheral portion of the flexible diaphragm from the peripheral portion of the flexible diaphragm. The first reflecting portion has a cylindrical reflecting surface surrounding the arrangement side space of the reflecting portion and a conical reflecting surface having an apex angle of θ, and the apex angle side is directed toward the ultrasonic output direction. The third anti-reflective unit arranged in the space where the ultrasonic waves reflected by the cylindrical reflecting surface of the two-reflecting portion propagate. Part focused ultrasound generator, characterized in that the fixedly provided. 2. In the focused ultrasonic wave generator, a high-order mode circular flexural vibration plate having a vibration drive source attached to the center is used as the ultrasonic wave generation source, and a normal line passing through the center of the flexural vibration plate is a common central axis. As, having a circular planar reflection surface having a diameter smaller than the diameter of the flexible diaphragm, when the radiation angle of the ultrasonic wave generated from the flexible diaphragm is θ, the wavelength of the ultrasonic wave is λa, A first reflecting portion whose reflection surface is arranged in parallel and opposed to the flexible diaphragm at a distance of [m · λa / 2cosθ] (where m is an integer), and a peripheral portion of the flexible diaphragm from the peripheral portion of the flexible diaphragm. 1 a second reflecting portion having a cylindrical reflecting surface surrounding a space on which the reflecting portion is arranged, and a paraboloid of revolution for reflecting the ultrasonic waves reflected by the second reflecting portion and converging the reflected ultrasonic waves to one point of the normal line It has a conical reflecting surface, and its apex side is directed to the ultrasonic output direction. A fourth member arranged in a space in which ultrasonic waves reflected by the cylindrical reflecting surface of the second reflecting section propagate.
A focused ultrasonic wave generator having a reflecting portion fixedly provided. 3. In the focused ultrasonic wave generator, a high-order mode circular flexural vibration plate having a vibration driving source attached to the center is used as the ultrasonic wave generation source, and a normal line passing through the center of the flexural vibration plate is a common central axis. As, having a circular planar reflection surface having a diameter smaller than the diameter of the flexible diaphragm, when the radiation angle of the ultrasonic wave generated from the flexible diaphragm is θ, the wavelength of the ultrasonic wave is λa, A first reflecting portion whose reflection surface is arranged in parallel and opposed to the flexible diaphragm at a distance of [m · λa / 2cosθ] (where m is an integer), and a peripheral portion of the flexible diaphragm from the peripheral portion of the flexible diaphragm. 1 The ultrasonic wave that covers the arrangement side space of the reflecting portion and that is reflected by the ultrasonic waves that are directly incident from the flexible diaphragm and the reflecting surface of the first reflecting portion and the surface of the flexible diaphragm that are reflected back and forth are reflected. Has a parabolic reflective surface that focuses on a point on the normal A focused ultrasonic wave generating device, wherein the fifth reflecting portion is fixedly provided.