JP2802425B2 - Focused ultrasonic generator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a focused ultrasonic generator, which is applied to the field of cleaning and drying of an object surface, and furthermore, to cleaning and fine processing of metal powder, and is generated from a stripe mode diaphragm. The present invention relates to a device for forming an ultrasonic wave as a line focused sound field with a small and simple structure.

[0002]

2. Description of the Related Art Recently, in the field of cleaning the surface of an object and fine processing of various materials, methods utilizing a strong sound field of focused ultrasonic waves have been studied and developed. And
The inventors of the present application have reported as related papers, `` Removal of droplets on the material surface by a powerful sound field '' (Ito, Kawamura, Proceedings of the Acoustical Society of Japan: P597-598, March 1983) and `` Powerful Aerial Ultrasound Of water droplets on the plate surface '' (Ito, Kawamura, Proceedings of the Acoustical Society of Japan: P755-756, March 1987). Report on the method of atomizing and removing water adhering to a relatively large area of a glass plate using a strong acoustic field that is reflected by a focusing direction changer placed in the area and focused linearly. Is going. In addition, a “cleaning method using ultrasonic waves” using the above method has been proposed (Japanese Patent Application No. 5-80080).
issue).

The ultrasonic focusing apparatus employed in the above-mentioned paper and the proposal of the "cleaning method using ultrasonic waves" has a basic schematic configuration as shown in FIG. In this device, a rectangular stripe mode diaphragm 51 is bolted to a Langevin type vibrator 52 and an exponential horn.
Vibration is performed using a sound source vibration system 55 including a 53 and a one-wavelength resonance rod 54, and all radiation ultrasonic waves generated by the vibration are focused on a straight line 57 by focusing direction converters 56a and 56b. Also, the radiated sound waves from the front and back sides of the fringe mode diaphragm 51 are in the same phase on the straight line 57, respectively.
And the positional relationship between the focusing direction converters 56a and 56b.

Accordingly, a strong line-focused sound field as shown in FIG. 17 is formed on the straight line 57, and when the surface of a wet object is placed at the position of the straight line 57, the moisture instantaneously becomes mist. And, in the process, dirt attached to the surface of the object is also removed. In addition, when the atomized water is removed by a vacuum method, drying can be performed at the same time, and the use of the above-mentioned strong sound field can be applied to the field of fine processing.

[0005]

By the way, in the focused ultrasonic generator shown in FIG. 16, due to its structure, the stripe mode diaphragm 51 is perpendicular to the cleaning surface and the like, and the focusing direction converters are provided on both sides thereof. The arrangement of the devices 56a and 56b increases the size of the entire apparatus, and the sound source vibration system 55 is connected to the striped mode diaphragm 51 from the side, so that the planar occupation size also increases. Further, there is a problem that the propagation distance of the ultrasonic wave from the stripe mode diaphragm 51 to the formed focused sound field becomes long, and the distortion and diffusion of the sound wave are apt to occur. As a result, the sound pressure is reduced in the focused sound field.

In view of the above-mentioned problems, the present invention can reduce the size of the entire apparatus, shorten the ultrasonic wave propagation distance, and efficiently focus the beam, thereby obtaining a stronger focused sound field. It was created to provide an ultrasonic generator.

[0007]

According to the present invention, there is provided a focused ultrasonic generator comprising: a band-shaped stripe mode vibration plate having a vibration driving source mounted at the center; and a plate along the longitudinal direction of the stripe mode vibration plate. And an opening having a constant width in a region facing the center line in the longitudinal direction of the fringe mode diaphragm, and the inner surface thereof is formed in a direction perpendicular to the plate surface of the fringe mode diaphragm. A reflecting plate formed of a paraboloid having a focal length that satisfies a condition that reflected ultrasonic waves are reflected by the fringe mode vibration plate and converge outside the opening, and the fringe mode vibration The present invention relates to a focused ultrasonic generator, comprising: a plate; and separators each of which divides an internal space formed by the reflection plate along each nodal line of the fringe mode diaphragm during bending vibration.

When the center of the band-shaped stripe mode diaphragm is sinusoidally driven by the vibration driving source, the stripe mode diaphragm bends and vibrates to generate a constant bending standing wave in the longitudinal direction. And
Ultrasonic waves are radiated from the area by the vibration between the nodal lines at the time of the bending vibration, but the separator separates the space between the nodal lines, and the ultrasonic wave generated from the bending vibration part generated individually Ultrasonic waves travel and propagate only in a direction perpendicular to the plate surface of the vibrating part without scattering and interference. On the other hand, the ultrasonic wave that has propagated between the separators is reflected by the inner surface of the reflector corresponding to the section, but the inner surface of the reflector has an opening when the reflected wave is reflected again by the stripe mode diaphragm. A parabolic surface whose focal length is set so that it can be focused outside the part is formed, and ultrasonic waves generated from each bending vibration part of the stripe mode diaphragm are strong lines outside the aperture of the reflector. Form a focused sound field.

Meanwhile, some ultrasonic waves generated from each bending vibration portion of the stripe mode diaphragm pass directly through the opening without being reflected by the inner surface of the reflector. In this case, if the ultrasonic wave directly passing through the opening has an opposite phase to the ultrasonic wave focused on the line-focused sound field, the sound pressure in the line-focused sound field may be reduced. To solve the problem, the focal length given by the parabolic surface of the reflector is changed from the area of the stripe mode diaphragm facing the opening of the reflector through ultrasonic waves and reflection passing directly through the opening. It can be eliminated by setting the ultrasonic waves focused outside the opening to have the same phase on the focused line.

Next, in the above-mentioned apparatus, since the fringe mode diaphragm vibrates in a bending standing wave state, the ultrasonic waves emitted from between the separators and focused are corresponding to the sections of the respective separators. Adjacent parts have opposite phase relationships. This causes the focused ultrasonic waves to interfere with each other at a joint portion of the section, which causes a reduction in average sound pressure. In other words, a stronger average sound pressure is obtained when the focused ultrasonic waves have the same phase in each section.

Regarding this problem, in the above-mentioned focused ultrasonic generator, a parabolic surface having a focal length different by (λa / 4) × odd number, where λa is the wavelength of the ultrasonic wave generated by the stripe mode diaphragm. Can be solved by alternately arranging the two types of divided reflectors constituted in the section between the separators so that their focal positions are on the same line to constitute the entire reflector. In other words, by shifting the propagation distance of the ultrasonic waves generated by the stripe mode diaphragm by (λa / 2) × integer times between adjacent sections, it becomes possible to make all the focused ultrasonic waves on the line have the same phase. Become.

By the way, in this in-phase type focused ultrasonic generator, there is also a problem that the sound pressure is reduced by the ultrasonic wave directly passing through the opening as described above. Since it is impossible to ensure the same phase on the converging line, the condition only needs to be ensured for any type of segmented reflector.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the "focused ultrasonic generator" of the present invention will be described below in detail with reference to FIGS. Here, the case where the ultrasonic waves on the convergence line have opposite phases in adjacent sections (Embodiment 1) and the case where they are in phase (Embodiment 2) will be described separately. << Embodiment 1; (opposite phase type) >> FIGS. 2 (side view) and 3 (QQ of FIG. 2) show the structure of the focused ultrasonic generator according to this embodiment.
(A cross-section in the direction of the arrow). In each figure, 1 is a fringe mode diaphragm, 2a and 2b are reflectors, 3 is a separator, 55 is a bolted Langevin type vibrator 52 and an exponential horn 53 for amplitude similar to those used in the prior art. And a one-wavelength resonance rod 54.

Here, the stripe mode diaphragm 1 is a band-shaped flat plate made of a titanium alloy, and a one-wavelength resonance rod 54 is provided at the center of the plate surface.
Are vertically mounted, and the bolted Langevin type vibrator 52 is driven to bend and vibrate as shown in FIG. 2 to generate a bending standing wave in the longitudinal direction.

On the other hand, the reflection plates 2a and 2b are made of acrylic plate material, and cover the upper space from both sides of the stripe mode diaphragm 1 along the longitudinal direction of the stripe mode diaphragm 1, An opening 4 having a constant width is formed in a region facing the direction center line. In addition, the separator 3 is made of an acrylic plate material like the reflectors 2a and 2b, and the reflectors 2a and 2b are arranged so as to divide the space formed between the stripe mode diaphragm 1 and the reflectors 2a and 2b. The separation interval is set to the interval between the nodal lines 5 in a state where the striped mode diaphragm 1 is flexurally vibrated, and the lower end face of each separator 3 is set to the striped mode diaphragm 1 In the vicinity of each of the nodal lines 5.

Next, the operation of the focused ultrasonic generator according to this embodiment and the detailed configuration of the reflectors 2a and 2b will be described. First, a fringe mode diaphragm 1 by a Langevin type vibrator 52 is used.
When the center is driven sinusoidally, as shown in FIG. 4, the striped mode diaphragm 1 is in a bending standing wave state, and generates ultrasonic waves from the surface section divided by each node line 5. In this case, the ultrasonic wave is radiated in two directions of a specific angle α (cos α = λa / λp: where λa is the wavelength of the sound wave and λp is the wavelength of the bending wave), but as shown in FIG. Are provided corresponding to the nodal lines 5, so that the ultrasonic waves radiated from the vibrating surface of each section independently propagate only in the z-axis direction without interference. However, the ultrasonic wave radiated by the vibrating surface of the adjacent section is
Since the fringe mode diaphragm 1 vibrates in a bending standing wave state, the diaphragm mode diaphragms 1 have opposite phases to each other.

The ultrasonic waves in each section propagate in the z-axis direction and are reflected by the inner surfaces of the reflectors 2a and 2b. FIG. 1 shows the shapes of the reflectors 2a and 2b and the stripe mode diaphragm 1 2 schematically shows a relative positional relationship with respect to the ultrasonic wave and a propagation path of an ultrasonic wave. FIG. 1 is a cross-sectional view of the stripe mode diaphragm 1 and the reflectors 2a and 2b when a section of the center portion in FIG. 4 is taken along a cross-section including the z-axis and the y-axis and viewed from the x-axis direction. In the x-axis direction, the section is the same in all sections, and therefore corresponds to FIG. As shown in FIG. 1, the reflection plates 2a, 2
The inner surface of b (shown by thick solid lines a1-a2, a3-a4 in this embodiment) is configured as a paraboloid that covers the upper space from both sides of the striped mode diaphragm 1, and is z Ultrasound propagating in the axial direction (shown by a thin solid line in this embodiment)
Is reflected so as to be focused on the focal point F. However, since the ultrasonic wave directed to the focal point F is incident on the surface of the ultrasonic wave at an incident angle (π / 2−θ) due to the presence of the fringe mode diaphragm 1, it is reflected at the same angle of reflection, and the reflected wave is y. It is focused on a point Fm corresponding to the mirror image focus about the axis.

On the other hand, an opening 4 (corresponding to between a2 and a3 in FIG. 1) is formed in the reflection plates 2a and 2b, and the ultrasonic wave reflected by the stripe mode diaphragm 1 passes through the opening 4 Passing point Fm
Form a strong focused sound field at Therefore, reflector 2
The focal lengths of the paraboloids a and 2b (between PF and fd) are set such that the mirror image focal point Fm about the y-axis is outside the aperture 4, and the aperture 4 is generated on the vibration surface of the section. And reflector 2
a, 2b and a width enough to pass most of the ultrasonic waves reflected on the surface of the stripe mode diaphragm 1.

In FIG. 1, the ultrasonic waves generated from the portions indicated by y1-y2 and y3-y4 in the y-axis direction of the vibration surface are focused on the point Fm as described above.
The ultrasonic wave generated from the portion -y3 passes through the opening 4 as it is and reaches the point Fm. In that case, if the former focused ultrasonic wave and the latter ultrasonic wave have an opposite phase relationship at the point Fm, the sound pressure of the focused sound field will decrease. Therefore, under the condition that the difference between the distance between OFm in FIG. 1 and the propagation distance until the reflected wave shown by the thin solid line reaches the point Fm is an integral multiple of the wavelength λa of the sound wave, the paraboloid of the reflectors 2a and 2b is used. Is set so that the focused ultrasonic wave and the ultrasonic wave passing through the opening 4 have the same phase at the point Fm.

Then, as described above, the separator 3 of the stripe mode diaphragm 1
The principle of operation for obtaining focused ultrasound in one section divided by the above has been described. However, the focused ultrasound generator according to this embodiment has the sections aligned in the longitudinal direction of the striped mode diaphragm 1 as shown in FIG. As a result, a focused ultrasonic wave is formed in each section according to the same principle, and the focused ultrasonic wave is obtained on a straight line along an axis (x ′ axis) perpendicular to the paper surface at the point Fm in FIG. . However, in this embodiment, since the ultrasonic waves radiated by the vibrating surfaces of the adjacent sections have an opposite phase relationship to each other, the focused ultrasonic waves formed on the straight line also have the opposite phases in the adjacent sections. ing.

<< Embodiment 2: (In-phase type) >> In this embodiment, while the focused ultrasonic waves according to the above-described Embodiment 1 are in opposite phases in the adjacent sections, the focused ultrasonic waves having the same phase are used. It is what we are trying to get. The structure of the focused ultrasonic generator according to this embodiment is shown in FIG. 5 (side view) and FIG. 6 (a cross section taken along line RR in FIG. 5). The apparatus according to this embodiment has two types of reflectors (2a ', 2b'), (6) which form a paraboloid whose focal length differs by λa / 4 in adjacent sections divided by the separator 3 '.
a ', 6b') is applied, and each reflector (2a ', 2b'), (6a ', 6b')
Are characterized in that they are alternately combined via a separator 3 ′ so that the paraboloids of the two focus on the same position.

The specific configuration will be described with reference to FIG. 1. The paraboloids of the reflectors 2a 'and 2b' are the reflectors 2a and 2b of the first embodiment.
(Shown by a thick solid line) has a focal length fd, but the paraboloids of the reflectors 6a 'and 6b' (shown by a thick dotted line) have a focal length longer by λa / 4 than the focal length fd. The vertex P ′ of the paraboloid supposed in the opening 7 (corresponding to between b2 and b3) of the reflectors 6a ′ and 6b ′ is set to the paraboloid on the reflectors 2a ′ and 2b ′ side. Of the reflectors (2a ', 2b') and (6a ', 6b') are focused on the same position F by displacing them by λa / 4 above the vertex P of It has become.

Thus, the reflection plates (2a ', 2b'), (6a ', 6b')
Are alternately provided for each section, the basic operating principle of obtaining focused ultrasonic waves in those sections is the same as in the first embodiment, and a strong focused sound field is formed at the point Fm in FIG. However, since the focal lengths are different by λa / 4 as described above, the phases at the point Fm of the focused ultrasonic waves obtained in both sections are the same. That is, since the fringe mode diaphragm 1 is vibrating in the state of the bending standing wave, the ultrasonic waves emitted by the vibrating surfaces of the adjacent sections have a relationship of opposite phases to each other, but the reflection plate 6a ′, The propagation distance of the sound wave in the application section of 6b 'is λa / 2 longer than that in the application section of the reflectors 2a' and 2b '.
As a result, in both sections, the phases of the ultrasonic waves focused on the point Fm become the same. Therefore, according to the focused ultrasonic generator of this embodiment, the point Fm in FIG.
The focused ultrasonic waves having the same phase can be continuously formed on a straight line along an axis (x ′ axis) perpendicular to the plane of the drawing.

Since the focal length fd of the reflectors 6a 'and 6b' is long as shown in FIG. 1, the width of the opening 7 (between b2 and b3) is set.
Is smaller than the width (between a2 and a3) of the opening 4 of the reflectors 2a 'and 2b', but as in the first embodiment,
The ultrasonic wave generated from the portion y2'-y3 'of FIG. 1 passes through the opening 7 as it is, reaches the point Fm, and lowers the sound pressure of the focused ultrasonic wave. However, if the phases of the ultrasonic wave and the focused ultrasonic wave directly passing through the opening 4 are secured on the reflectors 2a 'and 2b' side, it is necessary to secure it on the reflectors 6a 'and 6b' side. Is impossible. Therefore, in the case of this embodiment, it is to ensure the same phase of the ultrasonic wave and the focused ultrasonic wave that directly pass only in any one section,
The other has to be ignored.

[0025]

【Example】

Embodiment 1 (out-of-phase type);
Using a bolted Langevin type vibrator 52 for 0 kHz (D25540 made by Nippon Tokuhoku Togyo Co., Ltd.), an exponential horn 53 made of duralumin with an amplitude expansion ratio of about 6 and a one-wavelength resonance rod 54, the fringe mode diaphragm 1 is [frequency: 19.72 kHz, width: 18.14
cm, length: 31.00 cm, thickness: 03.5 cm, λa (wavelength of sound wave): 1.74 cm, λp (wavelength of bending wave of diaphragm): 4.00 c
m], a focused ultrasonic wave was obtained with the apparatus of Embodiment 1, and a sound field near the focused sound field was measured.

As a result, experimental data on sound pressure as shown in FIGS. 7 to 9 was obtained. First, FIG. 7 shows a sound pressure distribution on the x 'axis passing through a point Fm corresponding to a designed ultrasonic focusing point, and the horizontal axis represents the distance from the z axis. From the figure, it can be seen that the sound pressure distribution is such that the ultrasonic waves radiated from adjacent sections divided by the separator 3 are line-focused adjacently on the x'-axis in an anti-phase relationship, so that the interference is caused by interference in the fringe mode diaphragm. Nodal line of 1 5
It can be understood that the distribution state is such that the maximum / minimum almost corresponding to the interval is clearly seen. The focused sound field is formed in a range substantially equal to the length of the stripe mode diaphragm 1.

FIG. 8 shows the sound pressure distribution in the y direction passing through the point S1 in FIG. 7, and the horizontal axis represents the distance from the x 'axis. From the figure, it can be understood that the sound pressure is substantially maximized at the intersection with the x ′ axis, and that the sound wave radiated from the vibration surface of the stripe mode diaphragm 1 is focused. FIG.
The sound pressure distribution in the z direction passing through the point S1 in FIG. 7 is shown, and the horizontal axis represents the distance in the z axis direction from the designed focal point Fm of the sound wave. From the figure, it can be understood that the maximum value of the sound pressure is obtained almost at the focusing point in the design. In the actual device, the line focused sound of the maximum sound pressure is located about 1 cm outward from the opening 4. A place was formed.

Second Embodiment (In-Phase Type): Under the same conditions as in the first embodiment, the sound source vibration system 55 and the fringe mode diaphragm 1 are used to obtain a focused ultrasonic wave by the apparatus of the second embodiment and a focused sound field. The nearby sound field was measured.

As a result, experimental data relating to sound pressure as shown in FIGS. 10 to 14 were obtained. FIG. 10 shows a sound pressure distribution on the x′-axis passing through a point Fm corresponding to a designed ultrasonic focusing point, and corresponds to FIG. 7 according to the first embodiment.
From the figure, the sound pressure when the direct radiated sound wave from the vibrating surface of the fringe mode diaphragm 1 and the reflected sound waves from the reflectors 6a and 6b enter the point Fm in an opposite phase relationship (for example, point S3 in the figure) Is about 0.6 times as large as when both sound waves enter the point Fm in the same phase relationship (for example, point S2 in the figure).
This is because the direct radiated sound wave and the reflected sound wave interfere with each other at the point Fm and are weakened, and the opening 7 of the reflectors 6a and 6b is slightly narrower than the opening 4 of the reflectors 2a and 2b. And
It is considered that a part of the ultrasonic wave is trapped inside. Compared with FIG. 7 in the case of the first embodiment, since the ultrasonic waves radiated from the adjacent sections have the same phase relationship on the x ′ axis, the change in the maximum / minimum sound pressure is relatively small. And a smooth distribution state is obtained.

FIGS. 11 and 12 show the sound pressure distribution in the y-axis direction passing through the points S2 and S3 in FIG. 10, respectively.
This corresponds to FIG. 8 according to the first embodiment. Each result has a distribution in which the sound pressure is almost maximum near the intersection with the x 'axis, and the stripe mode diaphragm is similar to the case of the first embodiment.
It can be understood that the radiated sound waves from the vibrating surface 1 are focused. FIGS. 13 and 14 show the sound pressure distribution in the z-axis direction passing through the points S2 and S3 in FIG. 10, respectively, and correspond to FIG. 9 according to the first embodiment. In each case, it can be understood that the maximum value of the sound pressure is substantially obtained at the focal point of the design. As in the case of the first embodiment, the maximum sound pressure is about 1 cm outward from the opening 4. A line-focused sound field was formed.

FIG. 15 shows the results of measuring the relationship between the sound pressure of the focused sound field and the power supplied to the Langevin-type vibrator 52 in each of the above embodiments. Show. In the same figure, the plots marked with ○ are for the first embodiment, the plots marked with □ are for the second embodiment,
In any case, it can be understood that the sound pressure is proportional to about 1/2 power of the supplied power. In the focused ultrasonic generator shown in the related art, the sound pressure tends to be saturated when the supply power is about 100 [W] or more. However, in the apparatuses of Embodiments 1 and 2, the supply power is 200 [W]. ], The proportional relationship is maintained. It is considered that the reason is that in the device of the embodiment, the propagation distance of the sound wave from the striped mode diaphragm 1 to the ultrasonic focus point is short, so that distortion and diffusion accompanying the propagation of the sound wave are reduced.

[0032]

The "focused ultrasonic generator" of the present invention has the following effects due to the above configuration. According to the first and third aspects of the present invention, it is possible to obtain a stronger line-focused sound field by reducing the size of the entire apparatus, shortening the propagation distance of the ultrasonic waves, and efficiently focusing the ultrasonic waves. In particular, according to the third aspect of the invention, in the first aspect of the invention, the line-focused sound waves in adjacent sections have an opposite phase relationship due to the structure thereof, and the maximum / minimum sound pressure increases due to mutual interference. By making the line-focused ultrasonic waves in adjacent sections have the same phase, a powerful sound field is realized on average in a smooth distribution state. According to the second aspect of the present invention, the ultrasonic wave directly passing through the opening from the stripe mode diaphragm and the focused ultrasonic wave have the same phase to prevent a decrease in sound pressure. The invention of claim 4 clarifies that when the invention of claim 2 is applied to the invention of claim 3, it is sufficient that the invention of claim 2 is applied to only one of the sections.

[Brief description of the drawings]

FIG. 1 is a diagram schematically illustrating a shape of a reflector, a relative positional relationship with respect to a stripe mode diaphragm, and a propagation path of an ultrasonic wave according to each embodiment of the “focused ultrasonic generator” of the present invention.

FIG. 2 is a side view of the focused ultrasonic generator according to the first embodiment.

FIG. 3 is a sectional view taken along the line QQ in FIG. 2;

FIG. 4 is a diagram illustrating a radiation mode of an ultrasonic wave generated by a vibration plane between nodal lines in a state where the fringe mode diaphragm is flexibly vibrated.

FIG. 5 is a side view of the focused ultrasonic generator according to the second embodiment.

FIG. 6 is a sectional view taken along the line RR in FIG. 5;

FIG. 7 is a graph showing a sound pressure distribution on an x ′ axis passing through a point Fm corresponding to a designed ultrasonic focusing point in FIG. 1 in relation to the distance from a z axis in the first embodiment.

8 is a graph showing the sound pressure distribution in the y direction passing through a point S1 in FIG. 7 in relation to the distance from the x 'axis.

9 is a graph showing a relationship between a sound pressure distribution in the z direction passing through a point S1 in FIG. 7 and a distance in the z axis direction based on a point Fm corresponding to a designed ultrasonic focusing point.

FIG. 10 is a graph showing a sound pressure distribution on an x ′ axis passing through a point Fm corresponding to a designed ultrasonic focusing point in FIG. 1 in relation to a distance from a z axis in the second embodiment.

11 is a graph showing a sound pressure distribution in a y-axis direction passing through a point S2 in FIG. 10 in relation to a distance from an x ′ axis.

12 is a graph showing a sound pressure distribution in a y-axis direction passing through a point S3 in FIG. 10 in relation to a distance from an x 'axis.

FIG. 13 is a graph showing a sound pressure distribution in the z direction passing through a point S2 in FIG. 10 in relation to a distance in the z axis direction with reference to a point Fm corresponding to a designed ultrasonic focusing point.

14 is a graph showing the sound pressure distribution in the z direction passing through a point S3 in FIG. 10 in relation to the distance in the z axis direction with reference to a point Fm corresponding to a designed ultrasonic focusing point.

FIG. 15 is a graph showing a relationship between a sound pressure of a line focusing sound field and power supplied to a Langevin type vibrator.

FIG. 16 is a schematic diagram showing the configuration of a conventional ultrasonic focusing apparatus in principle.

FIG. 17 is a diagram illustrating an example of a line focusing sound field.

[Explanation of symbols]

1,51… Striped mode diaphragm, 2a, 2b, 2a ′, 2b ′, 6a, 6b… Reflector, 3,3 ′… Separator, 4,7… Opening, 5… Nodal, 52… Bolt tightening Langevin type vibrator, 53: Exponential horn, 54: One-wavelength resonance rod, 55: Sound source vibration system, 56a, 56b ...
Focusing direction changer, 57 ... straight line (focusing sound field).

Claims (4)

(57) [Claims] In a focused ultrasonic generator, a band-shaped striped mode vibration plate having a vibration driving source attached to the center thereof, and a space above both sides of the plate along a longitudinal direction of the striped mode vibration plate are defined. An opening having a fixed width is formed in a region opposed to the longitudinal center line of the stripe mode diaphragm while covering the same, and an ultrasonic wave traveling vertically from the plate surface of the stripe mode diaphragm is reflected on the inner surface thereof. A reflection plate formed of a paraboloid having a focal length satisfying a condition that the reflected wave is reflected by the stripe mode diaphragm and converged outside the opening, the stripe mode diaphragm and the reflector. A focused ultrasonic generator, comprising: a separator partitioning an internal space along each nodal line during bending vibration of the striped mode diaphragm. 2. A focal length given by a parabolic surface of a reflector is changed from an area of the stripe mode diaphragm facing the opening of the reflector by ultrasonic waves passing directly through the opening and reflected by the aperture. 2. The focused ultrasound generator according to claim 1, wherein the ultrasound focused on the outside of the section is set to have the same phase on its focusing line. 3. The focused ultrasonic generator according to claim 1, wherein the paraboloids have focal lengths different by (λa / 4) × odd number, where λa is the wavelength of the ultrasonic wave generated by the stripe mode diaphragm. A focused ultrasonic generator in which two kinds of configured divided reflectors are alternately arranged in a section between respective separators such that their focal positions are on the same line, thereby constituting the entire reflector. 4. In each section where any one type of segmented reflector is provided, an ultrasonic wave directly passing through the opening from a region of the striped mode diaphragm facing the opening of the segmented reflector is provided. 4. The focused ultrasonic generator according to claim 3, wherein the ultrasonic waves focused outside the opening through reflection are set to have the same phase on the focusing line.