JP4153805B2 - Ultrasonic device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ultrasonic device that transmits and receives ultrasonic waves, and more particularly to an ultrasonic device that can efficiently transmit energy.
[0002]
[Prior art]
Conventionally, in an ultrasonic device that transmits and receives ultrasonic waves, in order to increase the energy density of ultrasonic waves to be transmitted, the ultrasonic transducer surface that emits ultrasonic waves is curved in a concave shape with respect to the ultrasonic radiation direction. Structure is used.
[0003]
FIG. 6 shows an example of a conventional ultrasonic apparatus. The ultrasonic device 60 includes a vibrator 61 having a substantially U-shaped hemispherical cross section recessed in the ultrasonic radiation direction, a pair of lead wires 62 having one end connected to the vibrator, and the leads. It comprises input / output terminals 63 and 64 to which the other end of the line 62 is connected. Here, the vibrator 61 has a structure in which both sides of the piezoelectric plate 61a are sandwiched between metal electrodes 61b.
[0004]
In such an ultrasonic device 60, when an AC voltage is applied between the input / output terminals 63 and 64, the vibrator 61 repeatedly vibrates in the thickness direction and vibrates, and generates ultrasonic waves from the ultrasonic vibrator surface 61d. Let At this time, since the ultrasonic transducer surface 61d has a concavely curved structure, the emitted ultrasonic waves are focused almost at one point. Therefore, ultrasonic waves with high energy density can be obtained at the position where the ultrasonic waves are focused (focal position).
[0005]
FIG. 7 shows another example of a conventional ultrasonic apparatus. The ultrasonic device 70 has a hemispherical base 71 having a substantially U-shaped hemispherical shape recessed in the ultrasonic radiation direction, and a base surface 71a which is an inner surface of the base 71 in a mosaic shape. A plurality of planar vibrators 72 are arranged. Electric power is supplied to each vibrator 72 by a thin film wiring (not shown) formed on the base surface 71a.
[0006]
In the ultrasonic device 70, each of the transducers 72 is a flat surface, but the entire transducer 72 is disposed on the concave base surface 71a, and thus is equivalent to the ultrasonic transducer surface 61d described above. A transducer group having a concave ultrasonic transducer surface is formed. When an AC voltage is applied to the vibrator group, that is, all the vibrators 72, each vibrator 72 repeatedly vibrates by extending and contracting in the thickness direction, and the surface opposite to the surface in contact with the base 71 (vibration). Ultrasonic waves are emitted in a direction perpendicular to this plane from the child plane. As described above, the transducer group has a concavely curved structure, and therefore, the perpendicular to the transducer surface of each transducer 72 intersects at almost one point. Therefore, the ultrasonic waves radiated from the respective transducers 72 are converged at almost one point. A high energy density can be obtained at the focal position where the ultrasonic waves are focused.
[0007]
The applicant has not yet found prior art documents related to the present invention by the time of filing other than the prior art documents specified by the prior art document information described in this specification.
[0008]
[Non-Patent Document 1]
Junichi Miyoshi, supervised by others, "Ultrasonic Technology Handbook (new edition)", Nikkan Kogyo Shimbun, p. 839-844, 1882-1884
[Non-Patent Document 2]
Masanori Shimakawa, “Supersonic Engineering: Theory and Practice”, Industrial Research Committee, p. 57, 68-69, 523-524
[0009]
[Problems to be solved by the invention]
However, in the conventional ultrasonic apparatus, since the curvature radius of the concave shape of the ultrasonic transducer surface or the transducer group is fixed, the focal position where a high energy density can be obtained is limited to one place. That is, there is a problem that ultrasonic waves having a high energy density can be obtained only at a fixed focal position separated from the ultrasonic transducer surface by a “certain distance”.
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an ultrasonic apparatus capable of arbitrarily changing a position where an ultrasonic wave having a high energy density is obtained.
[0010]
[Means for Solving the Problems]
In order to solve the above-described problems, an ultrasonic device according to the present invention includes a flexible plate-like base and a plurality of vibrations disposed on one surface of the base and emitting ultrasonic waves. A child and a guide having an opening for fitting the base are provided.
[0011]
In the above ultrasonic apparatus, the guide may be formed in a cylindrical shape whose inner diameter changes along the axial direction, and the base may be slidably disposed on the inner surface of the guide.
In the ultrasonic apparatus, the base may be fitted to the guide so that one surface forms a concave surface.
The ultrasonic apparatus may have an arm extending radially from the center, and the vibrator may be disposed on the arm.
The ultrasonic apparatus may further include a mandrel having one end fixed to the other surface of the base and having a thread formed on the side surface, and the guide has a threaded portion that is screwed into the thread of the mandrel. May be.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the ultrasonic device of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram illustrating a configuration of an ultrasonic apparatus according to the present embodiment. The ultrasonic device 1 according to the present embodiment includes a guide 11 whose inner diameter changes along the axial direction, a flexible base 12 fitted inside the guide 11, and an inner side of the base 12. It comprises a plurality of planar vibrators 13 arranged in a mosaic pattern on a base surface 12a which is a surface.
[0013]
The guide 11 is made of a material that is more rigid than the base 12, and has an upper surface and a bottom surface that communicate with each other and open, and has a substantially frustoconical inner surface shape.
The base 12 is made of a flexible material such as resin or metal, and can move inside the guide 11 in the direction of the central axis of the guide 11 (in the direction of the arrow in FIG. 1), that is, in the ultrasonic radiation direction. As described above, the surface of the base 12 opposite to the base surface 12 a is brought into sliding contact with the inner surface of the guide 11 and is fitted inside the guide 11. When the base 12 is fitted inside the guide 11, the base 12 bends due to the external pressure received from the guide 11, and forms a concave surface in which the base surface 12 a side is recessed. When the base 12 moves inside the guide 11, the inner diameter of the guide 11 changes depending on the moving position, so that the external pressure received from the guide 11 changes. Since the base 12 has flexibility, the degree of bending of the concave surface, that is, the radius of curvature of the concave surface changes with a change in the external pressure received from the guide 11. Therefore, the curvature radius of the concave surface of the base 12 changes depending on the position inside the guide 11.
The vibrator 13 is composed of a known ultrasonic vibrator in which a piezoelectric plate is sandwiched between metal plates. Such a vibrator 13 is connected to a thin film wiring (not shown) formed on the base surface 12a, and is supplied with electric power from the outside through the thin film wiring.
[0014]
Next, the operation of the ultrasonic apparatus 1 according to this embodiment will be described.
When an AC voltage is applied to each vibrator 13, each vibrator 13 repeatedly vibrates in the thickness direction and vibrates, and the surface of the base 12 opposite to the surface in contact with the base surface 12 a ( Ultrasonic waves are emitted in a direction perpendicular to this surface from the transducer surface. The ultrasonic waves radiated from the respective transducers 13 are focused at almost one point because the base surface 12a side of the base 12 has a concave shape. Therefore, high energy density ultrasonic waves can be obtained at the focal position where the ultrasonic waves are focused.
[0015]
Here, it is assumed that the base 12 is slightly moved in the direction a shown in FIG. Then, since the inner diameter of the guide 11 is reduced, the external pressure applied from the guide 11 to the base 12 is increased, and the radius of curvature of the concave shape of the base 12 is decreased. When the radius of curvature of the concave shape of the base 12 decreases, the vibrator 13 disposed on the base surface 12a of the base 12 tilts, that is, the central axis of the guide 11 and the extension line of the ultrasonic wave radiation direction of each vibrator 13. The acute angle formed by is increased. For this reason, the focal position of the ultrasonic wave radiated from the ultrasonic apparatus 1 is closer to the base 12 side than before the base 12 is moved.
[0016]
On the other hand, it is assumed that the base 12 is slightly moved in the direction opposite to the direction a shown in FIG. Then, since the inner diameter of the guide 11 increases, the external pressure applied from the guide 11 to the base 12 decreases, and the radius of curvature of the concave shape of the base 12 increases. When the radius of curvature of the concave shape of the base 12 is increased, the vibrator 13 disposed on the surface of the base 12 is inclined, that is, formed by the central axis of the guide 11 and the extension line of the ultrasonic radiation direction of each vibrator 13. The acute angle is reduced. For this reason, the focal position of the ultrasonic wave radiated from the ultrasonic apparatus 1 is farther from the base 12 side than before the base 12 is moved.
[0017]
FIG. 2 is a graph schematically showing the relationship between the amount of movement of the base 12 in the direction a in the guide 11 and the distance from the base 12 to the focal position where high energy density ultrasonic waves are obtained. As described above, when the position of the base 12 is moved in the direction a (the amount of movement in the direction a is large), the ultrasonic device 1 has a concave curvature radius of the base 12 that is reduced from the base 12 to the focal position. Can be shortened. Further, if the position of the base 12 is moved in the direction opposite to the direction a (amount of movement in the direction a: small), the radius of curvature of the concave shape of the base 12 increases, so the distance from the base 12 to the focal position is increased. Can be long.
As described above, according to the present embodiment, the position of the base 12 in the guide 11 is changed to change the external pressure applied to the base 12, thereby reversibly and arbitrarily changing the focal position where the ultrasonic waves are focused. be able to.
In addition, the method of moving the base 12 can be arbitrarily set freely regardless of whether it is manual or automatic.
[0018]
In the present embodiment, the shape of the base 12 is not limited to the shape of a hemisphere having a substantially U-shaped cross section, and is emitted from a plurality of vibrators 13 arranged on the surface, such as a shape combined by a plane. If the structure is capable of changing the radiation angle of the ultrasonic wave so that the ultrasonic wave is focused at a certain position in the traveling direction and the focal position can be changed reversibly and arbitrarily, it can be set freely. can do.
[0019]
Next, an ultrasonic apparatus according to another embodiment of the present invention will be described with reference to FIGS. 3 is a perspective view of the ultrasonic device, FIG. 4 is a plan view of the ultrasonic device, FIG. 5A is a cross-sectional view of the ultrasonic device, and FIG. 3B is an ultrasonic wave when the mandrel 21 is rotated. It is sectional drawing of a sound wave apparatus.
The ultrasonic device 20 includes a mandrel 21 having a cylindrical shape, a guide 22 having an inner diameter that changes along the axial direction and screwed to the mandrel 21, a substantially cross shape in plan view, and a central portion 23a having a mandrel. An arm 23b fixed to one end of the base 21 and extending radially from the central portion 23a is configured to include a base 23 in pressure contact with the guide 22, and a vibrator 24 disposed on each arm 23b of the base 23.
[0020]
The mandrel 21 has a cylindrical shape having an axis 21a indicated by a one-dot chain line in FIG. 5, and a thread for engaging with the screwed portion 22b of the guide 22 is cut on the outer periphery.
[0021]
The guide 22 is made of a material that is more rigid than the base 23, and has a base portion 22a having a substantially truncated cone-shaped inner surface shape whose upper surface and bottom surface are open, and a cylindrical shape that extends from an end portion on the upper surface side of the base portion 22a. Screwing portion 22b. A screw thread is formed inside the screwing portion 22 b, and the guide 22 is screwed to the mandrel 21 by screwing the screw thread with a screw thread formed on the outer periphery of the mandrel 21. At this time, the central axis of the guide 22 substantially coincides with the axis 21 a of the mandrel 21. The edge 22c on the inner surface or bottom surface side of the base portion 22a is in contact with or pressed against each arm 23b of the base 23.
[0022]
The base 23 is made of a flexible material such as resin or metal, and is made up of a central portion 23a and rectangular arms 23b extending radially from the center of the central portion 23a. In the present embodiment, four arms 23b are formed. However, as long as the arms 23b extend radially from the center of the central portion 23a, the number of arms 23b is not limited to four and can be freely determined as appropriate. Can be set. The central portion 23 a is fixed to the end portion 21 b on the side close to the edge portion 22 c of the guide 22 of the mandrel 21. Such a base 23 is fitted inside the guide 22 with the surface (back surface) opposite to the base surface 23c of the arm 23b slidably contacted with the inner surface of the guide 22 or the edge 22c on the bottom surface side.
[0023]
The vibrator 24 is composed of a known ultrasonic vibrator in which a piezoelectric plate is sandwiched between metal plates, and is disposed on the base surface 23 c of the arm 23 b of the base 23. Such a vibrator 24 is connected to a lead wire (not shown) or the like, and is supplied with electric power from the outside through this lead wire.
[0024]
Next, the operation of the ultrasonic apparatus 20 will be described.
When an AC voltage is applied to each vibrator 24, each vibrator 24 repeatedly vibrates by stretching and contracting in the thickness direction, and the face opposite to the face in contact with the base 23 (vibrator face). To emit ultrasonic waves in a direction perpendicular to this plane.
[0025]
Normally, as shown in FIG. 5A, the ultrasonic device 20 has the end 21 b of the mandrel 21 and the edge 22 c of the guide 22 on the same plane, and the arm 23 b of the base 23 is aligned with the axis of the mandrel 21. On the other hand, the base 23 is disposed in a state of spreading in a plane. Therefore, the ultrasonic waves radiated from each transducer 24 propagate in parallel with the axis of the mandrel 21 without being particularly focused.
[0026]
On the other hand, when the mandrel 21 is rotated in a predetermined direction (positive direction) as shown in FIG. 5B with the base 23 fixed, the screw threads formed on the mandrel 21 and the screwed portion 22b of the guide 22 are removed. Acting, the mandrel 21 moves in the direction a in FIG. 3, that is, the end 21 b of the mandrel 21 moves away from the edge 22 c of the guide 22. Then, since the edge 22c of the guide 22 presses the back surface of the arm 23b of the base 23, the arm 23b is inclined toward the base surface 23c of the arm 23b, that is, toward the axis 21a of the mandrel 21. Accordingly, each transducer 24 is also tilted toward the axis 21a of the mandrel 21, so that the ultrasonic waves radiated from each transducer 24 are focused at a predetermined position.
[0027]
Here, when the mandrel 21 is further rotated in the forward direction, the external pressure applied to the base 23 is further increased, so that the arm 23b of the base 23 is further inclined toward the axis 21a side of the mandrel 21. Therefore, the focal position of the ultrasonic wave radiated from each transducer 24 approaches the end 21 b of the mandrel 21.
On the other hand, when the mandrel 21s is rotated in the opposite direction, the external pressure applied to the base 23 is reduced, so that the arm 23b of the base 23 is inclined in the direction perpendicular to the axis 21a of the mandrel 21, that is, the base 23 spreads in a planar shape. Return to the state. Therefore, the focal position of the ultrasonic wave radiated from each transducer 24 is moved away from the end 21 b of the mandrel 21.
[0028]
As described above, according to this embodiment, the mandrel 21 is rotated to change the external pressure applied from the guide 22 to the base 23, and the inclination of the transducer 24 is changed, thereby changing the focal position where the ultrasonic waves are focused. It can be changed reversibly and arbitrarily.
Further, by providing the mandrel 21, the external pressure applied from the guide 22 to the base 23 can be finely adjusted, so that the focal position where the ultrasonic waves are focused can be finely adjusted.
[0029]
Next, a useful usage example of the ultrasonic apparatus according to the present embodiment will be described. For example, it is assumed that the direction from the transmitting-side ultrasound apparatus to the receiving-side ultrasound apparatus is known, but the distance to the receiving-side ultrasound apparatus is unknown or not constant. In such a case, the ultrasonic device according to the present embodiment is used for the transmission-side ultrasonic device, and the ultrasonic energy density is increased while transmitting the ultrasonic wave toward the reception-side ultrasonic device. Is gradually changed. Then, when the focal position is almost the same as the distance to the receiving-side ultrasonic device, the ultrasonic energy density (sound pressure) received by the receiving-side ultrasonic device is maximized, and the energy density at this time is the receiving-side energy density. If it exceeds the threshold value at which it can be determined that the ultrasonic device has received the ultrasonic wave, it means that the ultrasonic wave has been transmitted from the ultrasonic device on the transmission side to the ultrasonic device on the reception side. As described above, the ultrasonic apparatus according to the present embodiment is very effective when the distance to the object is unknown or not constant.
[0030]
Next, a case where the transmission of ultrasonic waves over a long period of time is required, not the case where the transmission of ultrasonic waves as described above is completed in a short time, will be described. In this case, first, the transmission-side ultrasonic device transmits ultrasonic waves toward the reception-side ultrasonic device, and the ultrasonic energy density is high, as in the case where the ultrasonic transmission described above is short. The focal position is gradually changed. The reception-side ultrasonic device transmits a predetermined signal to the transmission-side ultrasonic device when the energy density of the ultrasonic wave received from the transmission-side ultrasonic device exceeds a threshold value. When receiving the predetermined signal from the receiving-side ultrasonic apparatus, the transmitting-side ultrasonic apparatus fixes the focal position to the focal position when the predetermined signal is received, and continues to transmit ultrasonic waves at this focal position. By doing in this way, the ultrasonic device concerning this embodiment can transmit an ultrasonic wave continuously over a long time.
In addition, it continuously transmits ultrasonic waves continuously or intermittently while sweeping the focal position of the ultrasonic device on the transmitting side reversibly for several cycles from far to near to far to near, and within a range where a predetermined signal is received. The focal position may be fixed at an intermediate position. Even in this case, the ultrasonic apparatus according to the present embodiment can transmit ultrasonic waves more efficiently.
Further, the intensity of the predetermined signal transmitted by the receiving-side ultrasonic device is set to be proportional to the energy density of the ultrasonic wave received by the receiving-side ultrasonic device, and the position where the intensity of the predetermined signal is maximum Alternatively, the focal position of the ultrasonic device on the transmission side may be fixed. Even in this case, the ultrasonic apparatus according to the present embodiment can efficiently transmit ultrasonic waves.
[0031]
Needless to say, the use example described above can also be applied to the embodiment described with reference to FIG.
[0032]
In any of the above-described embodiments, a horn (resonator) or the like for adjusting the directivity of the ultrasonic wave may be disposed on the vibrator surface side of the vibrator of the ultrasonic device.
[0033]
Moreover, the ultrasonic device of the present invention is not limited to the case of transmitting ultrasonic waves, and can be applied to the case of receiving ultrasonic waves. In this case, the ultrasonic device of the present invention changes the position of the base inside the guide, and tilts the transducer so that the transducer surface of the transducer is positioned perpendicular to the traveling direction of the received ultrasound. By changing, ultrasonic waves can be received effectively.
[0034]
Further, the ultrasonic apparatus of the present invention is not limited to a three-dimensional (three-dimensional) structure having at least three or more transducers, and may have a two-dimensional structure. For example, a two-dimensional structure in which the ultrasonic wave is focused at a certain position in the traveling direction by arranging vibrators in an arc shape can be used. In this case, two or more vibrators are provided.
[0035]
【The invention's effect】
As described above, according to the present invention, when the base is moved in the direction of the central axis of the guide, the inner diameter of the guide changes depending on the movement position of the base, and the external pressure that the base receives from the guide also changes with the change of the inner diameter. However, due to this change in external pressure, the deflection of the base changes, the tilt of the vibrator changes, and the position where the ultrasonic waves radiated from the vibrator converge changes, so that ultrasonic waves with high energy density can be obtained. Can be reversibly and arbitrarily changed.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a configuration of an ultrasonic apparatus.
FIG. 2 is a graph schematically showing a relationship between a movement amount of a base 12 in a direction in a guide 11 and a distance from the base 12 to a focal position where an ultrasonic wave having a high energy density is obtained.
FIG. 3 is a perspective view of an ultrasonic device.
FIG. 4 is a plan view of the ultrasonic apparatus.
5A is a cross-sectional view of an ultrasonic device, and FIG. 5B is a cross-sectional view of the ultrasonic device when a mandrel 21 is rotated.
FIG. 6 is a schematic diagram showing the structure of a conventional ultrasonic device.
FIG. 7 is a schematic diagram showing the structure of a conventional ultrasonic device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Ultrasonic device, 11 ... Guide, 12 ... Base, 12a ... Base surface, 13 ... Vibrator, 20 ... Ultrasonic device, 21 ... Mandrel, 21a ... Axis, 21b ... End, 22 ... Guide, 22a ... Base , 22b ... connection part, 22c ... edge part, 23 ... base, 23a ... central part, 23b ... arm, 23c ... base surface, 24 ... vibrator.

Claims (2)

A plate-like base having flexibility;
A plurality of vibrators disposed on one surface of the base and emitting ultrasonic waves;
A guide having an opening for fitting the base,
The guide has a cylindrical shape, and is formed such that the inner diameter changes along the axial direction of the cylindrical shape ,
The base has arms extending radially from the center of the base, and the other surface opposite to the one surface is in contact with the guide, and is slidably disposed on the inner surface of the guide. the fitted has been pre SL one side to the guide forms a concave surface,
The ultrasonic device, wherein the vibrator is disposed on the arm. The ultrasonic device according to claim 1,
One end is fixed to the other surface of the base, further comprising a mandrel threaded is formed on a side surface,
The ultrasonic device according to claim 1, wherein the guide has a screwing portion that is screwed into a screw thread of the mandrel.

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