KR101861354B1 - Focused Ultrasonic Transducer - Google Patents

Focused Ultrasonic Transducer Download PDF

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Publication number
KR101861354B1
KR101861354B1 KR1020150164724A KR20150164724A KR101861354B1 KR 101861354 B1 KR101861354 B1 KR 101861354B1 KR 1020150164724 A KR1020150164724 A KR 1020150164724A KR 20150164724 A KR20150164724 A KR 20150164724A KR 101861354 B1 KR101861354 B1 KR 101861354B1
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South Korea
Prior art keywords
piezoelectric element
electrode
liquid
matching layer
filled
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KR1020150164724A
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Korean (ko)
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KR20170060355A (en
Inventor
배영민
양종렬
김인수
이경희
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한국전기연구원
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Priority to KR1020150164724A priority Critical patent/KR101861354B1/en
Publication of KR20170060355A publication Critical patent/KR20170060355A/en
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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N7/00—Ultrasound therapy
    • A61N7/02—Localised ultrasound hyperthermia
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N7/00—Ultrasound therapy
    • A61N2007/0052—Ultrasound therapy using the same transducer for therapy and imaging
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N7/00—Ultrasound therapy
    • A61N2007/0056—Beam shaping elements

Abstract

The ultrasonic transducer is provided with a liquid chamber filled with liquid or an air chamber filled with air in the path of the ultrasonic wave generated in the center of the piezoelectric element to minimize the fluctuation of the vibration mode of the piezoelectric element constituting the ultrasonic transducer, And the increase in the sound pressure at the center of the piezoelectric element is effectively eliminated.

Description

{Focused Ultrasonic Transducer}

The present invention relates to an ultrasonic transducer, and more particularly, to an ultrasonic transducer in which a liquid chamber filled with a liquid or an air chamber filled with air is installed on the path of an ultrasonic wave generated at the center of the piezoelectric transducer in order to minimize fluctuation of a vibration mode of a piezoelectric element constituting an ultrasonic transducer To a focused ultrasound transducer that efficiently removes the increase in sound pressure at the center of the piezoelectric element while maintaining the vibration mode of the piezoelectric element.

Ultrasonic transducers are devices that convert electrical AC signals to ultrasonic waves, and are used in therapeutic applications as well as non-invasive medical diagnostic imaging fields.

1 is a view showing a configuration of an ultrasonic transducer according to the prior art.

The ultrasonic transducer 10 according to the related art drives the piezoelectric element 11 by applying an electrical alternating signal to the first electrode 12 and the second electrode 13 deposited on both surfaces of the piezoelectric element 11, A layer 14 and a matching layer 15 are formed.

The matching layer 15 is assembled on the side of the ultrasonic wave propagating direction to improve the ultrasonic wave transmission efficiency with the medium 16 and the band of the ultrasonic wave transducer can be controlled or the ringing phenomenon can be reduced through the design of the back surface layer 14 have.

Particularly, various materials such as epoxy are used for the matching layer 15 for efficient impedance matching between the piezoelectric element 11 and the medium 16.

The ultrasonic transducer 10 generates an ultrasonic wave by applying an electrical alternating signal to the piezoelectric element 11. Various vibration modes are formed according to the frequency of the electrical alternating signal and the matching layer 15 and the back layer 14 The vibration mode is changed.

Therefore, even if the conventional ultrasonic transducer 10 is designed to drive the piezoelectric element 11 in a constant vibration mode, the vibration mode is changed in the attaching step of the matching layer 15, and the ultrasonic wave generating efficiency is often lowered.

As shown in FIG. 2, a focused ultrasound transducer 20 has been fabricated and used to generate ultrasound with high output.

The focusing ultrasonic transducer 20 of the first embodiment includes a concave piezoelectric element 21 and a first electrode 21a and a second electrode 21b on the both sides of the piezoelectric element 21 and a back layer 22, The ultrasonic waves generated by the matching layer 23 are converged to a predetermined position of the medium 24.

In most cases, the concave piezoelectric element 21 is not uniform in intensity of the ultrasonic waves generated from the entire surface of the piezoelectric element 21 due to many factors such as size, shape, thickness, and the like.

For example, when the ultrasonic waves are strong at the center of the piezoelectric element 21 and weakly at the edge, the intensity distribution of the ultrasonic waves formed at the focus is long in the longitudinal direction and narrow in the width direction.

Conversely, when the ultrasonic waves are weak at the center of the piezoelectric element 21 and strongly generated at the edge, the distribution of the focused ultrasonic waves formed at the focus is relatively short in the longitudinal direction and wider in the width direction.

Ultrasonic waves generated in the piezoelectric element 21 may have side effects when strong ultrasonic waves are generated in a specific portion.

Particularly, in the case of a large problem, the ultrasonic wave is strong at the central portion of the piezoelectric element 21 and weakly at the edge. In this case, the energy distribution at the focal point may become excessively long in the longitudinal direction, which may affect the user to a deeper or shallower depth than the desired position (i.e., the target).

3, the focusing ultrasound transducer 30 of the second embodiment includes a concave piezoelectric element 31 having a hole 32 at the center thereof, a piezoelectric element 31 having a concave shape, The ultrasonic waves generated by the first electrode 32a, the second electrode 32b, the back layer 33 and the matching layer 34 are focused on the both sides of the medium 35 at a predetermined position.

Since the focused ultrasound transducer 30 generates ultrasonic waves with high sound pressure at the center portion, the center portion of the piezoelectric element 31 may be removed by piercing the hole 32 in the center portion of the piezoelectric element 31. Such a method of removing the center portion of the piezoelectric element 31 has a problem that the manufacturing process is difficult and the economical efficiency is low and the accurate curved surface of the piezoelectric element is difficult to maintain.

As a result, the conventional focusing ultrasound transducers 20 and 30 have limitations in effectively solving the increase in the sound pressure at the center of the piezoelectric elements 21 and 31 while maintaining the vibration mode of the piezoelectric elements 21 and 31.

In order to solve the above problems, the present invention provides a liquid chamber filled with a liquid or an air chamber filled with air in order to minimize the fluctuation of the vibration mode of the piezoelectric element constituting the ultrasonic transducer, in the path of ultrasonic waves generated in the center of the piezoelectric element The present invention provides a focused ultrasound transducer that efficiently removes the increase in sound pressure at the center of a piezoelectric element while maintaining a vibration mode of the piezoelectric element.

According to an aspect of the present invention, there is provided an ultrasonic transducer,

A piezoelectric element in the form of a flat plate;

A first electrode formed on one surface of the piezoelectric element;

A second electrode formed on the other surface of the piezoelectric element; And

And a liquid chamber filled with a liquid between the second electrode and the matching layer.

In the ultrasonic transducer according to the present invention,

A concave piezoelectric element;

A first electrode formed on one surface of the piezoelectric element;

A second electrode formed on the other surface of the piezoelectric element;

And a matching layer formed on one surface of the second electrode, and an air chamber filled with air is formed in the matching layer.

In the ultrasonic transducer according to the present invention,

A piezoelectric element in the form of a flat plate;

A first electrode formed on one surface of the piezoelectric element;

A second electrode formed on the other surface of the piezoelectric element;

A liquid chamber filled with a liquid between the second electrode and the concave acoustic lens; And

And a matching layer formed on a curved surface of the acoustic lens, wherein an air chamber filled with air is formed inside the matching layer.

According to the above-described configuration, the present invention has the effect of efficiently reducing the sound pressure increase at the center of the piezoelectric element while maintaining the vibration mode of the piezoelectric element of the ultrasonic transducer.

The present invention has the effect of manufacturing a focused ultrasound transducer using a flat piezoelectric transducer.

Since the present invention is not a method of removing the center portion of the piezoelectric element to reduce the fluctuation of the vibration mode of the piezoelectric element, the manufacturing cost of the ultrasonic transducer can be reduced and the fluctuation of the vibration mode of the piezoelectric element can be minimized.

1 is a view showing a configuration of an ultrasonic transducer according to the prior art.
2 is a view showing a configuration of a focusing type ultrasonic transducer according to a first embodiment of the related art.
3 is a view showing a configuration of a focusing type ultrasonic transducer according to a second embodiment of the prior art.
4 is a diagram illustrating the configuration of an ultrasonic transducer according to a first embodiment of the present invention.
5 is a diagram illustrating the configuration of a focused ultrasound transducer according to a second embodiment of the present invention.
6 is a diagram illustrating the configuration of a focused ultrasound transducer according to a third embodiment of the present invention.
7 is a view showing an acoustic field of a focused ultrasound transducer according to a third embodiment of the present invention.

Throughout the specification, when an element is referred to as "comprising ", it means that it can include other elements as well, without excluding other elements unless specifically stated otherwise.

4 is a diagram illustrating the configuration of an ultrasonic transducer according to a first embodiment of the present invention.

The ultrasonic transducer 100 according to the first embodiment of the present invention converts an electric signal into ultrasonic waves. The ultrasonic transducer 100 includes a first electrode (not shown) deposited on both surfaces of a piezoelectric element 110 formed inside a housing (not shown) The liquid chamber 160 is filled with a liquid between the second electrode 130 and the matching layer 150. The second electrode 130 and the rear layer 140 are formed on one surface of the first electrode 120, .

The piezoelectric element 110 is in the form of a flat plate, and the vibration frequency generated according to the thickness is determined, and includes all the vibration frequencies that can be implemented without limiting the range of the frequency. And generally covers a whole range of vibration frequencies that can be used for ultrasound therapy.

The size of the piezoelectric element 110 does not limit the size of the high-intensity focusing ultrasound transducer 100 so as to be suitably adapted to the size of the energy and the therapeutic use.

The first electrode 120 and the second electrode 130 are coupled to one surface and the other surface of the piezoelectric element 110 and are electrically connected to the current generator so as to receive an alternating current generated by a current generator .

When an alternating current is applied to the first electrode 120 and the second electrode 130 by the current generator, the applied alternating current flows through the piezoelectric element 110 and the piezoelectric effect of the piezoelectric element 110, (110) vibrates. These vibrations have ultrasonic characteristics.

The piezoelectric element 110 does not directly adhere to the matching layer 150 but forms the liquid chamber 160 between the second electrode 130 and the matching layer 150.

Ultrasonic waves generated in the piezoelectric element 110 are transmitted to the matching layer 150 through the liquid in the liquid chamber 160 and are transmitted to a predetermined position of the medium 170.

The liquid chamber 160 is filled with a liquid material such as glycerol that has a low acoustic attenuation.

Ultrasonic waves generated in the piezoelectric element 110 are firstly brought into contact with a liquid material having a fluidity filled in the liquid chamber 160 and low in acoustic damping and then brought into contact with the matching layer 150 to change the vibration mode of the piezoelectric element 110 Can be minimized.

5 is a diagram illustrating the configuration of a focused ultrasound transducer according to a second embodiment of the present invention.

The focused ultrasound transducer 200 according to the second embodiment of the present invention converts a electric signal into an ultrasonic wave and includes a concave piezoelectric element 210 formed inside a housing (not shown) A second electrode 212 and a back layer 220 formed on one surface of the first electrode 211 and a matching layer 212 formed on one surface of the second electrode 212. The first electrode 211, 230, and an air chamber 240 filled with air in the matching layer 230.

The first electrode 211 and the second electrode 212 are coupled to one surface and the other surface of the piezoelectric element 210 and are electrically connected to the current generator to receive an alternating current generated by a current generator .

When an alternating current is applied to the first electrode 211 and the second electrode 212 by the current generator, the applied alternating current flows through the piezoelectric element 210 and the piezoelectric effect of the piezoelectric element 210, (210) vibrates.

The air chamber 240 is formed inside the matching layer 230, particularly near the interface with the medium 250 among the inner center portions of the matching layer 230.

The air chamber 240 is a curved surface of a semicircular shape in which the surface of the air chamber 240 reflected by the ultrasonic waves generated by the piezoelectric element 210 is reflected.

Since the air chamber 240 is filled with air and the filled air has a very low acoustic impedance compared to the material constituting the matching layer 230, the ultrasonic waves generated at the center of the curved piezoelectric element 210 are transmitted to the air chambers 240 To prevent the ultrasonic waves from being transmitted to the medium 250.

A part of the ultrasonic waves generated in the piezoelectric element 210 is reflected at the interface of the air chamber 240 and the remaining part is focused at a predetermined position of the medium 250 through the matching layer 230.

The focused ultrasound transducer 200 reflects the ultrasonic waves generated at the center portion of the piezoelectric element 210 due to the air chamber 240 so that the edge portions of the piezoelectric element 110 having a relatively lower intensity than the center portion are equal in intensity to the ultrasonic waves Or may be made slightly weaker than the ultrasonic intensity of the edge portion of the piezoelectric element 110.

FIG. 6 is a view showing a configuration of a focused ultrasound transducer according to a third embodiment of the present invention, and FIG. 7 is a view showing an acoustic field of a focused ultrasound transducer according to a third embodiment of the present invention.

The focused ultrasound transducer 300 according to the third embodiment of the present invention converts a electric signal into an ultrasonic wave and includes a flat plate type piezoelectric element 310 formed inside a housing (not shown) A second electrode 330 and a back layer 332 formed on one surface of the first electrode 320 and a second electrode 330 formed on both surfaces of the first electrode 320 and the second electrode 330. The first electrode 320, And a liquid chamber 160 filled with a liquid between the liquid chamber 340 and the liquid chamber 340.

The acoustic lens 340 functions as a curved surface to concentrate ultrasound waves.

The acoustic lens 340 has a matching layer 350 formed on one surface thereof and the matching layer 350 includes an air chamber 240 filled with air.

The liquid chamber 160 minimizes the fluctuation of the vibration mode generated in the coupling of the piezoelectric element 310 and the acoustic lens 340.

Ultrasonic waves generated in the piezoelectric element 310 are first brought into contact with a liquid material filled in the liquid chamber 160 and having low acoustic attenuation, and then contacted with the acoustic lens 340 and the matching layer 350 in this order.

A high sound pressure is formed at the center of the acoustic lens 340 by the ultrasonic waves focused through the acoustic lens 340. At this time, the air chamber 240 reflects the ultrasonic wave generated at the center of the acoustic lens 340 to prevent it from being transmitted to the medium 360.

The focused ultrasound transducer 300 minimizes the fluctuation of the vibration mode by the liquid chamber 160 by using the ultrasonic waves generated in the piezoelectric element 310 and transmits the ultrasonic waves generated at the center of the acoustic lens 340 to the air chamber 240 And is focused at a constant position of the medium 360 through the matching layer 350. [

The acoustic field distribution of the focused ultrasound transducer 300 is a result of calculation using commercial software as shown in FIG. 7 (a), the result of analysis at a frequency of 230 kHz, It can be confirmed that the ultrasonic waves are focused.

As shown in FIG. 7 (b), the distribution profile of the sound pressure along the boundary surface between the matching layer 350 and the medium 360 and along the X direction (transverse direction) at the focusing portion is shown.

The ultrasonic waves generated from the piezoelectric element 310 are focused at a certain position of the medium 360 while the sound pressure at the center of the interface between the matching layer 350 and the medium 360 is sufficiently lowered.

The third embodiment is advantageous in that the focused ultrasound transducers 100 and 300 can be manufactured using the planar piezoelectric elements 110 and 310.

Since the first, second, and third embodiments are not a method of removing the center portion of the piezoelectric element, the manufacturing cost of the ultrasonic transducer can be reduced, and the advantage of minimizing fluctuation of the vibration mode of the piezoelectric element have.

The embodiments of the present invention described above are not implemented only by the apparatus and / or method, but may be implemented through a program for realizing functions corresponding to the configuration of the embodiment of the present invention, a recording medium on which the program is recorded And such an embodiment can be easily implemented by those skilled in the art from the description of the embodiments described above.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, It belongs to the scope of right.

100: Ultrasonic transducer
110: piezoelectric element
120: first electrode
130: second electrode
140: rear layer
150: matching layer
160: liquid chamber
170: medium
200: focused ultrasound transducer
210: piezoelectric element
211: first electrode
212: second electrode
220: rear layer
230: matching layer
240: air chamber
250: medium
300: focused ultrasound transducer
310: piezoelectric element
320: first electrode
330: second electrode
332: rear layer
340: Acoustic lens
350: matching layer
360: medium

Claims (9)

In the ultrasonic transducer,
A piezoelectric element in the form of a flat plate;
A first electrode formed on one surface of the piezoelectric element;
A second electrode formed on the other surface of the piezoelectric element; And
And a liquid chamber filled with a liquid between the second electrode and the matching layer, wherein the liquid to be filled in the liquid chamber is a liquid material having a low acoustic attenuation. delete In the ultrasonic transducer,
A piezoelectric element in the form of a flat plate;
A first electrode formed on one surface of the piezoelectric element;
A second electrode formed on the other surface of the piezoelectric element;
A liquid chamber filled with a liquid between the second electrode and the concave acoustic lens; And
And a matching layer formed on a curved surface of the acoustic lens, wherein an air chamber filled with air is formed inside the matching layer. The method of claim 3,
Wherein the liquid to be filled in the liquid chamber is a liquid material having a low acoustic attenuation. The method according to claim 1,
Wherein the ultrasonic waves generated from the piezoelectric element are first brought into contact with a liquid material filled in the liquid chamber and having a low acoustic attenuation and then contacted with the matching layer. The method of claim 3,
Wherein the ultrasonic waves generated from the piezoelectric element are first brought into contact with a liquid material filled in the liquid chamber and having a low acoustic attenuation, and then contacted in the order of the acoustic lens and the matching layer. The method of claim 3,
Wherein the air chamber is formed at an interface between the inner center portion of the matching layer and the medium. The method of claim 3,
Wherein the air chamber is a curved surface of a semicircular shape in which the surface reflected by the ultrasonic wave generated by the piezoelectric element is reflected. The method according to claim 1 or 3,
Further comprising a back layer formed on one surface of the first electrode.
KR1020150164724A 2015-11-24 2015-11-24 Focused Ultrasonic Transducer KR101861354B1 (en)

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Application Number Priority Date Filing Date Title
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Application Number Priority Date Filing Date Title
KR1020150164724A KR101861354B1 (en) 2015-11-24 2015-11-24 Focused Ultrasonic Transducer

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KR101861354B1 true KR101861354B1 (en) 2018-05-28

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Publication number Priority date Publication date Assignee Title
CN109925615B (en) * 2017-12-18 2021-11-19 深圳先进技术研究院 Magnetic compatible brain ultrasonic stimulation device and manufacturing method thereof
CN110227217A (en) * 2018-03-06 2019-09-13 重庆海扶医疗科技股份有限公司 Ultrasonic transducer
CN110227216A (en) * 2018-03-06 2019-09-13 重庆海扶医疗科技股份有限公司 Ultrasonic transducer

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