WO2016117721A1

WO2016117721A1 - Ultrasonic transducer having sound absorbing layer for improving heat dissipation

Info

Publication number: WO2016117721A1
Application number: PCT/KR2015/000599
Authority: WO
Inventors: 이재원; 이상곤
Original assignee: 알피니언메디칼시스템 주식회사
Priority date: 2015-01-20
Filing date: 2015-01-20
Publication date: 2016-07-28

Abstract

Disclosed is an ultrasonic transducer having a sound absorbing layer for improving heat dissipation. The ultrasonic transducer, according to one embodiment of the present invention, comprises: an active element; a matching layer formed on the front surface of the active element for matching the acoustic impedance of an ultrasonic wave propagated to the front surface of the active element; and a sound absorbing layer formed on the back surface of the active element for blocking or damping an ultrasonic wave propagated to the back surface of the active element, wherein the sound absorbing layer comprises a thermal conductor having a bracket structure with respect to an elevation direction.

Description

Ultrasonic Transducer with Sound Absorbing Layer for Improved Heat Dissipation

The present invention relates to an ultrasonic transducer for acquiring image information inside an object under examination using ultrasonic waves.

The ultrasound diagnosis apparatus is an apparatus for imaging an internal tissue of a subject by using an ultrasonic signal reflected by shooting an ultrasonic signal on the subject. The ultrasound diagnosis apparatus may transmit the ultrasound signal to a diagnosis part of the subject, and then acquire the image information of the diagnosis part by receiving an ultrasound signal reflected from the boundary of tissues inside the subject having different acoustic impedances. Can be.

The ultrasonic diagnostic apparatus includes an ultrasonic transducer for transmitting an ultrasonic signal to the subject and receiving an ultrasonic signal reflected by the subject. Ultrasonic transducers generally include an active element, a matching layer, and a backer layer.

According to one embodiment, an ultrasonic transducer having a sound absorbing layer for improving heat dissipation is proposed.

An ultrasonic transducer according to an embodiment includes an active element, a matching layer formed on a front surface of the active element and matching acoustic impedance of ultrasonic waves propagated to the front surface of the active element, and formed on a rear surface of the active element to form a rear surface of the active element. And a sound absorbing layer for blocking or attenuating the ultrasonic waves propagated to the sound absorbing layer, wherein the sound absorbing layer includes a thermal conductor having a bracket structure with respect to an elevation direction.

The thermal conductor of the sound absorbing layer according to the embodiment lowers the surface temperature of the ultrasonic transducer by generating heat generated in the active element toward the sound absorbing layer. The bracket structure according to an embodiment is integrally inserted into the sound absorbing layer in the form of a cover with a center toward the active element. At this time, in the bracket structure, thermal conductors are formed at both ends of the upper direction. The bracket structure may be inclined so that its ends become narrower in opposite directions of the ultrasonic traveling paths at both ends in the upward direction. The bracket structure may have a space in which the center in the upward direction is empty. Thermal conductor of the sound absorbing layer according to an embodiment is any one of copper, aluminum, PGS graphite sheet of graphite film, graphite, carbon nanotube, aluminum nitride, boron nitride, silicon carbide, beryllium oxide thereof In the form of a bond.

The sound absorbing layer according to an embodiment includes a first member composed of a thermal conductor which is a high impedance material around both ends of the upper direction, and a second member composed of a low impedance material around the center of the upper direction. The first member has a small acoustic pressure difference with the active element, so that the sound pressure transmitted in the direction of the predetermined ultrasonic wave propagation path is small, and the second member has a large acoustic impedance difference with the active element, and the sound pressure delivered in the direction of the predetermined ultrasonic wave path is high. The matching layer according to an embodiment has a multilayer structure.

According to one embodiment, as the heat dissipation characteristics are improved and the surface temperature of the ultrasonic transducer is lowered, there is no effect on the human body, which is a subject. The ultrasonic transducer according to an embodiment may be easily manufactured and improve heat dissipation characteristics of the transducer as the thermal conductor having a high thermal conductivity in the shape of a bracket is inserted into the sound absorbing layer.

In addition, since the acoustic impedance of the thermal conductors formed at both ends of the sound absorbing layer is higher than the sound impedance at the center of the sound absorbing layer, the sound pressure transmitted from the center to the acoustic lens in the upper direction is large, and from the peripheral part, the acoustic impedance is transmitted to the acoustic lens. The sound pressure is lowered. Accordingly, the beam shape is improved by apodization while the acoustic characteristics of the conventional transducer are not changed.

1 is a structural diagram showing the configuration of an ultrasonic transducer having a sound absorbing layer for improving heat dissipation according to an embodiment of the present invention;

2 is a stereoscopic view of a first member of a sound absorbing layer according to an embodiment of the present invention;

3 is a cross-sectional view of a first member of a sound absorbing layer according to various embodiments of the present disclosure;

4 is a block diagram of an ultrasonic diagnostic apparatus according to an embodiment of the present invention,

5 is a graph showing an effect of improving heat dissipation through a sound absorbing layer according to an embodiment of the present invention;

6 is a graph showing the degree of improvement of the beam shape of the sound absorbing layer and the conventional sound absorbing layer according to an embodiment of the present invention, Figure 7 is a graph showing the difference in the beam pattern accordingly.

Hereinafter, with reference to the accompanying drawings will be described embodiments of the present invention; In the following description of the present invention, if it is determined that detailed descriptions of related well-known functions or configurations may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. In addition, terms to be described below are terms defined in consideration of functions in the present invention, which may vary according to intention or custom of a user or an operator. Therefore, the definition should be made based on the contents throughout the specification.

In the present specification, when the first material layer is formed on the second material layer, it is a substrate that explicitly excludes it, as well as the case where the first material layer is formed directly on the second material layer. Unless otherwise, it is to be construed that the other third material layer includes all the intervening layers between the first material layer and the second material layer.

1 is a structural diagram showing the configuration of an ultrasonic transducer having a sound absorbing layer for improving heat dissipation according to an embodiment of the present invention.

Hereinafter, 'schematic' indicates that the depicted figure represents a relative positional or stacking relationship between components included in the ultrasonic transducer. Therefore, the specific shape or thickness of each of the components included in the ultrasonic transducer may not necessarily match those shown in the drawings.

Referring to FIG. 1, the ultrasonic transducer 1 includes a backer layer 10, an active component 12, and a matching layer 14, and includes a flexible printed circuit board. A flexible printed circuit board (FPCB, hereinafter referred to as FPCB) 16, a ground sheet (GRS, hereinafter referred to as GRS) 18, and an acoustic lens 19 may be further included.

The ultrasonic transducer 1 may be a single element transducer or an array transducer having a plurality of elements. The type of array transducer may be a linear array, a convex array, a phased array, or the like, and the present invention is applicable to all types of array arrays.

The direction in which the elements of the ultrasonic transducer 1 are arranged is called the azimuth direction, and the depth direction in which the ultrasonic signal travels is called the axial direction, and the direction orthogonal to these two directions is This is called the elevation direction.

The active element 12 generates an ultrasonic signal, transmits the ultrasonic signal to the object under test, and receives the ultrasonic signal reflected from the object under test. The sound absorbing layer 10 propagates in the direction of the sound absorbing layer 10, which is an unwanted direction of the ultrasonic signal generated from the active element 12 to minimize the return of the reflected wave. The matching layer 14 matches the difference in acoustic impedance between the active element 12 and the object under test so that ultrasonic waves propagate in the direction of the ultrasonic traveling path.

Inside the sound absorbing layer 10 according to an embodiment, a first member 101 made of a thermal conductor having high thermal conductivity and acoustic impedance is included. The first member 101 is formed inside the sound absorbing layer 10 in a bracket structure with respect to the upward direction. The bracket structure means a cover structure as shown in FIG. 1. Since the first member 101 of the bracket structure only needs to be inserted into the sound absorbing layer 10, the manufacturing process is simplified.

The thermal conductor of the first member 101 functions to disperse heat in the direction of the sound absorbing layer 10. As the heat conductor having a high heat capacity is inserted into the sound absorbing layer 10, heat generated by the ultrasonic transducer 1, for example, heat generated by the active element 112 and heat generated by multiple reflections, are absorbed. The heat is dissipated in the direction of the sound absorbing layer 10 having a high heat capacity without heat being transferred to the surface of (1), for example, the acoustic lens 19. As a result, the surface temperature of the ultrasonic transducer 1, for example, the temperature of the acoustic lens 19, is lowered. Since the acoustic lens 19 directly contacts the human body, which is the object to be inspected, it is preferable to reduce heat generation of the acoustic lens 19. In general, the surface temperature of the ultrasonic transducer 1 should be lowered in the transmission signal in a proportional relationship with the magnitude of the ultrasonic signal transmitted from the main body. However, according to the present invention, the surface temperature of the ultrasonic transducer 1 can be lowered by the thermal conductor structure of the sound absorbing layer 10 which dissipates heat while maintaining the level of the transmission signal.

The first member 101 composed of a thermal conductor according to an embodiment has a bracket structure having a center cover toward the active element 12. In this case, the first member 101 of the bracket structure may have thermal conductors formed at both ends of the first member 101. In this case, the heat dissipation characteristics of the ultrasonic transducer 1 can be improved without changing the existing acoustic characteristics. For example, due to the magnitude of the acoustic impedance of the thermal conductor formed at both ends of the sound absorbing layer 10 with respect to the upward direction, the sound pressure transmitted to the acoustic lens 19 is low at the periphery including both ends, and the sound absorption is performed. At the center of the layer 10, the sound pressure transmitted to the acoustic lens 19 is large. The acoustic characteristics maintain and enhance the existing acoustic characteristics, and the beam shape is improved by apodization. An embodiment thereof will be described later with reference to FIGS. 6 and 7.

Hereinafter, each configuration of the ultrasonic transducer 1 including the sound absorbing layer 10 for improving heat dissipation will be described in detail.

The sound absorbing layer 10 is configured such that the acoustic impedance is well matched with the active element 12. The sound absorption layer 10 may be configured to have sound attenuation characteristics, which are excellent sound absorption characteristics. The sound absorbing layer 10 having excellent sound absorbing properties not only reduces the pulse width of the ultrasonic wave by suppressing free vibration of the active element 12 formed on the front surface, but also occurs in the active element 12 and unnecessarily propagates the ultrasonic wave to the rear surface. Blocking the image effectively prevents image distortion.

Inside the sound-absorbing layer 10 according to an embodiment, the thermal conductivity and the thermal conductivity of the first member 101 and the first member 101 made of a thermal conductor having high thermal conductivity and acoustic impedance are high. And a second member 102 made of a material with low acoustic impedance.

The first member 101 made of a thermal conductor has a bracket structure, and is formed around both ends of the sound absorbing layer 10 in the upward direction. The first member 101 may be inserted into the sound absorbing layer 10 in the form of a cover with a center toward the active element 12. As shown in FIG. 1, the first member 101 according to an exemplary embodiment is inclined such that its end is gradually narrowed in the direction opposite to the ultrasonic traveling path (depth direction). The thermal conductor of the first member 101 disperses heat in the direction of the sound absorbing layer 10. The thermal conductor may be a PGS graphite sheet of graphite, copper, aluminum, or a polymer film, graphite, carbon nanotubes, aluminum nitride, boron nitride, silicon carbide, beryllium oxide, or a combination thereof.

The first member 101 formed at both ends of the upper direction by the thermal conductor in the form of a cover which is centered toward the active element 12 has a small acoustic impedance difference from the active element 12, and thus the predetermined ultrasonic propagation. The sound pressure transmitted in the path direction becomes small. On the other hand, since the second member 102 formed in the center portion of the upper direction is made of a low impedance material, the acoustic impedance difference with the active element 12 is large, so that ultrasonic waves do not propagate in the direction of the sound absorbing layer 10. The sound pressure transmitted in the ultrasonic traveling path direction becomes large. Thus, the size of the side lobe of the transducer is reduced, so that beam shape due to apodization is improved.

The active element 12 according to an embodiment generates an ultrasonic signal when energy is applied, such as an electrical signal is applied from the FPCB 16 and the GRS 18 located at both ends. The type of the active element 12 may vary depending on the type of the ultrasonic transducer 1, and is typically composed of a piezoelectric element. The piezoelectric element has a property that a voltage is generated when a mechanical pressure is applied through a piezoelectric effect, and a mechanical deformation occurs when a voltage is applied. There is no particular limitation on the shape or pattern of the piezoelectric elements. The piezoelectric element is made of a piezoelectric ceramic such as lead zirconate titanate (PZT), a single crystal, a composite piezoelectric compound of these materials and a polymer material, or a polymer material represented by polyvinylidene fluoride (PVDF). It may be formed of a piezoelectric body or the like.

The matching layer 14 is disposed between the active element 12 and the object under test to mediate the difference in acoustic impedance between the two components. For example, the ultrasonic wave generated by the active element 12 is transmitted to the inspected object or the loss of the reflected signal reflected and returned by the inspected object is reduced. The matching layer 14 may serve as a buffer for reducing problems such as image distortion caused by a sudden change in acoustic impedance between the active element 12 and the object under test.

The matching layer 14 may have a structure in which a plurality of layers are stacked. For example, as shown in FIG. 1, the first matching layer 141 and the second matching layer 142 may be configured, but the number of matching layers is not limited thereto. The reason why the matching layer 14 is composed of a plurality of layers is that the difference in acoustic impedance between the active element 12 and the human tissue under test is relatively large, so that the matching layer having the required characteristics is a single layer of material. Because it is difficult to form.

The FPCB 16 is formed between the active element 12 and the sound absorbing layer 10. The FPCB 16 is electrically connected to the active element 12 to apply a voltage to the active element 12. A GRS 18 may be formed between the matching layer 14 and the active element 12, and the matching layer 14 may exchange electrical signals with the active element 12 through the GRS 18. An acoustic lens 19 for focusing ultrasonic waves is formed on the front surface of the matching layer 14.

Meanwhile, in FIG. 1, the FPCB 16 is located in front of the sound absorbing layer 10 and the GRS 18 is located in the back of the matching layer 14, but the corresponding position is polling of the layers constituting the active element 12. It may vary depending on the direction. For example, the GRS 18 may be formed at the FPCB 16 location, and the FPCB 16 may be formed at the GRS 18 location.

2 is a stereoscopic view of a first member of a sound absorbing layer according to an embodiment of the present invention.

Referring to FIG. 2, the first member 101 made of a thermal conductor in the sound absorbing layer 10 has a bracket structure. The first member 101 of the bracket structure may be in the form of a cover whose center is toward the active element. In this case, as illustrated in FIG. 2, the first member 101 may have thermal conductors formed at both ends of the bracket structure with respect to the upper direction, and the center of the bracket structure may have an empty space. In this case, due to the magnitude of the acoustic impedance of the thermal conductor formed at both ends of the sound absorbing layer 10 on the basis of the upward direction, the sound pressure transmitted to the acoustic lens is low at the periphery including both ends, and the sound absorbing layer 10 is provided. In the center of, the sound pressure transmitted to the acoustic lens is large. The acoustic characteristics maintain and enhance existing acoustic characteristics, and the beam shape is improved by apodization.

3 is a cross-sectional view of a first member of a sound absorbing layer according to various embodiments of the present disclosure.

Referring to FIG. 3, a thermal conductor according to an embodiment is formed at both ends of the upper direction in a sound absorbing layer in a bracket structure, and may have a center cover toward the active element. The cross section of the first member may be (a) a triangle, (b) a rectangle, or (c) a circle based on an upward direction. Or (d), (e) or (f) may be geometric, but is not limited thereto. Furthermore, although not shown in FIG. 3, the center portion of the bracket structure may be formed as an empty space based on the upward direction.

4 is a block diagram of the ultrasonic diagnostic apparatus according to an embodiment of the present invention.

Referring to FIG. 4, the ultrasound diagnosis apparatus 40 includes an ultrasound transducer 1, a beamforming unit 2, an image processor 3, and an output unit 4.

The ultrasonic transducer 1 may be composed of a plurality of devices 400-1, 400-2,..., 300-n. In the sound absorbing layer of the ultrasonic transducer 1 according to an embodiment, a thermal conductor having a bracket structure is inserted to disperse heat in the direction of the sound absorbing layer. At this time, the bracket structure can be integrally inserted into the sound absorbing layer in the form of the cover cover the center toward the active element, as described above with reference to Figure 2, the thermal conductor is formed at both ends of the upper direction, The center of the direction may have an empty space. Furthermore, the bracket structure may be inclined so that the ends thereof become narrower in opposite directions of the ultrasonic traveling paths at both ends in the upward direction.

The beamforming unit 2 drives the ultrasonic transducer 1 to transmit an ultrasonic signal to the inspected object, and processes a reflected signal returned from the inspected object to generate a beam signal. The image processor 3 receives the beam signal from the beamformer 2 and generates an ultrasound image. The output unit 4 displays the ultrasound image generated by the image processor 3 to the outside.

5 is a graph showing an effect of improving heat dissipation through a sound absorbing layer according to an embodiment of the present invention.

Figure 5 shows the temperature change of the acoustic lens per hour in detail, the heat is dispersed in the direction of the sound absorbing layer by the thermal conductor inserted into the sound absorbing layer in the form of a bracket of the present invention to confirm that the temperature of the acoustic lens is lowered as a result Can be.

Referring to FIG. 6, as heat is dissipated in the direction of the sound absorbing layer by heat conductors formed at both ends of the sound absorbing layer, the sound pressure transmitted from the center to the sound lens is increased from the center to the sound lens. The sound pressure delivered is lowered. This acoustic characteristic is to maintain and enhance the existing acoustic characteristics, as shown in Figure 7, the beam shape is improved by apodization (apodization). Referring to FIG. 7, in the case of the present invention, it can be seen that the level of the side lobe is reduced. For example, while the maximum sidelobe level of the conventional side lobe is -12.5 dB, the maximum size of the side lobe of the bracket structure of the present invention can be confirmed that the maximum size of the side lobe is reduced to -15.0 dB. Accordingly, the thermal conductor of the bracket structure inserted into the sound absorbing layer can maintain and enhance the acoustic characteristics without changing the acoustic characteristics and improve the heat dissipation characteristics of the ultrasonic transducer.

So far, the present invention has been described with reference to the embodiments. Those skilled in the art will appreciate that the present invention can be implemented in a modified form without departing from the essential features of the present invention. Therefore, the disclosed embodiments should be considered in descriptive sense only and not for purposes of limitation. The scope of the present invention is shown in the claims rather than the foregoing description, and all differences within the scope will be construed as being included in the present invention.

Claims

Active element;

A matching layer formed on a front surface of the active element and matching an acoustic impedance of ultrasonic waves propagated to the front surface of the active element; And

A sound absorbing layer formed on a rear surface of the active element to block or attenuate ultrasonic waves propagated to the rear surface of the active element; Including;

The sound absorbing layer is an ultrasonic transducer, characterized in that it comprises a thermal conductor having a bracket (bracket) structure on the basis of the (elevation) direction.
The method of claim 1, wherein the thermal conductor of the sound absorbing layer is

Ultrasonic transducer, characterized in that to lower the surface temperature of the ultrasonic transducer by generating heat generated in the active element toward the sound absorbing layer.
The method of claim 1, wherein the bracket structure

A center is inserted into the sound absorbing layer integrally in the form of a cover (cover) toward the active element, the ultrasonic transducer.
4. The bracket of claim 3 wherein the bracket structure is

An ultrasonic transducer, characterized in that the thermal conductor is formed at both ends in the upward direction.
The method of claim 4, wherein the bracket structure

Ultrasonic transducer characterized in that the inclined so that the end is gradually narrowed in the opposite direction of the ultrasonic traveling path at both ends in the upward direction.
4. The bracket of claim 3 wherein the bracket structure is

Ultrasonic transducer, characterized in that the center in the upper direction has an empty space.
The method of claim 1, wherein the thermal conductor of the sound absorbing layer is

Ultrasonic transducer, characterized in that any one of the PGS graphite sheet, graphite, carbon nanotubes, aluminum nitride, boron nitride, silicon carbide, beryllium oxide or a combination thereof of graphite, copper, aluminum, polymer film.
The method of claim 1, wherein the sound absorbing layer

A first member composed of a thermal conductor which is a high impedance material around both ends of the phase direction, and a second member composed of a low impedance material around the center of the phase direction,

Since the first member has a small acoustic impedance difference from the active element, the sound pressure transmitted in the direction of the predetermined ultrasonic traveling path is small,

The second member has a large acoustic pressure difference between the active element and the ultrasonic transducer, characterized in that a large sound pressure transmitted in the direction of the predetermined ultrasonic traveling path.
The method of claim 1, wherein the matching layer is

Ultrasonic transducer, characterized in that the multilayer structure.