JP2009038675A - Ultrasonic transducer and ultrasonic probe equipped with same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ultrasonic transducer in which electrode leads embedded in a backing member and back-face driving electrodes of piezoelectric elements are securely connected while avoiding adhesion strength lowering and at least acoustic characteristics deterioration in combining the piezoelectric elements and the backing member. <P>SOLUTION: The ultrasonic transducer 100 includes a backing member 18, in which electrode leads 21 are embedded. One-side ends of the electrode leads 21 are exposed on a surface of the backing member 18, where concave-shaped combining portions 18a are formed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an ultrasonic probe technique, and more particularly to an ultrasonic transducer technique used in an ultrasonic probe.

  In order to acquire information on a desired diagnostic region of a subject using an ultrasonic probe, an ultrasonic diagnostic apparatus transmits (transmits) ultrasonic waves to the region, and reflects waves from tissue boundaries in the subject having different acoustic impedances. Receive. In this way, diagnosis is performed by scanning ultrasonic waves with an ultrasonic probe, obtaining information on the body tissue of the subject, and imaging it. This ultrasonic probe has an ultrasonic transducer in order to transmit an ultrasonic wave to a subject or the like and receive a reflected wave.

  Conventionally, as an ultrasonic transducer used in an ultrasonic probe of an ultrasonic diagnostic apparatus, a one-dimensional array ultrasonic transducer in which a plurality of piezoelectric elements are arranged in an array is used. However, in recent years, a two-dimensional array of ultrasonic transducers in which piezoelectric elements are arranged in a matrix has been used. A two-dimensional array of ultrasonic transducers can collect and display ultrasonic images in three dimensions. A three-dimensional ultrasonic image is useful for diagnosing a part that is easily overlooked in a two-dimensional image, and a tomographic image suitable for diagnosis and measurement can be obtained, so that improvement in diagnostic accuracy can be expected.

  However, in the method using the ultrasonic transducer of the two-dimensional array of the electronic scanning method, an increase in the number of elements of the piezoelectric elements (for example, 10 times to 100 times) is achieved by arranging the piezoelectric elements in two dimensions. It will be accompanied. The piezoelectric element and the ultrasonic diagnostic apparatus main body are connected via a relay substrate that performs processing of electrical signals, transmission / reception of electrical signals to / from the piezoelectric elements, and the increase in the number of piezoelectric elements The number of electrode leads for electrical connection between the relay substrate and the piezoelectric element is greatly increased.

  This significant increase in the number of electrode leads leads to a complicated connection structure between the piezoelectric element (piezoelectric body) in the ultrasonic probe and the transmission / reception circuit and the ultrasonic diagnostic apparatus main body in the relay substrate. If the connection structure is complicated, it may be difficult to realize a two-dimensional array of ultrasonic transducers. Therefore, the connection between the piezoelectric elements arranged on the two-dimensional array and the subsequent circuit, for example, the connection structure between the electrode lead and the relay substrate and the connection structure between the piezoelectric element and the electrode lead are not complicated. A configuration that enables realization of an ultrasonic transducer in the array is required.

  As an example of such a connection structure of each piezoelectric element and electrode lead, for example, it is conceivable that the electrode lead is directly drawn out from the back electrode disposed on the back surface of the piezoelectric element. For example, for the purpose of acoustic braking of a piezoelectric element, a flexible printed circuit board (hereinafter referred to as FPC) having electrode leads embedded in a backing material disposed on the back surface of the piezoelectric element, the FPC end face and back face There is a method of electrically connecting the electrodes. As an example of the electrical connection between the FPC end face and the back electrode, the piezoelectric element and the backing material are bonded to each other with a conductive adhesive having a high viscosity before curing, thereby exposing the back drive electrode of the piezoelectric element and the front surface of the backing material. The structure which connects with the electrode lead which did is considered (for example, patent document 1).

  Thus, when electrically connecting the backing material provided with the electrode lead inside and the back electrode of the piezoelectric element, a joining method as shown in FIG. 10 is generally used. Here, FIG. 10 is a schematic cross-sectional view showing a bonding structure between a backing material having an electrode lead embedded in a conventional ultrasonic transducer and a piezoelectric element.

  As shown in FIG. 10, the conventional ultrasonic transducer 300 is provided with a front electrode 312 on the front surface on the ultrasonic irradiation direction side of the piezoelectric elements (piezoelectric bodies) 314 arranged in a two-dimensional array. A back electrode 316 serving as a drive electrode is provided on the back surface facing the front surface. Further, a backing material 318 is bonded to the back side of the back electrode 316. Further, a second acoustic matching layer 311b and a first acoustic matching layer 311a are provided in front of the front electrode 312 (in the direction of ultrasonic wave irradiation / X direction in FIG. 10).

  In the backing material 318, an FPC 320 having electrode leads inside is embedded corresponding to the arrangement of the piezoelectric elements 314. An electrode lead is exposed from the end face of the FPC 320, and the exposed electrode lead and the back electrode 316 are electrically connected.

  As described above, in the conventional ultrasonic transducer 300 in which the FPC 320 is laminated and embedded in the backing material 318 and the end face of the FPC 320 provided with electrode leads inside and the back electrode 316 are electrically connected, In joining the material 318 and the piezoelectric element 314, a conductive adhesive having a high viscosity is generally used before curing.

JP 2000-166923 A

  In the conventional ultrasonic transducer 300 as shown in FIG. 10, the shape of the back surface of the piezoelectric element 314 and the front surface of the backing material 318 where the end surface of the FPC 320 is exposed is substantially flat. Therefore, when bonding is attempted through the conductive adhesive, the adhesive is not uniform due to the high viscosity of the conductive adhesive, and the center of the adhesive surface that is the connection portion between the backing material 318 and the end surface of the FPC 320 is the center. It is difficult for the conductive adhesive to spread over the entire surface, such as the thickness of the portion being increased and the peripheral portion being reduced.

  However, from the viewpoints of bonding strength and electrical connection, the conductive adhesive needs to be uniform with a certain thickness on the bonding surface. That is, for the connection between the backing material and the piezoelectric element in the ultrasonic transducer, that is, the connection between the back electrode and the FPC end face, the bonding is performed in order to maintain the electrical connection between the electrode lead and the back electrode of the piezoelectric element at the time of bonding. Since it is necessary to maintain the adhesive strength between the backing material and the piezoelectric element later, the thickness of the conductive adhesive layer must not be too thin.

  In addition, problems occur even when the conductive adhesive layer becomes too thick. That is, as the adhesive layer interposed between the backing material and the piezoelectric element becomes thicker, the acoustic surface as an ultrasonic transducer may have a negative effect on the characteristics (wave length, frequency band) of the emitted ultrasonic waves. There is.

  In this regard, there is a method of reducing the thickness of the conductive adhesive on the bonding surface by rubbing the bonding surface in the bonding step of bonding the backing material and the piezoelectric element, but also in this method, near the center of the rubbing surface However, it is difficult to make the thickness of the conductive adhesive layer uniform, and it is difficult to balance the maintenance of the adhesive strength and the improvement of the acoustic characteristics.

  The present invention has been made in view of the above problems, and the object thereof is to avoid a decrease in adhesive strength, at least a deterioration in acoustic characteristics, in the connection between the piezoelectric element and the backing material, while avoiding a deterioration in acoustic characteristics. It is an object to provide an ultrasonic transducer capable of reliably connecting an electrode lead embedded in a piezoelectric element and a back electrode of a piezoelectric element, and an ultrasonic probe including the ultrasonic transducer.

The present invention for solving the above problems includes a plurality of piezoelectric elements having a back electrode on the back surface opposite to the direction of irradiating ultrasonic waves, and a backing material disposed on the back surface of the piezoelectric elements, An electrode lead embedded in the backing material and having one end exposed from one surface of the backing material and bonded to the back electrode, the back surface of the piezoelectric element, or the one surface of the backing material An ultrasonic transducer characterized by comprising a formed concave joint.
Moreover, this invention for solving said subject is the backing material arrange | positioned in the said back surface of the several piezoelectric element which has a back electrode on the back surface on the opposite side to the direction which irradiates an ultrasonic wave, and the said piezoelectric element. An electrode lead embedded in the backing material, a part of which is exposed from one surface of the backing material and joined to the back electrode, the back surface of the piezoelectric element, or the one surface of the backing material An ultrasonic probe comprising an ultrasonic transducer having a concave joint formed on one side.

  According to the present invention, when the electrode lead that is partly exposed on one side of the backing material and the back electrode of the piezoelectric element are connected, the back side of the piezoelectric element and the electrode lead of the backing material are drawn out. In addition, a recess is formed at a position corresponding to the facing surface on either one side. Therefore, even if a conductive adhesive is used to bond the backing material and the piezoelectric element and the adhesive surfaces facing each other are rubbed together, the conductive adhesive spreads over the entire adhesive surface, and the conductive adhesive layer is left at the joint. Is done. Therefore, the conductive adhesive layer spreads evenly on the connection surface between the back electrode and the electrode lead, avoids a decrease in adhesive strength due to the conductive adhesive layer becoming too thin, and exists between the back electrode and the electrode lead. It is possible to prevent deterioration of acoustic characteristics due to the too thick conductive adhesive layer.

  Hereinafter, an ultrasonic transducer and an ultrasonic probe according to embodiments of the present invention will be described with reference to the drawings.

[Embodiment]
FIG. 1A is a schematic perspective view showing a state in which the ultrasonic transducer 100 according to the embodiment of the present invention is viewed from the first acoustic matching layer 11a side. FIG. 1B is a schematic perspective view showing the printed circuit board 20 embedded in the backing material according to the embodiment of the present invention. Hereinafter, the configuration of the ultrasonic transducer according to the present embodiment will be described.

(Schematic configuration of ultrasonic transducer)
As shown in FIG. 1A, the ultrasonic transducer 100 according to this embodiment has a front electrode on the front surface on the ultrasonic irradiation direction side of the piezoelectric elements (piezoelectric bodies) 14 arranged in a two-dimensional array. 12 is provided, and a back electrode 16 is provided on the back surface opposite to the front surface of the piezoelectric element 14. The piezoelectric element 14 converts an electrical signal applied between the back electrode 16 and the front electrode 12 (ground electrode) connected to the ground into an ultrasonic pulse and transmits it to the subject. An ultrasonic wave is received, and the ultrasonic wave is converted into an electric signal and output.

  Further, as shown in FIG. 1A, when an ultrasonic pulse is transmitted by the piezoelectric element 14, the ultrasonic pulse radiated to the opposite side to the ultrasonic irradiation direction is absorbed, and an extra piezoelectric element is obtained. In order to suppress vibration, a backing material 18 is bonded to the back side of the back electrode (drive electrode) 16 of the piezoelectric element 14. Further, in order to match the acoustic impedance between the piezoelectric element 14 and the subject, the first acoustic matching layer 11a and the second acoustic matching are further in front of the front electrode 12 (in the direction of ultrasonic wave irradiation / the X direction in FIG. 1). Layer 11b is provided.

  Further, a plurality of printed circuit boards 20 (for example, FPC: Flexible Printed Circuit) are embedded in the backing material 18. An electrode lead 21 having a conductive pattern is inserted from one end surface to the other end surface of the printed circuit board 20 as shown in FIG. In the ultrasonic transducer 100 shown in FIG. 1A, the backing material 18 is represented by a single material (for example, epoxy resin). However, the backing material of the present invention is not limited to this, and for example, a plurality of backing materials are used. You may be comprised with the material. In this way, when the backing material is composed of a plurality of materials, the constituent materials can be changed according to the distance from the joint portion with the piezoelectric element 14.

  The electrode lead 21 is connected to the back electrode 16 and the ultrasonic diagnostic apparatus main body, and also performs a post-stage electronic circuit (for example, the IC substrate 40 in FIG. 8) that processes electric signals transmitted and received between the piezoelectric element 14 and the like. ). The electrode leads 21 are arranged at substantially equal intervals inside the printed circuit board 20 and are exposed from one end surface and the other end surface of the printed circuit board 20. In this embodiment, the electrode lead 21 having a conductive pattern is connected to the subsequent electronic circuit via the printed circuit board 20, but the electrode lead of the present invention is not limited to this. For example, a configuration in which a needle-shaped electrode lead is embedded in a backing material, one end of the needle-shaped electrode lead is connected to the back electrode 16 of the piezoelectric element 14, and the other end with respect to the one end is connected to a subsequent electronic circuit. It may be.

(Structure of bonding surface of piezoelectric element and backing material)
Next, the structure of the bonding surface between the piezoelectric element 14 and the backing material 18 and the structure of the bonding surface between the back electrode 16 and the electrode lead 21 in the ultrasonic transducer 100 according to the present embodiment will be described with reference to FIGS. .

  FIG. 2 is a schematic perspective view showing a joint surface between the piezoelectric element 14 and the backing material 18 according to the embodiment of the present invention. FIG. 3 is a cross-sectional view taken along the line A-A ′ of the ultrasonic transducer 100 shown in FIG. 1.

  As shown in FIG. 2, a joining portion 18 a having a concave groove 18 d that is lowered below the periphery is formed on the front surface of the backing material 18 of the present embodiment. That is, a groove 18d is formed in each backing material 18 partially cut by the piezoelectric element separation groove 18e shown in FIG. 2 so as to be sandwiched between a pair of ridges 18b, and the bottom of the groove 18d. 18c is formed in a substantially planar shape. An electrode lead 21 exposed from the end face of the printed circuit board 20 as shown in FIG. 3 is drawn out to the substantially planar bottom portion 18c. Furthermore, a metal thin film is formed over the entire front surface of the backing material 18 including the surface of the bottom portion 18c. In the present embodiment, the metal thin film is formed over the entire front surface of the backing material 18, but it is sufficient that the metal thin film is formed at least on the surface of the bottom 18 c in the joint 18 a.

  The joint 18a is disposed corresponding to the position of the protrusion 14a formed on the back side of the piezoelectric element 14 disposed opposite to the joint 18a, and corresponds to the electrode lead 21 exposed from the end surface of the printed circuit board 20. Is formed. Further, the longitudinal direction of the groove 18d in the joint 18a is formed to be a direction (Y direction in FIG. 1A) that is substantially orthogonal to the direction in which the piezoelectric element 14 and the front surface of the backing material 18 face each other. .

  In addition, the width of the groove 18d (bottom 18c) in the joint 18a is formed to be slightly wider than the width of the protrusion 14a of the piezoelectric element 14, and the depth of the groove 18d (from the bottom 18c to the jetty 18b in the joint 18a). The height to the tip surface is formed to be slightly deeper than the height of the protrusion 14a. The depth of the joining portion 18a is desirably formed so that the adhesive layer made of the conductive adhesive 22 placed between the protrusion 14a and the bottom portion 18c of the joining portion 18a does not become too thick. .

  As shown in FIG. 2, a protrusion 14 a is formed on the back surface of the piezoelectric element 14 of the present embodiment so as to protrude toward the adjacent backing material 18 (rear). The protrusion 14a extends in the same direction as the longitudinal direction of the concave groove 18d of the joint 18a and passes through the substantially center of the back surface of the piezoelectric element 14, and the tip thereof is substantially planar. . A back electrode 16 is formed at the tip as shown in FIG.

  In the ultrasonic transducer 100 according to the present embodiment, the protrusion 14a of the piezoelectric element 14 is fitted and joined to the groove 18d of the concave joint 18a in the backing material 18. Furthermore, in joining of the joint part 18a and the protrusion 14a, it exposes to the surface of the bottom part 18c of the joint part 18a through the conductive adhesive 22 loaded on the bottom part 18c of the joint part 18a as shown in FIG. The metal thin film (the surface of the bottom 18c) formed on one end of the electrode lead 21 and the back electrode 16 formed on the tip of the protrusion 14a are bonded. Further, the conductive adhesive 22 bonds the wall surface of the groove 18d of the joint portion 18a (the surface connecting to the pier portion 18b and the bottom portion 18c) and the side surface of the protrusion portion 14a. For example, a conductive epoxy adhesive containing silver frit is used for the conductive adhesive 22.

  Thus, the projection 14a fits into the concave joining portion 18a, whereby the strength of joining between the backing material 18 and the piezoelectric element 14 can be improved. Further, by improving the bonding strength, even if the shape of the backing material 18 is deformed due to thermal stress or the like, it is possible to avoid adhesion peeling and poor contact between the back electrode 16 and the electrode lead 21 due to adhesion peeling. be able to. Therefore, it is possible to reduce the influence on the generation of the ultrasonic image due to the contact failure.

  Further, as shown in FIG. 3, the ultrasonic transducer 100 according to the present embodiment has a concave shape that forms a protrusion 14 a on the back surface of the piezoelectric element 14 and extends in the same direction as the protrusion 14 a on the front surface of the backing material 18. A joining portion 18a composed of a groove 18d is formed, and these are fitted. Therefore, in the joining process of the piezoelectric element 14 and the backing material 18, an operation of rubbing them together in order to spread the conductive adhesive 22 used for bonding uniformly on the bonding surface (the sliding movement in the Y direction in FIG. 2) is easy. It becomes.

  Further, in the ultrasonic transducer 100 according to the present embodiment, a bonding portion 18a including a concave groove 18d is formed on the front surface of the backing material 18, and the height of the protrusion 14a of the piezoelectric element 14 fitted to the bonding portion 18a. Is formed to be lower than the depth of the groove 18d of the joint 18a. Therefore, in the bonding process of the piezoelectric element 14 and the backing material 18, when the conductive adhesive 22 having a high viscosity used for bonding is spread on the bonding surface so as to spread both together, the protrusion 14 a of the piezoelectric element 14 is Since the conductive adhesive 22 is placed in the space between the front end surface and the bottom 18c of the joint 18a in the backing material 18, the situation where the layer of the conductive adhesive 22 becomes too thin due to the rubbing work is avoided, The thickness of the layer of the conductive adhesive 22 can be made uniform, the deterioration of the acoustic characteristics of the ultrasonic transducer 100 due to the layer being too thick, and the back electrode 16 due to the layer becoming too thin To prevent a decrease in the adhesive strength between the electrode lead 21 and the adhesive strength between the piezoelectric element 14 and the backing material 18 and to improve the adhesive strength. It can be.

  In FIG. 2, the conductive adhesive 22 is mounted only on the front surface of the backing material 18 on the surface of the bottom portion 18 c of the joint portion 18 a, but actually the joint portions 18 a of all the backing materials 18. A conductive adhesive 22 is placed on the surface of the bottom 18c of the substrate. Moreover, although the protrusion 14a of the piezoelectric element 14 in the present embodiment extends in the arrangement direction of the piezoelectric element 14, the protrusion of the present invention is not limited to this, and is orthogonal to the arrangement direction of the piezoelectric element 14, for example. You may extend in the direction to do. In this case, the extending direction of the groove 18d in the joining portion 18a of the backing material 18 is also formed in a direction orthogonal to the arrangement direction of the piezoelectric elements. In this way, the extending direction of the protrusion 14a and the extending direction of the groove 18d in the joint 18a may be formed in substantially the same direction.

  Further, as shown in FIG. 2, the surface of the bottom 18c of the groove 18d of the joint 18a in the backing material 18 of the present embodiment is substantially flat, but for the work of joining the piezoelectric element 14 and the backing material 18 together. As long as it does not hinder, it does not have to be formed in a substantially flat shape.

(Manufacturing process)
Next, the outline of the manufacturing process of the ultrasonic transducer 100 in the present embodiment will be described with reference to FIGS.

  FIG. 4 is a schematic perspective view showing the front surface of the backing material 18 in the manufacturing stage of the ultrasonic transducer 100 according to the embodiment of the present invention. FIG. 5 is a schematic perspective view showing the back surface of the piezoelectric element plate 4 before the piezoelectric element 14 according to the embodiment of the present invention is divided. FIG. 6 is a schematic perspective view showing a state before the piezoelectric element plate 4 and the backing material 18 according to the embodiment of the present invention are joined and divided. FIG. 7 is a schematic perspective view showing a state after the piezoelectric element plate 4 and the backing material 18 according to the embodiment of the present invention are joined and divided. Hereinafter, the outline of the manufacturing process of the ultrasonic transducer 100 according to the present embodiment will be described.

(Step 1)
First, a plurality of printed circuit boards 20 having conductive patterns formed therein as shown in FIG. 1B are stacked in the same direction and sealed with a resin having an acoustic attenuation effect. In this way, one side of the resin embedded and sealed with the printed board 20 and the other side facing the one side are cut together with the plurality of embedded printed boards 20, and the printed board 20 is formed on the end face of the sealed resin. Expose the end face of. Thus, by exposing the cut end face of the printed circuit board 20 to the end face of the resin, the backing material 18 with the electrode leads 21 exposed on one side and the other opposite side is formed.

(Step 2)
When the backing material 18 is formed, a groove is formed on one surface where the electrode lead 21 is exposed, and a joining portion 18a of the backing material 18 shown in FIG. 4 is formed. The groove is formed corresponding to the position where the printed circuit board 20 is exposed on one surface of the backing material 18, and the longitudinal direction of the groove is a direction in which the piezoelectric element 14 and the front surface of the backing material 18 face each other. It is formed in a direction that is substantially orthogonal (the Y direction in FIG. 1A). In this way, one surface of the backing material 18 on which the joint portion 18 a is formed becomes a front surface on the ultrasonic irradiation direction side, and the front surface becomes a joint surface with the piezoelectric element 14. Further, when the joining portion 18 a is formed, a metal thin film is formed on the front surface of the backing material 18. This metal thin film is for widening the contact area between the electrode lead 21 and the back electrode 16.

(Step 3)
The back surface of the piezoelectric element plate 4 before being divided as shown in FIG. 5 is fitted to the front surface of the backing material 18 formed with the joint 18a as shown in FIG. 4 (FIG. 6). That is, when the metal thin film is formed on the front surface of the backing material 18 shown in FIG. 4, the conductive adhesive 22 is placed on the surface of the bottom portion 18c of the groove 18d of the joint portion 18a. When the conductive adhesive 22 is loaded, the protruding rail 4a formed on the back surface of the piezoelectric element plate 4 as shown in FIG. 5 is fitted into the joint 18a. When the protruding rail 4a and the joint 18a are fitted, the piezoelectric element plate 4 and the backing material 18 are aligned in the direction in which the groove 18d of the joint 18a extends (the direction in which the protruding rail 4a extends), and the conductive adhesive. Uniform the 22 layers. Although not shown, a back electrode 16 is formed on the tip surface of the protruding rail 4a of the piezoelectric element plate 4 (the surface facing the front surface of the backing material 18) (see FIG. 3).

(Step 4)
When the piezoelectric element plate 4 and the backing material 18 are subjected to the alignment operation, the piezoelectric element plate 4 is divided into a two-dimensional array as shown in FIG. The piezoelectric element separation groove 18e is formed to reach the backing material 18 as shown in FIGS. In this way, by forming the cut groove extending to the backing material 18, the piezoelectric element plate 4 can be reliably divided and the adjacent piezoelectric elements 14 can be reliably separated from each other.

(Step 5)
When the piezoelectric element plate 4 is divided, plate-like front electrodes 12 are formed that are bonded to the front surfaces of all the piezoelectric elements 14. When the front electrode 12 is formed, a second acoustic matching layer plate and a first acoustic matching layer plate are formed in front of the front electrode 12 (a direction from the front electrode 12 toward the ultrasonic wave irradiation direction). When formed, an acoustic matching layer separation groove that divides only the second acoustic matching layer plate and the first acoustic matching layer plate is formed, and the first acoustic matching layer 11a and the second acoustic matching layer 11b are formed (FIG. 1 and FIG. 3). In this way, an ultrasonic transducer 100 as shown in FIG. 1 is formed.

  The manufacturing process of the ultrasonic transducer 100 according to the present embodiment is an example of the manufacturing process of the ultrasonic transducer according to the present invention, and is not limited to this process.

(Connection between ultrasonic transducer and IC board)
Next, an example of a connection configuration between the ultrasonic transducer 100 and the IC substrate 40 according to the present embodiment will be described with reference to FIG. FIG. 8 shows an example of a method for connecting the ultrasonic transducer 100. The ultrasonic transducer 100 is connected to the mechanism for connecting the ultrasonic transducer 100 and the IC substrate 40, the IC 45 on the IC substrate 40, and the ultrasonic diagnostic apparatus main body. It is a schematic perspective view which shows the mechanism which connects the cable to be connected.

  As shown in FIG. 8, the ultrasonic transducer 100 and the IC substrate 40 are connected via a relay substrate 41. That is, the other end of each printed board 20 opposite to one end on the ultrasonic wave irradiation direction side is connected to the relay board 41, and the plurality of electrode leads 21 arranged on both surfaces of the connected printed board 20 are connected to the relay board. The IC 45 is connected to the IC 45 on the IC substrate 40 through 41.

  In the relay substrate 41, for example, a relay pad is disposed on the surface facing the ultrasonic transducer 100 according to the position of each electrode lead 21, and is connected to each electrode lead 21 of the ultrasonic transducer 100. At this time, an electrode pad may be provided on the end face of the printed circuit board 20 on the ultrasonic transducer 100 side, and the electrode pad and the relay pad may be connected. Further, as the relay substrate 41, it is desirable to use a flat plate substrate made of resin or ceramics.

  Although not shown, the front electrode 12 is grounded via, for example, a housing of an ultrasonic probe (not shown).

  Further, as shown in FIG. 8, the IC substrate 40 is connected via a cable (both not shown) that is electrically connected to the ultrasonic diagnostic apparatus body, and the IC substrate 40 and the cable are connected to the cable connection substrate 50. Connected by. For example, a flexible FPC is used as the cable connection board 50, and one end of the FPC is connected to one end of the IC board 40 opposite to the one provided with signal leads (not shown). .

  The connectors 62 are provided at the other end of the cable connection board 50 and one end of the cable, respectively. The connector 62 connects the cable connection board 50 and the cable connected to the ultrasonic diagnostic apparatus main body.

  As shown in FIG. 8, an IC 45 is formed on an IC substrate 40 provided between the ultrasonic transducer 100 and the ultrasonic diagnostic apparatus main body, and the IC 45 is connected to the electrode lead 21 via a relay substrate 41 or the like. Has been. Further, the IC 45 drives the piezoelectric element 14 to transmit or receive an ultrasonic wave by the ultrasonic transducer 100, and processes a signal received by the piezoelectric element 14. With such a configuration, the piezoelectric element 14 receives a wave, converts it into a signal, is transmitted to each IC 45 on the IC substrate 40, and the signal processed by the IC 45 is transmitted through the cable connection substrate 50 to the ultrasonic diagnostic apparatus main body. Will be sent to. In this embodiment, the IC 45 is used, but includes an ASIC and other means.

(Action / Effect)
The operation and effect of the ultrasonic transducer 100 according to the present embodiment described above will be described.

  The ultrasonic transducer 100 and the ultrasonic probe using the ultrasonic transducer 100 according to the present embodiment include a bonding portion 18a in which a groove 18d is formed in a portion corresponding to the position of the exposed printed board 20 and electrode lead 21 on the front surface of the backing material 18. Is provided.

  Therefore, when the conductive adhesive 22 is used to join the piezoelectric element 14 and the backing material 18 and the opposing adhesive surfaces are rubbed together to reduce the thickness of the conductive adhesive 22 layer, the conductive adhesive 22 The agent 22 spreads over the entire bonding surface, and the conductive adhesive layer is placed in the groove 18d of the joint 18a. Therefore, the conductive adhesive layer spreads uniformly on the bonding surface between the back electrode 16 and the electrode lead 21, avoiding a decrease in adhesive strength due to the conductive adhesive layer becoming too thin, and the back electrode 16 and the electrode lead. It is possible to prevent an increase in electrical resistance and deterioration of acoustic characteristics due to the conductive adhesive layer existing between 21 being too thick.

  Further, as shown in FIG. 3, the ultrasonic transducer 100 and the ultrasonic probe using the same according to the present embodiment extend in the same direction as the groove 18d of the joint 18a of the backing material 18 on the back surface of the piezoelectric element 14. Protrusions 14a are formed and are configured to fit together.

  Therefore, in the joining process of the piezoelectric element 14 and the backing material 18, an operation of rubbing them together (Y1 direction and Y2 direction in FIG. 2) in order to spread the conductive adhesive 22 used for adhesion uniformly on the adhesion surface is facilitated. Become.

  Further, in the ultrasonic transducer 100 and the ultrasonic probe using the ultrasonic transducer 100 according to the present embodiment, the protruding portion 14a of the piezoelectric element 14 is fitted into the concave joint portion 18a formed on the front surface of the backing material 18. Thus, the bonding strength between the backing material 18 and the piezoelectric element 14 can be improved. Further, by improving the bonding strength, even if the shape of the backing material 18 is deformed, it is possible to avoid adhesion peeling and poor contact between the back electrode 16 and the electrode lead 21 due to adhesion peeling. Therefore, it is possible to reduce the influence on the generation of the ultrasonic image due to the contact failure.

(Modification)
Next, modifications of the ultrasonic transducer according to the present invention will be described below.

  In the ultrasonic transducer 100 of this embodiment and the ultrasonic probe using the ultrasonic transducer 100 described above, the protrusion 14a is formed on the front surface of the piezoelectric element 14, but the ultrasonic transducer 100 of the present invention is not limited to this. Absent. For example, the back surface of the piezoelectric element 14 may be a substantially flat surface.

  Also in this modified example, when bonding the piezoelectric elements 14 and the backing material 18 with the conductive adhesive 22, the conductive adhesive 22 spreads over the entire bonded surface, and the conductive adhesive layer Is placed in the groove 18d of the joint 18a. Therefore, a decrease in the adhesive strength due to the thin layer of the conductive adhesive 22 is avoided, and an increase in electrical resistance due to the conductive adhesive layer existing between the back electrode 16 and the electrode lead 21 being too thick and It is possible to prevent deterioration of acoustic characteristics.

  Moreover, in the ultrasonic transducer 100 of this embodiment and the ultrasonic probe using the same, the protrusion 14a is formed on the front surface of the piezoelectric element 14, but the ultrasonic transducer 100 of the present invention is not limited to this. . For example, a groove may be formed on the back surface of the piezoelectric element 14 and the front surface of the backing material 18 may be formed in a substantially flat surface. However, in this case, it is necessary to prevent the depth of the groove formed on the back surface of the piezoelectric element 14 from affecting the acoustic characteristics of the ultrasonic transducer 100.

  Also in this modified example, when bonding the piezoelectric elements 14 and the backing material 18 with the conductive adhesive 22, the conductive adhesive 22 spreads over the entire bonded surface, and the conductive adhesive layer Is placed in the groove of the piezoelectric element 14. Therefore, a decrease in the adhesive strength due to the thin layer of the conductive adhesive 22 is avoided, and an increase in electrical resistance due to the conductive adhesive layer existing between the back electrode 16 and the electrode lead 21 being too thick and It is possible to prevent deterioration of acoustic characteristics.

  Moreover, in the ultrasonic transducer 100 of this embodiment and the ultrasonic probe using the same, the protrusion 14a is formed on the back surface of the piezoelectric element 14, but the ultrasonic transducer 100 of the present invention is not limited to this. . For example, a groove may be formed in the piezoelectric element 14 and a protrusion may be formed on the front surface of the opposing backing material 18. However, in this case, it is necessary to prevent the depth of the groove formed on the back surface of the piezoelectric element 14 from affecting the acoustic characteristics of the ultrasonic transducer 100.

  Also in this modification, the conductive adhesive 22 used for bonding is bonded in the bonding process of the piezoelectric element 14 and the backing material 18 by fitting the grooves of the piezoelectric element 14 and the protrusions of the backing material 18 together. In order to spread it evenly on the surface, it becomes easy to rub them together. Further, the strength of the bonding between the backing material 18 and the piezoelectric element 14 can be improved, and even if the backing material 18 is deformed, adhesion peeling and contact failure between the back electrode 16 and the electrode lead 21 due to adhesion peeling are prevented. It can be avoided. Therefore, it is possible to reduce the influence on the generation of the ultrasonic image due to the contact failure.

  Further, in the ultrasonic transducer 100 and the ultrasonic probe using the ultrasonic transducer 100 in the present embodiment, the backing material 18 in which the printed circuit board 20 in which the conductive pattern is formed is embedded and the piezoelectric element 14 are joined, The back electrode 16 formed on the back surface of the piezoelectric element 14 and the electrode lead 21 exposed on the front surface of the backing material 18 are electrically connected via a conductive adhesive 22. The structure of the front surface of the backing material or the back surface of the piezoelectric element of the ultrasonic transducer can be applied to the following ultrasonic transducer, for example.

  FIG. 9 is a schematic perspective view showing a state in which the structure of the front surface of the backing material 218 and the back surface of the piezoelectric element 214 of the ultrasonic transducer 200 according to the present invention is applied to a modification of the present embodiment.

  In the ultrasonic transducer 200 shown in FIG. 9, an acoustic matching layer 211 is formed along one side of the multilayer printed circuit board 220, a piezoelectric element 214 is formed on the back surface thereof, and the acoustic matching layer 211 is interposed between the piezoelectric element 214. A front electrode 212 is formed. Further, similarly to the piezoelectric element 14 shown in FIG. 2, the back surface of the piezoelectric element 214 is formed with a protrusion protruding in the back surface direction, and a back electrode is formed at the tip of the protrusion 214a. In addition, a backing material 218 is formed on the back surface of the piezoelectric element 214, and a joint portion 218a including a concave groove is formed on the front surface of the backing material 218 at a position facing the protrusion 214a. In addition, the electrode lead in this modified example is configured to be connected to both the front electrode 212 and the back electrode 216 through each layer of the multilayer printed circuit board 220 and to the subsequent electronic circuit (IC substrate 40 or the like). Yes.

  Also in this modified example, the groove of the piezoelectric element 214 and the protrusion of the backing material 218 are fitted to each other, and the bonding strength between the backing material 218 and the piezoelectric element 214 can be improved. Even if there is deformation of 218, adhesion peeling and contact failure between the back electrode 216 and the electrode lead due to adhesion peeling can be avoided. Therefore, it is possible to reduce the influence on the generation of the ultrasonic image due to the contact failure. Further, it is possible to output a bipolar pulse by connecting a pulser for each of the two poles (front electrode and back electrode) of the piezoelectric element and operating them alternately.

  Further, in the ultrasonic transducer 100 and the ultrasonic probe using the ultrasonic transducer 100 according to the present embodiment, the tip of the pier portion 18b, the surface of the bottom portion 18c, and the wall surface connected to the pier portion 18b and the bottom portion 18c are substantially planar. However, the ultrasonic transducer 100 of the present invention is not limited to this. For example, these may be formed in a curved surface shape.

  Also in this modification, the conductive adhesive 22 used for bonding is bonded in the bonding process of the piezoelectric element 14 and the backing material 18 by fitting the grooves of the piezoelectric element 14 and the protrusions of the backing material 18 together. In order to spread it evenly on the surface, it becomes easy to rub them together. Further, the strength of the bonding between the backing material 18 and the piezoelectric element 14 can be improved, and even if the backing material 18 is deformed, adhesion peeling and contact failure between the back electrode 16 and the electrode lead 21 due to adhesion peeling are prevented. It can be avoided. Therefore, it is possible to reduce the influence on the generation of the ultrasonic image due to the contact failure. This modification can also be applied to the ultrasonic transducer according to the modification described above.

(A) The schematic perspective view which shows the ultrasonic transducer concerning embodiment of this invention. (B) The schematic perspective view which shows the printed circuit board embed | buried under the backing material concerning embodiment of this invention. The schematic perspective view which shows the piezoelectric element and backing material concerning embodiment of this invention. 1 is a schematic sectional view of an ultrasonic transducer according to an embodiment of the present invention. The schematic perspective view which shows the front surface of the backing material in the manufacturing stage of the ultrasonic transducer concerning embodiment of this invention. The schematic perspective view which shows the back surface of the piezoelectric element board before the piezoelectric element concerning embodiment of this invention is divided | segmented The schematic perspective view which shows the state before the piezoelectric element board and backing material concerning embodiment of this invention are joined and divided | segmented. The schematic perspective view which shows the state after the piezoelectric element board and backing material concerning embodiment of this invention were joined and divided | segmented. FIG. 2 is a schematic perspective view showing a mechanism for connecting an ultrasonic transducer and an IC substrate in the present embodiment and a mechanism for connecting an IC on the IC substrate and an ultrasonic diagnostic apparatus main body, which is an example of an ultrasonic transducer connection method. The schematic perspective view which shows the state which applied the structure of the backing material and piezoelectric element of the ultrasonic transducer | vibrator concerning this invention to the modification of this embodiment. The schematic sectional drawing which shows the connection structure of the backing material which embedded the electrode lead in the conventional ultrasonic transducer, and the piezoelectric element.

Explanation of symbols

4 Piezoelectric Element Plate 11a First Acoustic Matching Layer 11b Second Acoustic Matching Layer 12 Front Electrode 14 Piezoelectric Element 14a Protrusion 16 Back Electrode 18 Backing Material 18a Joint 18b Jetty 18c Bottom 18d Groove 18e Piezoelectric Element Separation Groove 20 Printed Circuit Board 21 Electrode lead 22 Conductive adhesive 40 IC substrate 41 Relay substrate 45 IC
50 Cable connection board 62 Connector

Claims (6)

A plurality of piezoelectric elements having a back electrode on the back side opposite to the direction of irradiating ultrasonic waves,
A backing material disposed on the back surface of the piezoelectric element;
An electrode lead embedded in the backing material and having one end exposed from one surface of the backing material and bonded to the back electrode;
A concave joint formed on either the back surface of the piezoelectric element or the one surface of the backing material;
Ultrasonic transducer characterized by. Protrusions that fit into the joints are formed on the other side of the back surface of the piezoelectric element on which the concave joints are formed or the one surface of the backing material,
The ultrasonic transducer according to claim 1. The joint portion is a concave groove configured to include a jetty portion having a substantially flat tip, and a substantially flat bottom portion sandwiched between the jetty portions and exposing one end portion of the electrode lead. Yes,
The protrusion is fitted to the bottom of the concave shape;
The ultrasonic transducer according to claim 2. The one end of the electrode lead and the back electrode are bonded via a conductive adhesive between the bottom and the protrusion;
The ultrasonic transducer according to claim 3. Than the height of the protrusion, the direction from the bottom to form the groove of the joint to the tip of the jetty is formed deeper,
The conductive adhesive is detained between the tip of the protrusion and the bottom of the joint;
The ultrasonic transducer according to claim 4. A plurality of piezoelectric elements having a back electrode on the back side opposite to the direction of irradiating ultrasonic waves,
A backing material disposed on the back surface of the piezoelectric element;
An electrode lead embedded in the backing material, partly exposed from one surface of the backing material and bonded to the back electrode;
An ultrasonic transducer having a concave joint formed on either the back surface of the piezoelectric element or the one surface of the backing material;
Ultrasonic probe characterized by.