WO2017109929A1

WO2017109929A1 - Ultrasonic oscillator and ultrasonic medical device

Info

Publication number: WO2017109929A1
Application number: PCT/JP2015/086175
Authority: WO
Inventors: 塩谷　浩一; 長英坂井; 伊藤　寛
Original assignee: オリンパス株式会社
Priority date: 2015-12-25
Filing date: 2015-12-25
Publication date: 2017-06-29

Abstract

An ultrasonic oscillator, provided with: a piezoelectric body part in which a plurality of piezoelectric bodies is arranged in the lamination direction and bonded; and a metal block bonded to an end part of the piezoelectric body part in the lamination-direction. The metal block-facing bonded surface of the piezoelectric body nearest to the metal block from among the plurality of piezoelectric bodies and/or the block-bonded surface of the metal block, the block-bonded surface being bonded to the piezoelectric body part, has a non-bonded region capable of moving relative to the piezoelectric body or the metal block to which the bonded surface or the block-bonded surface is bonded.

Description

Ultrasonic vibrator and ultrasonic medical device

The present invention relates to an ultrasonic transducer and an ultrasonic medical device using the ultrasonic transducer.

2. Description of the Related Art Conventionally, an ultrasonic medical apparatus that performs various treatments on a tissue by using friction and heat generated by ultrasonic vibration is known.
Such an ultrasonic medical device includes an ultrasonic transducer that generates ultrasonic vibrations. The ultrasonic transducer is disposed, for example, in an operation unit on the hand side of the ultrasonic medical apparatus. The ultrasonic vibration generated in the operation unit is transmitted to the treatment unit on the distal end side through a rod-like probe or the like.

An ultrasonic vibrator having a structure as described in Patent Document 1 is known. The ultrasonic transducer described in Patent Document 1 has a structure in which piezoelectric elements (piezoelectric bodies) and a plurality of metal blocks are alternately stacked and integrated. The piezoelectric element and the metal block are joined by, for example, a thermosetting resin adhesive.

Japanese Unexamined Patent Publication No. 2008-128875

In the ultrasonic vibrator described in Patent Document 1, after heating to cure the adhesive that joins the piezoelectric element and the metal block, when the temperature of the ultrasonic vibrator is lowered to room temperature (environment temperature), The piezoelectric element may be damaged. One cause of the damage is a difference in thermal expansion coefficient between the piezoelectric element and the metal block. That is, when the adhesive is cured and the piezoelectric element and the metal block are joined in a state where the piezoelectric element and the metal block are expanded at different expansion rates at the time of thermosetting, the piezoelectric element and the terminal plate are contracted by returning to room temperature. Stress is generated at the joint site. The generated stress may damage the piezoelectric element.

In view of the above circumstances, an object of the present invention is to provide an ultrasonic transducer that has a piezoelectric laminated structure and is less likely to be damaged during the manufacturing process.
Another object of the present invention is to provide an ultrasonic medical device that can be efficiently manufactured.

A first aspect of the present invention includes a piezoelectric body portion in which a plurality of piezoelectric bodies are arranged and bonded in the stacking direction, and a metal block bonded to an end portion in the stacking direction of the piezoelectric body portion, At least one of the bonding surface facing the metal block in the piezoelectric body closest to the metal block among the plurality of piezoelectric bodies and the block bonding surface bonded to the piezoelectric body portion in the metal block are bonded counterparts. It is an ultrasonic transducer having a non-bonding region that can move relative to the piezoelectric body or the metal block.

The second aspect of the present invention is an ultrasonic medical device including the ultrasonic transducer of the present invention.

According to the ultrasonic transducer of the present invention, it is possible to suitably prevent damage in the manufacturing process while having a laminated structure of piezoelectric bodies.
Moreover, according to the ultrasonic medical device of the present invention, the ultrasonic transducer can be efficiently manufactured by including the ultrasonic transducer.

It is a figure showing the ultrasonic medical device concerning a first embodiment of the present invention in a partial section. It is a perspective view which shows the ultrasonic transducer | vibrator of the ultrasonic medical device. It is a perspective view which shows the piezoelectric material of the ultrasonic transducer | vibrator. It is a figure which shows the other example of a non-joining area | region. It is a figure which shows the other example of a non-joining area | region. It is a figure which shows the other example of a non-joining area | region. It is a figure which shows the other example of a non-joining area | region. It is a figure which shows the other example of a non-joining area | region. It is a figure which shows the metal block in the modification of the same ultrasonic transducer | vibrator. It is a perspective view which shows the ultrasonic transducer | vibrator which concerns on 2nd embodiment of this invention. It is a perspective view which shows the insulator in the same ultrasonic transducer | vibrator. It is a perspective view which shows the ultrasonic transducer | vibrator which concerns on 3rd embodiment of this invention. It is a perspective view which shows the metal block in the same ultrasonic transducer | vibrator.

A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a schematic diagram showing a partial cross-sectional view of the overall configuration of an ultrasonic medical device 1 including the ultrasonic transducer according to the present embodiment.

The ultrasonic medical device 1 includes an insertion unit 10 to be inserted into a living body, a treatment unit 20 provided at a distal end of the insertion unit 10, an operation unit 30 connected to the insertion unit 10, and an operation unit 30. The vibrator unit 40 is disposed.

In the transducer unit 40, the ultrasonic transducer 50 of the present embodiment is disposed. The transducer unit 40 is connected to an ultrasonic power source (not shown) via a cable 41. The treatment unit 20 includes a probe 21 inserted through the insertion unit 10. The proximal end of the probe 21 is connected to the transducer unit 40.

When the handle 31 of the operation unit 30 is operated, the living tissue can be grasped by the treatment unit 20. When power is supplied from the ultrasonic power supply to the transducer unit 40 while the treatment unit 20 holds the living tissue, the ultrasonic transducer 50 vibrates. The ultrasonic vibration generated by the ultrasonic vibrator 50 is transmitted to the distal end portion of the probe 21, and the treatment section 20 vibrates. Thereby, desired treatments such as coagulation and incision can be performed on the grasped living tissue.

FIG. 2 is a perspective view showing the ultrasonic transducer 50. The ultrasonic transducer 50 includes a piezoelectric body portion 52 in which a plurality of piezoelectric bodies 51 are arranged and joined in the stacking direction, and a metal block 55 joined to the piezoelectric body portion 52, and functions as a Langevin vibrator. To do.

Each piezoelectric body 51 is a rectangular parallelepiped having a square front and back, and the front and back surfaces of adjacent piezoelectric bodies are joined together and stacked in a stacking direction connecting the front and back surfaces.
In the present embodiment, a single crystal of lithium niobate (LiNbO ₃ ) is used as the piezoelectric body 51. The material of the piezoelectric body 51 is not limited to lithium niobate, but from the viewpoint of use in the ultrasonic medical device 1, lithium niobate having high resistance to high temperatures is preferable. In particular, it is preferable to form the piezoelectric body 51 using a crystal orientation LiNbO ₃ substrate called 36 degrees Y-Cut because the electromechanical coupling coefficient in the stacking direction of the piezoelectric bodies 51 can be increased.

The two metal blocks 55 are respectively joined to both end portions in the stacking direction of the piezoelectric body portion 52. Examples of the material of the metal block 55 include duralumin, titanium alloy, and the like, and may be appropriately selected in consideration of required strength, vibration efficiency, and the like. The dimension in the stacking direction of the metal blocks 55 is appropriately set based on the vibration frequency set in the ultrasonic transducer 50.

In the ultrasonic vibrator 50, the adjacent piezoelectric bodies 51, and the piezoelectric body 51 and the metal block 55 are joined together using solder 56 which is a brazing material. The ultrasonic vibrator 50 has improved resistance to high temperatures by using a solder (a brazing material), which is a metal material, for bonding, and can be suitably used for the ultrasonic medical device 1. In order to improve solder wettability, a base metal layer is provided on the entire front and back surfaces of the piezoelectric body 51 excluding

piezoelectric bodies

51A and 51B, which will be described later, and the bonding surface of the metal block 55 with the piezoelectric body 51. Yes.

FIG. 3 shows a state before joining of the piezoelectric body 51A located on the most distal end side in the piezoelectric body portion 52 among the plurality of piezoelectric bodies 51. A base metal layer 53 is formed on a front surface (bonding surface) 51 a bonded to the metal block 55. The base metal layer 53 is formed so as to have a single-layer or multiple-layer structure using, for example, titanium, platinum, gold, or the like. The base metal layer 53 can be formed on the surface of the piezoelectric body 51 by, for example, vapor deposition or sputtering.

In the piezoelectric body 51A, a base metal layer 53 is formed on the entire surface on the back surface 51b to be joined with another piezoelectric body. In the front surface 51a of the piezoelectric body 51A, the base metal layer 53 is not formed on a part of the periphery including the four corners of the square of the front surface 51a, and the piezoelectric body 51 is exposed at a portion where the base metal layer 53 is not formed. is doing. The base metal layer having such a shape can be formed, for example, by vapor deposition using a mask or sputtering.

By forming the base metal layer 53 in the above-described shape, the front surface 51a of the piezoelectric body 51A has a non-bonded region 54 that is not bonded to the metal block 55 at a part of the periphery including the four corners.
Although not shown, in the piezoelectric body 51B (see FIG. 2) located closest to the base end side in the piezoelectric body portion 52, the base metal layer 53 formed on the back surface (joint surface) 51b joined to the metal block 55. However, it has the same shape as the base metal layer formed on the front surface 51a of the piezoelectric body 51A. Thereby, the piezoelectric body 51 </ b> B also has a non-bonding region 54 on the bonding surface with the metal block 55. A base metal layer 53 is formed on the entire front surface of the piezoelectric body 51B.

An example of a manufacturing procedure of the ultrasonic transducer 50 having the above structure will be described.
First, the plurality of piezoelectric bodies 51 on which the base metal layer 53 is formed are arranged in the stacking direction, and the metal blocks 55 are arranged on both sides of the plurality of piezoelectric bodies 51 in the stacking direction. Further, a sheet-like or film-like solder 56 is sandwiched between the adjacent piezoelectric bodies 51 and between the piezoelectric body 51 and the metal block 55, and the piezoelectric body 51 and the metal block 55 are brought into close contact with each other via the solder 56.

Next, the piezoelectric body 51, the metal block 55, and the solder 56 are heated to a temperature equal to or higher than the melting temperature of the solder 56 while maintaining the state where the piezoelectric body 51 and the metal block 55 are in close contact with each other. Thereby, the solder 56 is melted and spreads on the base metal layer 53. When the temperature of the piezoelectric body 51, the metal block 55, and the solder 56 is lowered after the solder 56 is melted, the solder 56 is solidified and the adjacent piezoelectric bodies 51, and the piezoelectric body 51 and the metal block 55 are replaced with the solder 56. Are joined together. However, on the non-bonding region 54 on the bonding surfaces of the

piezoelectric bodies

51A and 51B, the piezoelectric body melts away from the solder 56. Therefore, even if the solder 56 exists between the piezoelectric body and the metal block 55, The piezoelectric body and the metal block 55 are not joined.
Through the above procedure, the ultrasonic transducer 50 in which the piezoelectric body portion 52 and the metal block 55 are joined by the solder 56 is completed.

In the above-described procedure, when the solder 56 is heated to melt, the piezoelectric body 51 and the metal block 55 expand based on the thermal expansion coefficient of each material. Thereafter, when the temperature decreases, the piezoelectric body 51 and the metal block 55 contract to a state equivalent to that before heating. However, since the solder 56 is solidified and joined together before the contraction of the piezoelectric body 51 and the metal block 55 is completed, between the piezoelectric body 51 and the metal block 55 after joining, Stress based on the difference in expansion coefficient is generated. When the generated stress is large, the piezoelectric body 51A and the piezoelectric body 51B joined to the metal block 55 may be damaged.

The ultrasonic transducer 50 of the present embodiment has non-bonded regions 54 on the front surface 51a of the piezoelectric body 51A and the back surface 51b of the piezoelectric body 51B, which are the bonding surfaces of the piezoelectric body portion 52 and the metal block 55, respectively. In the non-bonded region 54, since the piezoelectric body 51 and the metal block 55 are not integrally bonded, the piezoelectric body and the metal block that is the counterpart to be bonded behave differently during expansion and contraction. It is possible to move. As a result, no stress is generated in the non-bonded region 54 due to the difference in thermal expansion coefficient. Further, a part of the stress generated in the joined part is released from the non-joined region 54, and the stress remaining in the joined part is also reduced.
Therefore, according to the ultrasonic transducer 50 of the present embodiment, it is possible to suitably suppress the breakage of the piezoelectric body during the manufacturing process while having a laminated structure of piezoelectric bodies.

Further, according to the ultrasonic medical device 1 of the present embodiment, it is possible to efficiently manufacture by using the ultrasonic transducer 50 in which breakage of the piezoelectric body in the manufacturing process is suitably suppressed.

The size of the non-bonding region 54 may be appropriately set depending on the shape, size, material, and the like of the piezoelectric body 51 and the metal block 55. As the area of the non-bonded region increases, the damage suppressing effect increases, but the bonding strength decreases. According to the inventor's study, the stress generated between the piezoelectric body and the metal block decreases as the proportion of the non-bonded region in the bonded surface (for example, the area of the non-bonded region 54 / the area of the front surface 51a) increases. The decrease rate rapidly decreased when the proportion of the non-bonded area in the bonding surface exceeded 8%. From this result, it is considered that the proportion of the non-bonded region in the bonding surface is preferably about 5% to 10%.

The position and shape of the non-bonded region 54 can be appropriately set by changing the shape of the base metal layer 53. For example, as shown in FIG. 4A, a non-joining region 54 may be formed in a region excluding four corners on the periphery of the joining surface. As shown in FIG. 4B, the non-bonding region 54 may be formed on the entire periphery including the four corners.
Further, when the material forming the piezoelectric body has a different thermal expansion coefficient depending on the direction, the non-bonding region may be formed so as to extend only in a specific direction. For example, in a piezoelectric body having a rectangular joint surface, when the thermal expansion coefficient x in the direction in which one side extends is different from the thermal expansion coefficient y in the direction in which the other side perpendicular to the one side extends, as shown in FIG. A non-joining region may be provided only in a portion orthogonal to the direction in which the difference in thermal expansion coefficient with the metal block becomes larger (FIG. 4C shows an example in which the thermal expansion difference in the x direction is larger).

Furthermore, the site | part which provides a non-joining area | region is not restricted to the periphery of a joining surface. For example, as shown in FIG. 4D, a non-joining region 54 may be formed in a frame shape inside the periphery of the joining surface. As shown in FIG. 4E, the non-joining regions may be formed only in the portions close to the four corners inside the periphery of the joining surface.
However, it is preferable to provide a non-joining region at the periphery because stress is easily released from the non-joining region and the stress reduction effect is large. In addition, since the base metal layer does not exist in the dicing line when cutting out the piezoelectric body, there is an advantage that the piezoelectric body can be easily cut out.

Further, as shown in FIG. 5, the base metal layer 53 formed on the metal block 55 may have the same shape as the base metal layer formed on the bonding surface of the piezoelectric body. In this case, the base metal layer of the piezoelectric body closest to the metal block may be provided on the entire bonding surface. By not providing the base metal layer on a part of the joint surface of the metal block, the part of the joint surface of the piezoelectric body joined to the metal block that faces the part where the base metal layer does not exist becomes a non-joint region. The effect of can be obtained.

A second embodiment of the present invention will be described with reference to FIGS. The ultrasonic transducer of this embodiment is different from the ultrasonic transducer 1 of the first embodiment in that an insulator is provided.
In the following description, components that are the same as those already described are assigned the same reference numerals and redundant description is omitted.

FIG. 6 is a perspective view showing the ultrasonic transducer 150 of the present embodiment. An insulator 151 is disposed between the piezoelectric body portion 52 and the metal block 55, and the piezoelectric body portion 52 and the metal block 55 are joined with the insulator 151 interposed therebetween.

The insulator 151 has substantially the same shape and dimensions as the piezoelectric body 51, but the thickness (dimension in the stacking direction) may be set as appropriate.
Although there is no restriction | limiting in particular in the material of the insulator 151, From viewpoints, such as rigidity and an ultrasonic absorption property, a ceramic material is preferable. In particular, when the piezoelectric body 51 is formed of an anisotropic material such as a lithium niobate substrate having a crystal orientation of 36 degrees Y-Cut or the like, the thermal expansion coefficient in one direction in the bonding surface (for example, X described above) The insulator 151 is preferably made of a material having a thermal expansion coefficient that is intermediate between the thermal expansion coefficient (for example, Y described above) in a direction orthogonal to the one direction. If it does in this way, generation | occurrence | production of the stress in a piezoelectric material can be suppressed suitably. Examples of the material of the insulator 151 that exhibits such an effect include zirconia (ZrO ₂ ).

FIG. 7 shows the insulator 151 before being joined. A base metal layer 53 is formed on each surface of the insulator 151 in the stacking direction. The base metal layer 53 provided on the first surface 151a in the stacking direction has the same shape as the base metal layer formed on the bonding surface of the piezoelectric body to be bonded to the metal block 55 in the first embodiment. A base metal layer 53 is formed on the entire surface of the second surface 151b in the stacking direction.

Each of the two insulators 151 is disposed with the first surface 151a facing the metal block 55 side. In addition, in the

piezoelectric bodies

51C and 51D closest to the insulator 151, a base metal layer 53 is provided on the entire surface of the bonding surface with the insulator 151.
In this state, when joining by the solder 56 is performed in the same procedure as in the first embodiment, the entire joining surfaces of the

piezoelectric bodies

51C and 51D and the insulator 151 are joined. However, only the region where the base metal layer 53 is formed is bonded to the metal block 55 and the insulator 151. As a result, in the

piezoelectric bodies

51C and 51D closest to the metal block 55, the region corresponding to the portion of the first surface 151a where the base metal layer 53 is not provided, that is, the ultrasonic transducer 150 is viewed in the stacking direction. In some cases, a region of the first surface 151 a that overlaps a portion where the base metal layer 53 is not provided is a non-bonded region that is not bonded to the metal block 55 integrally.
Therefore, also in the ultrasonic transducer 150 of this embodiment, the non-bonded region behaves differently from the metal block during expansion / contraction due to temperature change, so that the piezoelectric body is damaged during the manufacturing process as in the first embodiment. It can suppress suitably.

Further, since the insulator 151 is disposed between the piezoelectric body portion 52 and the metal block 55, it is easy to ensure insulation between the metal block 55 and other surrounding members when the ultrasonic vibrator 150 is disposed. can do.

In the present embodiment, the first surface 151a of the insulator 151 may be directed not to the metal block 55 side but to the

piezoelectric bodies

51C and 51D. In this case, the metal block 55 and the insulator 151 are bonded to each other on the entire bonding surface, but the piezoelectric body 51 and the insulator 151 are bonded only to the region where the base metal layer 53 is formed. In the

piezoelectric bodies

51C and 51D closest to the block 55, a region corresponding to a portion of the first surface 151a where the base metal layer 53 is not provided is similarly a non-bonded region. Therefore, also in this case, the same effect as the above-described aspect is obtained.
Furthermore, one of the metal blocks 55 may be bonded to the first surface 151a, and the other may be bonded to the second surface 151b.

A third embodiment of the present invention will be described with reference to FIGS. The ultrasonic transducer of this embodiment is different from the ultrasonic transducers of the above embodiments in the shape of the metal block.

FIG. 8 is a perspective view showing the ultrasonic transducer 250 of the present embodiment. FIG. 9 is a perspective view showing the metal block 255 of the ultrasonic transducer 250. In the metal block 255, four corners on the side of the bonding surface (block bonding surface) 255a bonded to the piezoelectric body portion 52 are chamfered. Thereby, the joint surface 255a is octagonal.

In the present embodiment, the metal block 255 and the piezoelectric body 51 have different joint surfaces, and the joint surface 255a of the metal block 255 is smaller. Therefore, a part of the joint surface of the piezoelectric body 51 is part of the metal block 255. It does not come into contact with the joint surface 255a. As a result, a portion of the bonding surface of the piezoelectric body 51 that does not come into contact with the bonding surface 255a becomes a non-bonding region.

Also in the ultrasonic transducer 150 of the present embodiment, similarly to the ultrasonic transducers of the respective embodiments described above, it is possible to suitably suppress the breakage of the piezoelectric body during the manufacturing process.
In the present embodiment, a part of the bonding surface of the piezoelectric body 51 is set as a non-bonding region by making the area of the bonding surface 255a of the metal block 255 smaller than the bonding surface of the piezoelectric body 51. Therefore, in both the piezoelectric body 51 and the metal block 255, the base metal layer 53 can be provided on the entire bonding surface, so that it is not necessary to use a mask or the like to make the base metal layer into a predetermined shape. As a result, the process of forming the base metal layer can be simplified and the manufacturing cost can be reduced.

In the present embodiment, the shape of the block joint surface is not limited to the octagon described above. For example, by chamfering the entire periphery of the block bonding surface, the shape of the block bonding surface may be a square that is slightly smaller than the bonding surface of the piezoelectric body.

In the above description, an example in which the shape of the block joint surface is changed is used. However, when an insulator is disposed between the metal block and the piezoelectric body as in the second embodiment, the insulator The shape of the bonding surface (insulator bonding surface) may be changed so that the area of the insulator bonding surface is smaller than the bonding surface of the piezoelectric body.

Furthermore, instead of chamfering, the area of the block joint surface may be reduced by making the cross-sectional shape in the stacking direction of the metal blocks smaller than that of the piezoelectric body. However, when the area of the block joint surface is reduced by chamfering, the position of a part of the periphery in the cross-sectional shape in the stacking direction can be matched with the piezoelectric body. As a result, when the piezoelectric body and the metal block are arranged in the stacking direction in the manufacturing process of the ultrasonic vibrator, there is an advantage that it is easy to position the two so that their centers coincide with each other.

In addition, the bonding surface may be formed so that the area of the bonding surface of the piezoelectric body becomes smaller than the area of the block bonding surface, for example, by removing four corners of the piezoelectric body. In this case, the non-bonding region is generated on the block bonding surface. In this case, a part of the expansion / contraction generated in the metal block is absorbed by the non-bonding region of the block bonding surface or released from the non-bonding region. Therefore, substantially the same effect can be obtained.
Further, non-bonding regions may be provided on both the bonding surface and the block bonding surface of the piezoelectric body.

The embodiments of the present invention have been described above. However, the technical scope of the present invention is not limited to the above-described embodiments, and combinations of components or components may be changed without departing from the spirit of the present invention. It is possible to make various changes to or delete them.

For example, in the ultrasonic transducer of the present invention, the shape of the bonding surface of the piezoelectric body is not limited to the above-described square. Therefore, it may be a rectangle, a polygon other than a rectangle, or a circle having no corners. However, since the cross-sectional shape in the stacking direction of the ultrasonic transducer is preferably a shape with high rotational symmetry, the shape of the joint surface is more preferably a polygon such as a polygon with a high rotational symmetry or a perfect circle.

Further, the metal block may be provided only on one side in the stacking direction.

The present invention can be applied to an ultrasonic transducer and an ultrasonic medical device.

DESCRIPTION OF SYMBOLS 1 Ultrasonic

medical device

50, 150, 250

Ultrasonic vibrator

51, 51A, 51B Piezoelectric body 51a Front (bonding surface)
51b Rear surface (joint surface)
52 Piezoelectric part 53 Underlying metal layer 54

Non-bonding region

55, 255 Metal block 56 Solder (brazing material)
151 Insulator 255a Bonding surface (Block bonding surface)

Claims

A piezoelectric body portion in which a plurality of piezoelectric bodies are aligned and joined in the stacking direction;
A metal block joined to an end of the piezoelectric body portion in the stacking direction;
With
At least one of a joint surface facing the metal block in the piezoelectric body closest to the metal block among the plurality of piezoelectric bodies and a block joint surface joined to the piezoelectric body portion in the metal block are joined to each other. A non-bonding region movable relative to the piezoelectric body or the metal block,
Ultrasonic vibrator.
The ultrasonic transducer according to claim 1, wherein the non-bonding region is provided on the bonding surface.
The ultrasonic transducer according to claim 2, wherein the non-bonded region is located at a portion including a periphery of the bonding surface.
The ultrasonic transducer according to claim 2, wherein the joining surface has a polygonal shape, and the non-joining region is located at a portion including a corner portion of the polygonal shape.
Further comprising a base metal layer provided on the bonding surface,
The piezoelectric body part and the metal block are joined by a brazing material,
The ultrasonic transducer according to claim 2, wherein the non-bonding region is located in a portion of the bonding surface where the base metal layer does not exist.
Further comprising a base metal layer provided on the block bonding surface,
The piezoelectric body part and the metal block are joined by a brazing material,
The ultrasonic transducer according to claim 2, wherein the non-bonding region faces a portion where the base metal layer does not exist on the block bonding surface.
The ultrasonic transducer according to claim 2, wherein an area of a block joint surface joined to the piezoelectric body portion in the metal block is smaller than an area of the joint surface.
The ultrasonic transducer according to claim 1, wherein an area of the bonding surface is smaller than an area of the block bonding surface, and the block bonding surface has the non-bonding region.
The ultrasonic transducer according to claim 1, further comprising an insulator disposed between the piezoelectric body portion and the metal block.
10. The ultrasonic transducer according to claim 9, wherein in the insulator, an area of an insulator bonding surface bonded to the piezoelectric body portion is smaller than an area of the bonding surface.
An ultrasonic medical device comprising the ultrasonic transducer according to claim 1.