DESCRIPTION JP2015211535

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DESCRIPTION JP2015211535
PROBLEM TO BE SOLVED: To provide an ultrasonic transducer and an ultrasonic medical device
which prevent breakage at the time of joining materials having anisotropic thermal expansion
coefficient, reduce stress, and have a good vibration transmission efficiency at the time of
ultrasonic vibration occurrence. Do. SOLUTION: An ultrasonic vibrator 1 comprises two metal
blocks 2, a plurality of piezoelectric elements 3 stacked between the metal blocks 2, and a
junction for joining the metal blocks 2 and the piezoelectric elements 3 and 3 to each other. The
piezoelectric element 3 has a thermal expansion coefficient in the x direction and ay direction in
the x-direction with respect to one direction in the joint plane with the metal block 2 and the ydirection orthogonal to the x-direction The metal block 2 is made of an anisotropic material
different from the thermal expansion coefficient, and the metal block 2 is formed with the groove
21 determined in accordance with the difference of the thermal expansion coefficient with the
piezoelectric element 3 in the x direction or y direction. It is characterized by [Selected figure]
Figure 1
Ultrasonic transducer and ultrasonic medical device
[0001]
The present invention relates to an ultrasonic transducer and an ultrasonic medical device.
[0002]
As an ultrasonic transducer, there is an ultrasonic transducer called a Langevin transducer in
which a piezoelectric element such as a piezoelectric ceramic is fixed by being sandwiched
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between metal blocks from both sides thereof.
The Langevin vibrator is an element capable of generating efficient ultrasonic vibration by
vibrating the entire element at the natural frequency of the metal block and the entire
piezoelectric element. In general, the Langevin vibrator has a structure in which bonding
between the piezoelectric element and the metal block is fixed with an adhesive or tightened with
a bolt.
[0003]
However, when the piezoelectric element and the metal block are joined with a brazing material
such as solder in order to efficiently transmit the vibration, a process of raising the temperature
of the junction is required. Then, since the thermal expansion coefficients of the piezoelectric
element and the metal block are different, stress is generated at the joint portion.
[0004]
Therefore, by providing grid-like grooves or a plurality of depressions in the joint plane of each
metal block joined by an adhesive to the electrodes provided on the upper and lower surfaces of
the piezoelectric element, generation of shear strain generated during driving An ultrasonic
vibrator is disclosed which suppresses or reduces dielectric loss at a bonding plane, thereby
reducing temperature rise during driving to prevent the occurrence of cracks in the piezoelectric
element and stabilize the vibration mode. (See Patent Document 1).
[0005]
JP, 2008-128875, A
[0006]
On the other hand, transmission of ultrasonic vibration is a main function of the ultrasonic
transducer.
It is important for the ultrasonic transducer to make the transmission efficiency of ultrasonic
vibration better.
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In order to transmit the vibration generated from the piezoelectric element to the metal block, it
is preferable that the area of the bonding surface of the piezoelectric element and the metal block
be large.
[0007]
In the conventional ultrasonic transducer as described in Patent Document 1, the piezoelectric
element and the metal block are each formed of a material having an isotropic thermal expansion
coefficient. In the case of an isotropic material, the direction in which the member expands due
to heat is uniform in all directions, and in order to prevent breakage, it is preferable to form
grooves or depressions at regular intervals in at least two directions in the joint surface.
[0008]
However, in the case where the thermal expansion coefficient of one material is isotropic and the
thermal expansion coefficient of the other material is anisotropic in the piezoelectric element of
the ultrasonic transducer and the metal block, the magnitude of expansion varies depending on
the direction. If grooves or the like are formed at regular intervals in at least two directions,
grooves that do not contribute to damage prevention will be present, which may reduce the
transmission efficiency of ultrasonic vibration.
[0009]
An embodiment according to the present invention prevents an breakage at the time of joining
materials having anisotropic thermal expansion coefficient, reduces stress, and an ultrasonic
transducer and an ultrasonic transducer having good vibration transmission efficiency at the
time of generation of ultrasonic vibration. An ultrasonic medical device is provided.
[0010]
An ultrasonic transducer according to an aspect of the present invention comprises two metal
blocks, a plurality of piezoelectric elements stacked between the metal blocks, and a junction for
joining the metal blocks, the piezoelectric element, and the piezoelectric elements. And the
piezoelectric element has a thermal expansion coefficient in the x direction and the y direction
with respect to the x direction in one direction and the y direction orthogonal to the x direction
in the bonding surface with the metal block. The metal block is formed with a groove defined in
the x direction or the y direction according to the difference in the coefficient of thermal
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expansion with the piezoelectric element It is characterized by
[0011]
According to the embodiment of the present invention, an ultrasonic transducer and an
ultrasonic medical device that prevent breakage when joining materials having anisotropic
thermal expansion coefficient and have a good vibration transmission efficiency at the time of
ultrasonic vibration occurrence It is possible to provide
[0012]
The ultrasonic transducer | vibrator of 1st Embodiment is shown.
The 1st example of the metal block of the ultrasonic transducer | vibrator of 1st Embodiment is
shown.
It is a graph of the simulation which compared the stress relative value with the case where
groove is formed, and the case where groove is not formed.
The 2nd example of the metal block of the ultrasonic transducer | vibrator of 1st Embodiment is
shown.
The 3rd example of the metal block of the ultrasonic transducer | vibrator of 1st Embodiment is
shown. The 4th example of the metal block of the ultrasonic transducer | vibrator of 1st
Embodiment is shown. The ultrasonic transducer | vibrator of 2nd Embodiment is shown. The
example of the metal block of the ultrasonic transducer | vibrator of 2nd Embodiment is shown.
1 shows an overall configuration of an ultrasonic medical device according to the present
embodiment. The schematic structure of the whole vibrator | oscillator unit of the ultrasonic
medical device which concerns on this embodiment is shown. The whole structure of the
ultrasound medical device of the other aspect of the ultrasound medical device which concerns
on this embodiment is shown.
[0013]
Hereinafter, the ultrasonic transducer 1 of the present embodiment will be described.
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[0014]
FIG. 1 shows an ultrasonic transducer 1 of the present embodiment.
FIG. 1A shows the ultrasonic transducer 1 of the present embodiment before bonding. FIG. 1 (b)
shows the ultrasonic transducer 1 of the present embodiment after bonding.
[0015]
As shown in FIG. 1A, the ultrasonic transducer 1 according to the present embodiment includes
two metal blocks 2, a plurality of piezoelectric elements 3 stacked between the metal blocks 2, a
metal block 2, and a piezoelectric element And 3 and a bonding material 4 for bonding the
piezoelectric elements 3 to each other.
[0016]
The metal block 2, the piezoelectric element 3 and the piezoelectric element 3 are in close
contact with each other by the bonding material 4 as shown in FIG. 1 (b).
The bonding may be cooled after heating to a temperature at which the bonding material 4 melts.
[0017]
Each material of the ultrasonic transducer 1 of the present embodiment will be described.
[0018]
It is preferable to use a single crystal lithium niobate having a high Curie point for the
piezoelectric element 3.
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For example, it is preferable to use a lithium niobate wafer having a crystal orientation called 36degree rotation Y-cut so that the electromechanical coupling coefficient in the thickness direction
of the piezoelectric element 3 becomes large, and the wettability between lithium niobate and
lead-free solder After base metals such as Ti / Pt and Cr / Ni / Au are formed on the front and
back surfaces of the lithium niobate wafer so as to improve adhesion, they are cut out into a
rectangular shape by dicing or the like.
[0019]
As the bonding material 4, a lead-free solder having a melting point lower than the Curie point,
preferably a melting point equal to or less than half the Curie point is used.
[0020]
As the metal block 2, an aluminum alloy such as duralumin, a titanium alloy such as 64Ti, pure
titanium, stainless steel, mild steel, nickel chrome steel, tool steel, brass, monel metal or the like
is used.
[0021]
In the ultrasonic transducer 1 of the present embodiment, as an example, 64 titanium alloy (64
Ti) is used for the metal block 2 and 36 Y lithium niobate (LiNb03) having a crystal orientation
called a 36 degree rotation Y-cut is used for the piezoelectric element 3.
As shown in Table 1, the 64 titanium alloy has an isotropic thermal expansion coefficient of 9 ×
10 6 <6> [1 / ° C.] in both the x and y directions.
On the other hand, 36Y lithium niobate has a thermal expansion coefficient of 15 × 10 <-6> [1 /
° C] in the x direction and 8 × 10 <-6> [1 / ° C] in the y direction. It is an anisotropic material
that differs in the plane. Note that x and y indicate orthogonal directions in the plane.
[0022]
Therefore, for example, an anisotropy occurs in the stress when joining the rectangular metal
block 2 and the piezoelectric element 3 having the same aspect ratio of the cross-sectional shape,
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and the difference between the thermal expansion coefficient and the x direction is the largest. It
will be different in the smallest y direction. Then, in the x direction in which the difference in
thermal expansion coefficient is large, the stress becomes large at the time of joining, and it
becomes difficult not only to transmit power efficiently but also to damage the piezoelectric
element at worst.
[0023]
Therefore, in the present embodiment, when the metal block 2 and the piezoelectric element 3
are bonded by forming the groove 21 in the bonding surface of the metal block 2 according to
the difference between the thermal expansion coefficients of the metal block 2 and the
piezoelectric element 3 Relieve the stress of
[0024]
With such a configuration, the stress at the time of bonding in the x direction, which has a large
difference in thermal expansion coefficient, is relaxed in the x direction and y direction
orthogonal to the bonding surface 2 a of the metal block 2 and the piezoelectric element 3 It is
possible to provide an ultrasonic transducer and an ultrasonic medical device having good
vibration transmission efficiency because the damage of 3 is suppressed and there is no groove
that does not contribute to the prevention of damage, and the area of the bonding surface is also
increased. Become.
[0025]
In the ultrasonic transducer 1 formed as shown in FIG. 1 (b), a flexible substrate connected to an
electric cable (not shown) is attached to the side, and laminated in the same manner as a general
ultrasonic transducer. The positive electrode layer and the negative electrode layer are
alternately attached between the bonding surfaces of the piezoelectric element 3.
In the present invention, the electric cable and the joint 4 are electrically connected, and the joint
4 doubles as an electrode layer.
Then, by applying a drive electric signal to each piezoelectric element 3, it becomes possible to
drive the ultrasonic transducer 1.
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[0026]
FIG. 2 shows a first example of the metal block 2 of the ultrasonic transducer 1 of the first
embodiment.
[0027]
In the metal block 2 of the ultrasonic transducer 1 according to the first embodiment, the groove
21 is formed on the bonding surface 2 a with the piezoelectric element 3 shown in FIG. 1.
The groove 21 of the metal block 2 of the first example is formed of a groove 21a in the y
direction formed of a plurality of straight lines parallel to two opposing side surfaces. That is, in
the joint surface 2a of the metal block 2 and the piezoelectric element 3, the groove 21 in the y
direction orthogonal to the x direction having the largest thermal expansion coefficient
difference is formed in the x direction and the y direction orthogonal to each other. And the
junction division part 2b divided by the groove | channel 21 is formed in the rectangle where the
edge which consists of the groove | channel 21a of the y direction with a small difference of a
thermal expansion coefficient becomes long.
[0028]
FIG. 3 is a graph of a simulation comparing stress relative values between the case where the
groove is formed and the case where the groove is not formed.
[0029]
The material of the simulation model is 64 titanium metal block, 36 Y lithium niobate
piezoelectric element, and solder joint.
The grooves formed in the "grooved" metal block were formed in the direction orthogonal to the
direction in which the difference in thermal expansion coefficient between the metal block and
the piezoelectric element is the largest, that is, ten in the Y direction in FIG. The groove has a
width of 0.1 mm and a depth of 1 mm.
[0030]
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The stress generated in the piezoelectric element was calculated by simulation using the thermal
expansion coefficient when the temperature at the time of bonding of the metal block of this
model and the piezoelectric element was reduced from about 200 ° C to 20 ° C, which is room
temperature. .
[0031]
As a result, as shown in FIG. 3, assuming that “without groove” is 100%, in the case “with
groove”, a result that the stress is reduced by about 25% was obtained.
[0032]
That is, with such a configuration, in the joint surface of the metal block 2 and the piezoelectric
element 3, the difference in thermal expansion coefficient is large in the x direction in a
predetermined direction and in the y direction orthogonal to the x direction. The stress in the
direction is reduced, the breakage of the piezoelectric element 3 is suppressed, and there is no
groove in the y direction having a small thermal expansion coefficient difference, so the bonding
area is larger than in the case where the grooves are formed in at least two directions. It is
possible to provide an ultrasonic transducer and an ultrasonic medical device having good
vibration transmission efficiency.
[0033]
FIG. 4 shows a second example of the metal block 2 of the ultrasonic transducer 1 of the first
embodiment.
[0034]
The groove 21 of the metal block 2 of the second example is a second groove in the x direction
orthogonal to the first groove 21a in the y direction and the first groove 21a in the y direction
formed from a plurality of straight lines parallel to two opposing side surfaces It consists of 21b.
That is, the difference between the thermal expansion coefficients orthogonal to each other in the
joint surface 2a of the metal block 2 and the piezoelectric element 3 is the second groove 21b in
the x direction having the largest difference in thermal expansion coefficient and the thermal
expansion orthogonal to the x direction The first groove 21a in the y direction with the smallest
coefficient difference is formed.
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In the joint section 2b divided by the groove 21, the side formed by the first groove 21a in the y
direction having a small difference in thermal expansion coefficient is more than the second
groove 21b in the x direction having a largest difference in thermal expansion coefficient. It is
formed in a long rectangular shape.
That is, the distance between the adjacent second grooves 21b is larger than the distance
between the adjacent first grooves 21a.
[0035]
With such a configuration, it is possible to reduce the stress corresponding to the difference in
the thermal expansion coefficient in the x direction and the y direction orthogonal to each other
in the joint surface of the metal block 2 and the piezoelectric element 3.
And since breakage of the piezoelectric element 3 is suppressed and grooves corresponding to
the thermal expansion coefficient difference are formed, grooves not contributing to the
breakage can be reduced, so the bonding area is large and the vibration transmission efficiency is
good. It is possible to provide an ultrasonic transducer and an ultrasonic medical device.
[0036]
FIG. 5 shows a third example of the metal block 2 of the ultrasonic transducer 1 of the first
embodiment.
[0037]
The groove 21 of the metal block 2 of the third example is in the y direction orthogonal to the x
direction having the largest thermal expansion coefficient difference between the x direction and
the y direction orthogonal to the joint surface 2 a of the metal block 2 and the piezoelectric
element 3. It is formed at an acute angle.
The grooves 21a having an acute angle with the y direction intersect at an acute angle with
respect to one of the opposite side surfaces parallel to the y direction and with an obtuse angle
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with respect to the other opposite side surface parallel to the x direction. Formed as. Then, most
of the joint section 2b divided by the groove 21 is formed in a shape in which the side formed of
the groove 21a having an acute angle with the y direction having a small difference in thermal
expansion coefficient is long.
[0038]
With such a configuration, the stress in the x direction having a large difference in thermal
expansion coefficient can be easily reduced in the x direction and the y direction orthogonal to
each other in the joint surface of the metal block 2 and the piezoelectric element 3. In addition,
since there is no groove formed at an acute angle to the x direction, which is effective for
reducing stress in the y direction, which has a small thermal expansion coefficient difference,
bonding is more effective than when grooves are formed in at least two directions. It becomes
possible to provide an ultrasonic transducer and an ultrasonic medical device having a large area
and good vibration transmission efficiency. In addition, it is not necessary to form the groove
reliably in the direction orthogonal to the x direction having the largest thermal expansion
coefficient difference, and the groove 21 can be easily formed.
[0039]
FIG. 6 shows a fourth example of the metal block 2 of the ultrasonic transducer 1 of the first
embodiment.
[0040]
The groove 21 of the metal block 2 of the fourth example is formed at an acute angle with
respect to the y direction orthogonal to the x direction, one of which has the largest difference in
thermal expansion coefficient, in the joint surface 2a of the metal block 2 and the piezoelectric
element 3 The other is formed in the x direction orthogonal to the y direction.
The first grooves 21a having an acute angle with the y direction intersect each other at an acute
angle with respect to one of the opposing side surfaces parallel to the y direction, and an obtuse
angle with respect to the other opposing side surface parallel with the x direction. It is formed to
cross. Then, in most of the joint sections 2b divided by the grooves 21, the long side consisting of
the first groove 21a in the y direction with a small difference in thermal expansion coefficient is
from the second groove 21b in the x direction with a large difference in thermal expansion
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coefficient. Is formed to be longer than the short side. That is, the distance between the adjacent
second grooves 21b is larger than the distance between the adjacent first grooves 21a.
[0041]
With such a configuration, it is possible to reduce the stress corresponding to the difference in
the thermal expansion coefficient in the x direction and the y direction orthogonal to each other
in the joint surface of the metal block 2 and the piezoelectric element 3. Then, since breakage of
the piezoelectric element 3 is suppressed and grooves corresponding to the thermal expansion
coefficient difference are formed, grooves not contributing to the breakage can be reduced. It is
possible to provide an ultrasonic medical device. In addition, it is not necessary to form the
groove reliably in the direction orthogonal to the x direction having the largest thermal
expansion coefficient difference, and the groove 21 can be easily formed.
[0042]
FIG. 7 shows the ultrasonic transducer 1 of the second embodiment. FIG. 7A shows the ultrasonic
transducer 1 of the second embodiment before bonding. FIG. 7B shows the ultrasonic transducer
1 of the second embodiment after bonding. FIG. 8 shows an example of the metal block of the
ultrasonic transducer of the second embodiment.
[0043]
As shown in FIG. 7A, in the ultrasonic transducer 1 of the second embodiment, the cross section
of the bonding surface 2a of the metal block 2 and the piezoelectric element 3 is formed in a
circular shape. The materials of the metal block 2 and the piezoelectric element 3 are the same as
in the first embodiment.
[0044]
The grooves 21 of the ultrasonic transducer 1 of the second embodiment may be similar to the
grooves 21 of the first to fourth examples described in the ultrasonic transducer 1 of the first
embodiment. For example, as shown in FIG. 8, a groove 21 a in the y direction orthogonal to the
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x direction with the largest difference in thermal expansion coefficient is formed. And the
junction division part 2b divided by the groove | channel 21a is formed in the shape where the
edge which consists of the groove | channel 21a of the y direction with a small difference of a
thermal expansion coefficient becomes long.
[0045]
With such a configuration, it is possible to reduce the stress in the x direction having a large
difference in thermal expansion coefficient in the x direction and the y direction orthogonal to
each other in the bonding surface of the metal block 2 and the piezoelectric element 3. Further,
since the breakage of the piezoelectric element 3 is suppressed and there is no groove in the y
direction having a small thermal expansion coefficient difference, the bonding area becomes
large, and the ultrasonic transducer and the ultrasonic medical device having good vibration
transmission efficiency are provided. It is possible to
[0046]
FIG. 9 shows the entire configuration of the ultrasonic medical apparatus according to the
present embodiment. FIG. 10 shows a schematic configuration of the entire transducer unit of the
ultrasonic medical apparatus according to the present embodiment.
[0047]
The ultrasonic medical device 10 shown in FIG. 9 includes a transducer unit 13 having an
ultrasonic transducer 1 mainly generating ultrasonic vibration, and a handle unit 14 for treating
an affected area using the ultrasonic vibration. It is provided.
[0048]
The handle unit 14 includes an operation portion 15, an insertion sheath portion 18 formed of
an elongated outer tube 17, and a distal end treatment portion 40.
The proximal end portion of the insertion sheath portion 18 is attached to the operation portion
15 so as to be rotatable around the axis. The distal end treatment section 40 is provided at the
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distal end of the insertion sheath section 18. The operation unit 15 of the handle unit 14
includes an operation unit main body 19, a fixed handle 20, a movable handle 21, and a rotation
knob 22. The operation unit main body 19 is integrally formed with the fixed handle 20.
[0049]
A slit 23 through which the movable handle 21 is inserted is formed on the back side of the
connecting portion between the operation portion main body 19 and the fixed handle 20. The
upper portion of the movable handle 21 is extended to the inside of the operation portion main
body 19 through the slit 23. A handle stopper 24 is fixed to the lower end of the slit 23. The
movable handle 21 is rotatably attached to the operation unit main body 19 via a handle support
shaft 25. The movable handle 21 is designed to be opened and closed with respect to the fixed
handle 20 as the movable handle 21 pivots about the handle support shaft 25.
[0050]
A substantially U-shaped connecting arm 26 is provided at the upper end of the movable handle
21. In addition, the insertion sheath portion 18 has an outer tube 17 and an operation pipe 27
axially movably inserted into the outer tube 17. A large diameter portion 28 having a diameter
larger than that of the distal end portion is formed at the proximal end portion of the sheath tube
17. The rotation knob 22 is mounted around the large diameter portion 28.
[0051]
A ring-shaped slider 30 is provided on the outer peripheral surface of the operation pipe 27 so as
to be movable along the axial direction. A fixing ring 32 is disposed behind the slider 30 via a
coil spring (elastic member) 31.
[0052]
Furthermore, the proximal end of the grip 33 is rotatably coupled to the distal end of the
operation pipe 27 via an action pin. The grasping portion 33 constitutes a treatment portion of
the ultrasonic medical apparatus 10 together with the distal end portion 41 of the probe 16.
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Then, when the operation pipe 27 moves in the axial direction, the gripping portion 33 is pushed
and pulled in the front-rear direction via the action pin. At this time, when the operation pipe 27
is moved to the hand side, the grip 33 is pivoted counterclockwise around the fulcrum pin via the
action pin. As a result, the gripping portion 33 pivots in the direction (close direction) in which
the tip portion 41 of the probe 16 approaches. At this time, the living tissue can be gripped
between the one-sided gripping portion 33 and the tip portion 41 of the probe 16.
[0053]
With the living tissue thus held, power is supplied from the ultrasonic power source to the
ultrasonic transducer 1 to vibrate the ultrasonic transducer 1. The ultrasonic vibration is
transmitted to the tip 41 of the probe 16. Then, treatment of the living tissue held between the
holding portion 33 and the distal end portion 41 of the probe 16 is performed using this
ultrasonic vibration.
[0054]
As shown in FIG. 10, the transducer unit 3 integrally assembles the ultrasonic transducer 1 and a
probe 16 which is a rod-like vibration transmitting member for transmitting the ultrasonic
vibration generated by the ultrasonic transducer 1. It is
[0055]
In the ultrasonic transducer 1, a horn 42 for amplifying the amplitude of the ultrasonic
transducer is continuously provided.
The horn 42 is formed of duralumin, stainless steel, or a titanium alloy such as 64Ti (Ti-6Al-4V).
The horn 42 is formed in a conical shape in which the outer diameter becomes smaller toward
the distal end side, and an outward flange 43 is formed on the proximal end outer peripheral
portion. Here, the shape of the horn 42 is not limited to the conical shape, but it is an exponential
shape in which the outer diameter becomes exponentially smaller toward the tip end, or a step
shape etc. May be
[0056]
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The probe 16 has a probe main body 44 formed of a titanium alloy such as 64Ti (Ti-6Al-4V). On
the proximal end side of the probe main body 44, the ultrasonic transducer 1 connected to the
horn 42 described above is disposed. Thus, a transducer unit 13 in which the probe 16 and the
ultrasonic transducer 1 are integrated is formed. In the probe 16, the probe main body 44 and
the horn 42 are screwed, and the probe main body 44 and the horn 42 are joined.
[0057]
The ultrasonic vibration generated by the ultrasonic transducer 1 is amplified by the horn 42 and
then transmitted to the tip 41 side of the probe 16. The distal end portion 41 of the probe 16 is
formed with a treatment portion described later for treating a living tissue.
[0058]
Further, on the outer peripheral surface of the probe main body 44, two rubber linings 45 are
attached at several points of the node position of the vibration located halfway in the axial
direction at intervals formed in a ring shape with an elastic member. The rubber lining 45
prevents contact between the outer peripheral surface of the probe main body 44 and the
operation pipe 27 described later. That is, at the time of assembly of the insertion sheath portion
18, the probe 16 as a transducer-integrated probe is inserted into the inside of the operation
pipe 27. At this time, the rubber lining 45 prevents the contact between the outer peripheral
surface of the probe main body 44 and the operation pipe 27.
[0059]
Further, the ultrasonic transducer 1 is electrically connected to an unshown power supply device
main body that supplies a current for generating ultrasonic vibration through an electric cable
46. The ultrasonic transducer 1 is driven by supplying electric power from the power supply
device main body to the ultrasonic transducer 1 through the wiring in the electric cable 46. The
transducer unit 13 includes an ultrasonic transducer 1 for generating ultrasonic vibration, a horn
42 for amplifying the generated ultrasonic vibration, and a probe 16 for transmitting the
amplified ultrasonic vibration.
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[0060]
FIG. 11 shows an entire configuration of an ultrasonic medical device of another aspect of the
ultrasonic medical device according to the present embodiment.
[0061]
The ultrasonic transducer 1 and the transducer unit 13 do not necessarily have to be housed in
the operation section main body 19 as shown in FIG. 9, and for example, are housed in the
operation pipe 27 as shown in FIG. May be
In the ultrasonic medical apparatus 10 of FIG. 11, the electric cable 46 between the break 62 of
the ultrasonic transducer 1 and the connector 48 disposed at the base of the operation unit main
body 19 is inserted into the metal pipe 47. It has been stored. Here, the connector 48 is not
essential, and the electric cable 46 may be extended to the inside of the operation portion main
body 19 and may be directly connected to the break 62 of the ultrasonic transducer 1. With the
configuration as shown in FIG. 11, the ultrasonic medical apparatus 10 can further improve
space saving in the operation unit main body 19. The function as the ultrasonic medical device
10 of FIG. 11 is the same as that of FIG. 9, and thus the detailed description will be omitted.
[0062]
As described above, in the ultrasonic transducer 1 of the present embodiment, two metal blocks
1, a plurality of piezoelectric elements 3 stacked between the metal blocks 1, the metal block 2,
the piezoelectric elements 3, and the piezoelectric elements 3 are joined to each other The
piezoelectric element 3 has a thermal expansion coefficient in the x direction with respect to the
x direction in one direction and in the y direction orthogonal to the x direction in the joint
surface 2 a with the metal block 2. The metal block 2 is made of an anisotropic material different
from the thermal expansion coefficient in the y direction, and the metal block 2 is formed with a
groove defined in accordance with the difference in thermal expansion coefficient with the
piezoelectric element 3 in the x direction or y direction. It is possible to prevent damage when
joining materials with anisotropic thermal expansion coefficient, and to reduce grooves that do
not contribute to damage prevention, so that it is possible to improve the vibration transmission
efficiency when ultrasonic vibration occurs. Become.
[0063]
Further, the metal block 2 is a groove in the y direction orthogonal to the x direction having the
largest difference in thermal expansion coefficient with the piezoelectric element 3 in at least the
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x direction or the y direction at the bonding surface 21 with the piezoelectric element Therefore,
it is possible to further reduce the stress and to improve the vibration transmission efficiency at
the time of the generation of the ultrasonic vibration.
[0064]
Further, the metal block 2 is a bonding surface with the piezoelectric element 3 and at an acute
angle with respect to the direction orthogonal to the x direction having the largest difference in
thermal expansion coefficient with the piezoelectric element 3 at least in the x direction or y
direction. Since the grooves are formed, it is not necessary to form the grooves reliably in the y
direction which is largely orthogonal to the x direction having the largest thermal expansion
coefficient difference, and the grooves 21 can be formed easily.
[0065]
In addition, since the metal block 2 is made of an isotropic material whose thermal expansion
coefficients in the x and y directions are equal to each other, the stress can be more accurately
reduced to improve the vibration transmission efficiency at the time of ultrasonic vibration
occurrence. Is possible.
[0066]
Further, in the metal block 2, the second groove 21 b is formed such that the distance between
the adjacent grooves 21 a is larger than the first groove 21 a in the direction orthogonal to the
first groove 21 a, with the groove 21 as the first groove 21 a It is possible to adjust the distance
between the grooves 21 according to the relation of the expansion coefficient, to reduce the
stress more accurately, and to improve the vibration transmission efficiency when ultrasonic
vibration occurs.
[0067]
Further, since the piezoelectric element 3 is a single crystal material, it is possible to reduce the
stress more accurately.
[0068]
Further, since the piezoelectric element 3 is lithium niobate and the metal block 2 is a 64
titanium alloy, it is possible to reduce the stress more accurately.
[0069]
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In addition, since the piezoelectric element 3 has a crystal orientation called a 36-degree rotation
Y-cut, it is possible to more accurately reduce the stress.
[0070]
Moreover, since the piezoelectric element 3 and the metal block 2 are rectangular, they can be
easily processed.
[0071]
Furthermore, since the ultrasonic medical device 10 of the present embodiment includes the
ultrasonic transducer 1 and a probe tip that transmits ultrasonic vibration generated by the
ultrasonic transducer 1 to treat a living tissue, It is possible to provide an ultrasonic medical
device 10 with reduced stress and good vibration transmission efficiency.
[0072]
The present invention is not limited by this embodiment.
That is, although many specific details are included for illustration in the description of the
embodiment, those skilled in the art can change the scope of the present invention even if
various variations and modifications are added to these details. You can understand that it does
not exceed.
Accordingly, the exemplary embodiments of the present invention are as described for the
claimed invention without loss of generality and without any limitation.
[0073]
1 ... ultrasonic transducer 2 ... metal block 3 ... piezoelectric element 4 ... junction
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