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JP2015142172

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DESCRIPTION JP2015142172
The present invention provides a laminated ultrasonic vibration device which can be
manufactured inexpensively and prevents the piezoelectric body from being damaged by the
stress caused by the difference between the thermal expansion coefficient of the metal block as
the mass material and the piezoelectric body. Do. A multi-layered ultrasonic vibration device 2
has a multi-layered piezoelectric unit 75 in which a plurality of piezoelectrics and a plurality of
electrode layers are integrally stacked and integrated with each other, and a plurality of
piezoelectrics. The first bonding material that melts at a first bonding temperature lower than
half the Curie temperature of the first bonding material, and the stacked piezoelectric unit 75
and the two mass members 42 and 43 are bonded, and is lower than the first bonding
temperature And a second bonding material 76 that melts at a second bonding temperature
higher than the maximum temperature at the time of driving. [Selected figure] Figure 12
Stacked ultrasonic vibration device, method of manufacturing stacked ultrasonic vibration device,
and ultrasonic medical device
[0001]
The present invention relates to a laminated ultrasonic vibration device for exciting ultrasonic
vibration, a method of manufacturing the laminated ultrasonic vibration device, and an ultrasonic
medical apparatus provided with the laminated ultrasonic vibration device.
[0002]
Among ultrasonic treatment tools for coagulating / incising living tissue using ultrasonic
vibration, there is one in which an ultrasonic vibrator using a piezoelectric vibrator is built in a
hand piece as an ultrasonic vibration source in a handpiece.
04-05-2019
1
[0003]
In such an ultrasonic vibrator, a piezoelectric element that converts an electrical signal to
mechanical vibration is sandwiched between two block-shaped metal members serving as a front
mass or a back mass, and integrated by some method including adhesion. There is something
that vibrates.
Such an ultrasonic transducer is called a Langevin transducer.
[0004]
As a method of integrating a piezoelectric element and a metal member, for example, a boltclamped Langevin vibration in which a piezoelectric element is sandwiched between two metal
members, is firmly fastened by a bolt, and the whole is integrally vibrated. The child is known.
[0005]
Generally, a piezoelectric element used for such a bolt-clamped Langevin vibrator is made of lead
zirconate titanate (PZT, Pb (Zrx, Ti1-x) O3), and the shape of the piezoelectric element is
processed into a ring shape. The bolt is pushed inside.
[0006]
PZT has high productivity and high electromechanical conversion efficiency, and has excellent
characteristics as a piezoelectric material, and has been used for many years in various fields
such as ultrasonic transducers and actuators.
[0007]
However, since PZT uses lead, it has recently been desired to use a lead-free piezoelectric
material which does not use lead from the viewpoint of adverse effects on the environment.
A piezoelectric single crystal lithium niobate (LiNbO3) is known as such a lead-free piezoelectric
material having high electromechanical conversion efficiency.
04-05-2019
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[0008]
Conventionally, as a configuration for realizing a Langevin vibrator using lithium niobate at low
cost, a method of integrally bonding while sandwiching a piezoelectric element by a metal block
has been known conventionally.
In particular, when bonding is performed using a brazing material such as solder without using
an adhesive as a method of bonding the metal block and the piezoelectric element, the Langevin
vibrator has better vibration characteristics than the adhesive.
[0009]
However, when a metal block and a piezoelectric element are joined by a brazing material such
as solder, a high temperature process is generally required, and in a dissimilar material joint as a
portion where the metal block and the piezoelectric element are joined, piezoelectric single
crystal There is a problem that the element is broken.
[0010]
As a technique for solving such problems, for example, an ultrasonic vibrator disclosed in Patent
Document 1 is disclosed.
In this conventional ultrasonic vibrator, a structure such as a groove or a recess is provided in
the bonding surface of each metal block bonded by an adhesive to the electrodes provided on the
upper and lower surfaces of the piezoelectric vibrator, and shear generated during driving There
are known techniques for suppressing the occurrence of distortion, reducing the dielectric loss at
the bonding surface, and the like, preventing the occurrence of cracks in the piezoelectric
vibrator, and stabilizing the vibration mode.
[0011]
JP, 2008-128875, A
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3
[0012]
However, in the conventional ultrasonic vibrator disclosed in Patent Document 1, there is a
problem that a processing step is required on the surface of the metal block and the
manufacturing cost is increased.
[0013]
That is, the conventional ultrasonic vibrator absorbs the thermal stress generated at the joint
between dissimilar materials when bonding the metal block and the piezoelectric element by
bonding, and the stress generated by the cure shrinkage of the adhesive, etc. Since the structure
such as a groove or a recess is provided in the case, an extra processing process is required,
which causes a problem of cost increase.
[0014]
Further, when a thermosetting adhesive is used to bond and fix the piezoelectric vibrator and the
metal block, the conventional ultrasonic vibrator heats the vicinity of the bonding surface when
the adhesive is cured.
Thus, in the conventional ultrasonic vibrator, after curing of the adhesive, a shear strain
corresponding to the temperature difference between the bonding temperature and the normal
temperature may occur due to the difference in the thermal expansion coefficient of the
piezoelectric vibrator and the metal block. is there.
[0015]
Then, residual stress always exists on the bonding surface of the piezoelectric vibrator and the
metal block, and there is also a problem that a crack is generated inside the piezoelectric vibrator
due to this.
[0016]
Therefore, the present invention has been made in view of the above circumstances, and can be
manufactured inexpensively, and the piezoelectric body is broken due to the stress caused by the
difference between the thermal expansion coefficients of the metal block as the mass material
and the piezoelectric body. It is an object of the present invention to provide a laminated
ultrasonic vibration device, a method of manufacturing the laminated ultrasonic vibration device,
and an ultrasonic medical device, which are prevented from being generated.
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[0017]
A laminated ultrasonic vibration device according to one aspect of the present invention is a
laminated ultrasonic vibration device in which a plurality of piezoelectric bodies are provided
between two mass materials, and the plurality of piezoelectric bodies and a plurality of electrode
layers are laminated. And a first bonding material which is joined at the first joining temperature
lower than a half of the Curie temperature of the plurality of piezoelectric bodies. A second
bonding material which is bonded to the laminated piezoelectric unit and the two mass materials
and which melts at a second bonding temperature lower than the first bonding temperature and
higher than a maximum temperature during driving; Have.
[0018]
Further, in the method of manufacturing a stacked ultrasonic vibration device according to one
aspect of the present invention, the plurality of piezoelectric members are joined with a stacked
piezoelectric unit in which a plurality of piezoelectric members and a plurality of electrode layers
are stacked and integrated. A first bonding material that melts at a first bonding temperature
lower than half the Curie temperature of the plurality of piezoelectric bodies, and the two mass
materials are bonded to the laminated piezoelectric unit, the first bonding material A method of
manufacturing a stacked ultrasonic vibration device, comprising: a second bonding material that
melts at a second bonding temperature lower than a bonding temperature and higher than a
maximum temperature during driving, the plurality of piezoelectric single crystals Forming a
base metal on the front and back surfaces of the wafer; bonding the plurality of piezoelectric
single crystal wafers on which the base metal is formed with the first bonding material to
produce the laminated wafer. The laminated wafer is The steps of: singulating to cut out the
plurality of stacked piezoelectric units; and bonding one of the stacked piezoelectric units and the
two mass materials with the second bonding material to produce a stacked vibrator. Prepare.
[0019]
Furthermore, in the ultrasonic medical device according to one aspect of the present invention,
the plurality of piezoelectric members are joined with a stacked piezoelectric unit in which a
plurality of piezoelectric members and a plurality of electrode layers are stacked and integrated,
The first bonding material melting at a first bonding temperature lower than half the Curie
temperature of the piezoelectric material, and the laminated piezoelectric material unit and two
mass materials are bonded, and are lower than the first bonding temperature And a second
bonding material that melts at a second bonding temperature higher than the maximum
temperature at the time of driving, and the ultrasonic vibration generated in the stacked
ultrasonic vibration device is transmitted. And a probe tip for treating a living tissue.
04-05-2019
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[0020]
According to the present invention, it is possible to manufacture at low cost, and to prevent the
piezoelectric body from being damaged by the stress caused by the difference between the
thermal expansion coefficients of the metal block as the mass material and the piezoelectric
body. It is possible to provide a method of manufacturing a stacked ultrasonic vibration device
and an ultrasonic medical device.
[0021]
The sectional view showing the whole composition of the ultrasonic medical equipment
concerning one mode of the present invention. The figure showing the outline composition of the
whole vibrator unit. The perspective view showing the composition of an ultrasonic vibrator. The
same. The side view showing the configuration, the flow chart showing the manufacturing
process of the ultrasonic transducer, the same, the perspective view showing the piezoelectric
single crystal wafer, the same, the perspective view showing the piezoelectric single crystal wafer
on which the base metal is deposited A perspective view showing a plurality of piezoelectric
single crystal wafers, and a perspective view showing a laminated wafer in which a plurality of
piezoelectric single crystal wafers are laminated, a perspective view showing a laminated wafer
to be diced, and a laminated piezoelectric body cut out from the laminated wafer The perspective
view showing the unit The same, an exploded perspective view of the transducer unit including
the ultrasonic transducer, the same, an exploded perspective view showing the state of mounting
the flexible printed circuit board on the ultrasonic transducer of the transducer unit Fig. 6 is a
perspective view showing a transducer unit in which an FPC is mounted on the same element.
[0022]
Hereinafter, the present invention will be described using the drawings.
In the following description, the drawings based on the respective embodiments are schematic,
and the relationship between the thickness and the width of each portion, the ratio of the
thickness of each portion, and the like are different from the actual ones. It should be noted that
there may be parts where the relationships and proportions of dimensions differ from one
another among the drawings.
[0023]
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First, an embodiment of an ultrasonic medical apparatus provided with a laminated ultrasonic
vibration device for exciting ultrasonic vibration according to one aspect of the present invention
will be described below based on the drawings.
FIG. 1 is a cross-sectional view showing the entire configuration of the ultrasonic medical device,
FIG. 2 is a view showing the general configuration of the transducer unit, FIG. 3 is a perspective
view showing the configuration of the ultrasonic transducer, and FIG. 5 is a flow chart showing
the manufacturing process of the ultrasonic transducer, FIG. 6 is a perspective view showing a
piezoelectric single crystal wafer, and FIG. 7 is a piezoelectric single crystal wafer on which a
base metal is formed 8 is a perspective view showing a plurality of piezoelectric single crystal
wafers to be stacked, FIG. 9 is a perspective view showing a multilayer wafer in which a plurality
of piezoelectric single crystal wafers are stacked, and FIG. 10 is a multilayer wafer to be diced 11
is a perspective view showing a laminated piezoelectric unit cut out from a laminated wafer, FIG.
12 is an exploded perspective view of a transducer unit including an ultrasonic transducer, and
FIG. 13 is an ultrasonic vibration of the transducer unit Disassembly indicating the state of
mounting the FPC to the child FIG, 14 is a perspective view showing a transducer unit which is
implemented FPC to the ultrasonic transducer, FIG. 15 is a graph showing the temperature
relationship for manufacturing and driving of the ultrasonic vibrator.
[0024]
(Ultrasonic Medical Device) The ultrasonic medical device 1 shown in FIG. 1 mainly uses a
transducer unit 3 having an ultrasonic transducer 2 for generating ultrasonic vibration, and
coagulation / disappearance of the affected area using the ultrasonic vibration. A handle unit 4 is
provided to perform an incision procedure.
[0025]
The handle unit 4 includes an operation portion 5, an insertion sheath portion 8 composed of a
long outer tube 7, and a distal end treatment portion 30.
The proximal end portion of the insertion sheath portion 8 is attached to the operation portion 5
so as to be rotatable around the axis.
[0026]
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The distal end treatment unit 30 is provided at the distal end of the insertion sheath unit 8.
The operation unit 5 of the handle unit 4 includes an operation unit main body 9, a fixed handle
10, a movable handle 11, and a rotation knob 12.
The operation unit main body 9 is integrally formed with the fixed handle 10.
[0027]
A slit 13 through which the movable handle 11 is inserted is formed on the back side of the
connecting portion between the operation portion main body 9 and the fixed handle 10.
The upper portion of the movable handle 11 extends inside the operation portion main body 9
through the slit 13.
[0028]
A handle stopper 14 is fixed to the lower end of the slit 13.
The movable handle 11 is rotatably attached to the operation unit main body 9 via a handle
support shaft 15.
The movable handle 11 is designed to be opened and closed with respect to the fixed handle 10
as the movable handle 11 pivots about the handle support shaft 15.
[0029]
A substantially U-shaped connecting arm 16 is provided at the upper end of the movable handle
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8
11.
Further, the insertion sheath portion 8 has an outer tube 7 and an operation pipe 17 axially
movably inserted into the outer tube 7.
[0030]
A large diameter portion 18 larger in diameter than the distal end portion is formed at the
proximal end portion of the sheath tube 7.
The rotary knob 12 is mounted around the large diameter portion 18.
[0031]
A ring-shaped slider 20 is provided on the outer peripheral surface of the operation pipe 19 so as
to be movable along the axial direction.
A fixing ring 22 is disposed behind the slider 20 via a coil spring (elastic member) 21.
[0032]
Furthermore, the proximal end of the grip portion 23 is rotatably connected to the distal end of
the operation pipe 19 via an action pin.
The grasping portion 23 constitutes a treatment portion of the ultrasonic medical device 1
together with the distal end portion 31 of the probe 6. Then, when the operation pipe 19 moves
in the axial direction, the gripping portion 23 is pushed and pulled in the front-rear direction via
the action pin.
[0033]
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At this time, when the operation pipe 19 is moved to the hand side, the grip 23 is pivoted
counterclockwise around the fulcrum pin via the action pin.
[0034]
As a result, the gripping portion 23 pivots in a direction (close direction) in which the tip end
portion 31 of the probe 6 approaches.
At this time, the living tissue can be gripped between the one-sided grip type gripping portion 23
and the tip end portion 31 of the probe 6.
[0035]
With the living tissue thus held, power is supplied from the ultrasonic power source to the
ultrasonic transducer 2 to vibrate the ultrasonic transducer 2. This ultrasonic vibration is
transmitted to the tip 31 of the probe 6. Then, coagulation / dissection treatment of the living
tissue held between the holding portion 23 and the distal end portion 31 of the probe 6 is
performed using the ultrasonic vibration.
[0036]
(Silver Unit) Here, the vibrator unit 3 will be described. As shown in FIG. 2, the transducer unit 3
integrally assembles the ultrasonic transducer 2 and a probe 6 which is a rod-like vibration
transmitting member for transmitting ultrasonic vibration generated by the ultrasonic transducer
2. It is
[0037]
In the ultrasonic transducer 2, a horn 32 for amplifying the amplitude of the ultrasonic
transducer is continuously provided. The horn 32 is formed of stainless steel, duralumin, or a
titanium alloy such as 64Ti (Ti-6Al-4V).
04-05-2019
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[0038]
The horn 32 is formed in a conical shape in which the outer diameter becomes smaller toward
the distal end side, and the outward flange 33 is formed on the proximal end outer peripheral
portion. Here, the shape of the horn 32 is not limited to the conical shape, but is an exponential
shape in which the outer diameter decreases exponentially as it goes to the tip side, or a step
shape that gradually narrows as it goes to the tip side. May be
[0039]
The probe 6 has a probe main body 34 formed of a titanium alloy such as 64Ti (Ti-6Al-4V). On
the proximal end side of the probe main body 34, the ultrasonic transducer 2 connected to the
above-described horn 32 is disposed.
[0040]
Thus, a transducer unit 3 in which the probe 6 and the ultrasonic transducer 2 are integrated is
formed. In the probe 6, the probe main body 34 and the horn 32 are screwed, and the probe
main body 34 and the horn 32 are joined.
[0041]
The ultrasonic vibration generated by the ultrasonic transducer 2 is amplified by the horn 32 and
then transmitted to the tip 31 side of the probe 6. The distal end portion 31 of the probe 6 is
formed with a treatment portion described later for treating a living tissue.
[0042]
Further, on the outer peripheral surface of the probe main body 34, two rubber linings 35 are
attached at several points of the node position of vibration located halfway in the axial direction
at intervals formed in a ring shape by elastic members. The rubber lining 35 prevents contact
04-05-2019
11
between the outer peripheral surface of the probe main body 34 and the operation pipe 19
described later.
[0043]
That is, at the time of assembly of the insertion sheath portion 8, the probe 6 as a transducerintegrated probe is inserted into the inside of the operation pipe 19. At this time, the rubber
lining 35 prevents contact between the outer peripheral surface of the probe main body 34 and
the operation pipe 19.
[0044]
In addition, the ultrasonic transducer 2 is electrically connected to a not-shown power supply
device main body that supplies a current for generating ultrasonic vibration via an electric cable
36. The ultrasonic transducer 2 is driven by supplying power from the power supply device main
body to the ultrasonic transducer 2 through the wiring in the electric cable 36.
[0045]
From the above description, the transducer unit 3 transmits the ultrasonic transducer 2
generating ultrasonic vibration, the horn 32 amplifying the ultrasonic vibration generated by the
ultrasonic transducer 2 and the amplified ultrasonic vibration. A probe 6 is provided.
[0046]
(Ultrasonic Transducer) Here, the ultrasonic transducer 2 as a laminated type ultrasonic vibration
device of the present invention will be described below.
As shown in FIG. 3 and FIG. 4, the ultrasonic transducer 2 of the transducer unit 3 has the abovementioned horn 32 screwed and connected to the probe main body 34 which is one of the
vibration transfer members in order from the tip The laminated vibrator 41 as a rectangular
(square pole-shaped) laminated piezoelectric unit continuously connected to the rear of the horn
32 and the laminated vibrator 41 from the base end of the horn 32 to the electric cable 36 And a
cover body 51.
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[0047]
Note that the cover 51 covering the laminated vibrator 41 is broken at the base end portion so as
to cover the wires 36a and 36b of the electric cable 36 electrically connected to the two FPCs
(flexible printed circuit boards) 47 and 48 as current-carrying members. There is a stop 52. The
current-carrying members are not limited to the FPCs 47 and 48, and may be simple metal wires.
[0048]
The laminated vibrator 41 is joined to a rectangular (square prism) front mass 42 connected to
the horn 32 by screwing or the like on the front side, and is joined to a rectangular (square
prism) back mass 43 on the rear side. ing.
[0049]
The front mass 42 and the back mass 43 are formed of duralumin as in the horn 32.
The front mass 42 and the back mass 43 may be stainless steel or a titanium alloy such as 64Ti
(Ti-6Al-4V).
[0050]
Furthermore, the laminated vibrator 41 may have an insulating member between the front mass
42 and the back mass 43 which is insulating and difficult to damp the vibration. As this
insulating member, for example, an insulating plate formed of a ceramic material such as
alumina, silicon nitride or the like on a rectangular (square columnar) plate may be used.
[0051]
As described above, even if the multi-layered vibrator 41 is provided with the insulating member,
the ultrasonic medical apparatus 1 shown in FIG. And breakage due to high frequency from the
treatment tool is prevented.
04-05-2019
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[0052]
The laminated vibrator 41 uses a piezoelectric element formed of a lead-free single crystal
material having a high Curie point, and a plurality of piezoelectric single crystals 61 as a
piezoelectric single crystal chip, which is this piezoelectric element, are stacked in this case. It is
arranged.
[0053]
Between the four piezoelectric single crystals 61, the front mass 42 and the back mass 43, a
positive electrode layer is formed as a bonding metal layer formed of a lead-free solder, which
will be described later, as a brazing material. The electric bonding metal 62 and the negative
bonding metal 63 to be a negative electrode layer are alternately interposed.
[0054]
The laminated vibrator 41 is not limited to the positive side bonding metal 62 or the negative
side bonding metal 63 provided between the piezoelectric single crystal 61 and between the
piezoelectric single crystal 61 and the front mass 42 or the back mass 43. The electrical contact
portions of the FPCs 47 and 48 are electrically connected by conductive paste or the like.
[0055]
(Method of Manufacturing Ultrasonic Transducer) Next, a method of manufacturing the
ultrasonic transducer 2 described above will be described in detail below.
First, the ultrasonic transducer 2 uses a piezoelectric material which has a high Curie
temperature (Curie point) and whose piezoelectric characteristics do not deteriorate even at the
melting point of a bonding metal. Here, the ultrasonic transducer 2 is made of a lithium niobate
(LiNbO3) wafer as a single crystal material. It is made of a piezoelectric single crystal wafer 71
(see FIG. 6).
[0056]
The piezoelectric single crystal wafer 71 has a crystal orientation called a 36-degree rotation Ycut so as to increase the electromechanical coupling coefficient in the thickness direction of the
piezoelectric element.
04-05-2019
14
[0057]
As shown in the flowchart of FIG. 5, first, the base metal 72 (see FIG. 7) is formed on the front
and back surfaces of the piezoelectric single crystal wafer 71 (see FIG. 6) (S1).
Specifically, the piezoelectric single crystal wafer 71 has good adhesion and wettability with leadfree solder on the front and back surfaces, for example, Ti / Ni / Au, Ti / Pt / Au, Cr / Ni / Au or
An underlying metal 72 composed of Cr / Ni / Pd / Au is deposited by vapor deposition,
sputtering, plating or the like.
[0058]
Next, the number of piezoelectric single crystal wafers 71 (see FIGS. 8 and 9) corresponding to
the desired specification of the ultrasonic transducer 2 is stacked and bonded (S2).
Specifically, as shown in FIG. 8, among the base metals 72 of the four piezoelectric single crystal
wafers 71, as a first bonding material using a lead-free solder, for example, a Zn̶Al-based
solder, The brazing material 73 is provided.
The first brazing filler metal 73 is disposed on one of the base metals 72 of the piezoelectric
single crystal wafer 71 by screen printing or in the form of a ribbon.
[0059]
And, since the Zn̶Al based solder is used as the first brazing material 73 for bonding the four
piezoelectric single crystal wafers 71 to each other, the first bonding temperature at which the
first brazing material 73 melts becomes the first bonding temperature. It is heated to about 380
° C. and cooled slowly.
Thus, the four piezoelectric single crystal wafers 71 are bonded to each other by the first brazing
04-05-2019
15
material 73, as shown in FIG.
[0060]
As a result, a bonding metal layer composed of the base metal 72 and the first brazing material
73 is formed between the four piezoelectric single crystal wafers 71 to form a laminated wafer
74 integrated.
[0061]
In the heating step of bonding the four piezoelectric single crystal wafers 71, pressure may be
applied so as to compress in the stacking direction as necessary.
[0062]
Next, the laminated piezoelectric unit 75 (see FIGS. 10 and 11) is cut out of the laminated wafer
74 (S3).
Specifically, the laminated wafer 74 is cut out in a block shape along a broken line (virtual line)
shown in FIG. 10 by a thin dicing blade, and a plurality of rectangular piezoelectric material
blocks shown in FIG. 11 are obtained. A plurality of stacked piezoelectric units 75 are extracted.
[0063]
That is, the laminated piezoelectric unit 75 integrated in a state where four piezoelectric single
crystals 61 are laminated is extracted from the laminated wafer 74.
Further, the base metal 72 and the first brazing filler metal 73 among the four piezoelectric
single crystal bodies 61 constitute the positive electrode side bonding metal 62 or the negative
electrode side bonding metal 63 of the laminated piezoelectric unit 75.
[0064]
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The shape of the laminated piezoelectric unit 75 here is a rectangular block according to the
specification of the ultrasonic transducer 2. The laminated piezoelectric unit 75 cut out from the
laminated wafer 74 by dicing can be manufactured at the lowest cost by forming it into a
rectangular block shape.
[0065]
Next, one cut out laminated piezoelectric unit 75 is joined to the front mass 42 and the back
mass 43 which are mass members (S4). Specifically, as shown in FIG. 12, the front mass 42 and
the back mass 43 which are metal blocks are joined so that both ends of the laminated
piezoelectric unit 75 are sandwiched.
[0066]
Here, a second brazing material 76 as a second bonding material using, for example, a
Sn̶Ag̶Cu-based solder as a non-lead solder between the laminated piezoelectric unit 75 and
the front mass 42 and the back mass 43. Is provided. The second brazing material 76 is disposed
on the base metal 72 or on one surface of the front mass 42 and the back mass 43 on both end
surfaces of the laminated piezoelectric unit 75 by screen printing or ribbon form.
[0067]
Since the laminated piezoelectric unit 75, the front mass 42, and the back mass 43 use
Sn̶Ag̶Cu based solder as the second brazing material 76 for joining them to each other, this
Sn̶Ag̶Cu based solder is used. Is heated to about 220 ° C., which is the temperature at which
is melted, and then slowly cooled. Thus, the laminated piezoelectric unit 75, the front mass 42
and the back mass 43 are bonded to each other by the second brazing material 76.
[0068]
As a result, a bonding metal layer composed of the base metal 72 and the second brazing
material 76 is formed between the laminated piezoelectric unit 75, the front mass 42 and the
back mass 43 to form an integrated ultrasonic transducer 2 It is molded. Here, also in the heating
04-05-2019
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step of joining the laminated piezoelectric unit 75, the front mass 42 and the back mass 43, it is
preferable to apply pressure so as to compress in the laminating direction as necessary.
[0069]
In addition, the ultrasonic vibrator 2 is formed of the laminated piezoelectric unit 75, the second
brazing material 76 interposed between the front mass 42 or the back mass 43, and the base
metal provided on both end surfaces of the laminated piezoelectric unit 75. Reference numeral
72 constitutes the negative electrode side joining metal 63 of the laminated piezoelectric unit 75.
[0070]
In the center of one end face of the front mass 42, a tapped screw hole 42a is machined.
The horn 32 and the front mass 42 are screwed together by screwing the screw portion 32a
integrally formed with the horn 32 in the screw hole 42a.
[0071]
Then, two FPCs 47 and 48 (see FIGS. 13 and 14), which are current-carrying members, are
mounted on the ultrasonic transducer 2 (S5). As shown in FIGS. 13 and 14, the positive side
bonding metal 62 and the negative side bonding metal 63 of the ultrasonic vibrator 2 are
electrically connected to the electrical contacts of the FPCs 47 and 48 using conductive paste or
the like. It is electrically connected through the part 49.
[0072]
That is, in order to electrically connect the positive side bonding metal 62 and the negative side
bonding metal 63 to the FPCs 47, 48, the electrical properties of the FPCs 47, 48 on the outer
surfaces of the positive side bonding metal 62 and the negative side bonding metal 63 The
contact points are in contact via the electrical connection 49, and the FPCs 47 and 48 are fixed
to the laminated piezoelectric unit 75.
[0073]
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In this manner, the electrical connection between the positive and negative bonding metals 62
and 63 and the FPCs 47 and 48 is established.
And wiring 36a, 36b (refer FIG. 3 and FIG. 4) of the above-mentioned electric cable 36 is
connected to FPC47 and 48.
[0074]
Although FIGS. 13 and 14 show the horn 32 and the front mass 42 in a screwed state, the
ultrasonic wave in step S5 described above is used for bonding by the horn 32 and the front
mass 42 by screwing. It may be performed either before or after attachment of the FPCs 47 and
48 to the vibrator 2.
[0075]
With such a configuration, on the positive electrode side, the wiring 36a of the electric cable 36,
the FPC 47, the electrical connection portion 49, and the positive electrode side metal 62 are
electrically connected.
Further, as the negative electrode side, the wiring 36 b of the electric cable 36, the FPC 48, the
electrical connection portion 49, and the negative electrode metal 63 are electrically connected.
By these electrical connections, a drive signal is applied to the four piezoelectric single crystals
61 via the positive side bonding metal 62 and is returned from the negative side bonding metal
63.
[0076]
Note that the exposed surface portions of the positive side bonding metal 62, the negative side
bonding metal 63, and the electrical connection portion 49 may be covered with an insulator
such as a resin to prevent the occurrence of unnecessary electrical connection which becomes
defective. In order to reinforce the mechanical fixing of the FPCs 47 and 48, the FPCs 47 and 48
may be fixed to the positive side bonding metal 62 and the negative side bonding metal 63 with
an adhesive. Furthermore, the FPCs 47 and 48 may be fixed to the surfaces of the side portions
04-05-2019
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of the four piezoelectric single crystal bodies 61 with an adhesive.
[0077]
According to the manufacturing process of the ultrasonic transducer 2 described above, the front
mass 42, the four piezoelectric single crystals 61, and the back mass 43 are stacked by the
positive side bonding metal 62 and the negative side bonding metal 63 to be a bonding metal
layer. By applying a drive signal to the positive side bonding metal 62 from the FPCs 47 and 48
provided on the side surface of the laminate through the electrical connection 49 and returning it
by the negative side bonding metal 63. The whole of the acoustic transducer 2 is made to vibrate
ultrasonically.
[0078]
As described above, in the ultrasonic medical apparatus 1 according to the present embodiment,
after the base metal 72 is formed on a plurality of, in this case, four piezoelectric single crystal
wafers 71, the ultrasonic transducers 2 as stacked ultrasonic vibration devices are used. The four
piezoelectric single crystals 61, the positive side bonding metal 62 and the negative side bonding
metal 63 are obtained by dicing and cutting out the laminated wafer 74 in which the four
piezoelectric single crystal wafers 71 are laminated and bonded by the first brazing material 73.
It is configured to have a rectangular block-shaped laminated piezoelectric unit 75 to be
laminated.
[0079]
As a result, the laminated piezoelectric unit 75 provided in the ultrasonic transducer 2 does not
require the step of individually bonding the piezoelectric single crystals 61, and a plurality of
laminated piezoelectric units 75 can be manufactured collectively from the laminated wafer 74.
[0080]
Therefore, the ultrasonic vibrator 2 does not have to cut out the piezoelectric single crystal
bodies 61 individually from the piezoelectric single crystal wafer 71, so the number of times of
dicing is reduced, the processing time is shortened, and the cost is reduced.
As a result, the ultrasonic transducer 2 can be manufactured inexpensively.
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[0081]
In addition, although the example of the shape which can manufacture the ultrasonic transducer
2 in the rectangular block shape most cheaply was mentioned above, it is not limited to this, Even
if the shape of these members was made cylindrical shape, for example Good.
Furthermore, it is not limited that the laminated piezoelectric unit 75 is cut out from the
laminated wafer 74 by dicing to form a rectangular block, for example, the piezoelectric single
crystal wafer 71 on which the base metal 72 is formed is diced in advance It is good also as
lamination piezoelectric body unit 75 which carried out lamination joining using two or more
sheets of this.
[0082]
In the ultrasonic transducer 2, a Zn̶Al-based solder is used as the first brazing material 73 for
joining the four stacked piezoelectric single crystal wafers 71, and a laminated piezoelectric unit
cut out from the laminated wafer 74. A Sn̶Ag̶Cu-based solder is used which has a lower
melting point (melting temperature) than the first brazing material 73 as the second brazing
material 76 for joining the front mass 42 and the back mass 43 with the 75.
[0083]
Specifically, the first bonding temperature when bonding four piezoelectric single crystal wafers
71 is set to the melting temperature (about 380 ° C.) of the first brazing filler metal 73 and cut
out from the laminated wafer 74 The second bonding temperature when bonding the stacked
piezoelectric unit 75 to the front mass 42 and the back mass 43 is set to the melting temperature
(about 220 ° C.) of the second brazing material 76 lower than the first bonding temperature Ru.
[0084]
That is, as shown in FIG. 15, the ultrasonic vibrator 2 has a first bonding temperature of about
380 ° C. for bonding four piezoelectric single crystal wafers 71 (piezoelectric single crystal
bodies 61). The second bonding temperature for bonding the cut out laminated piezoelectric unit
75 to the front mass 42 and the back mass 43 is about 220 ° C. lower than the first bonding
temperature (about 380 ° C.).
[0085]
04-05-2019
21
In the laminated piezoelectric unit 75, four piezoelectric single crystals 61 are joined by the first
brazing material 73 at the time of joining with the front mass 42 and the back mass 43. Even
when heated to a melting temperature of 76 (about 220 ° C.), the first brazing filler metal 73
having a melting temperature (about 380 ° C.) higher than that is used. The reliability of the
bonding between the piezoelectric single crystals 61 is not impaired without the first brazing
material 73 melting.
[0086]
By the way, when the front mass 42 and the back mass 43 are joined to the laminated
piezoelectric unit 75 in the manufacturing process of the ultrasonic transducer 2, the
piezoelectric single crystal 61 is affected, and a crack is generated inside the piezoelectric single
crystal 61. May.
As the reason, in the case where the ultrasonic vibrator 2 causes shear strain on the piezoelectric
single crystal 61 side due to the difference in thermal expansion coefficient between the
piezoelectric single crystal 61, the front mass 42 and the back mass 43, residual stress always
occurs. Because there is
[0087]
As described above, this thermal expansion is achieved by setting the melting temperature of the
second brazing filler metal 76 used for joining the front mass 42 or the back mass 43 and the
laminated piezoelectric unit 7 lower than that of the first brazing filler metal 73. The influence of
the difference in coefficient can be suppressed, and the crack generated inside the piezoelectric
single crystal 61 can be prevented.
[0088]
Furthermore, in the ultrasonic transducer 2, lithium niobate (LiNbO 3) is used for the four
piezoelectric single crystals 61 stacked as the stacked piezoelectric unit 75.
The lithium niobate (LiNbO 3) has a Curie point (Curie temperature) of about 1200 ° C., and
about 600 ° C., which is a half temperature thereof, is considered as the upper limit of the
usable state.
04-05-2019
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[0089]
Then, the ultrasonic vibrator 2 melts the first brazing material 73 when bonding the piezoelectric
single crystal wafer 71 having a maximum temperature of four at the time of manufacture, and
the four piezoelectric single crystal wafers 71 (piezoelectric single crystal body The first bonding
temperature for bonding 61) is about 380 ° C., which is lower than about 600 ° C., which is
half of the Curie temperature of the piezoelectric single crystal 61.
Therefore, the piezoelectric performance of the four piezoelectric single crystals 61 formed from
the piezoelectric single crystal wafer 71 is not degraded.
[0090]
By the way, the temperature of the ultrasonic transducer 2 during operation rises up to about
100 ° C. at the maximum.
That is, as shown in FIG. 15, the ultrasonic transducer 2 has the melting temperature (about 380
° C.) of the first brazing material 73 joining the four piezoelectric single crystal wafers 71, the
laminated piezoelectric unit 75, and the front mass. The melting temperature (about 220 ° C.) of
the second brazing filler metal 76 joining the B.42 and the back mass 43 is higher than the
maximum temperature (about 100 ° C.) in operation.
[0091]
Therefore, the ultrasonic transducer 2 does not reach a temperature at which the positive side
bonding metal 62 and the negative side bonding metal 63 formed from the first brazing material
73 or the second brazing material 76 melts during operation. Therefore, the reliability of the
bonding between the four piezoelectric single crystals 61 and the bonding of the stacked
piezoelectric unit 75 and the front mass 42 or the back mass 43 is not impaired.
[0092]
In other words, in the ultrasonic transducer 2, the second bonding temperature (about 220 ° C.)
at which the stacked piezoelectric unit 75 is bonded to the front mass 42 and the back mass 43
04-05-2019
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becomes four at the time of manufacturing the stacked piezoelectric unit 75. The temperature is
lower than the first bonding temperature (about 380 ° C.) when bonding the piezoelectric single
crystal wafer 71 and higher than the maximum temperature (about 100 ° C.) when the
ultrasonic transducer 2 is in operation.
[0093]
Thus, the ultrasonic transducer 2 has a second bonding temperature (about 220 ° C.) set
between the maximum driving temperature (about 100 ° C.) and the first bonding temperature
(about 380 ° C.). By setting the temperature relationship as described above, the ultrasonic
transducer 2 can be made without impairing the reliability of the connection between the four
piezoelectric single crystal bodies 61 and the connection between the stacked piezoelectric unit
75 and the front mass 42 and the back mass 43. It can be manufactured.
[0094]
In addition to this, in operation, even when the maximum temperature of about 100 ° C. is
reached, the ultrasonic vibrator 2 has a junction between the four piezoelectric single crystals 61
and the laminated piezoelectric unit 75 and the front mass 42. And, the positive side metal 62
and the negative side metal 63 which form the junction with the back mass 43 are not affected.
[0095]
In the ultrasonic transducer 2 of the present embodiment, the thermal expansion coefficient of
the second brazing material 76, which is a bonding material of the portion where the laminated
piezoelectric unit 75 and the front mass 42 and the back mass 43 are bonded, is made of the
piezoelectric single crystal 61 And the range between the front mass 42 and the back mass 43.
[0096]
For this reason, the ultrasonic vibrator 2 may be generated by the difference between the
thermal expansion coefficients of the piezoelectric single crystal 61, the front mass 42, and the
back mass 43 provided at both ends of the laminated piezoelectric unit 75. The shear strain on
the side can be suppressed, and cracks generated inside the piezoelectric single crystal 61 can be
prevented.
[0097]
Specifically, in the ultrasonic transducer 2, lithium niobate (LiNbO 3) is used for the piezoelectric
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single crystal 61, and duralmin is used for the front mass 42 and the back mass 43.
The thermal expansion coefficient of lithium niobate (LiNbO3) is 8 to 15 × 10 <-6> [1 / ° C.],
and the thermal expansion coefficient of duralumin is 24 × 10 <-6> [1 / ° C].
[0098]
Therefore, in the present embodiment, Sn̶Ag̶Cu solder has a thermal expansion coefficient
between the thermal expansion coefficients of lithium niobate (LiNbO 3) piezoelectric single
crystal 61, duralumin front mass 42 and back mass 43. A second braze material 76 is used.
[0099]
The thermal expansion coefficient of the Sn-Ag-Cu solder is larger than that of lithium niobate
(LiNbO3) (8 to 15 x 10 <-6> [1 / ° C]), and the thermal expansion of duralumin It is 21 × 10
<−6> [1 / ° C.] smaller than the coefficient (24 × 10 <−6> [1 / ° C.]).
[0100]
As a result, the second brazing material 76 of Sn̶Ag̶Cu based solder, which is a bonding
material of the laminated piezoelectric unit 75 and the front mass 42 and the back mass 43,
becomes the laminated piezoelectric unit 75, the front mass 42, and the back It serves to absorb
the thermal expansion coefficient difference of the mass 43, and the stress on the piezoelectric
single crystal 61 is reduced, and the occurrence of cracks inside the piezoelectric single crystal
61 is prevented.
[0101]
The second brazing filler metal 76 only needs to have a thermal expansion coefficient between
the thermal expansion coefficients of lithium niobate (LiNbO3) and duralumin, and in addition to
the Su-Ag-Cu solder, for example, Sn Based solder, Sn-Ag solder or Sn-Cu solder may be used.
[0102]
In addition, although the first brazing material 73 used as a bonding material of the piezoelectric
single crystal bodies 61 is Zn-Al based solder, the melting temperature (first bonding
temperature) and the melting of the second brazing material 76 are used. Other brazing
materials may be used if the magnitude relationship with the temperature (second bonding
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temperature) is established.
That is, the first brazing material 73 may have a melting temperature (first bonding
temperature> second bonding temperature) higher than the melting temperature of the second
brazing material 76.
However, it is desirable that the difference in melting temperature be several tens of degrees C.
or more in consideration of temperature variations during manufacturing.
[0103]
Furthermore, the solder used for the first brazing material 73 and the second brazing material 76
does not reach the melting temperature, and even when it is not melted, the Young's modulus
decreases and becomes soft when the temperature approaches the melting temperature, and
ultrasonic vibration The performance of child 2 is reduced.
Therefore, in particular, it is desirable to use one having a large difference between the melting
temperature of the second brazing material 76 and the maximum temperature (about 100 ° C.)
at which the ultrasonic transducer 2 is driven.
[0104]
By the way, lead zirconate titanate (PZT, Pb (Zrx, Ti1-x) O3) widely used at present as a
piezoelectric material of a conventional ultrasonic transducer has a Curie temperature of about
300 ° C., and half thereof The upper limit of usable temperature is about 150.degree. C., so that
even if a low melting point solder is used, the difference between the first bonding temperature
and the second bonding temperature can not be obtained, as in the present embodiment. It can
not be applied to the method of manufacturing the ultrasonic transducer 2.
[0105]
As described above, the ultrasonic transducer 2 which is the layered ultrasonic vibration device
of the present embodiment and the ultrasonic medical device 1 having the ultrasonic transducer
2 can be manufactured at low cost, and can be used as a mass material. The piezoelectric body
can be prevented from breakage or the like due to the stress caused by the difference between
the thermal expansion coefficients of the metal block and the piezoelectric body.
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[0106]
The invention described in the above-described embodiment is not limited to the embodiment
and the modifications, and in the implementation stage, various modifications can be made
without departing from the scope of the invention.
Furthermore, the above embodiments include inventions of various stages, and various
inventions can be extracted by appropriate combinations of a plurality of disclosed configuration
requirements.
[0107]
For example, even if some of the configuration requirements are removed from all the
configuration requirements shown in the embodiment, the configuration requirements can be
eliminated if the problems described can be solved and the described advantages can be
obtained. The configuration can be extracted as the invention.
[0108]
Reference Signs List 1 ultrasonic medical device 2 ultrasonic transducer 3 transducer unit 4
handle unit 5 operation unit 6 probe 7 outer sheath tube 8 insertion sheath portion 9 operation
unit main body 10 fixed handle 11 movable handle 12: rotation knob 13: slit 14: handle stopper
15: handle support shaft 16: connection arm 17: operation pipe 18: large diameter portion 19:
operation pipe 20: slider 22: fixing ring 23: grip portion 30: tip treatment portion 31 ... Tip
portion 32 ... Horn 32a ... Threaded portion 33 ... Outgoing flange 34 ... Probe main body 35 ...
Rubber lining 36 ... Electric cable 36a, 36b ... Wiring 41 ... Layered vibrator 42 ... Front mass 42a
... Screw hole 43 ... Back mass 47, 48 ... FPC 49 ... electrical connection portion 51 ... cover body
52 ... bending stop 61 ... piezoelectric single crystal body 62 ... positive electrode Bonding metal
63: Negative bonding metal 71: Piezoelectric single crystal wafer 72: Base metal 73: first brazing
material 74: laminated wafer 75: laminated piezoelectric unit 76: second brazing material
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