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DESCRIPTION JP2012182758

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DESCRIPTION JP2012182758
The present invention provides a method of manufacturing an ultrasonic probe capable of
suppressing deterioration of a piezoelectric effect due to cutting of a polarized piezoelectric
material. In a first step, a plurality of columnar piezoelectric elements 31 arranged at
predetermined intervals in an at least one-dimensional array, and a polymer layer 32 made of a
polymer material located between the piezoelectric elements 31 are formed. The acoustic
matching layer 40 and the backing layer 10 are provided by being laminated on a composite
piezoelectric body having the electrode 21 and the common electrode 22 on the surface that
transmits and receives ultrasonic waves and the surface that faces the surface. Then, in the
second step, the composite piezoelectric material is cut along the polymer layer 32 together with
the acoustic matching layer 40 from the side opposite to the side on which the backing layer 10
is provided, and the ultrasonic transducers 33 are arrayed. Form a plurality of [Selected figure]
Figure 3
Method of manufacturing an ultrasound probe
[0001]
The present invention relates to a method of manufacturing an ultrasound probe.
[0002]
Conventionally, ultrasonic probes are used in medical ultrasonic diagnostic apparatuses,
ultrasonic flaw detection apparatuses, and sonar apparatuses.
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The ultrasonic probe is configured to include a plurality of ultrasonic transducers arranged in a
row in the azimuth direction. Grooves are formed between the ultrasonic transducers, whereby
the ultrasonic transducers are divided individually.
[0003]
Conventionally, a plurality of such transducers are formed by laminating one piezoelectric body
and an acoustic matching layer, and cutting at predetermined pitches by dicing (for example, for
example, Patent documents 1 and 2).
[0004]
JP-A-7-303637 JP-A-2000-14672
[0005]
However, in any of the techniques described in the above-mentioned patent documents,
polarization processing needs to be performed by applying an electric field to electrodes
provided on the upper and lower surfaces of the piezoelectric body before the piezoelectric body
is cut by dicing.
Then, dicing is performed on the polarized piezoelectric material, so that depolarization occurs in
the cut piezoelectric material (piezoelectric element) due to heat or mechanical impact generated
at the time of cutting by dicing.
The piezoelectric effect in which the depolarization has occurred is deteriorated in the
piezoelectric effect, and the sensitivity in the reception of the ultrasonic wave is lowered, so that
the problem of the performance deterioration such as an inability to obtain an accurate reception
signal occurs. On the other hand, in the technique described in Patent Document 2 described
above, repolarization is performed on the depolarized piezoelectric element, but in the case
where repolarization is individually performed on the piezoelectric elements after cutting, It takes
time and effort, as it is necessary to consider various conditions.
[0006]
An object of the present invention is to provide a method of manufacturing an ultrasonic probe
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2
capable of suppressing deterioration of a piezoelectric effect due to cutting of a polarized
piezoelectric material.
[0007]
In order to solve the above problems, the invention according to claim 1 is a method of
manufacturing an ultrasonic probe in which ultrasonic transducers transmitting and receiving
ultrasonic waves are arranged in an array, and at least one-dimensional array And a plurality of
columnar piezoelectric elements arranged at predetermined intervals, and a polymer layer made
of a polymer material located between the piezoelectric elements, and a pair of surfaces on which
ultrasonic waves are transmitted and received and a surface opposite thereto. A first step of
providing an acoustic matching layer and a base on the composite piezoelectric body provided
with the electrode layer, and the acoustic matching from the side opposite to the side on which
the base is provided. And a second step of forming a plurality of the ultrasonic transducers in an
array by cutting along the polymer layer together with the layer.
[0008]
The invention according to claim 2 is the method for manufacturing an ultrasonic probe
according to claim 1, wherein the composite piezoelectric body is formed of the polymer layer of
a hard resin.
[0009]
The invention according to claim 3 relates to the method for producing an ultrasonic probe
according to claim 1 or 2, wherein the polymer layer is formed in a cut portion formed by cutting
the polymer layer. The method further includes a third step of filling a material having a
hardness smaller than that of the material.
[0010]
The invention according to claim 4 is the method according to claim 3, wherein the base is a
backing layer, and in the first step, the acoustic matching layer, the composite piezoelectric
material, The body and the backing layer are laminated in this order, and in the third step, the cut
portion is filled with an organic synthetic adhesive, and an acoustic lens is filled with the organic
synthetic adhesive. It is characterized in that it is stuck to the surface of the layer.
[0011]
The invention according to claim 5 is the method for manufacturing an ultrasonic probe
according to any one of claims 1 to 4, wherein the composite piezoelectric body is formed of the
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polymer layer in the arrangement direction of the piezoelectric elements. The width is 110% to
150% of the width of the groove produced by the cutting in the second step.
[0012]
According to the present invention, it is possible to suppress the deterioration of the piezoelectric
effect due to the cutting of the polarized piezoelectric material.
[0013]
It is a perspective view which represents typically the internal structure of the intermediate |
middle laminated body of the ultrasound probe manufactured by the manufacturing method of
the ultrasound probe which concerns on 1st Embodiment.
FIG. 5 is a perspective view of the intermediate laminated body shown in FIG. 1 with the acoustic
matching layer and the common electrode omitted.
It is a perspective view which represents typically the internal structure of the ultrasound probe
manufactured by the manufacturing method which concerns on 1st Embodiment.
It is a side view explaining the other example of cutting processing of the manufacturing method
of the ultrasound probe concerning this embodiment.
It is a perspective view which represents typically the internal structure of the intermediate |
middle laminated body of the ultrasound probe manufactured by the manufacturing method of
the ultrasound probe which concerns on 2nd Embodiment.
FIG. 6 is a perspective view of the intermediate laminated body shown in FIG. 5 with an acoustic
matching layer and an electrode omitted.
It is a perspective view which represents typically the internal structure of the ultrasonic probe
manufactured by the manufacturing method which concerns on 2nd Embodiment.
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It is a perspective view which represents typically the internal structure of the ultrasound probe
manufactured by the manufacturing method which concerns on 3rd Embodiment. It is the
elements on larger scale of the ultrasound probe shown by FIG.
[0014]
Hereinafter, embodiments of the present invention will be described with reference to the
drawings. However, the scope of the invention is not limited to the illustrated example. In the
following description, components having the same function and configuration are denoted by
the same reference numerals, and the description thereof is omitted. The ultrasonic probe
applied in the embodiment of the present invention is a main component of a medical ultrasonic
diagnostic apparatus, which transmits an ultrasonic wave by receiving an electric signal and
receives an ultrasonic wave. It has a function of outputting an electrical signal.
[0015]
First Embodiment First, a method of manufacturing an ultrasonic probe according to a first
embodiment will be described with reference to FIGS. 1 to 3.
[0016]
First, as a first step, as shown in FIG. 1, the intermediate layer in which the backing layer 10, the
electrode 21, the composite piezoelectric body 30, the common electrode 22, and the acoustic
matching layer 40 are adhered and stacked in this order from the lower front The laminate 100a
is formed.
[0017]
The backing layer 10 is an ultrasonic wave absorber that supports the composite piezoelectric
body 30 and can absorb unnecessary ultrasonic waves.
That is, the backing layer 10 is mounted on a plate surface opposite to the direction of
transmitting and receiving ultrasonic waves to the subject of the composite piezoelectric body
30, and absorbs the ultrasonic waves generated on the opposite side of the direction of the
subject.
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[0018]
The backing material constituting the backing layer 10 may be natural rubber, ferrite rubber,
epoxy resin, or a rubber-based composite material or epoxy resin composite material obtained by
pressing powder of tungsten oxide, titanium oxide, ferrite, etc. into these materials and pressing
it. , Polyvinyl chloride, polyvinyl butyral (PVB), ABS resin, polyurethane (PUR), polyvinyl alcohol
(PVAL), polyethylene (PE), polypropylene (PP), polyacetal (POM), polyethylene terephthalate
(PETP), fluorine resin (PTFE) Thermoplastic resins such as polyethylene glycol and polyethylene
terephthalate-polyethylene glycol copolymer can be used.
[0019]
A preferable backing material is made of a rubber composite material and / or an epoxy resin
composite material, and the shape thereof can be appropriately selected according to the shape
of the composite piezoelectric body 30 and the probe head including the same. .
[0020]
An electrode 21 and a common electrode 22, which are a pair of electrode layers, are provided
on the surface of the composite piezoelectric body 30 that transmits and receives ultrasonic
waves and the surface that faces the surface.
The electrode 21 applies a power supply voltage from a signal extraction flexible printed circuit
(FPC) (not shown) to the composite piezoelectric body 30.
The common electrode 22 is connected to ground through a ground lead FPC (not shown).
A wraparound electrode may be provided on the side surface of the composite piezoelectric body
30, the common electrode 22 may be drawn out so as to be insulated from the electrode 21 on
the lower surface side of the piezoelectric body, and connected to a power source or earth
through FPC.
[0021]
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Materials used for the electrode 21 and the common electrode 22 include gold (Au), platinum
(Pt), silver (Ag), palladium (Pd), copper (Cu), aluminum (Al), nickel (Ni), tin Sn) and the like. The
electrode 21 and the common electrode 22 are formed first of a base metal such as titanium (Ti)
or chromium (Cr) by a sputtering method to a thickness of 0.002 to 1.0 μm, and then a metal
mainly composed of the above metal element And a metal material made of such an alloy, and, if
necessary, a partial insulating material, is formed to a thickness of 0.02 to 10 μm by a
sputtering method, a vapor deposition method or another appropriate method. These electrodes
can also be formed by screen printing, dipping, or thermal spraying other than sputtering, using
a conductive paste in which fine powder metal powder and low melting point glass are mixed.
[0022]
The composite piezoelectric body 30 is a so-called 2-2 composite piezoelectric body in which
prismatic piezoelectric elements 31 and polymer layers 32 are alternately arranged in a onedimensional array as shown in FIG. In the present embodiment, the external dimensions of the
piezoelectric element 31 and the polymer layer 32 in the X direction (arrangement direction) are
respectively 70 μm for the piezoelectric element 31 and 30 μm for the polymer layer 32. That
is, the pitch of the arrangement of the piezoelectric element 31 and the polymer layer 32 is 100
μm. Here, it is preferable to set the dimension in the X direction of the polymer layer 32 so as to
be adapted to a predetermined transducer pitch. Further, in the present embodiment, although it
is represented by five piezoelectric elements 31 and four polymer layers 32 in between for ease
of explanation, in practice, a large number (for example, 192) of them are represented. A
piezoelectric element 31 is provided, and a polymer layer 32 is provided between each
piezoelectric element.
[0023]
Examples of materials used for the piezoelectric element 31 include piezoelectric ceramics such
as lead zirconate titanate (PZT), relaxor-based, lead niobate-based and lead titanate-based
ceramics, lead zirconate titanate niobate (PZNT), Single crystals such as magnesium niobate
titanic acid (PMNT) are preferred. As a polymer material which comprises the polymer layer 32,
organic synthetic polymer materials, such as an epoxy resin, a silicone resin, a urethane resin, a
polyethylene resin, a polyurethane resin, can be used. In addition, you may apply organic natural
polymer materials, such as natural rubber. These organic polymer materials have a large specific
heat and a small thermal conductivity as compared with the above-described piezoelectric
materials, and therefore, can suppress thermal damage such as frictional heat generated in the
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cutting process described later. For example, epoxy resins have a thermal conductivity of about
0.2 W / (m · K), which is advantageous in terms of specific heat and thermal conductivity. In
addition, these organic polymer materials can prevent physical damage to the piezoelectric
material during the cutting process. As the organic polymer material applied to the present
embodiment, it is preferable to apply a hard resin having a predetermined hardness in order to
improve cutting accuracy at the time of cutting processing, for example, one having a Rockwell
hardness of 80 or more Is preferred. In addition, in order to improve the element characteristics
after arraying, the speed of sound of the polymer material is preferably 1 km / s or more. In the
present embodiment, an epoxy resin having a sound velocity of 2 km / s or more and a Rockwell
hardness of M80 or more is applied. In addition, it may replace with an organic polymer material
and may apply an inorganic polymer material.
[0024]
The composite piezoelectric body 30 configured as described above is manufactured by a known
manufacturing method. That is, a plurality of piezoelectric elements 31 are formed by cutting a
piezoelectric material such as the above-mentioned piezoelectric ceramic or single crystal into a
predetermined size and providing a gap of a predetermined distance. The plurality of
piezoelectric elements 31 may be molded by molding. Then, the polymer material is filled and
cured in the gaps between the plurality of piezoelectric elements 31 to form the polymer layer
32. Then, the upper and lower surfaces of the integrated piezoelectric element 31 and the
polymer layer 32 are polished to form a composite piezoelectric body 30 so as to have a
predetermined thickness. Electrodes are sandwiched between upper and lower surfaces of the
polished composite piezoelectric body 30, and a predetermined polarization voltage is applied to
perform polarization processing.
[0025]
The acoustic matching layer 40 matches the acoustic impedance between the ultrasonic
transducer and the object to suppress reflection at the interface. The acoustic matching layer 40
is mounted via the common electrode 22 on the subject side of the composite piezoelectric body
30, which is the transmission / reception direction in which transmission / reception of
ultrasonic waves is performed. The acoustic matching layer 40 has an acoustic impedance
substantially intermediate between that of the composite piezoelectric body 30 and the subject.
[0026]
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Materials used for the acoustic matching layer 40 include aluminum, aluminum alloy (for
example, AL-Mg alloy), magnesium alloy, macor glass, glass, fused quartz, copper graphite, PE
(polyethylene) and PP (polypropylene), PC (polycarbonate) ), ABC resin, ABS resin, AAS resin, AES
resin, nylon (PA6, PA6-6), PPO (polyphenylene oxide), PPS (polyphenylene sulfide: may be
contained in glass fiber), PPE (polyphenylene ether), PEEK (poly Ether ether ketone), PAI
(polyamide imide), PETP (polyethylene terephthalate), epoxy resin, urethane resin and the like
can be used. It is preferable to use a thermosetting resin such as epoxy resin as a filler, which is
formed by adding zinc flower, titanium oxide, silica or alumina, bengara, ferrite, tungsten oxide,
ytterbium oxide, barium sulfate, tungsten, molybdenum, etc. Applicable
[0027]
The acoustic matching layer 40 may be a single layer or a plurality of layers, but is preferably
two or more layers, more preferably four or more layers. The layer thickness of the acoustic
matching layer 40 is preferably determined to be λ / 4, where λ is a wavelength of ultrasonic
waves. If the layer thickness of the acoustic matching layer 40 is not properly made, a plurality of
unnecessary spurs may appear at frequency points different from the original resonance
frequency, and the basic acoustic characteristics may greatly fluctuate. As a result, the
reverberation time may increase, and the sensitivity or S / N may be reduced due to waveform
distortion of the reflection echo. The thickness of such an acoustic matching layer is generally in
the range of about 20 to 500 μm.
[0028]
Each part mentioned above is laminated | stacked and the intermediate | middle laminated body
100a is formed. That is, first, the backing material is attached to the electrode 21 formed on the
above-described polarized composite piezoelectric member 30 to form the backing layer 10, and
the acoustic matching layer 40 is attached to the common electrode 22. To form an intermediate
laminate 100a. The electrode 21 and the common electrode 22 are not directly provided on the
composite piezoelectric body 30 but are sandwiched with respect to the FPC and the acoustic
matching layer 40 which are bonded to each other with the piezoelectric body 30 interposed
therebetween. It may be adhered.
[0029]
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Next, in the second step, the intermediate laminated body 100 a formed as described above is
subjected to a cutting process to form the ultrasonic probe 100.
[0030]
In the present embodiment, as shown in FIG. 3, with respect to the intermediate laminated body
100a formed as described above, acoustic matching is performed in the Y direction along the
polymer layer 32 with the backing layer 10 as a base. From the layer 40 side to the backing layer
10, dicing is performed with a dicing blade at predetermined intervals.
At this time, a dicing blade having a cutting width such that the polymer layer 32 partially
remains is selected. As a result, the composite piezoelectric body 30 is divided into a plurality of
parts, and the ultrasonic probe 100 in which the ultrasonic transducers 33 of a plurality of
channels are formed in a one-dimensional array is formed. Between the ultrasonic transducers
33, a cutting portion 34 formed of a gap having a width corresponding to the blade thickness of
the dicing blade that has been cut is formed. In this embodiment, since the polymer layers 32
arranged at predetermined intervals are cut, the element pitch of the ultrasonic transducers 33
(pitch of the elements formed by cutting at predetermined intervals) is the piezoelectric element
31. And the same as the pitch of the arrangement of the polymer layers 32 (100 μm in the
above example). Here, the width of the polymer layer 32 is preferably 110 to 150% of the width
of the cut portion 34. In this way, the dicing blade is not in direct contact with the piezoelectric
element 31 at the time of dicing, even when there is deviation or cutting wear at the time of
dicing by the dicing blade. In addition, since the polymer layer 32 remains after dicing, the aspect
ratio of the piezoelectric element 31 is larger than that of only the piezoelectric element 31
alone. Therefore, the efficiency of the input energy is high, and the conversion efficiency of the
vibration in the thickness direction can be improved. In addition, as the ratio of the polymer layer
32 to the entire ultrasonic transducer 33 is larger, matching with the subject such as a living
body is improved, and ultrasonic waves can be efficiently transmitted to the subject. In the
present embodiment, as described above, since the width of the polymer layer 32 is 30 μm in
relation to the wavelength of the transmission ultrasonic wave, dicing is performed using a dicing
blade having a blade thickness of 20 μm. There is. Although the width of the cut portion 34 in
this case depends on the conditions of dicing, the width is usually slightly larger than the
thickness of the dicing blade and about 20 μm to 24 μm. The blade thickness of the dicing
blade can be appropriately selected in consideration of the width of the polymer layer 32, and it
is more preferable to select the width of the cutting portion 34 so as to fall within the above
range.
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[0031]
In the conventional ultrasonic probe, the polarized piezoelectric material is diced to form an
ultrasonic transducer, so that the piezoelectric material is depolarized by mechanical shock and
frictional heat accompanying dicing. (Also referred to as depolarization), which degrades the
sensitivity of the ultrasonic transducer. Assuming that the polarization intensity at the time of
polarization processing is 100%, according to the conventional method of manufacturing an
ultrasonic probe, depolarization of about 10% occurs on an average basis for each vibrator from
experience. Conventionally, repolarization processing for applying high voltage again has been
performed on such depolarized ultrasonic transducers, but appropriate polarization processing
needs to be performed on each of the transducers. Because of this, there were a lot of issues to
consider for polarization.
[0032]
On the other hand, in the present embodiment, the ultrasonic vibrator 33 is formed by cutting
the polymer layer 32 without directly cutting the piezoelectric element 31. Therefore, the impact
on the piezoelectric element 31 is small. In addition, since the frictional heat is also less likely to
be transmitted, the influence of the depolarization of the piezoelectric element 31 can be
extremely reduced. According to this embodiment, the deterioration of the piezoelectric constant
can be improved by about 10% as compared with the conventional one in which the piezoelectric
body is directly cut.
[0033]
In the present embodiment, the cutting is performed for each of the polymer layers 32. However,
the ultrasonic probe may be formed by cutting each of the predetermined number of polymer
layers 32. For example, as shown in FIG. 4, when cutting is performed for every three polymer
layers 32, an ultrasonic probe 100b in which an ultrasonic transducer 33a of one channel is
formed by three piezoelectric elements 31 is formed. can do. In this case, the element pitch of the
ultrasonic transducer 33a is 100 μm × 3 = 300 μm.
[0034]
Second Embodiment Next, a method of manufacturing an ultrasonic probe according to a second
embodiment will be described with reference to FIGS. 5 to 7.
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[0035]
First, as a first step, as shown in FIG. 5, the intermediate layer in which the backing layer 210,
the electrode 221, the composite piezoelectric body 230, the common electrode 222, and the
acoustic matching layer 240 are adhered and stacked in this order from the lower front The
laminate 200a is formed.
The second embodiment is the same as the first embodiment except that the configuration and
cutting process of the composite piezoelectric body 230 are different from the first embodiment,
so the first embodiment is the same as the first embodiment. The points different from the first
embodiment are mainly described, and the description of the same configuration as that of the
first embodiment is omitted.
[0036]
As shown in FIG. 6, in the composite piezoelectric body 230 according to the present
embodiment, a plurality of rectangular piezoelectric elements 231 are arranged in a twodimensional array at predetermined intervals, and a polymer is formed in a gap formed by the
plurality of piezoelectric elements 231. It is a so-called 1-3 composite piezoelectric body in which
the layer 232 is formed. In the present embodiment, the external dimensions of the piezoelectric
element 231 in the X and Y directions are 70 × 70 μm. Further, the width dimension of the
polymer layer 232 in the X direction or the Y direction is 30 μm. That is, the pitch in the X
direction and the Y direction of the piezoelectric element 231 is 100 μm. About the material of
each part of other compound piezoelectric material 230, and a manufacturing method, since the
compound piezoelectric material in a 1st embodiment is the same, explanation is omitted.
[0037]
Next, in the second step, the intermediate laminated body 200a formed as described above is
subjected to a cutting process to form the ultrasonic probe 200. That is, in the second
embodiment, as shown in FIG. 7, an acoustic matching layer is formed along the polymer layer
232 in the X and Y directions with respect to the intermediate laminated body 200a formed as
described above. From the 240 side to the backing layer 210, cutting is performed with a dicing
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blade at predetermined intervals. As a result, the intermediate laminated body 200a is divided
into a plurality of parts, and the ultrasonic probe 200 in which the ultrasonic transducers 233 of
a plurality of channels are formed in a two-dimensional array is formed. Between the ultrasonic
transducers 233, a cutting portion 234 formed of an air gap of the width of the dicing blade
which has been cut is formed.
[0038]
As described above, as in the second embodiment, even as a two-dimensional array ultrasonic
transducer, it is possible to manufacture an ultrasonic probe that can obtain the same effect as
that of the first embodiment. .
[0039]
In the second embodiment, the composite piezoelectric member 230 is cut in both the X and Y
directions. However, cutting is performed only in the Y direction to form ultrasonic transducers
in a one-dimensional array. You may do it.
According to this, the ratio of the polymer layer to the ultrasonic transducer in one channel
increases, and the impedance of the entire ultrasonic transducer can be lowered. Also in the
second embodiment, as in the first embodiment, cutting may be performed for each of the
predetermined number of polymer layers 32.
[0040]
Third Embodiment Next, a method of manufacturing an ultrasonic probe according to a third
embodiment will be described with reference to FIGS. 8 and 9.
[0041]
As shown in FIG. 8, the ultrasonic probe 100c according to the third embodiment forms the
ultrasonic probe 100 in the manner described above in the first embodiment, and A
predetermined filler is filled to form the separation portion 60 and the acoustic lens 50 is
laminated on the upper surface of the acoustic matching layer 40.
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The other configuration is the same as that of the first embodiment, so the points different from
the first embodiment will be mainly described, and the description of the same configuration as
the first embodiment will be made. I omit it.
[0042]
The acoustic lens 50 in the present embodiment is disposed to focus the ultrasonic beam using
refraction to improve the resolution. That is, the acoustic lens 50 is provided on the side in
contact with the subject of the ultrasound probe 100b, and efficiently makes the ultrasound
generated by the ultrasound transducer 33 incident on the subject. The acoustic lens 50 has a
convex or concave lens shape in accordance with the internal sound speed at a portion in contact
with the object, and the ultrasonic wave incident on the object has a thickness direction
orthogonal to the imaging section (elevation Converge in the
[0043]
The acoustic lens 50 is formed of a soft polymeric material having an acoustic impedance
substantially between the object and the acoustic matching layer 40.
[0044]
As materials for constituting the acoustic lens 50, homopolymers such as conventionally known
silicone rubber, butadiene rubber, polyurethane rubber, epichlorohydrin rubber, etc., ethylenepropylene copolymer rubber obtained by copolymerizing ethylene and propylene, etc. Copolymer
rubber etc. are applicable.
Among these, silicone rubber and butadiene rubber are preferably used.
[0045]
As silicone type rubber applied to this embodiment, silicone rubber, fluorine silicone rubber, etc.
are mentioned. In particular, in view of the characteristics of the lens material, it is preferable to
use silicone rubber. Silicone rubber refers to an organopolysiloxane having a molecular skeleton
consisting of Si-O bonds, and a plurality of organic groups mainly bonded to the Si atom, and
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usually, the main component is methylpolysiloxane and the whole organic 90% or more of the
groups are methyl groups. It is also possible to use one in which a hydrogen atom, a phenyl
group, a vinyl group, an allyl group or the like is introduced instead of the methyl group. The
silicone rubber can be obtained, for example, by kneading an organopolysiloxane having a high
degree of polymerization with a curing agent (vulcanizing agent) such as benzoyl peroxide,
heating and curing and curing. If necessary, an organic or inorganic filler such as silica or nylon
powder, a vulcanizing aid such as sulfur or zinc oxide, or the like may be added.
[0046]
Examples of butadiene-based rubbers applied to the present embodiment include copolymer
rubbers in which butadiene alone or butadiene as a main component and a small amount of
styrene or acrylonitrile is copolymerized thereto. In particular, butadiene rubber is preferably
used in view of the characteristics of the lens material. Butadiene rubber refers to a synthetic
rubber obtained by polymerization of butadiene having a conjugated double bond. The butadiene
rubber can be obtained by polymerization of butadiene alone having a conjugated double bond
by 1.4 or 1.2. As the butadiene rubber, those vulcanized with sulfur or the like can be used.
[0047]
In the acoustic lens 50 according to the present embodiment, one produced by mixing and curing
a silicone-based rubber and a butadiene-based rubber is used. For example, it can be obtained by
mixing silicone rubber and butadiene rubber in appropriate proportions with a kneading roll,
adding a vulcanizing agent such as benzoyl peroxide, and heating and curing and crosslinking
(curing). At that time, it is preferable to add zinc oxide as a vulcanization aid. Zinc oxide can
accelerate vulcanization acceleration and shorten the vulcanization time without deteriorating
lens characteristics. Other additives may be added as long as the properties of the colorant and
the acoustic lens are not impaired. The mixing ratio of silicone rubber and butadiene rubber can
be set as appropriate, but the acoustic impedance is similar to the object, and the speed of sound
in the acoustic lens 50 is smaller than the object and the attenuation is reduced. It is preferable
to set, and 1: 1 is optimal.
[0048]
The silicone rubber can be obtained as a commercial product, for example, Shin-Etsu Chemical
Co., Ltd., KE742U, KE752U, KE931U, KE941U, KE951U, KE961U, KE850U, KE555U, KE575U,
etc., TSE221-3U, TE221 manufactured by Momentive Performance Materials, Inc. -4U,
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TSE2233U, XE20-523-4U, TSE27-4U, TSE260-3U, TSE-260-4U, SH35U, SH55UA, SH831U,
SE6749U, SE1120USE4704U, etc. manufactured by Dow Corning Toray Industries, Inc. can be
used.
[0049]
In the present embodiment, a rubber material such as silicone rubber is used as a base (main
component), and an inorganic filler such as silica, alumina, titanium oxide, nylon, or the like
depending on the purpose of sound speed adjustment, density adjustment, etc. Etc. can also be
blended.
[0050]
The acoustic lens 50 is bonded to the top surface of the acoustic matching layer 40 by the filler
that forms the separation portion 60.
That is, in the present embodiment, an adhesive is applied as a filler to be filled in the cutting
portion 34, thereby forming the separating portion 60.
Then, the filler is filled from the cutting portion 34 to form the adhesive layer 61 on the surface
of the acoustic matching layer 40. The acoustic lens 50 is bonded to the acoustic matching layer
40 by laminating the acoustic lens 50 on the adhesive layer 61 formed on the surface of the
acoustic matching layer 40 and curing the adhesive layer 61.
[0051]
Here, as the adhesive filled in the cutting portion 34, an organic synthetic adhesive such as an
epoxy resin type, a silicone type, a urethane resin type, a polyethylene resin type, and a
polyurethane resin type can be applied. The material of the filler forming the separation portion
60 may be different from the material of the adhesive layer 61. In this case, various organic
polymer materials can be applied as the material of the filler forming the separation portion 60,
but various resins such as epoxy resin, silicone resin, urethane resin, polyethylene resin,
polyurethane resin, or silicone rubber, Various rubbers such as urethane rubber and butadiene
rubber are suitable. Further, as the adhesive forming the adhesive layer 61, the various organic
synthetic adhesives described above can be applied. In particular, as the filler forming the
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separation unit 60, in order to reduce the propagation of the transverse wave, the influence of
the phase wave or the like generated according to the space factor or the transmission frequency
of the piezoelectric element 31 configured in the ultrasonic transducer 33 It is preferable to
select one in consideration of the above, and one including materials having a Rayleigh wave
velocity of 1500 m / s or less. Further, in the present embodiment, it is more preferable to use
one in which the acoustic lens 50 is hard to peel off and whose hardness is smaller than that of
the polymer layer 32. In this way, the strength of the ultrasonic probe 100b can be maintained,
and acoustic crosstalk is less likely to occur. In the present embodiment, a silicone adhesive is
applied.
[0052]
In the present embodiment, although the example applied to the ultrasonic probe 100 in the first
embodiment has been described as an example, the ultrasonic probe 200 in the second
embodiment is described. It goes without saying that also applies. Alternatively, only the
separation unit 60 may be provided, and the acoustic lens 50 may not be provided.
[0053]
As described above, according to the first to third embodiments of the present invention, in the
first step, the plurality of columnar piezoelectric elements 31 (231) arranged at predetermined
intervals in a one-dimensional array form. And a polymer layer 32 (232) made of a polymer
material located between the piezoelectric elements 31 (231), and on the surface transmitting /
receiving the ultrasonic wave and the surface opposite thereto, the electrode 21 (221) and the
common electrode The acoustic matching layer 40 (240) and the backing layer 10 (210) are
provided by being stacked on the composite piezoelectric body 30 (230) provided with each 22
(222). Then, in the second step, the composite piezoelectric body 30 (230) is placed on the
polymer layer 32 (232) together with the acoustic matching layer 40 (240) from the side
opposite to the side on which the backing layer 10 (210) is provided. A plurality of ultrasonic
transducers 33 (233) are formed in an array by cutting along. As a result, since the ultrasonic
transducer can be formed without cutting the polarized piezoelectric element, the ultrasonic
probe can suppress the deterioration of the piezoelectric effect due to the cutting of the polarized
piezoelectric body. It can produce children.
[0054]
Further, according to the first to third embodiments of the present invention, the polymer layer
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32 (232) is formed of a hard resin, so that the machinability at the time of the cutting process is
good and the cutting process is highly accurate. It can be performed.
[0055]
Further, according to the third embodiment of the present invention, the polymer material 32
(232) is formed on the cut portion 34 (234) formed by cutting the polymer layer 32 (232). The
method further includes a third step of filling the material with low hardness.
As a result, it is possible to secure the strength of the ultrasonic probe while suppressing acoustic
crosstalk.
[0056]
Further, according to the third embodiment of the present invention, in the first step, the acoustic
matching layer 40, the composite piezoelectric body 30, and the backing layer 10 are laminated
in this order. Then, in the third step, the polymer 34 is filled with the polymer adhesive, and the
acoustic lens 50 is attached to the surface of the acoustic matching layer 40 with the polymer
adhesive filled. . As a result, the acoustic lens is less likely to come off. In addition, since the work
of filling the cutting portion 34 and the work of bonding the acoustic lens can be performed
simultaneously, the process of attaching the acoustic lens can be simplified.
[0057]
Further, according to the first to third embodiments of the present invention, the width of the
polymer layer 32 (232) in the arrangement direction of the piezoelectric elements 31 (231) is
the width of the groove produced by cutting in the second step. Since it is 110% to 150% of the
above, deterioration of the piezoelectric constant can be improved as compared with the case
where the piezoelectric material is directly cut to form an ultrasonic transducer.
[0058]
The description in the embodiment of the present invention is an example of the ultrasound
probe according to the present invention, and the present invention is not limited to this.
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The detailed configuration and the detailed operation of each functional unit constituting the
ultrasonic probe can be appropriately changed.
[0059]
In the present embodiment, when the composite piezoelectric body 30 (230) is cut, the backing
layer 10 (210) is used as a base, and the ultrasonic transducer 33 (233) is cut from the acoustic
matching layer 40 (240). The ultrasonic transducer can also be formed as follows. That is, for
example, after laminating the composite piezoelectric material and the acoustic matching layer, a
discard plate as a base is attached to the surface of the acoustic matching layer, and cut from the
composite piezoelectric material side to the discard plate along the polymer layer . Then, a
backing layer is attached to the cut composite piezoelectric body, and the discard plate is
removed from the acoustic matching layer. Similar effects can be obtained by forming the
ultrasonic transducer in this manner.
[0060]
100, 100b, 100c Ultrasonic Probe 100a Intermediate Laminate 10 Backing Layer 21 Electrode
22 Common Electrode 30 Composite Piezoelectric Body 31 Piezoelectric Element 32 Polymeric
Layer 33 Ultrasonic Vibrator 34 Cutting Section 40 Acoustic Matching Layer 50 Acoustic Lens
200 Super 200 Acoustic wave probe 200a Intermediate laminated body 210 Backing layer 221
Electrode 222 Common electrode 230 Composite piezoelectric body 231 Piezoelectric element
232 Polymer layer 233 Ultrasonic vibrator 234 Cutting portion 240 Acoustic matching layer
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