JPH07308317

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DESCRIPTION JPH07308317
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a
flaw detection or intracavity ultrasonic diagnostic apparatus for obtaining and diagnosing
ultrasonic tomographic images, and more particularly, to the structure of the tip of a transmitting
and receiving ultrasonic probe.
[0002]
2. Description of the Related Art In recent years, in addition to nondestructive inspection devices,
ultrasonic probes have been rapidly growing in demand as medical ultrasonic diagnostic devices.
A probe such as an ultrasonic endoscope radiates high-frequency acoustic vibration from an
ultrasonic transducer into a living body, reflects the reflected ultrasonic wave back by the
ultrasonic transducer, and has a slight interface characteristic. By processing different
information depending on the difference, a cross-sectional image of the inside of a living body
can be obtained.
[0003]
The ultrasonic transducer is roughly divided into a piezoelectric element, an acoustic matching
layer, and a backing material. The ultrasonic transducer applies a high frequency voltage pulse to
the piezoelectric element using the electrode formed on the surface of the piezoelectric element
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to cause the piezoelectric element to resonate and cause deformation rapidly to generate an
ultrasonic pulse. It is. However, if the ultrasonic probe for blood vessels needs high frequency
and small size, the shape of the piezoelectric element becomes small and the thickness becomes
very thin, and the mounting method and connection method of the ultrasonic transducer are
Since it has become very difficult, various inventions have been proposed. The applicant of the
present invention also proposes the invention described in JP-A-5-300593.
[0004]
Here, a conventional ultrasonic probe, in particular, an ultrasonic probe for an ultrasonic
diagnostic apparatus will be specifically described with reference to FIGS. 1 and 2. The acoustic
matching layer 4 is provided on the ultrasonic radiation surface of the piezoelectric element 5
provided with the surface electrodes 7 and 8, and the back damping material 3 is provided on
the non-emission surface of the piezoelectric element 5. After bonding such an ultrasonic
transducer unit 25 to the conductive housing 6, the housing 6 and the lead wire are respectively
connected by the conductive member 9 in order to use the surface electrodes 7 and 8 as input /
output electrodes. After that, sealing and insulation are performed with an insulating resin as
necessary.
[0005]
The housing 6 is connected to the flexible shaft 24 by silver solder 14, which enables the
ultrasonic probe to be driven back and forth and in the rotational direction with respect to the
axial direction of the flexible shaft 24. The ultrasonic probe thus produced is inserted into a
cover called a tubular sheath 29 made of polyethylene or the like, and is used as an acoustic
medium in the sheath, liquid paraffin, water, saline or gel. It is inserted in the body cavity in the
state which filled up the substance etc.
[0006]
In addition, silver solder, solder, a conductive adhesive, etc. are used for the conductive member
9, and it is common to seal the periphery with the epoxy resin which is an insulating resin.
However, as described above, with the miniaturization of the ultrasonic probe, the conductive
adhesive has recently been used to prevent the piezoelectric element from being damaged by
heat and to be excellent in the workability of the minute part. Is increasingly used. As the
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conductive adhesive, for example, a material obtained by adding silver powder as a conductive
filler in a proportion of 50 parts by weight or more to 100 parts by weight of an epoxy resin as
described in JP-A-62-161300, etc. It is common.
[0007]
On the other hand, as a recent technology, for example, in order to obtain slip at the time of
contact between an ultrasonic probe and a human body and to ensure the chemical resistance of
an acoustic lens, for example, in JP-A-4-181896, PTFE particles are used. The invention of
coating an acoustic lens with a paint in which is dispersed in an organic binder has been
proposed.
[0008]
However, in the invention disclosed in the above-mentioned Japanese Patent Application LaidOpen No. 62-161300, the tip of the ultrasonic probe is immersed in a liquid or gel-like acoustic
medium for acoustic matching. It will be
In the above-mentioned structure, while the ultrasonic probe is used, the acoustic medium
directly or permeates the sealing layer of the epoxy resin, and the phenomenon of swelling the
conductive adhesive occurs.
[0009]
In the conductive adhesive, conductive fillers (silver powder, copper powder, etc.) added to the
adhesive come into contact with each other by the cure shrinkage of the adhesive made of an
organic resin such as epoxy, so that the conductivity is developed. When the agent swells, the
contact between the conductive fillers is cut off, the conductivity is lost, or the resistance
increases and the characteristics deteriorate. In addition to the degradation of the conductive
adhesive, the penetration of the acoustic medium also causes degradation of the back load
material and the acoustic matching layer itself, for example, degradation such as peeling and
swelling.
[0010]
On the other hand, among the acoustic media, physiological saline and ultrasonic gel generally
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used contain alkali ions, and therefore, the sealing layer of epoxy resin is transmitted, and
ceramics such as alumina provided as an acoustic matching layer and piezoelectric are provided.
There is also a problem of attacking ceramics such as PZT, lead titanate, PLZT, lead meta niobate
and the like, which are elements, and electrodes, which may become a problem even when using,
for example, solder which does not use a conductive adhesive.
[0011]
In the invention described in JP-A-4-181896, although a fluorine resin is coated on an acoustic
lens, the acoustic medium penetrates also from a portion other than the coated acoustic lens, for
example, an adhesive layer or the like. It will cause deterioration.
Further, since the fluorocarbon resin in the above invention is composed of PTFE particles, a
thermoplastic or thermosetting resin and a curing agent, it is practically possible if the remaining
thermoplastic or thermosetting resin is hydrophilic even if the PTFE is hydrophobic. Also, the
acoustic medium intrudes into the interior from this coat layer to cause characteristic
deterioration. In addition, although the specific component of a fluorine resin is not described by
the said gazette, the coating material currently distribute ¦ circulating as a commercial item does
not solve this problem in all.
[0012]
An object of the present invention is to provide an ultrasonic probe for preventing the
occurrence of characteristic deterioration due to the penetration of a liquid or gel acoustic
medium into at least the exposed organic polymer material at the tip of the ultrasonic probe. It is
to provide a tentacle.
[0013]
The object of claim 2 is to prevent the occurrence of characteristic deterioration due to the
penetration of liquid or gel acoustic medium into the conductive adhesive connecting the
piezoelectric element at the tip of the ultrasonic probe and the input / output electrode.
Providing an ultrasound probe.
[0014]
The object of claim 3 is to provide an ultrasonic probe which prevents the characteristic
deterioration of the ultrasonic probe due to high temperature curing exceeding the heat resistant
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tolerance of the ultrasonic probe.
[0015]
The present invention provides a piezoelectric element having ± electrodes on its surface, an
acoustic matching layer in contact with the ultrasonic radiation surface of the piezoelectric
element, and a back damping material in contact with the opposite emission surface of the
piezoelectric element. And an input / output electrode for inputting / outputting current to /
from the piezoelectric element, a conductive member connecting the piezoelectric element and
the input / output electrode, an insulating resin for covering the conductive member, and a
housing for housing the respective members. In the ultrasonic probe, an ultrasonic probe
characterized in that at least the exposed portion of the tip of the ultrasonic probe is covered
with a film of a hydrophobic organic inorganic material containing silicon oxide or a metal oxide.
It is a tentacle.
[0016]
In addition, a piezoelectric element having ± electrodes on the surface, an acoustic matching
layer in contact with the ultrasonic radiation surface of the piezoelectric element, a back damping
material in contact with the opposite emission surface of the piezoelectric element, and an input
/ output electrode for inputting / outputting current to the piezoelectric element An ultrasonic
probe comprising: a conductive adhesive for connecting the piezoelectric element and the input /
output electrode; an insulating resin covering the conductive adhesive; and a housing for
containing the respective members. The ultrasonic probe is characterized in that the piezoelectric
element at the tip of the stylus, the input / output electrode and the conductive adhesive are
coated with a film of a hydrophobic organic inorganic material containing silicon oxide or metal
oxide.
[0017]
Furthermore, the hydrophobic organic inorganic material is an ultrasonic probe characterized by
containing silicon oxide or a metal oxide and curing at a low temperature of 150 ° C. or less.
[0018]
The function of claim 1 is that the hydrophobic organic inorganic material covering the exposed
organic polymer material at the tip of the ultrasonic probe protects the organic polymer material
and does not transmit the acoustic medium or very much. Since it is difficult to transmit, it
prevents deterioration of each part of the ultrasonic probe.
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[0019]
Note that the hydrophobic organic inorganic material is not necessarily required to cover the
entire tip in the form of a film, and a film is selectively formed on a portion that the acoustic
medium does not want to touch directly or a portion that the acoustic medium easily intrudes.
You may cover it.
Therefore, it is effective to cover the exposed electrodes, the acoustic matching layer and the
ceramic element made of ceramics, and the epoxy resin portion for sealing and acoustic
matching.
[0020]
Also, the film thickness of the hydrophobic organic polymer material needs to be thick enough to
prevent transmission of the acoustic medium sufficiently, and must be thin enough not to
degrade the acoustic characteristics.
Specifically, 0.5 μm or more is desirable to prevent transmission of the acoustic medium, and 1
μm or less is desirable to prevent deterioration of the acoustic characteristics.
[0021]
According to the second aspect of the present invention, in the case of using an acoustic medium
having no corrosiveness to ceramics etc., a hydrophobic organic system covered with a
conductive adhesive connecting the piezoelectric element at the tip of the ultrasonic probe and
the input / output electrode The inorganic material protects the conductive adhesive itself and
prevents or very hardly transmits the acoustic medium, thereby preventing a decrease in the
conductivity due to swelling in the acoustic medium.
In addition, since the membrane made of the hydrophobic organic polymer material is not
rubbed with other members, such as a sheath, and the detachment or destruction due to peeling
or friction does not occur, stable performance can be ensured.
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Furthermore, the film need not necessarily be covered, and instead of the sealing epoxy resin, it
may be filled for the purpose of sealing.
[0022]
According to the function of claim 3, the low temperature curing hydrophobic organic inorganic
material cures at a low temperature within the heat tolerance of the ultrasound probe, and the
ultrasound probe functions normally.
The hydrophobic organic inorganic material is at least an organosilicon compound (for example,
a silyl isocyanate compound, a chlorosilane compound, a perhydropolysilazane etc.) or an organic
metal compound excluding silicon (for example an aluminum alcoholate compound, an aluminum
chelate compound and a cyclic compound An aluminum compound such as an aluminum
oligomer, an alumina sol, a titanate compound, a Zr alcoholate compound, etc. can be obtained.
[0023]
However, in the solvent-soluble organic-based inorganic material, it is necessary that the solventsoluble organic inorganic material is soluble in the solvent for dilution and insoluble in the liquid
or gel-like acoustic medium, and specifically water, physiology It must be insoluble in aqueous
solutions such as saline and alcoholic solutions.
When such conditions are satisfied, it is a liquid substance that is easy to form a film, and a
hardened film is insoluble in the acoustic medium, and a highly durable film is obtained to
prevent deterioration of the ultrasonic probe. become.
[0024]
Furthermore, it is desirable that the boiling point of the solvent is not too high, and it is desirable
that drying be possible at 150 ° C. or less.
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Particularly desirable is that it can be dried at 100 ° C. or less. Also, the hydrophobic organic
inorganic material has high moisture and water proof properties, but it can not always be
difficult to transmit all acoustic media other than water, so it is transparent to acoustic media
other than water. By using a hard-to-use material, it is possible to prevent the deterioration of the
ultrasonic probe even if a desired acoustic medium other than water is used. The transmission
amount of the acoustic medium of the hydrophobic organic inorganic material is preferably "0.05
g / cm 2 · 24 hours" or less under 20 ° C. environment, and particularly preferably "0.002 g /
cm 2 · 24 hours" Or less.
[0025]
Embodiment 1 FIGS. 3 to 8 show the present embodiment, and FIGS. 3 and 4 are perspective
views showing a method of producing the transducer portion of the ultrasonic probe, and FIGS. 5
and 6 show the produced vibration. FIGS. 7 and 8 are cross-sectional views of the ultrasonic
probe.
[0026]
An acoustic matching layer 4 made of epoxy resin is applied to the side of the GND electrode 7 as
shown in FIG. 3 to the piezoelectric element 5 having the GND electrode 7 and the + side
electrode 8 formed on the surface. The back load material 1 is formed on the side of the positive
electrode 8 to produce a laminate.
Next, it is cut by a precision cutting machine as shown by the arrow 40 in FIG. 4 to produce one
small transducer portion 25 as shown in FIG. In FIG. 5, only the back load material 1 made of an
epoxy resin containing tungsten filler is used as the back damping material 3. In FIG. 6, the
backing material 3 made of an epoxy resin containing tungsten filler and the backing material 2
made of an epoxy resin not containing tungsten for insulation are used as the backing braking
material 3.
[0027]
As shown in FIG. 7, the vibrator 25 (hereinafter referred to as a transducer) is adhesively fixed on
the insulating plate 19 fixed by an adhesive to the housing 6 in which the metal pipe is
processed, and the thickness exposed on the side of the transducer 25 Wire connection is made
from the meat electrode portion through the conductive resin 9. At this time, the GND electrode 7
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on the acoustic radiation surface side is once connected to the housing 6 with the conductive
resin 9a, and the housing 6 pipe portion is connected to the peripheral wire 11 of the coaxial
cable 13 passing through the flexible shaft 24 by the conductive resin 9b. It is done. On the other
hand, the connection of the positive electrode 8 is connected to the coaxial cable signal line 10
by the conductive resin 9c on the back load material 1 in order to ensure the insulation with the
housing 6, and the ultra-compact ultrasonic wave with the above configuration. The probe 18
was produced.
[0028]
The conductive resin portion 9 is sealed and protected by an epoxy resin 12. The housing 6 and
the flexible shaft 24 are brazed with silver solder 14, and the housing 6 is made of corrosionresistant stainless steel electrolessly plated with nickel. The ultrasonic probe 18 thus produced is
dipped (dipped) in a 3% ethanol diluted solution of an organosilicon compound, here, a silane
coupling agent KBM-503 (Shin-Etsu Chemical Co., Ltd.) and pulled up. After that, heat treatment
was performed at 100 ° C. for 1 hour to complete an ultrasonic probe 18 protected by a film 30
containing silicon oxide (see FIG. 8).
[0029]
Hereinafter, the operation of the present embodiment will be described. By applying the
hydrophobic organic inorganic material film 30 to the entire surface of the ultrasonic probe 18,
the acoustic medium is prevented from intruding into the ultrasonic probe 18. Therefore, the
acoustic medium does not swell the conductive resins 9a to 9c, and the conductivity does not
deteriorate. In addition, an ultrasonic gel in the acoustic medium, such as saline or a commonly
used alkali ion, passes through the sealing layer of the epoxy resin to form a ceramic, such as
alumina, which is the acoustic matching layer, or a piezoelectric element. There is no risk of
attacking certain ceramics such as PZT, lead titanate, PLZT and lead metaniobate and electrodes.
In addition, silicon oxide is chemically stable, and the acoustic characteristics of the coating
material are low in acoustic impedance, so that the acoustic characteristics are not degraded.
[0030]
According to this example, it is possible to obtain a compact, durable, high-performance
ultrasonic probe without deterioration of characteristics and materials due to an acoustic
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medium. In particular, since the entire ultrasonic probe is covered with a film of a hydrophobic
organic inorganic material, as a result, it is more durable than the conventional one against
sterilization by gas or vapor.
[0031]
The coating agent is not limited to the silane coupling agent used in this example, and may be a
hydrophobic organic inorganic material, and an organic silicon compound such as a dilute
solution of tetraisocyanate silane (Si (NCO) 4) in ethanol, Alkoxysilane (Si (OR) 4), and organic
metal compounds: NT-L 2003 (Nissan Chemical Industries, Ltd.), Tonen Polysilazane PHP-2
(Tonen Co., Ltd.), Advanced Hard Coat (Tonen Co., Ltd.) ) Are also effective. In addition to the
immersion method, spray spraying is also effective.
[0032]
Embodiment 2 FIG. 9 is a cross-sectional view of an ultrasonic probe showing this embodiment.
The ultrasonic probe main body of this embodiment is manufactured in the same manner as in
Embodiment 1 except that the acoustic matching layer 4 is made of an alumina flat plate and
adhesively laminated on the GND electrode 7 with an epoxy resin (see FIG. 7) . In order to cover
the epoxy-based sealing resin 12 of the ultrasonic probe 18 manufactured in this manner, 3 of
the organosilicon compound here, silane coupling agent KBM-503 (manufactured by Shin-Etsu
Chemical Co., Ltd.) Apply a% ethanol diluted solvent with a brush. At this time, brush coating is
performed with the acoustic matching layer 4 removed. Thereafter, the film is dried at 100 ° C.
for 1 hour to form a film 30 of a hydrophobic organic inorganic material, and the ultrasonic
probe 18 is completed.
[0033]
Hereinafter, the operation of the present embodiment will be described. The ultrasonic probe
which is not coated with the hydrophobic organic inorganic material passes through the epoxy
resin to which the acoustic medium is exposed and penetrates into the inside. However, in the
present embodiment, the portion of the ultrasonic probe 18 where the epoxy-based
encapsulation resin 12 is exposed is coated with a coating agent that constitutes a film
containing silicon oxide with extremely low moisture permeability, thereby making it possible to
manufacture an acoustic medium. Is prevented from invading the inside of the ultrasonic probe
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18.
[0034]
Therefore, in the case of using an acoustic medium other than saline and an ultrasonic gel, such
as fluid paraffin, water, and other alcohol-based solutions, among the acoustic media, the
acoustic medium can be used as the conductive resin 9a to c does not swell and the conductivity
does not deteriorate. In addition, since the acoustic matching layer 4 which is an ultrasonic
radiation surface is not coated, it is possible to form a thick film without considering the acoustic
characteristics, and in particular, the long-term durability becomes high. In addition, the amount
of the expensive coating agent can be reduced as compared to the case where the entire surface
is coated.
[0035]
According to this embodiment, the same effect as that of the first embodiment can be obtained.
Furthermore, higher durability can be obtained. It is also possible to reduce the price.
[0036]
As a matter of course, the hydrophobic organic inorganic material is not limited to the material
used in the present embodiment, but the material used in the first embodiment can be applied,
and the inherent action of each material is also the same. To be present. As the application
method, in addition to brushing, application using a dispenser is also effective.
[0037]
[Embodiment 3] FIG. 10 is a cross-sectional view of an ultrasonic probe showing the present
embodiment. In this embodiment, in the same ultrasonic probe as that of the first embodiment,
the above-described embodiment is performed except that connection is made by solders 9'a to c
instead of the conductive resins 9a to c and sealing by an epoxy resin is not performed. Example
1 Prepared in the same manner. The acoustic matching layer 4, the solders 9 ′ a to c, and the
exposed surfaces of the surface electrodes 7 and 8 of the ultrasonic probe 18 manufactured in
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this manner and the input connected to the surface electrodes A 3% ethanol diluted solution of a
silane coupling agent KBM-503 (Shin-Etsu Chemical Co., Ltd.) is dropped here so as to cover the
exposed surface of the output electrode 10, in this case an organosilicon compound placed in a
syringe. The coating is followed by drying at 100 ° C. for 1 hour to form a film 31 of a
hydrophobic organic inorganic material, and the ultrasonic probe 18 is completed.
[0038]
Hereinafter, the operation of the present embodiment will be described. The acoustic medium
contacts the electrode and the acoustic matching layer by coating the input / output electrode 10
or the acoustic matching layer 4 portion of the ultrasonic probe with the coating agent
constituting the film containing silicon oxide with extremely low moisture permeability. To
prevent that. Therefore, even when using an acoustic medium such as a saline solution or an
ultrasonic gel that contains alkali ions, which are particularly excellent in acoustic characteristics,
among the acoustic media, deterioration of the ultrasonic probe 18 is prevented without
attacking each member. It will prevent.
[0039]
According to this example, it is possible to obtain a high-performance ultrasonic probe which is
small in size, durable, and free from deterioration of properties and materials due to the acoustic
medium.
[0040]
[Embodiment 4] FIG. 11 is a cross-sectional view of an ultrasonic probe showing this
embodiment.
This embodiment will be described using FIGS. 3 to 7 together. As shown in FIG. 3, the acoustic
matching layer 4 made of epoxy resin is applied to the piezoelectric element 5, and the back load
material 1 made of the epoxy resin containing tungsten filler is formed, and a laminate is
manufactured. Then, the solid line portion 40 of FIG. 4 is cut with a precision cutting machine to
produce one small transducer 25 as shown in FIGS. 5 and 6.
[0041]
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Then, as shown in FIG. 7, the transducer 25 is adhesively fixed on the insulating plate 19 fixed
with an adhesive to the housing 6 in which the metal pipe is processed, and the thick electrode
portion exposed on the side surface portion of the transducer 25 is conductive. Wire connection
via resin 9. At this time, the GND electrode 7 on the acoustic radiation surface side is once
connected to the housing 6 with the conductive resin 9a, and is connected by the conductive
resin 9b to the circumferential wire 11 of the coaxial cable 13 passing through the flexible shaft
24 in the housing 6 pipe part. It is done. On the other hand, the connection of the positive
electrode 8 is connected to the coaxial cable signal line 10 by the conductive resin 9c on the
back load material 1 in order to ensure insulation with the housing 6, and an ultra-compact The
acoustic probe 18 was produced.
[0042]
After masking the housing 6 and the acoustic matching layer 4 with a masking tape, the
ultrasonic probe 18 produced in this manner is masked with an organosilicon compound, here
the silane coupling agent KBM-503 (Shin-Etsu Chemical Co., Ltd.) (Dipping) in a 3% ethanol
diluted solution (made in Japan), and after pulling up, heat treatment is performed at 100 ° C.
for 1 hour to complete an ultrasonic probe 18 protected by a film 30 containing silicon oxide.
Thereafter, the masking tape was peeled off, and the remaining gap of the housing 6 was sealed
and protected by the epoxy resin 12 (see FIG. 11). The housing 6 and the flexible shaft 24 are
previously brazed with silver solder 14, and the housing 6 is made of corrosion-resistant
stainless steel and subjected to electroless nickel plating.
[0043]
Hereinafter, the operation of the present embodiment will be described. The ultrasonic probe 18
is coated with a coating agent that constitutes a film containing silicon oxide with extremely low
moisture permeability, thereby preventing the acoustic medium from intruding into the
ultrasonic probe 18. Therefore, the acoustic medium does not swell the conductive resins 9a to
9c, and the conductivity does not deteriorate. Further, in the acoustic medium, a saline solution
or an ultrasonic gel containing an alkali ion penetrates the sealing layer of the epoxy resin and
corrodes ceramics such as PZT and PLZT which are piezoelectric elements, and an electrode.
There is no need to lose it. In addition, since the upper surface of the coating film 30 is sealed
with the epoxy resin 12, defects such as the coating hitting the sheath and falling off are
prevented, and the durability is further improved.
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[0044]
According to this embodiment, it is possible to obtain a high-performance ultrasonic probe which
is small in size, particularly durable, without deterioration of characteristics and materials due to
the acoustic medium.
[0045]
The coating film may be formed directly on a member that is not desired to be in contact with the
acoustic medium, and for example, in the case of protecting the conductive resins 9a to 9c and
the piezoelectric element 5, assembly without providing the acoustic matching layer 4; It is also
possible to coat further and then to provide the acoustic matching layer 4.
[0046]
According to the first aspect of the present invention, at least the exposed organic polymer
material at the tip of the ultrasonic probe is infiltrated / transmitted with a liquid or gel acoustic
medium to cause characteristic deterioration. It was possible to provide an ultrasound probe to
prevent.
According to the second aspect of the present invention, the liquid or gel acoustic medium is
prevented from penetrating and transmitting to the conductive adhesive connecting the
piezoelectric element at the tip of the ultrasonic probe and the input / output electrodes, thereby
preventing the characteristic deterioration. Provided an ultrasonic probe.
The effect of Claim 3 was able to provide the ultrasound probe which prevents the characteristic
degradation of the ultrasound probe by high temperature hardening exceeding the heat-resistant
tolerance ¦ permissible̲range of an ultrasound probe.
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