JPS6089199

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DESCRIPTION JPS6089199
[0001]
[Technology 1 of the Invention (.i. Field)] The present invention relates to an array-type
ultrasonic probe which has improved mechanical strength and reduced cross-talk between
elements. [Technical back pressure of light and light problems In recent years, ultrasonic
diagnostic methods have come to be widely used in the medical field. For example, a diagnostic
method has been proposed in which ultrasonic pulses are emitted into the body from the body
surface and acoustic information in the living body is used as a key to diagnosis. Compared with
X-ray equipment, such an ultrasonic diagnostic apparatus can easily image soft tissue in vivo
without using a contrast agent, has no radiological damage, and is easy to handle. The image
quality has been improved more than before due to the progress of the technology, and it has
been generalized in the medical field as a clinical diagnostic device. However, since these
conventional ultrasonic diagnostic devices transmit and receive ultrasonic pulses almost from the
surface of the living body, it is difficult to diagnose organs deep from the surface of the body, and
high frequency with excellent resolution There are disadvantages such as the inability to
diagnose ultrasound in the body, the presence of sites that can not be diagnosed due to the
presence of bones and gas, and the effect of individual differences in subcutaneous fat, etc. An
intracorporeal ultrasound diagnostic apparatus has been commercialized that contains an
ultrasound probe that transmits and receives ultrasound waves in a tubular container that can be
inserted into a body cavity. An ultrasonic probe that transmits and receives the above-mentioned
ultrasonic waves by coming into contact with the body surface from the outside of the body
cavity does not need to be so compact, but is small when inserted into a body cavity through
esophagus etc. Is required. FIG. 1 shows the structure of a conventional array-type ultrasonic
probe used in a body cavity or the like, and FIG. 2 shows a side cross-sectional view of FIG. That
is, the array type ultrasonic probe 1 of the conventional example cuts a thin piezoelectric element
plate such as PZT, which can be divided in the thickness direction of the plate shape, from the
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vertical direction, Slightly spaced J: array-type piezoelectric elements aligned with the square 1
tee. ..., 2 is formed. Electrodes 3a and 3b are formed on both sides in the thickness direction of
each piezoelectric element 2 by vapor deposition of silver or the like, and one side of the
lightning + 138 on the side to which ultrasonic waves are transmitted and received is a ground
side electrode. The first and second acoustic matching layers 5 and 6 are formed conductively on
the flexible flexible substrate 4 in the shape of a circle, and elongated on the flexible substrate 4
in the same shape as each piezoelectric element 2. Is formed in a laminated form by pasting and
the like. On the upper surface of the second matching layer 6 is formed an acoustic lens 7 whose
center in the longitudinal direction of each piezoelectric element 2 is convex.
On the other hand, the positive electrode 3b surface of each of the piezoelectric elements 2 is
fixed to the damping portion (layer) 9 with the insulating layer 8 using an insulating member
interposed therebetween, and each ultrasonic transducer element is formed. . The positive
electrode 3b is drawn to the back side of the damping portion 9 from both sides in the
longitudinal direction by the flexible leads 10b, and the ground side N base 3a is also drawn to
the back side by the flexible lead 10a. In the gaps on both sides of the insulating layer 8, the
insulating layer 8 is fixed to the damping layer 9 using an adhesive 11 such as an epoxy-based
adhesive. The first and second matching layers 5 and 6 reduce the reflection of ultrasonic waves
transmitted and received from the piezoelectric element 2 to the internal cavity wall or the like to
which the front surface (upper surface) of the acoustic lens 7 abuts. Is set to an intermediate
value of the acoustic impedance between the piezoelectric element 2 and the internal cavity wall
so that the energy can be efficiently transmitted to the internal cavity wall side, and it is more
matched to the circularity by forming two matching layers 5.6. It is possible to do it. The
damping layer 9 causes the ultrasonic wave to be quickly tamped by the back surface (lj11 when
the piezoelectric element 2 is excited by the high frequency pulse applied to the both electrodes
3a and 3b, and the tamping is performed. It is for preventing that what was reflected by the back
of the moon 9 is received and aggravation of resolution is deteriorated. Although this damping
layer 9 can be made to have a sufficient attenuation 1 function when it is used outside the body
cavity, it has the smallest thickness because it becomes the most bulky member when used in the
body cavity. Be required. In this case, the material of the tamping m9 is substantially satisfied by
using tungsten powder dispersed in epoxy, silicone 1M vinyl resin or the like so that the
proportion ni of the tungsten powder is about 95% in terms of hanging ratio. It is possible to
realize a possible amount of attenuation. In the case of the dumping muscle 9 made of the above
material, the electric transmission / reception side is the ground potential side and the damping
layer 9 side is the positive side, for the safety measures against the human body because the
electric resistance is low. Since direct contact with the positive electrode side causes a problem in
that each of the ultrasonic transducers divided in the form of an array is electrically conducted
due to the low resistance (impedance) of the member forming the damping layer 9, the above
insulating layer Insulated by 8. By the way, in each ultrasonic transducer, an air gap is formed
between adjacent nirels 1 in order to prevent crosses between nirels 1-1 and in this case, in this
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case, between the piezoelectric elements 2 and 2 By forming the void 12 over the three layers
including the first and second matching layers 5.6, it is possible to prevent the crosstalk more
reliably than in the case where the void 12 is crooked only. It is.
The ultrasonic transducers separated by the air gap 12 are, for example, insulation fi! A
piezoelectric element plate having electrodes formed on both sides fixed to 8 and first and
second matching layer plates rolled on the piezoelectric element plate are integrated and cut to a
part of the insulating layer 8 with a diamond cutter Thus, the positive electrode charge 9% 3b is
formed by cutting to separate. In this case, the flexible substrate 4 is valved so as to be in contact
with the ground electrodes 3a after cutting. In the conventional example configured as described
above, since the adjacent piezoelectric elements 2.2 are separated by the air gap 12 including the
matching layer 5.6, crosstalk is sufficiently prevented. However, since each element is arranged
in a thin and elongated state and the elongated sides are not held, there is a disadvantage that
the element is very weak mechanically. In addition, moisture penetrates into the cavity 12 due to
moisture or the like, and the moisture remains in the cavity 12 for a long time, and the silver of
the electrodes 3a and 3b applied on both sides of each pressure N element 2 causes migration to
generate ultrasonic waves. There is a risk that the function of transmitting and receiving may be
degraded, and in a worse case, it may be in a state of showing 1 to 1 and 1q. SUMMARY OF THE
INVENTION The present invention has been made in view of the above-mentioned point, and it is
possible to prevent crosstalk between adjacent elements, and to maintain the mechanical
strength and prevent moisture absorption. It aims at providing an acoustic wave probe.
SUMMARY OF THE INVENTION The present invention is to prevent crosstalk, increase the
mechanical strength and prevent moisture from entering, by filling the hollow portion between
the elements with a hollow body. [Example of the Invention] The present invention will be
specifically described with reference to the drawings. FIGS. 3 and 4 relate to an embodiment of
the present invention, and FIG. 3 shows a cross section of the structure seen from the direction
perpendicular to the scanning direction of the ultrasonic beam, and FIG. Show. In the array type
ultrasonic probe 2 of one embodiment, hollow glass spheres 22 are filled in the respective void
portions 12 formed in the same manner as the conventional example described above. The
hollow crow spheres 22 have a thickness of 1 to 2 [珈] and a maximum diameter of about 40
[round], and an average density of 0.37 [g, 匡], for example. When the hollow glass spheres 22
are backed, the void volume ratio of the spheres becomes about 35%. After filling such hollow
callus spheres 22 in, for example, 50 [voids 12 having a width of a square], an epoxy adhesive
having a viscosity of about 500 [CI] S is dropped onto the respective voids 12 one by one from
the injection needle. When the hollow glass spheres 22 are fixed, the hollow glass spheres 22
facing the side face of each element are fixed to the side face to fix the hollow glass spheres 22
adjacent to each other. The gap between the two is made of a composite material of a glass-airadhesive agent 71-a lix material.
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This composite matrix moon contains a considerable amount of air, and the space between
adjacent nirelmens 1 is substantially close to being filled with air. While maintaining sufficient
mechanical strength by means of the hollow fixed hollow spheres 22 and by means of which the
hollow hollow spheres 22 and the adhesive prevent moisture penetration. The other
configuration is the same as that of the above-described conventional example, and the same
members are denoted by the same reference numerals. According to one embodiment configured
as described above, the hollow glass spheres 22 are filled in the gaps 12 between the ultrasonic
transducer elements, and the gaps of the hollow glass spheres are further penetrated by an
adhesive such as epoxy. It hardens by dropping it onto the surface, and forms an air-crowsadhesive interface with a large ultrasonic reflectance between each element, so it is possible to
reduce the cross-over and increase the mechanical strength and moisture etc. Can prevent
migration because it does not enter. In the above-described embodiment, hollow hollow spheres
are used as the hollow structural members to be packed into the void portion 12. However, the
present invention is not limited to this, and may be porous members, heat treatment or laser The
hollow member which formed the hole by light etc. is also included. Further, in the above
embodiment, the matching layer is 2rv1 and Si, but the present invention includes the case of 30
or more and the case of 1B as well as the case of 2 later. In addition, those in which the ratio of
the composition is continuously varied and the 't S ¥ 1 impedance of the matching layer is
continuously varied are also included in the present invention b. In the above embodiment, after
forming the air gap portion 12 for separation, the flexible substrate 4 can be interposed to
conduct electricity to the ground electrode 3 a of each piezoelectric element 2. In the case where
the gap 4 is formed by projecting a part of its longitudinal direction so as to project and bond the
matching layer 5.6 and also integrating it together to form the void portion 12, it is a flexible,
projecting part of the substrate 4. A construction in which the ground sides of the respective
elements can be conducted in common also yields to the present invention. [Effects of the
Invention] As described above, according to the present invention, the space for separating the
ultrasonic transducer elements arranged in an array is formed so as to be packed with a hollow
member such as a glass sphere having a hollow. In particular, cross talk is sufficiently prevented
in the hollow portion, mechanical strength is increased in the stuffed members, and further, the
migration is performed by preventing moisture from entering between the stuffed members with
the adhesive. It can prevent.
[0002]
Brief description of the drawings
[0003]
1 and 2 relate to the prior art, and FIG. 1 is a cross-sectional view showing a conventional array-
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type ultrasound probe, and FIG. 2 is a cross-sectional view perpendicular to FIG. FIG. 3 and FIG. 4
relate to an embodiment of the present invention, FIG. 3 is a side sectional view of one
embodiment, and FIG. 4 is an enlarged view of a part of FIG. 6 is an enlarged cross-sectional view
of FIG.
Reference Signs List 2: Piezoelectric element 3a, 3b: Electrode 4: flexible substrate 5, 6: matching
layer 7: acoustic lens 8: insulating solid 9: damping portion (layer) 10a, 10b: flexible lead 11:
adhesive 12: void portion 21: ultrasonic probe 22: hollow glass sphere Fig. 1 Fig. 2 Fig. 3 Fig. 4
Fig. 22 3b
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