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JP2011004806

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DESCRIPTION JP2011004806
A conventional mechanical scanning ultrasonic probe has problems of weight increase and size
increase because a liquid chamber is provided. A gel 36 is provided on an inner surface 22B of a
contact wall 22. The transducer unit 24 swings, and the transmitting / receiving wavefront 24A
is in close contact with the upper surface 36B of the gel 36 at each movement position.
Specifically, the portion in contact with the transmission / reception wavefront 24A is slightly
recessed. The gel 36 has properties such as elasticity, wettability, low friction, and chemical
stability. A structure for replacing the gel 36 may be provided, or a biasing structure may be
employed to bring the gel 36 into close contact with the transmission / reception wave face 24A.
[Selected figure] Figure 1
Ultrasound probe
[0001]
The present invention relates to an ultrasound probe, and more particularly to the structure of an
ultrasound probe provided with a mechanically scanned transducer unit.
[0002]
An ultrasound probe is used in ultrasound diagnosis of a living body to transmit and receive
ultrasound waves.
Various ultrasound probes have been put to practical use. Among them, a mechanical scanning
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ultrasonic probe (mechanical scanning probe) has a probe case, a transducer unit, a mechanical
scanning mechanism, and the like. In such an ultrasound probe, the transducer unit is linearly
scanned in parallel, oscillated in an arc, or rotationally scanned. When the transducer unit is
constituted by a single transducer, a fan-shaped two-dimensional beam scanning surface is
formed by oscillating and scanning such a transducer unit. On the other hand, when the
transducer unit is constituted by a 1D array transducer, the two-dimensional beam scanning
surface is swung when the transducer unit is swung in a mechanical scanning direction
orthogonal to the electronic scanning direction. Thus, a three-dimensional echo data acquisition
space (three-dimensional space) is constructed.
[0003]
In the mechanical scanning ultrasonic probe, if there is an air layer between the inner surface of
the probe case (the inner surface of the biological contact portion) and the transmission /
reception wavefront of the transducer unit as the movable body, ultrasonic wave propagation is I
can not secure it. This is because a significant step in acoustic impedance occurs between the
transducer unit and the air layer, and ultrasonic waves are reflected there. Therefore, the
conventional mechanical scanning ultrasonic probe is provided with a liquid tank filled with a
liquid for acoustic propagation inside. The liquid is oil, water or the like having an acoustic
impedance close to that of the living body. By moving the transducer unit in the liquid tank, the
liquid always intervenes between the transmission / reception wavefront of the transducer unit
and the inner surface of the probe case, so that good acoustic propagation can be secured.
[0004]
Patent Document 1: Japanese Patent Application Laid-Open No. 5-228143 Patent Document 2:
International Publication No. 2003/093337 Patent Document 2: International Publication No.
2004/015012 Patent Document 2: Japanese Patent Application Laid-Open No. 10-248847
[0005]
However, when using the above-described liquid tank, the transducer unit (in particular, a
relatively large transducer unit equipped with a 1D array transducer) receives a large resistance
from the liquid during its movement.
For this reason, it is necessary to provide a large drive mechanism in the probe case. Moreover,
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in order to prevent the external outflow of the liquid and the generation of air bubbles, it is
necessary to adopt a special watertight structure as the liquid tank. For these reasons, it has been
pointed out that the size and weight of the ultrasound probe are increased.
[0006]
Patent Document 1 discloses a semi-solid oily gel provided between a vibrator and a living body.
The gel is an acoustic medium that is used in place of the conventional echo jelly and has shape
retention. That is, it is deformed by an external force, but returns to its original shape when it is
lost. Patent Document 2 discloses a hydrogel having a shape retaining property containing a
large amount of water. Patent Document 3 discloses a low friction organogel containing silicone
oil. It is also understood that this is a gel having gel formation. However, Patent Documents 1, 2
and 3 disclose nothing about the use of such a gel inside an ultrasound probe.
[0007]
In FIG. 1 and FIG. 2 of Patent Document 4, the transducer array and the matching layer are
integrated to form a rotating body, and the lower surface (transmission / reception wavefront) of
the rotating body is formed on the inner surface of the disk-shaped acoustic lens. Contacting is
disclosed. In this configuration, when the rotating body is rotated, the lower surface of the
rotating body slips on the surface of the acoustic lens. However, the purpose of adopting such a
configuration is to make it possible to form two orthogonal cross sections by rotating the
transducer by 90 degrees without rotating the probe itself by 90 degrees, That is, the said
structure does not transmit / receive an ultrasonic wave during rotation of a vibrator ¦ oscillator.
Further, reference document 4 does not disclose the use of a gel having a shape-retaining
property inside the ultrasonic probe at all. Patent Document 5 discloses an ultrasonic probe
provided with an acoustic lens containing oil.
[0008]
An object of the present invention is to simplify the internal structure of an ultrasonic probe or to
reduce the weight of the ultrasonic probe.
[0009]
Alternatively, an object of the present invention is to ensure good sound propagation at each
movement position of the transducer unit without using a liquid tank.
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[0010]
The present invention relates to an ultrasonic probe used in ultrasonic diagnosis of a living body,
which is a probe case having a living body contact portion, and a movable member provided in
the probe case, the transmission / reception wavefront being And a mechanical scanning
mechanism mechanically scanning an ultrasonic beam or a beam scanning surface formed by the
transducer unit by mechanically scanning the transducer unit in the probe case. And a gel-like
material provided between the inner surface of the living body contact portion and the
transmission / reception wave front and having shape retention property, for securing ultrasonic
wave propagation between the inner surface and the transmission / reception wave front. And a
gel-like medium layer.
[0011]
According to the above configuration, the ultrasonic waves emitted from the transmission /
reception wavefront pass through the gel-like medium layer and the biological contact portion
and are emitted into the living body.
The reflected wave from the inside of the living body passes through the biological contact
portion and the gel-like medium layer to reach the transmission / reception wavefront.
Since the gel-like medium layer is provided between the transmission / reception wavefront of
the transducer unit and the inner surface of the living body contact portion, good ultrasonic wave
propagation can always be ensured in the mechanical scanning process of the transducer unit.
Therefore, the liquid tank (the room filled with the liquid) required in the conventional ultrasonic
probe can be unnecessary, and at the same time, the liquid resistance that has been applied to
the entire side surface of the transducer unit can be eliminated. As a result, it is possible to obtain
the advantages of downsizing and weight reduction of the ultrasonic probe while securing sound
propagation.
[0012]
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The ultrasonic probe is preferably abutted against the surface of a living body, but may be
inserted into a body cavity. The living body contact portion functions as a partition wall or a
partition film which prevents the liquid from flowing out or exuding from the inside of the
ultrasonic probe. If the biological contact portion is made of a member having transparency, the
gel-like medium tank provided inside can be observed from the outside. The outer surface of the
biological contact portion may be in direct contact with the living body, or may be indirectly in
contact with the living body via a standoff material or the like. At that time, a fluid eco jelly may
be applied to the living body or the outer surface as in the prior art. Any of a transducer unit
having a single transducer and a transducer unit having a 1D array transducer can be used. As a
method of mechanical scanning, linear scanning, circular arc scanning (or oscillating scanning),
rotational scanning and the like can be mentioned. The transducer unit may have a matching
layer, an acoustic lens, a backing, and the like in addition to the transducer. The biological
contact unit may exert the function of the acoustic lens.
[0013]
The gel-like medium layer is made of a material having shape retention. That is, if it does not
consider deterioration due to long-term use, it has an action of maintaining a constant shape, in
other words, it does not plastically deform due to external force, but elastically deforms due to
external force. Thus, the gap between the transmission / reception wavefront of the transducer
unit and the inner surface of the living body contact portion can be filled with the acoustic
medium. The gel-like medium layer is preferably made of a material having liquid wettability
from the viewpoint of removing the air layer on the ultrasonic wave propagation path or from
the viewpoint of improving the adhesion. In such a case, it is desirable that the liquid used be
stable for a long period of time, that is, not easily deteriorated. Also, the gel-like medium layer is
desirably made of a material having low friction. Depending on the situation, gels described in
Patent Literature 1-3 and other gels can be used. In recent years, various gels have been put to
practical use, and it is thought that various new gels will be put to practical use in the future, so it
is desirable to select an optimum gel according to the conditions of use.
[0014]
Preferably, the gel-like medium layer is a non-moving member disposed on the inner surface of
the biological contact portion, and the vibrator is maintained while the transmission / reception
wavefront is in contact with the surface of the gel-like medium layer. The unit is mechanically
scanned and the surface of the gelled media layer constitutes a slip surface. According to this
configuration, the transmitting and receiving wavefronts slip on the surface of the gel-like
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medium tank. Since the transmitting and receiving wavefronts always contact the surface of the
gel-like medium tank regardless of the movement position of the transducer unit, sound
propagation can be secured over all the mechanical scanning positions.
[0015]
Although it is possible to provide a gel-like medium layer on the side of the vibrator unit
(movable body), the above configuration (gel fixing method) has wider parts where abrasion
occurs than such a gel movement method. It is advantageous in that it can be dispersed. While
providing a gel-like medium layer as a non-moving member, it is also possible to provide a gel
medium layer also on a moving member (oscillator unit) and to perform slip movement between
the two. In that case, the lower surface (moving surface) of the moving gel medium layer
constitutes the transmission / reception wavefront.
[0016]
Desirably, the gel-like medium layer has elasticity, and in the gel-like medium layer, the portion
receiving the pressing force of the transmission / reception wavefront becomes a hollow portion,
and the hollow portion becomes an original shape after the pressing force disappears. To return.
According to this configuration, even if the mechanical scan is repeatedly executed at relatively
high speed, in such a process, the adhesion between the transmission / reception wavefront and
the surface of the gel-like medium layer can always be maintained. The responsivity of
reconstitution can be adjusted by changing the composition of the gel.
[0017]
Desirably, the gel-like medium layer is liquid-wettable, and the liquid contained therein exudes in
the recess portion. The amount of depression of the depression can be varied by adjusting the
pressure, the size of the gap, the thickness of the medium layer, and the like. It is desirable to set
the amount of depression so that the adhesion can be made good and the load on the transducer
unit is not much. If the liquid exudes due to the pressing force, it is advantageous because the
liquid functions as a lubricating liquid and also exerts the effect of excluding the air layer. An
agent for preventing foaming may be added to the medium layer, or a structure for eliminating
bubbles may be provided in the case.
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[0018]
Preferably, the liquid contained in the gel-like medium layer is an oil. Oil can prevent
deterioration over a long period of time. Physiological saline can also be used. In order to prevent
the liquid from leaking out easily from the movement space of the transducer unit, it is desirable
to adopt a seal structure when constructing the movement chamber. However, it is not always
necessary to adopt a strict seal structure (in which even generation of air bubbles is not
permitted) as in a conventional liquid tank.
[0019]
Desirably, the gel-like medium layer has a thickness larger than the gap between the inner
surface of the biological contact portion and the transmission / reception wave surface in its
natural state. According to this configuration, it is possible to easily form a close contact state by
using the elasticity of the gel-like medium layer as it is. If the size of the gap changes in the
mechanical scanning direction (and the electronic scanning direction), the thickness of the gellike medium layer may be changed in accordance with the change. In that case, it is desirable to
determine the shape of the gel-like medium layer so that the thickness of the gel-like medium
layer is slightly larger than the gap at any location.
[0020]
Desirably, a means for applying a biasing force to at least one of the transducer unit and the
living body contact portion is included so that a gap between the transmission / reception
wavefront of the transducer unit and the inner surface of the living body contact portion is
reduced. According to this configuration, in addition to the elasticity of the gel-like medium layer,
a biasing force is applied by the biasing means to enhance the degree of adhesion. In any case, it
is desirable that a close contact state be always formed for the entire transmission / reception
wavefront.
[0021]
Preferably, the probe case has an exchange structure for exchange of the gel-like medium layer.
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A structure in which only the gel-like medium layer is exchanged may be adopted, or a structure
in which other structures such as the gel-like medium layer and the biological contact wall may
be adopted. According to this configuration, when the gel-like medium layer is deteriorated, it
can be replaced with a new one. The determination of deterioration can be made directly by
visual observation or can be made indirectly from noise or the like included in an ultrasonic
image. It may be regularly replaced regardless of actual deterioration.
[0022]
Desirably, the probe case is provided with a motion chamber containing the vibrator unit, and a
refill liquid consisting of the same liquid as the liquid contained in the gel-like medium layer is
previously inserted in the motion chamber. Be The replenishment solution can prevent the drying
of the gel-like medium layer and maintain its wettability.
[0023]
Desirably, the probe case is provided with a replenishing solution supply means for supplying a
replenishing solution composed of the same liquid as the liquid contained in the gel-like medium
layer to the gel-like medium layer. Preferably, the replenisher supply means includes a
replenisher containing member which is crushed by the vibrator unit when the vibrator unit
moves. According to this configuration, the motion of the transducer unit can be used for
medium replenishment.
[0024]
Preferably, the transducer unit has a 1D array transducer having a plurality of transducer
elements arranged in the element arrangement direction, and the transmission / reception
wavefront of the transducer unit has a length extended in the element arrangement direction.
The mechanical scanning mechanism reciprocates the transducer unit in a mechanical scanning
direction orthogonal to the element arrangement direction, and the gel-like medium layer has a
lateral width equal to or more than the length of the transmission / reception wavefront, and It
has a longitudinal width equal to or greater than the movement range of the transducer unit in
the machine scanning direction. According to this configuration, the entire surface of the
transmitting / receiving surface can always be in close contact with the gel-like medium layer
also by the movement of the transmitting / receiving wave surface.
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[0025]
Preferably, the transmission and reception wavefront of the transducer unit has rounded edges.
According to this configuration, it is possible to reduce the load resistance at the time of exercise
and to relieve the local stress generated in the gel-like medium layer.
[0026]
Preferably, the transducer unit swings about a predetermined rotation axis with the transmission
/ reception wavefront facing downward, and the biocontact portion and the gel-like medium
layer are curved along the machine scanning direction. Have.
[0027]
According to the present invention, the internal structure of the ultrasound probe can be
simplified.
Alternatively, it can be made lighter. Alternatively, good acoustic propagation can be secured at
each movement position of the transducer unit without immersing the transducer unit in the
liquid tank.
[0028]
1 is a first cross-sectional view of an ultrasound probe according to the present invention. FIG. 5
is a second cross-sectional view of the ultrasound probe according to the present invention. FIG.
5 is a cross-sectional view for making a structure for exchanging a gel. It is a perspective view for
demonstrating the fixation method of gel. It is sectional drawing for demonstrating the urging ¦
biasing mechanism for making a gel contact ¦ adhere. It is a figure showing a flat type linear
vibrator unit. It is a figure which shows a convex-type linear vibrator unit. It is a figure which
shows a concave linear vibrator unit. It is a figure which shows a flat type convex oscillator unit.
It is a figure which shows a convex-type convex vibrator unit. It is a figure which shows a
concave convex oscillator unit.
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[0029]
Hereinafter, preferred embodiments of the present invention will be described based on the
drawings.
[0030]
FIG. 1 shows a preferred embodiment of an ultrasonic probe according to the present invention,
and FIG. 1 is a cross-sectional view thereof.
The ultrasound probe is connected to the ultrasound diagnostic apparatus via a probe cable (not
shown). The ultrasonic probe is used in contact with the surface of a living body, and transmits
and receives ultrasonic waves in this state. A received signal is thereby obtained, and an
ultrasound image is formed based on the received signal.
[0031]
The ultrasound probe 10 shown in FIG. 1 has an upper case 12 and a lower case 14. The upper
case 12 and the lower case 14 are made of resin or the like, and they are vertically connected to
constitute a probe case. The outer surface of the upper case 12 is held by the examiner's hand
and constitutes a grip. The lower case 14 has a contact wall 22 that is in contact with the surface
of the living body.
[0032]
An inner case 16 is provided inside the ultrasonic probe 10. A room surrounded by the inner
case 16 and the lower case 14 is an exercise room 18. The motion chamber 18 is an enclosed
space that does not leak liquid. Therefore, a seal structure is adopted. However, it is not always
necessary to have a strict sealing structure as in a conventional ultrasonic probe. The internal
space 20 of the upper case 12 is provided with a motor 28 which is a part of a scanning
mechanism 23 described later.
[0033]
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The ultrasound probe 10 has a scanning mechanism 23 and a transducer unit 24. The scanning
mechanism 23 has a motor 28 and a worm gear 30. The worm gear 30 is configured of a gear
32 and a gear 34. The gear 32 is connected to the motor shaft 28A. The motor 28 is fixed to the
inner case 16. The scanning mechanism 23 may have a reduction gear mechanism or the like.
[0034]
The vibrator unit 24 swings around the rotation shaft 26. The transducer unit 24 has the 1D
array transducer 25 at its tip end, that is, its lower end. The 1D array transducer is composed of
a plurality of transducer elements arranged in the electronic scanning direction. An ultrasonic
beam is formed by the 1D array transducer, and the beam scanning surface is configured by
electronically scanning the ultrasonic beam. The swinging motion of the transducer unit 24 also
swings the beam scanning surface, thereby forming a three-dimensional data acquisition area.
[0035]
Specifically, the rotational movement of the motor 20 is converted to the rotational movement of
the rotary shaft 26 by the worm gear 30, and the rotation of the rotary shaft 26 causes the
vibrator unit 24 fixedly connected thereto to rotate. The direction of movement is represented by
θ in FIG. The vibrator unit 24 may be provided with known members such as a matching layer,
an acoustic lens and a backing layer.
[0036]
As described above, the lower case 14 has the contact wall 22. The contact wall 22 functions as
an opening film, and has an outer surface 22A and an inner surface 22B. The outer surface 22A
is a surface that contacts a living body. An echo jelly etc. are apply ¦ coated to the outer surface
22A as needed. The contact wall 22 is formed to be rounded, and in the cross-sectional view
shown in FIG. 1, the contact wall 22 is formed to have a constant curvature centered on the
rotating shaft 26. The contact wall 22 has a uniform thickness, but of course the thickness may
vary continuously if desired.
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[0037]
In the present embodiment, at least the contact wall 22 in the lower case 14 may be made of a
member having transparency. As a result, the inside of the motion chamber 18, specifically the
gel 36 described below, can be easily observed from the outside.
[0038]
A gel 36 is provided on the inner surface 22B of the contact wall 22 as shown. The gel 36
spreads in both the electronic scanning direction and the mechanical scanning direction to form
a medium layer, and in the embodiment shown in FIG. 1, has a uniform thickness in the θ
direction in its natural state. Similarly, as shown in FIG. 2 below, the gel 36 has a certain
thickness in the range in which the transmission / reception wave front 24A of the transducer
unit 24 is in contact. The gap between the transmission / reception wavefront 24A and the inner
surface 22B is substantially the same regardless of the rotation angle of the transducer unit 24.
Then, a gel 36 having a predetermined thickness is internally affixed to the contact wall 22 in
order to fill the gap between the transmission / reception wavefront 24A and the inner surface
22B to secure acoustic transmission. Although the gel 36 is fixed by the adhesive in this
embodiment, it may of course be fixed using a frame, a screw or the like.
[0039]
The gel 36 has shape retention. That is, although the depression is locally depressed by the
pressing of the transducer unit 24, the depression is restored by the passage of the transducer
unit 24. As illustrated, only the portion to which the transmission / reception wavefront 24A
abuts is recessed to form a recess, and the recess moves with the reciprocating motion of the
transducer unit 24. The gel 36 is resilient to allow such collapse. Also, the gel 36 has wettability.
That is, the gel 36 is made of a polymer material containing oil as a liquid, and has wettability
such that the liquid exudes from the inside at the pressed portion of the transmission / reception
wavefront 26. In FIG. 1, such exuded liquid is indicated by reference numeral 38B. By the liquid
exuding in this manner, the wet state of the surface of the gel 36 is maintained, the friction with
the transmission / reception wavefront 24A can be extremely small, and the air layer between
the transmission / reception wavefront 24A and the upper surface 36B of the gel 36 Can be
effectively prevented. Incidentally, the lower surface 36A of the gel 36 is bonded to the inner
surface 22B of the contact wall 22 by the adhesive as described above. If it is difficult to fix with
an adhesive, it is desirable to use a frame or the like described later. The gel 36 is preferably
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constructed of a low friction, flexible polymeric material having chemical stability. Using such a
material makes it possible to maintain the transmission / reception wavefront 24A and to reduce
the resistance during its movement.
[0040]
In order to move the transmission / reception wavefront 24A smoothly, it is desirable to form the
four sides, that is, the ring-like corner portions with roundness. According to this, it is possible to
prevent the problem that the upper surface 36B of the gel 36 is unnecessarily damaged by the
edge of the transmission / reception wavefront 24A. However, as the gel 36, a durable one is
used, which is not easily deteriorated and can be used continuously for a long period of time.
However, it is desirable that the gel 36 be constructed so that it can be replaced with a new one
when degradation or the like occurs.
[0041]
As described above, the motion chamber 18 is configured as an airtight space, and evaporation
and outflow of the liquid contained in the gel 36 are prevented. Therefore, if a small amount of
the same liquid 38A is put in the motion chamber 18 in the probe manufacturing stage, the wet
state of the gel 36 can be maintained for a long period of time. Although the replacement fluid is
free to exercise in the exercise room 18, such exercise is not a diagnostic problem as it is only to
maintain a moisturizing condition.
[0042]
Another cross-sectional view of the ultrasound probe 10 is shown in FIG. The cross sectional
view shown in FIG. 1 and the cross sectional view shown in FIG. 2 are in an orthogonal
relationship.
[0043]
Two bearings 16A and bearings 16B are formed in the inner case 16, and the rotating shaft 26 is
rotatably held by these. The detailed structure of each bearing 16A and bearing 16B is omitted. A
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gear 34 is connected to the rotation shaft 26, and the gear 34 meshes with the gear 32. The
vibrator unit 24 is a linear type unit in the illustrated example, and the lower end portion thereof
is provided with the 1D array vibrator as described above. In the figure, the x direction is the
electronic scanning direction, that is, the element arrangement direction. The gel 36 having a
substantially uniform thickness is provided between the transmission / reception wavefront 24A
and the inner surface 22B of the contact wall 22 as described above, and the gel 36 is used
regardless of the movement position of the transducer unit 24. , And in close contact with the
front surface of the transmission / reception wavefront 24A. The transmission / reception
wavefront 24A is a rectangular surface elongated in the x direction, and in the x direction, the gel
36 has a lateral width larger than the width of the transmission / reception wavefront 24A. As
shown in FIG. 1, the gel 36 has a length greater than the movement path of the transducer unit
24 also in the θ direction. That is, regardless of the movement position of the transducer unit, all
of the transmission / reception wavefronts adhere to the upper surface of the gel.
[0044]
According to the ultrasonic probe 10 shown in FIGS. 1 and 2, it is not necessary to provide a
chamber filled with liquid in the probe case, and only the motion chamber 18 filled with air as
shown in the drawing is provided. Therefore, it is possible to solve the problem of the liquid
resistance that occurs when the transducer unit 24 is mechanically scanned, that is, the problem
of the load caused by the collision with the liquid. However, since the transmission / reception
wavefront 24A is in contact with the gel 36, a load is generated there, but since the load is
considerably smaller than the conventional medium load, the scanning mechanism is smaller and
lighter than in the prior art. It is possible to This leads to the miniaturization and weight
reduction of the ultrasound probe itself. The gel 36 described above is preferably made of a
material having an acoustic impedance equal to or close to the acoustic impedance of a living
body, and in that case, elasticity, wettability, low friction, chemical as described above It is
desirable to select materials that satisfy each condition such as stability. As such a material, it is
desirable to select an appropriate one from a large number of gel materials currently existing,
according to the application and conditions. For example, it is also possible to use what was
shown to patent documents 1-3. By impregnating the gel 36 with oil, an advantage is obtained
that the deterioration is unlikely to occur even over a long period of time. However, it is also
possible to use physiological saline or the like as a liquid. In the embodiment described above,
the gel 36 is used as a fixing member, but it is also possible to provide the gel 36 on the
transmission / reception wavefront 24A and use the gel 36 as a motion member. In that case, the
lower surface of the gel 36 comes into contact with the inner surface 22 B of the contact wall 22
while slipping. Alternatively, the gel as the moving member and the gel as the non-moving
member may be in sliding contact.
04-05-2019
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[0045]
Next, FIG. 3 shows an exchange structure. In the ultrasound probe 40, a lower case 14 is
provided below the upper case 12, but they are fastened by a connecting member 42.
Specifically, a screw groove 44 is formed at the lower end of the upper case 12, and a screw
groove 46 is also formed on the upper inner surface of the connecting member 42. If the
connecting member 42 is rotated with the upper end 48 of the lower case 14 held in place by the
connecting member 42, the upper end 48 is securely fixed by screwing the screw groove 44 and
the screw groove 46. Is possible. Of course, bolts or the like may be used regardless of the
engagement of such screws, or mechanical connection structures such as hooks may be used. In
any case, if the lower case 14 is configured to be removable from the main body of the
ultrasound probe, the gel 36 provided inside the lower case 14 can be easily replaced. In that
case, the lower case 14 may be replaced with the gel 36, or the gel 36 may be separated from the
lower case 14 and only the gel 36 may be replaced.
[0046]
In the configuration example shown in FIG. 3, a pair of sponges 50 is provided at both ends of
the gel 36 in the θ direction. The sponges 50 are members holding the same liquid as the liquid
contained in the gel 36, that is, oil, and when the vibrator unit 24 moves, when it reaches the
forward end and the backward end, the vibrator 50 is moved. The side 52 of the unit 24
squeezes each sponge 50 from which the oil bleeds. Thus, the liquid can be replenished. Such
liquid supply may be performed using a pump or the like without using the sponge 50.
Alternatively, as described above, only a predetermined amount of liquid may be placed in the
motion chamber 18 in advance.
[0047]
The fixing structure of the gel 36 is shown in FIG. The gel 36 may be fixed by attaching a frame
54 to the inner surface of the lower case 14 using a frame 54 surrounding and holding the gel
36 as illustrated. An adhesive, screwing, or the like can be used to fix the frame 54. Instead of
using the frame 54, a member for maintaining the adhesion between the gel 36 and the inner
surface of the lower case 14 may be provided.
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[0048]
Incidentally, the amount of depression due to the contact of the transmission / reception
wavefront with the gel is, for example, 1 mm or less. The thickness of the gel 36 may be, for
example, about 5 mm to 10 mm. The gel 36 is preferably made of a transparent member, and if
both the contact wall and the gel have transparency, it is easy to observe the inside of the motion
chamber 18 from the outside of the contact wall 22 .
[0049]
An example of a biasing mechanism is shown in FIG. The illustrated biasing mechanism 56 uses a
spring 62 to bring the top surface 36B of the gel 36 into intimate contact with the transmission /
reception wavefront 24A of the transducer unit. Specifically, the upper case 12 and the lower
case 14 are attached so as to be movable in the vertical direction. A pedestal 58 is formed on the
inner case 16, while the upper end of the lower case 14 functions as a pedestal 60. A spring 62 is
provided between the pedestal 58 and the pedestal 60. In practice, a plurality of springs are
provided to surround the motion chamber. The springs 62 exert a force in the pulling direction,
that is, a biasing force is exerted in the direction in which the outer case 14 approaches the inner
case 16. Thereby, the gel 36 can be brought into close contact with the transducer unit. In such a
configuration, the adhesion can be further enhanced by the two actions of the elasticity of the gel
36 and the biasing force of the biasing mechanism 56. For example, even if the thickness of the
gel 36 varies due to aging, the adhesion can be reliably maintained by the biasing force.
[0050]
A variation of the transducer unit will be described using FIGS. 6 to 11. A linear transducer unit
60 is shown in FIG. 6, and the transmission / reception wavefront 60A has a flat shape. A linear
transducer unit 62 is shown in FIG. 7, and its transmission / reception wave front 62A has a
convex shape. The transducer unit 64 of the linear type shown in FIG. 8 has a concave-shaped
transmission / reception wavefront 64A.
[0051]
The convex type transducer unit 66 shown in FIG. 9 has a flat type transmission / reception wave
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front 66A. The convex-type transducer unit 68 shown in FIG. 10 has a transmission / reception
wavefront 68A having a convex shape. The convex type transducer unit 70 shown in FIG. 11 has
a concave type transmission / reception wavefront 70A. When a concave transmission /
reception wave front is employed, a gel may be embedded therein to make the transmission /
reception wave front a flat surface or a convex surface so that the adhesion does not decrease. In
that case, the gel to be embedded becomes a part of the movable body, and the lower surface
thereof constitutes the transmission / reception wavefront of the movable body.
[0052]
10 ultrasonic probe, 12 upper case, 14 lower case, 16 inner case, 18 motion chamber, 22 contact
wall, 23 scanning mechanism, 24 transducer unit, 36 gel.
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