JP3777348B2 - Ultrasonic probe - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ultrasonic probe, and more particularly to an ultrasonic probe used in an ultrasonic diagnostic apparatus or the like that renders an ultrasonic diagnostic image by scanning ultrasonic waves electrically or mechanically. It is.
[0002]
[Prior art]
As a scanning ultrasonic probe used in an ultrasonic diagnostic apparatus, an ultrasonic element that transmits and receives ultrasonic waves is rotated or oscillated in a medium chamber in which an acoustic coupling medium having an acoustic impedance close to that of a living body is enclosed. It has been known. Such an ultrasonic probe is described in, for example, Japanese Patent Laid-Open Nos. 4-325146, 2-1248, and 8-112280.
[0003]
In JP-A-4-325146, a thin film made of an elastic body is provided in a medium chamber so that one surface thereof is in contact with an acoustic coupling medium, and this thin film is allowed to function as a pressure adjusting unit that adjusts expansion and contraction of the acoustic coupling medium. An ultrasonic probe is described (hereinafter referred to as “conventional example 1”). Japanese Patent Laid-Open No. 2-1248 describes an ultrasonic probe that includes a bellows that is filled with an acoustic coupling medium and that can be circulated with the medium chamber (hereinafter, referred to as “an acoustic probe”). “Conventional example 2”). In this probe, a support plate is provided so as to contact the bellows, and the volume of the bellows can be adjusted by adjusting the position of the support plate. Japanese Laid-Open Patent Publication No. 8-112280 describes an ultrasonic probe that rotates and scans an ultrasonic element portion and that can slide in a direction along the rotation axis (hereinafter referred to as an ultrasonic probe). “Conventional example 3”).
[0004]
[Patent Document 1]
JP-A-4-325146 [Patent Document 2]
Japanese Patent Laid-Open No. 2-1248 [Patent Document 3]
JP-A-8-112280 [0005]
[Problems to be solved by the invention]
In such an ultrasonic probe, when the acoustic coupling medium expands with a change in temperature, the internal pressure of the medium chamber rises excessively. As a result, the seal portion of the medium chamber is broken and bubbles are mixed. There is a fear. In addition, even if the medium chamber is sufficiently sealed, resin is used as a material constituting the medium chamber because of acoustic characteristics. Therefore, during use over a long period of time, the pressure in the medium chamber is increased by elongation due to the creep phenomenon of the resin. In some cases, the pressure gradually decreases, and as a result, the pressure inside the medium chamber becomes lower than the external pressure, and air may enter through the resin constituting the medium chamber. When bubbles are mixed in the medium chamber, this becomes an ultrasonic reflector, which inhibits transmission / reception of ultrasonic waves and causes deterioration of ultrasonic diagnostic images. In order to suppress the generation of such bubbles, the pressure adjustment in the medium chamber is an important issue in this type of ultrasonic probe.
[0006]
In the ultrasonic probe of Conventional Example 1, the expansion and contraction of the acoustic coupling medium is absorbed by the elongation of the thin film made of an elastic body, thereby adjusting the pressure in the medium chamber. However, in order to avoid the tearing of the thin film, it is necessary to increase the thickness of the thin film. However, if the thickness of the thin film increases, it becomes difficult to sufficiently absorb the expansion and contraction of the acoustic coupling medium, and the pressure change in the medium chamber Becomes larger. On the contrary, if the thickness of the thin film is reduced, the pressure change in the medium chamber can be reduced, but the strength of the thin film is lowered, and there is a possibility that the pressure change in the medium chamber may cause a tear or the like. As described above, Conventional Example 1 has a problem that it is difficult to maintain both the strength of the thin film and a sufficient pressure adjustment function.
[0007]
In the above conventional example 2, the volume of the bellows is adjusted by moving a support plate provided so as to contact the bellows, thereby adjusting the pressure in the medium chamber. However, when the pressure in the medium chamber fluctuates during the use period of the probe, it is necessary to repair the probe by disassembling the probe and adjusting the position of the support plate to adjust the pressure. Therefore, the conventional example 2 has a problem that the pressure in the medium chamber cannot be controlled within an appropriate range over a long period of time.
[0008]
Moreover, in the said prior art example 3, the pressure in a medium chamber is adjusted by moving the position of an ultrasonic element part to the direction along a rotating shaft. However, in this conventional example 3, it is necessary to provide the ultrasonic element portion so as to be rotatable in order to realize scanning, and to be slidable in the rotation axis direction in order to adjust the internal pressure. A complicated mechanism is required to achieve both a rotational motion and a sliding motion.
[0009]
Accordingly, an object of the present invention is to provide an ultrasonic probe capable of realizing pressure adjustment in a medium chamber with a relatively simple mechanism and suppressing generation of bubbles in an acoustic coupling medium.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, a first ultrasonic probe according to the present invention includes an ultrasonic element that transmits and receives ultrasonic waves, a medium chamber that houses the ultrasonic element, and an acoustic that is filled in the medium chamber. An ultrasonic probe comprising a coupling medium, and further a reservoir filled with the acoustic coupling medium and connected to the medium chamber so that the acoustic coupling medium can flow between the medium chamber and the reservoir wherein the reservoir, have a concave in the initial state, the concave is deformed convex, the volume of the reservoir is increased by the deformation by bending force due to filling of the acoustic coupling medium and said by the deformation An elastic container having a shape in which a bending stress is generated as a restoring force to an initial state, and the acoustic coupling medium is filled in the reservoir in a state in which the restoring force is generated .
[0011]
In order to achieve the above object, a second ultrasonic probe according to the present invention includes an ultrasonic element that transmits and receives ultrasonic waves, a medium chamber that houses the ultrasonic element, and an acoustic that is filled in the medium chamber. An ultrasonic probe comprising a coupling medium, and further a reservoir filled with the acoustic coupling medium and connected to the medium chamber so that the acoustic coupling medium can flow between the medium chamber and the reservoir And pressurizing means for pressurizing the reservoir.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
In the first ultrasonic probe, a reservoir having a concave shape is used as a reservoir in a state of being deformed into a convex shape by filling with an acoustic coupling medium. In such a reservoir, a restoring force that causes the convex surface to return to the concave surface acts, so that when the acoustic coupling medium contracts, the acoustic coupling medium is replenished from the reservoir to reduce the internal pressure change of the acoustic coupling medium. it can. Further, when the acoustic coupling medium expands with a temperature change or the like, the expansion can be absorbed. Thus, according to the ultrasonic probe as described above, the pressure adjustment in the medium chamber can be realized by a relatively simple mechanism, and the generation of bubbles in the acoustic coupling medium can be suppressed.
[0013]
In the second ultrasonic probe, since the reservoir is pressurized by the pressurizing means, when the acoustic coupling medium contracts, the acoustic coupling medium is replenished from the reservoir, and the pressure change in the medium chamber is changed. Can be small. Further, when the acoustic coupling medium expands with a temperature change or the like, the expansion can be absorbed. As described above, the pressure adjustment in the medium chamber can be realized by a relatively simple mechanism, and the generation of bubbles in the acoustic coupling medium can be suppressed.
[0014]
In the second ultrasonic probe, it is preferable that the pressurizing means pressurizes by the action of a spring. Furthermore, it is preferable to use a constant load spring.
[0015]
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0016]
(First embodiment)
FIG. 1 is a cross-sectional view showing an example of the structure of an ultrasonic probe according to the first embodiment of the present invention. In this ultrasonic probe, a medium chamber is formed by joining the frame 2 and the window 1, and the medium chamber is filled with a degassed acoustic coupling medium 5. An ultrasonic element unit is accommodated in the medium chamber. In the ultrasonic element section, the ultrasonic transducer 3 is attached to the rotor 4. A rotational force transmission mechanism 7 is connected to the rotor 4, and the rotational force transmission mechanism 7 has a drive device (for example, a motor, not shown) for generating rotational force via a shaft 8. It is connected. Thereby, the rotational force output from the drive device can be transmitted to the shaft 8 and transmitted to the rotor 4 via the rotational force transmission mechanism 7 to rotate the ultrasonic transducer 3.
[0017]
Further, in the ultrasonic probe, a reservoir 6 is provided outside the medium chamber. The reservoir 6 is also filled with the acoustic coupling medium 5. The reservoir 6 is provided so as to communicate with the medium chamber through a through hole provided in the frame 2. Thereby, the acoustic coupling medium 5 is configured to be able to flow between the reservoir 6 and the medium chamber.
[0018]
In the present embodiment, as shown in FIG. 2 (A), the reservoir 6 uses a container whose initial shape (the shape when the acoustic coupling medium is not filled therein) is a shape having a concave surface. Composed. When the container is filled with the acoustic coupling medium, the concave surface of the container is greatly involved in a bending force in each minute range of the surface of the container, and is deformed into a convex surface as shown in FIG. That is, in a state where it is used as a reservoir, the container has a shape having a convex surface. In such a reservoir, a bending stress is generated because the concave shape which is the initial state is a convex shape, and this force tends to return to the initial shape with respect to the container (that is, the convex surface of the container is It works as a restoring force to return to the concave surface. The material of the container used for the reservoir is not particularly limited as long as the restoring force as described above works. For example, an elastic body such as a resin material such as rubber, polyethylene, or polypropylene, or a metal material having a thickness that can be easily deformed can be used.
[0019]
Next, an example of an ultrasonic diagnostic apparatus using the ultrasonic probe will be described. This ultrasonic diagnostic apparatus includes an ultrasonic probe and an apparatus main body as main components. The ultrasonic probe is an ultrasonic probe according to the present embodiment as described above. The apparatus main body includes a control unit that drives the probe, a transmission / reception unit that transmits and receives signals to the probe, an image configuration unit that creates an image of the test object based on the received signal, and a creation And an image display unit for displaying the tomographic image.
[0020]
The operation of the ultrasonic diagnostic apparatus will be described below. First, an ultrasonic probe is arranged in the vicinity of the test object. Then, the drive device connected to the rotor is driven by the drive signal from the control unit of the ultrasonic diagnostic apparatus to rotate the rotor. Next, an electric signal (transmission signal) is transmitted to the ultrasonic probe from the transmission / reception unit of the ultrasonic diagnostic apparatus. The transmission signal is converted into ultrasonic waves by the ultrasonic transducer of the probe, propagates through the acoustic coupling medium, and is transmitted from the window to the test object. This ultrasonic wave is reflected by the test object, and a part of the reflected wave is received by the ultrasonic transducer, converted into an electric signal (received signal), and transmitted to the transmission / reception unit of the ultrasonic diagnostic apparatus. By repeating this transmission / reception operation while rotating the rotor, ultrasonic scanning becomes possible. The received signal is subjected to processing such as amplification and detection, and then output to the image construction unit. The image construction unit creates an ultrasonic image (such as a tomographic image) of the test object based on the received signal, and outputs this to the image display unit.
[0021]
At this time, if bubbles are present in the acoustic coupling medium filled in the medium chamber of the ultrasonic probe, this becomes an ultrasonic reflector, so that the obtained ultrasonic image may be deteriorated. However, according to the ultrasonic probe of the present embodiment, since generation of such bubbles can be suppressed, a good ultrasonic image can be obtained. The reason will be described below.
[0022]
As described above, a restoring force acts on the reservoir so that the container returns to the initial shape (that is, the convex surface of the container returns to the concave surface). By this restoring force, the hydraulic pressure of the acoustic coupling medium can be increased, and the internal pressure of the medium chamber can be maintained at a pressure higher than the normal pressure. Thereby, while suppressing generation | occurrence | production of the bubble in an acoustic coupling medium, even if it is a case where a bubble generate | occur | produces, the magnitude | size can be suppressed small. Further, even when the acoustic coupling medium contracts due to a temperature change or the like and the internal pressure of the medium chamber decreases, it is possible to increase the internal pressure of the medium chamber by increasing the hydraulic pressure of the acoustic coupling medium by the restoring force.
[0023]
In addition, when the acoustic coupling medium expands due to an influence of a temperature change or the like, there is a possibility that the sealing performance of the medium chamber deteriorates due to an excessive increase in internal pressure, and bubbles are mixed. However, in the probe according to the present embodiment, since the reservoir absorbs the expansion of the acoustic coupling medium, it is possible to maintain a suitable medium chamber pressure, and thus it is possible to suppress such bubble contamination. .
[0024]
In FIG. 7, the ultrasonic probe according to the present embodiment is manufactured as Example 1, and the acoustic coupling medium is intentionally expanded by additionally injecting the acoustic coupling medium into the reservoir. The results of evaluating the change in the internal pressure of the medium chamber are shown below. This result exemplifies a case where an ultrasonic probe having the same structure as that shown in FIG. 1 is manufactured and evaluated using rubber having a rubber hardness of 50 and a thickness of 1 mm as a reservoir material. In addition, FIG. 7 also shows the result of producing an ultrasonic probe as shown in FIG. 8 and performing the same evaluation as a comparative example. In the probe according to this comparative example, as shown in FIG. 9A, a reservoir having no concave surface in its initial shape is used as a reservoir. As shown in FIG. 9B, the container expands due to the material itself being stretched by being filled with the acoustic coupling medium. The reservoir has the same structure as that shown in FIG. 1 except that the reservoir has a different shape.
[0025]
As shown in FIG. 7, in the comparative example, the internal pressure of the medium chamber rapidly increases as the amount of additional liquid increases. On the other hand, in Example 1, the internal pressure change accompanying the increase in the amount of additional liquid is small. As described above, when the internal pressure of the medium chamber is adjusted only by using the elongation of the reservoir material, it is difficult to sufficiently suppress the change in the internal pressure of the medium chamber. However, according to the present embodiment, not only the expansion of the reservoir material but also the internal pressure of the medium chamber is adjusted using the restoring force accompanying the deformation, and therefore, the change in the internal pressure of the medium chamber can be sufficiently suppressed.
[0026]
The reason why the above effect can be obtained will be described below. In a reservoir using an elastic container, the force required to be deformed by the elongation of the entire material is relatively large. Therefore, as in the comparative example, if the reservoir volume is adjusted only by the elongation of the material, the amount of change in the internal pressure increases. In contrast, the force required to deform the reservoir surface by a bending force or the like is small. Therefore, if the volume of the reservoir is adjusted by the amount of deformation, the amount of change in the internal pressure becomes small. In this embodiment, most of the restoring force acting on the reservoir (the force that the convex surface tries to return to the concave surface) is the force that attempts to deform the reservoir by bending in each minute range of the container surface. That is, in the present embodiment, the internal pressure is adjusted by adjusting the volume of the reservoir by using the bending force. Therefore, the amount of change in internal pressure can be reduced.
[0027]
Moreover, according to this embodiment, since the above effects can be realized only by forming the reservoir shape into a concave shape, the convenience is high in terms of component cost and assemblability.
[0028]
(Second Embodiment)
FIG. 3A is a cross-sectional view showing an example of an ultrasonic probe according to the second embodiment of the present invention. In this ultrasonic probe, as in the first embodiment, the ultrasonic element unit including the ultrasonic transducer 3 and the rotor 4 is housed in the medium chamber constituted by the frame 2 and the window 1. The acoustic coupling medium 5 is filled. Further, a reservoir 6 is provided so as to communicate with the medium chamber, and the acoustic coupling medium 5 is also filled in the reservoir 6.
[0029]
In the present embodiment, the shape of the reservoir 6 is not limited at all. Further, the material is not particularly limited as long as it does not transmit liquid and can be deformed by pressurization of a clamping member described later. For example, in addition to the elastic body exemplified in the first embodiment, it is also possible to use a material having no elasticity such as a vinyl bag.
[0030]
Furthermore, in this embodiment, a clamping member that clamps the reservoir 6 is provided. This clamping member is configured to apply pressure to the reservoir by the action of a spring. In addition, it does not specifically limit as a spring used for a clamping member, Various springs, such as a coil spring and a leaf | plate spring, can be used.
[0031]
As an example of the holding member, as shown in FIG. 3B, a fixed member 9a fixed to the frame 2 and a non-fixed movable member 9b are arranged so as to face each other via the reservoir 6. The structure which provided the tension spring 10 between both can be mentioned. Moreover, it may replace with a tension spring and you may arrange | position a compression spring in contact with the surface on the opposite side to the fixed member side of a movable member. Further, as shown in FIG. 4, one end of the tension spring 10 may be attached to the frame 2, the other end may be attached to the movable member 9 b, and the reservoir 6 may be sandwiched between the frame 2 and the movable member 9.
[0032]
Further, the clamping member may use a constant load spring. FIG. 5 is a view showing an example of an ultrasonic probe provided with a holding member using a constant load spring, and FIG. 6 is a view showing an example of such a holding member. The clamping member includes a fixing member 9 a fixed to the frame 2, a belt 11, and a constant load spring 12. As the constant load spring 12, a wound thin plate spring can be used, one end of which is connected to the belt 11 and the other end is connected to the fixing member 9a. Further, as described above, the belt 11 has one end connected to the constant load spring 12 and the other end connected to the fixing member 9a. That is, one loop is formed by the fixing member 9 a, the belt 11, and the constant load spring 12. By disposing the reservoir 6 in the loop, a constant load can be applied to the reservoir 6. In the figure, reference numeral 13 denotes a screw for fixing the belt 11 to the fixing member 9a.
[0033]
The ultrasonic probe has the same configuration as that of the first embodiment except that the configuration of the reservoir is different and that a clamping member is provided.
[0034]
The ultrasonic diagnostic apparatus using the ultrasonic probe and the operation thereof are also substantially the same as those in the first embodiment.
[0035]
According to the ultrasonic probe of the present embodiment, as described above, pressure is applied to the reservoir by the action of the spring of the clamping member, and the reservoir is deformed by this pressure to reduce its volume. be able to. Therefore, the hydraulic pressure of the acoustic coupling medium can be increased and the internal pressure of the medium chamber can be maintained at a pressure higher than the normal pressure. Therefore, as in the first embodiment, the generation of bubbles in the acoustic coupling medium can be suppressed and the size thereof can be suppressed small. Similarly to the first embodiment, even when the acoustic coupling medium contracts due to the influence of a temperature change or the like and the pressure in the medium chamber decreases, the acoustic coupling medium is replenished to the medium chamber and the internal pressure is reduced. Can be raised.
[0036]
Similarly to the first embodiment, even when the acoustic coupling medium expands due to the influence of a temperature change or the like, the reservoir absorbs the expansion, so that a suitable medium chamber pressure is maintained, and externally Of air bubbles can be suppressed.
[0037]
In particular, when a constant load spring is used for the clamping member, the pressure change in the medium chamber can be further reduced, and the generation of bubbles in the medium chamber can be further suppressed. In FIG. 7, as Example 2, an ultrasonic probe according to the present embodiment using a constant load spring was produced. On the other hand, an expanded state of the acoustic coupling medium was intentionally created, The result of having evaluated the internal pressure change is shown. This result exemplifies a case where an ultrasonic probe having the same structure as that shown in FIG. 5 is manufactured and evaluated. In this embodiment, the change in internal pressure accompanying the increase in the amount of additional liquid is extremely small. In this way, when pressure is applied to the reservoir by the action of the constant load spring, the pressure change in the medium chamber can be further reduced.
[0038]
【The invention's effect】
As described above, in the first ultrasonic probe of the present invention, as a reservoir, an elastic container having a concave surface is used in a state where the concave surface is deformed into a convex surface by filling the acoustic coupling medium. Thus, the pressure adjustment in the medium chamber can be realized by a relatively simple mechanism, and the generation of bubbles in the acoustic coupling medium can be suppressed.
[0039]
Further, in the second ultrasonic probe of the present invention, pressure is applied to the reservoir by the pressurizing means, so that the pressure in the medium chamber is adjusted with a relatively simple mechanism, and the bubbles in the acoustic coupling medium are realized. Can be suppressed.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an example of an ultrasonic probe according to a first embodiment.
2A and 2B are cross-sectional views showing an example of a reservoir constituting the ultrasonic probe, where FIG. 2A shows a state before the acoustic coupling medium is filled, and FIG. 2B shows a state where the acoustic coupling medium is filled. Indicates the state.
FIG. 3A is a cross-sectional view showing an example of an ultrasonic probe according to a second embodiment, and FIG. 3B is an example of a reservoir and a holding member that constitute the ultrasonic probe. It is sectional drawing shown.
FIG. 4 is a cross-sectional view showing another example of an ultrasonic probe according to the second embodiment.
FIG. 5 is a cross-sectional view showing still another example of an ultrasonic probe according to the second embodiment.
FIG. 6 is a cross-sectional view showing an example of a reservoir constituting the ultrasonic probe.
FIG. 7 is a graph showing the results of evaluating the change in the internal pressure of the medium chamber accompanying the expansion of the acoustic coupling medium for the ultrasonic probes according to Examples and Comparative Examples.
FIG. 8 is a cross-sectional view showing the structure of an ultrasonic probe according to a comparative example.
FIGS. 9A and 9B are cross-sectional views showing an example of a reservoir constituting the ultrasonic probe, where FIG. 9A shows a state before the acoustic coupling medium is filled, and FIG. 9B shows a state where the acoustic coupling medium is filled. Indicates the state.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Window 2 Frame 3 Ultrasonic vibrator 4 Rotor 5 Acoustic coupling medium 6 Reservoir 7 Rotational force transmission mechanism 8 Shaft 9a Fixed member 9b Movable member 10 Tension spring 11 Belt 12 Constant load spring 13 Screw

Claims (1)

An ultrasonic probe comprising: an ultrasonic element that transmits and receives ultrasonic waves; a medium chamber that houses the ultrasonic element; and an acoustic coupling medium filled in the medium chamber,
And a reservoir that is filled with the acoustic coupling medium and connected to the medium chamber so that the acoustic coupling medium can flow between the medium chamber and the medium.
The reservoir, have a concave in the initial state, the said concave surface is deformed convexly by bending force due to the filling of the acoustic coupling medium, the volume of the reservoir is increased by the deformation, and, to the initial state by the deformation It is an elastic container with a shape that generates bending stress as the restoring force of
An ultrasonic probe , wherein the acoustic coupling medium is filled in a state where the restoring force is generated in the reservoir .

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