JPH0355132B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an ultrasonic probe that uses a shape memory alloy to easily change the direction of transmitting and receiving ultrasonic waves.

[Technical background of the invention and its problems] In recent years, by inserting an insertion section into a body cavity,
In addition to endoscopes that can optically observe the inside of body cavities or perform therapeutic procedures using forceps, ultrasound diagnostic devices that send and receive ultrasound to provide acoustic information inside body cavities are used for diagnosis. be. This ultrasonic diagnostic device emits ultrasonic pulses from the body surface to a target object, and when the emitted ultrasonic waves propagate, the acoustic impedance, which is expressed as the product of the density of the medium and the speed of sound, increases. Since it is reflected at a discontinuous boundary surface, the reflected ultrasonic pulse wave is received and acoustic information such as its reflection intensity is used for diagnosis.

Compared to X-ray devices, such ultrasonic diagnostic equipment has the following advantages: it can easily obtain information about living soft tissue without using pre-shaped materials, it does not destroy living tissue with radiation, it is easy to handle, and it is not dangerous. It has many advantages such as the fact that it is small in size, and furthermore, as technology related to ultrasound has advanced in recent years, the quality and quantity of information obtained has improved, so it is becoming popular as a powerful clinical diagnostic device in the medical field.

In contrast to the above-mentioned diagnosis that transmits and receives ultrasound pulses from the body surface, the intrabody cavity ultrasound diagnostic method that transmits and receives ultrasound pulses from a position close to the living organ within the body cavity has a (relatively) large amount of attenuation as it propagates. It is possible to transmit and receive high frequency ultrasonic waves, thus obtaining information with high resolution and precision, and it is not affected by the subcutaneous fat layer interposed between the objects, etc. Since it has many advantages, it is likely to be used more and more in the future. This intracorporeal ultrasound diagnostic device, which is inserted into a body cavity, is used either as an integrated unit with an endoscope as a means for optical observation, or with a removable endoscope (optical viewing tube) attached. It is also called an ultrasound endoscope.

FIG. 1 schematically shows the tip of the conventional ultrasonic endoscope. In the figure, on the side of the distal end of the insertion section 1 covered with a flexible bellows, an illumination window 2 and a specimen 3 illuminated with illumination light emitted from the illumination window 2 can be observed. Observation windows 4 are arranged in parallel. A triangular prism, an objective lens, etc. are disposed inside the observation window 4 (not shown), and an image transmission means such as an image guide inserted through the insertion section 1 transmits the image formed by the objective lens. It is now possible to observe from the hand side through the .

A balloon holding frame 5 is attached to the distal end of the insertion section 1.
A bag-shaped balloon 6 made of a material such as silicone rubber that is highly elastic and highly transparent to ultrasonic waves is held therein.

An ultrasonic transducer for transmitting and receiving ultrasonic waves in a predetermined direction is disposed inside the balloon 6, and the surrounding area is made of ultrasonic material such as oil having a value matching the acoustic impedance of the human body as the subject 3. It is filled with a sound wave transmission medium.

When forming an ultrasonic end contact that transmits and receives an ultrasonic beam (indicated by code A) to the subject 3 to which the balloon 6 is abutted using the ultrasonic transducer, the ultrasonic beam is transmitted from the abutted area. A sector scanning method is widely used that can obtain a fan-shaped ultrasonic tomographic image by emitting radial ultrasonic beams and receiving echo signals of the radially emitted ultrasonic beams.

As a means for scanning this sector, there is a conventional example shown in FIG.

That is, an ultrasonic transducer 9 within a rigid housing 8
A bearing 10 whose outer periphery is fixed to the housing 8
The balloon 6 filled with the transmission medium 12 without air bubbles is attached to the tip of the shaft 11 which is rotatably supported by the shaft 11 with the balloon 6 in contact with the subject.
An ultrasonic probe that transmits and receives ultrasonic beams radially in a direction perpendicular to this surface 9A from an ultrasonic transmitting/receiving surface 9A of an ultrasonic transducer 9 that is both rotationally driven. A child is formed.

Incidentally, signals are now transmitted and received through a lead wire 13 that is inserted through the hollow tip of the shaft 11 and through a brush or the like that comes into contact with the shaft 11 in the middle of the shaft 11. There is.

In this case, the scanning direction (scanning plane) of the ultrasonic waves transmitted and received radially is a fan-shaped one including the symbol B, and is constant, so the obtained ultrasonic image is also limited unless the position and direction of the bellows are changed. It becomes something.

In other words, in order to obtain information in other scanning directions, the position of the bellows must be changed using the bending operation mechanism on the hand side.

Another means for scanning the sector is shown in FIG. In this conventional example, an ultrasonic transducer 9 is fixed inside the tip of a housing 8, and the ultrasonic transducer 9 has a reflecting surface 15A of 45 degrees at a position opposite to an ultrasonic transmitting/receiving surface 9A, and is rotatably driven. The mirror 15 (for ultrasonic wave reflection) attached to the tip of the shaft 11 is rotated.

In this conventional example, the ultrasonic beam transmitted from the transmitting/receiving surface 9A of the ultrasonic transducer 9 in a direction perpendicular to the surface 9A is reflected in the direction perpendicular to the reflecting surface 15A of the mirror 15, as shown by the broken line. Since the mirror 15 is rotationally driven, the ultrasonic beam is transmitted radially as in FIG. 2.

Even in this conventional example, unless the orientation of the bellows is changed, the ultrasound images that can be obtained are limited. In addition, there is a conventional electronic scanning method in which a large number of ultrasonic transducers are arranged in an array to scan electronically, but similar to the mechanical scanning method described above, when the bellows is fixed, will result in a single ultrasound image, and multiple ultrasound images cannot be obtained.

In the conventional mechanical scanning type ultrasonic probe described above, it is structurally difficult to provide a means for moving the ultrasonic transducer in addition to a means for rotationally driving the ultrasonic transducer. Furthermore, even in the conventional electronic scanning method, it has been difficult to construct an appropriate means for moving the ultrasonic transducer within the narrow space of the distal end of the endoscope.

Therefore, it has not been possible to obtain ultrasonic images in multiple directions while the device is in contact with a subject, making it impossible to further increase its value as diagnostic material.

In other words, when the bellows is moved, the state of contact with the object tends to change, which is inconvenient when it is desired to compare and examine ultrasound images taken in different directions under the same conditions.

Further, it is troublesome to properly operate the bellows in order to obtain ultrasound images in different directions.

[Object of the Invention] The present invention has been made in view of the above-mentioned points, and provides an ultrasonic wave that can easily and variably control ultrasonic waves in different directions from the outside without forming a means for mechanically moving the bellows. The purpose is to provide a sonic probe.

[Summary of the Invention] The present invention fixes an ultrasonic transducer via a shape memory alloy whose external shape changes above and below a transition temperature, and includes means for heating and cooling the shape memory alloy. By configuring the ultrasonic probe in two directions, it is possible to easily transmit and receive ultrasonic waves in different directions.

[Embodiments of the Invention] The present invention will be specifically described below with reference to the drawings.

FIG. 4 shows a first embodiment of the invention.

In the figure, a housing 22 that accommodates a function of transmitting and receiving ultrasonic waves is configured further toward the distal end of an endoscope section (not shown) on the distal end side of the insertion section 21.

A rigid frame 23 forming this housing 22
has a cylindrical shape with one end, which is the distal end, closed, and most of the side circumference of the cylinder is cut out, and this notch is molded using silicone rubber etc. that transmits ultrasonic waves. It is closed with a balloon 24.

Inside the frame 23, an array-type ultrasonic transducer 25 is housed, which is formed by arranging minute piezoelectric elements adjacent to each other in order and arranging divers on the back side of these elements. In other words, it is rotatably held via disks 26 and 27 attached to each end face on the front end side and the rear end side (base side). In other words, the contact portions 23A, 23B in contact with the disks 26, 27 in the frame 23, and the contact portions 23A, 23
The outer peripheries of the disks 26 and 27 that come into contact with B are coated with Teflon, for example, so that they can rotate with little friction.

Between the center of the circular upper surface of the disk 26 and the inner surface of the tip of the frame 23 facing the center, there is a shape memory alloy (metal) 28 which becomes plate-like in the low temperature phase.
The shape memory alloy 28 holds the ultrasonic transducer 25 so that it does not rotate. Moreover, heaters 29 are fixed to one end of each of the plate-shaped shape memory alloys 28 (they may be provided around the periphery) as heating means.
29 (a single heater may also be used) is the frame 2
3 is accommodated between the inner surface of the tip and the disk 26.

On the other hand, a lead wire (bundle) 31 covered with a flexible member is attached to the center of the rear end surface of the disk 27 on the base side, and the lead wire 31 is connected to an external signal processing circuit via the insertion portion 21. By applying a high-frequency pulse to each piezoelectric element in the array-type ultrasonic transducer 25 via a delay element, the ultrasonic beam is sectored in the range indicated by C in FIG. 4 (in the case of high temperature phase). It is designed to be able to scan and receive echo signals of the sector-scanned ultrasonic beam.

If necessary, a focusing lens 32 is attached to the ultrasonic transmitting/receiving surface of the array type ultrasonic transducer 25 so that the ultrasonic beam can be focused for transmission and reception.

An insertion portion 2 is provided on the base side of the rear end of the frame 23.
An injection port 33 is formed by providing a through hole in the axial direction of the balloon 24, and an ultrasonic wave material such as liquid paraffin that has a small loss component for ultrasonic transmission from the injection port 33 into the balloon 24 and matches the acoustic impedance of the human body. A transmission medium 34 can be supplied.
Further, an outlet 35 is formed in the frame body 23 at a portion facing, for example, the injection hole 33 with the array-type ultrasonic transducer 25 sandwiched therebetween. medium 3
I'm getting better at ejecting 4.

Furthermore, a communication hole 36 communicating with the cavity in which the heaters 29 are accommodated is formed in a portion of the frame 23 around the portion holding the disk 26, facing forward from the portion where the injection port 33 is provided. At the same time, a communication hole 37 is also formed in the front part facing the discharge port 35, and when the transmission medium 34 injected from the injection port 33 fills the balloon 24 to inflate it, the communication hole 37 and 3
7 and fills around the heaters 29, 29 and the plate-shaped shape memory alloy 28.

When the balloon 24 is filled with the transmission medium 34 and electric power is supplied to the heaters 29 through lead wires (not shown), the heater 2
9 and 29 is substantially sealed except for the communication holes 36 and 37, the temperature of the transmission medium 34 filling that part rises rapidly, and at the same time the temperature of the plate-shaped shape memory alloy 28 rises. It also increases the temperature.

The crystal structure of the plate-shaped shape memory alloy 28 changes significantly between its high-temperature phase and low-temperature phase with the transition temperature as the boundary, and in this first embodiment, the normal temperature becomes the martensitic phase on the low temperature side. ,
At this temperature, the state in which the outer shape becomes a flat plate is the stable phase, and the outer shape is maintained. However, heater 2
9, 29 becomes a high temperature phase as shown in FIG. 4, the flat plate is twisted as shown in FIG.
(Contrary to the above, the shape memory alloy 28 may be configured to have a twisted outer shape in the low temperature phase and a flat plate shape in the high temperature phase.) After transferring to the high-temperature phase side, the transmission medium 34 inside the balloon 24 is refluxed by injecting the transmission medium 34 from the injection port 33, sucking it from the proximal side, and discharging the transmission medium 34 from the discharge port 35. When the shape memory alloy 28 is heated, the transmission medium 34 around the shape memory alloy 28 passes through the communication hole 37 and is discharged from the discharge port 35, and the transmission medium 34 injected from the injection port 33 passes through the communication hole 36 and changes the shape. memory alloy 28
Since the shape memory alloy 28 is rapidly cooled, the shape memory alloy 28 is configured to be rapidly cooled and transition to the low temperature phase side.

In this way, in the first embodiment, the array type ultrasonic transducer 25 is fixed via the shape memory alloy 28, and the shape memory alloy 28 is heated (warmed) to quickly transition to the high temperature phase side. It is characterized in that it serves both as a means for supplying and discharging the transmission medium 34 to form a cooling means for refluxing the medium 34 and rapidly transferring it to the low temperature phase side.

According to the ultrasonic probe of the first embodiment configured in this way, when the insertion portion 21 is inserted into a body cavity or the like,
The distal end of the insertion section 21 is guided around the target region of the subject 38 while observing with the endoscope section. Inlet 33
The balloon 24 is inflated by injecting the transmission medium 34, and the front side of the focusing lens 32 and its side periphery are brought into close contact with the surface of the subject 38. In this state, the array type ultrasonic transducer is passed through the delay element. By applying a high frequency pulse to the balloon 25, an ultrasonic beam is transmitted inside the subject 38 through the abutting balloon 24. The transmitted ultrasound beam is reflected at the discontinuous boundary surface of the acoustic impedance of the abnormal region 39 and becomes an echo signal, a part of which is received by the array type ultrasound transducer 25. A fan-shaped ultrasonic tomographic image is displayed on a display unit such as a cathode ray tube by sequentially transmitting and receiving an ultrasonic beam through a delay element in a connection state different from the above. be able to.

Next, if you want an image in a different direction from the ultrasonic tomographic image described above, operate an external switch etc. to turn the heater 2
When power is supplied to 9 and 29, the shape memory alloy 28
is heated and becomes a twisted state as shown in FIG. The situation will be as shown. Therefore, the ultrasonic tomographic image obtained in this state has an orientation in which ultrasonic waves are transmitted and received in the range indicated by the symbol C, which is different from the above-mentioned one, and in this case, the fan-shaped plane where the waves are transmitted and received is This is within the plane of the paper in FIG. 4 (before rotation, it is within the plane in the scanning direction from the center of the array type ultrasonic transducer 25 to the front side perpendicular to the plane of the paper).

If you want to see the image in the state before rotation again, discharge the transmission medium 34 from the discharge port 35, and
By injecting from the injection port 33 and refluxing the transmission medium 34, the shape memory alloy 28 can be quickly cooled and returned to the low temperature phase side where the outer shape is flat. At the same time, the array type ultrasonic transducer 25 is rotated in the direction opposite to the arrow D and returned to its original state.

FIG. 5 shows a second embodiment of the present invention, in which FIG. 5a shows the structure at room temperature, and FIG. 5b shows the structure when heated and transferred to the high temperature side.

In this second embodiment, an array type ultrasonic transducer 4 housed in a frame 41 forming a housing.
Both end faces in the direction in which each piezoelectric element is arranged in 2,
In other words, one end of each of the shape memory alloys 43 and 44, which can be expanded and contracted depending on the temperature, is fixed to the front end face and the rear end face, respectively, so that the folded shape of the plate becomes a stable shape in the low temperature phase, and the shape memory alloys 43 and 44 can be expanded and contracted depending on the temperature so that they elongate in the high temperature phase. The respective ends of the memory alloys 43 and 44 are fixed to the inner surface of the front end and the inner surface of the rear end (base side) of the frame 41.

The array type ultrasonic transducer 42 has an ultrasonic transmitting/receiving surface 42A interposed with a lens 32 as necessary.
and the back surface of the damping member formed on the back surface of the sending/receiving surface 42, as shown by arrow E, so as to be rotatable around a rotating shaft (rotating shaft) 45. The direction perpendicular to this transmitting/receiving surface 42A (indicated by reference numeral 46) is the central axis from which the ultrasonic beam is radiated.

Thus, each shape memory alloy 4 fixed to the tip and rear end surfaces of the array type ultrasonic transducer 42
For example, as shown in FIG. The shape memory alloys 43 and 44 are heated by a heater (not shown) and transformed into a high temperature phase,
When stretched into a planar shape (or similar shape), corner forces as shown in FIG.

Other than this, the structure is substantially the same as that of the first embodiment, and the same elements are designated by the same reference numerals, and some of them are omitted. In this second embodiment, as in the first embodiment, by heating with a heater, the shape memory alloys 43 and 44 are deformed as shown in FIGS. The array type ultrasonic transducer 42 rotates. Also, transmission medium 3
By refluxing 4, the shape memory alloys 43 and 44 deformed as shown in FIG.
It can be restored as shown in . According to the second embodiment, when the array-type ultrasonic transducer 42 has the same shape as the first embodiment (in FIGS. 4 and 5, the direction in which the ultrasonic beam is transmitted is (Omitted) The left and right sides are reversed.) In the first embodiment, the fan-shaped surface is to be moved in the direction perpendicular to the surface, but in this second embodiment, the surfaces are the same. (that is, corresponds to the plane of the paper in FIG. 5), the sector is rotated within the plane of the paper.

FIG. 6 shows a third embodiment of the present invention, and FIG.
shows the structure on the high-temperature phase side, and b
shows the structure on the low temperature phase side.

This third embodiment has substantially the same structure as the first embodiment described above.

In other words, in the first embodiment, the array type ultrasonic transducer 25 is structured to rotate in a fitted state (via the disks 26 and 27).
In this third embodiment, the disk 26,
27 is not provided, shape memory alloys 51 and 52 are fixed between the inner surface of the frame body 23 facing not only the front end surface but also the rear end surface of the array type ultrasonic transducer 25, respectively, and heating. As a result, the array type ultrasonic transducer 25 is twisted as shown in FIG. 6B to FIG. It goes without saying that the state shown in FIG. 6A returns to that shown in FIG. 6B after cooling.

Other than this, the second embodiment is almost the same as the first embodiment, and the same elements are given the same reference numerals and some of them are omitted.

Note that the central direction (central axis) in the direction in which the ultrasonic beam is transmitted and received is indicated by reference numeral 53.

FIG. 7 shows a fourth embodiment of the present invention.

This fourth embodiment has a structure in which the heater (not shown) in the second embodiment shown in FIG. 5 is not provided.

In this case, the means for warming the shape memory alloys 43 and 44 is carried out by supplying a pre-warmed transmission medium 34 from the inlet 33 (or the outlet 35) as shown by arrow F. Cooling can be performed by circulating the cooled transmission medium 34 in the same manner as described above.

FIG. 8 shows a fifth embodiment of the invention.

In the fifth embodiment, the heating means in the fourth embodiment is formed using a positive temperature coefficient thermistor 61, such as a PCT thermistor.

This positive temperature coefficient thermistor 61 is coated with an insulating material 62, and the shape memory alloy 43 is heated by applying a constant voltage or the like, and the shape memory alloy 43 is heated via the heated transmission medium 34 or the shape memory alloy 43 on the base side is heated.
Positive characteristic thermistor (not shown) installed close to 4
The shape memory alloy 44 can be heated at Cooling is performed in the same manner as in the fourth embodiment.

FIG. 9 shows a sixth embodiment of the invention.

In this sixth embodiment, an ultrasonic probe is formed using a polymer film such as PVDF.

This ultrasonic probe 63 has a flexible polymer piezoelectric array 64 molded to a thickness that is 1/4 of the wavelength λ of the ultrasonic wave used, and a flexible printed circuit board 65 is connected to the back side of the plate-shaped ultrasonic probe 63. Abbreviation L
It is bonded to a shape memory alloy 66 that is bent into a letter shape.

The polymer piezoelectric material is flexible, has an acoustic impedance close to that of the human body, and does not require an acoustic matching layer.
By setting the thickness of the piezoelectric film to λ/4, broadband characteristics can be obtained.
The shape memory alloy 66 has an angle that is, for example, a right angle or an acute angle (an obtuse angle may also be used) on the side opposite to the ultrasonic wave transmitting/receiving surface.
Only this bent portion (nearby) 66A is processed to have a shape memory effect. The center of the transmitting and receiving surface is shaped to be a concave surface along the arrangement direction of the polymer piezoelectric array 64, so that the beam can be transmitted and received in a convergent manner.

The heating element 67, such as the heater 29 or the positive temperature coefficient thermistor 61, is attached to the inside of the side adjacent to the bent portion 66A.
By supplying power to the heating element 67 via the lead wires 68 and 69, the shape memory alloy 66
It is now possible to heat the

Further, at the end of the shape memory alloy 66 opposite to the side part, when the bent part 66A is deformed by heating from the state shown in FIG. Holder 7
This holder 71, to which one end of 1 is fixed,
For example, by molding a silicone rubber plate into a folded structure as shown in the figure, it is made to have sufficient elasticity.

Each piezoelectric element forming the polymer piezoelectric array 64 has a grounding lead wire 73 attached to a line-shaped grounding electrode 72 that has a common end, and each of the other electrodes is attached to a printed circuit board 65 on the back side. It is designed to be conductive.

Incidentally, reference numeral 74 designates the ultrasonic probe 63 having the above-described configuration.
It is a base with

High-frequency electrical pulses are applied to the ground electrode 72 of the ultrasonic probe 63 configured as described above and the other electrode of each element constituting the polymer piezoelectric array 64 so that the ultrasonic beam scans linearly or sectorally. By applying the voltage, the ultrasonic beam is scanned in a direction approximately perpendicular to the concave surface of the shape memory alloy 66 in a state where the curvature of the concave surface creates a sound field pattern with the best resolution near the focal point. Become.

Therefore, the obtained image is a tomographic image in a direction perpendicular to the concave surface that serves as the ultrasonic wave transmitting and receiving surface.

If the ultrasound probe 63 having the above structure is used in an ultrasound endoscope, one image can be obtained at room temperature, and when an image in a different direction is desired, heat is generated via the lead wires 68 and 69. By supplying electric power to the element 67, the bending angle of the bent portion 66A of the shape memory alloy 66 can be changed to obtain a tomographic image in a different orientation from the above.

FIG. 10 shows a seventh embodiment of the invention.

In this seventh embodiment, an ultrasonic transducer made of, for example, PZT ceramic instead of the flexible polymer piezoelectric array 64 in the sixth embodiment is used, and the bending angle of the bending portion is variable as in the sixth embodiment. It has been made possible.

That is, the open end of the bag-shaped balloon 81 is fixed to the outer periphery of the rigid base 80 on the distal end side of the insertion portion 21 .

A flat shape memory alloy 82 is bent rearward into an L-shape at a bent portion 82A near the end, and the bent rear end portion is fixed to the end surface of the base 80. A heating element 83 is attached to the inner surface of this bent side part as in the sixth embodiment, and when electric power is supplied through lead wires 84 and 85, heat is generated, and the shape memory alloy 82 The bending angle of the bending portion 82A, which is a portion having a shape memory effect, can be changed. Further, the end of the shape memory alloy 82 on the side opposite to this side is attached to the aforementioned holder 8 whose other end is fixed to the base 80.
6 and is held elastically.

A damping layer 87 made of a damping member is formed on the front surface of the shape memory alloy 82 bent backward into an L shape, and a flexible printed circuit board 88 is formed on the front surface (upper surface) of this damping layer 87.
A piezoelectric element (or piezoelectric element array) 89 made of ceramic such as PZT is attached,
Further, a beam converging lens 90 is attached to the front surface of the piezoelectric element 89. The piezoelectric element 89
The flexible printed circuit board 88 connected to the ground electrode and the other electrode is connected to a lead wire 9, respectively.
1,92 are connected.

On the other hand, the base 80 includes an injection port 94 through which a transmission medium 93 can be injected around the ultrasonic probe having the above-described structure housed in the balloon 81;
A discharge port 95 through which the transmission medium 93 filled therein can be discharged is formed by providing a through hole in the distal end surface of the base 80 or by inserting a tube into the through hole. Furthermore, by circulating the cooled transmission medium 93, the heated bent portion 82A of the shape memory alloy 82 can be cooled.

According to the seventh embodiment configured in this manner, the inside of the balloon 81 is filled with the transmission medium 93, and the inflated front end side of the balloon 81 is brought into contact with the subject as shown in FIG. , by applying high-frequency electric pulses to the piezoelectric element (array) 89 via lead wires 91 and 92, an ultrasonic beam is transmitted to the subject side, and reflected waves of the transmitted ultrasonic beam are received. Ultrasonic tomographic images can be obtained by waving.

However, in order to obtain an ultrasonic tomographic image in a direction different from that described above, the heating element 83 is heated by supplying power, and the ultrasonic wave is emitted while changing the bending angle of the bending portion 82A. This is possible by transmitting and receiving waves.

It is clear that the application of the present invention is not limited to the ultrasonic transducers forming the ultrasonic probe shown in each figure. For example, in Fig. 4, the transducer array is arranged so that the transducers are adjacent to each other in the vertical direction, but it may also be arranged perpendicular to this direction so that the transducers are arranged adjacent to each other in the vertical direction of the page. . In this case, the surface that is sector-scanned in a fan shape becomes a horizontal surface perpendicular to the plane of the paper (when the shape memory alloy 28 is in the state shown in FIG. 4). The direction of will change.

Further, the ultrasonic transducer can be applied not only to one for sector scanning but also to one for linear scanning, and can also be applied to a single transducer.

It should be noted that shape memory alloys can be improved by controlling the heating or cooling means, for example by controlling the energy value of the electric power supplied per unit time for heating, or by controlling the temperature of the transmission medium injected for heating. Since the deformation speed can be controlled, the deformation speed can be slowed down as necessary with respect to the scanning time, so that ultrasonic tomographic images can be obtained with each direction slightly different due to minute deformation. You can also do it.

In each of the above-mentioned embodiments or when slowly deforming as described above, an orientation detection means is installed in parallel that can detect how far the ultrasound tomographic image is deviated from the reference orientation or how much the ultrasound tomographic image is deviated from the orientation. You can also. As this means, for example, the fourth
The direction (reflection) can be adjusted by providing a linear reflective part and a non-reflective part on the end face of the base side disk 27 in the figure, and arranging a photoreflector formed of a light emitting diode and a light receiving element to face the end face. movement angle) can be detected. In this case, the amount of reflected and received light may be made to gradually become smaller or larger as the rotation angle increases. This orientation detection means is not limited to the above-mentioned one, but may also be configured using a known rotation detection means.

It is also possible to configure the orientation to be variably controlled in stages. For example, in FIG. 4, the plate-shaped shape memory alloy 28 is constructed by pasting together plate-shaped shape memory alloys having different transition temperatures, each having a narrow width or a thin thickness. By processing or setting the angle of twist when deformed to be large, when heated to (near) a predetermined temperature, the shape memory alloy with a transition temperature below that temperature changes from the outer shape of the low temperature phase side. It can be deformed to twist at a certain angle. If the heating temperature is further increased, it is possible to twist the wire even more. In this way, the sending direction of the ultrasonic beam can be varied stepwise, and it can also be maintained at a specific direction. In this case, it is convenient to provide temperature detection means such as a thermocouple or a thermistor. Moreover, the temperature can also be controlled by these. Although these are described in FIG. 4, they can be similarly applied to other embodiments.

Furthermore, the present invention is not limited to those used in ultrasonic endoscopes.

[Effects of the Invention] As described above, according to the present invention, a shape memory alloy and a means for heating and cooling the same are provided in a part of an ultrasonic probe having a conventional structure. Since the ultrasonic probe is configured to change the direction of the ultrasonic beam of the ultrasonic probe, for example, when it is attached to the tip of an endoscope, it can be easily moved without mechanically manipulating the bellows of the endoscope. By operating the electrical switch, it is possible to obtain ultrasonic tomographic images at different angles with good reproducibility.

[Brief explanation of drawings]

Figure 1 is an external view showing the tip side of the ultrasound endoscope.
Fig. 2 is a sectional view showing the tip of a conventional ultrasonic endoscope that mechanically transmits and receives ultrasonic waves, Fig. 3 is a sectional view showing another conventional example, and Fig. 4 is a sectional view showing the tip of a conventional ultrasound endoscope that mechanically transmits and receives ultrasonic waves. FIG. 5 is a cross-sectional view showing the tip of an ultrasound endoscope that accommodates the ultrasound probe of the embodiment; FIG. Figure a is an explanatory diagram showing the state in the low temperature phase, Figure b is an explanatory diagram showing the state in the high temperature phase, and Fig. 6 shows the tip of an ultrasound endoscope containing the third embodiment of the present invention. Figure a is an explanatory diagram showing the state in the high temperature phase,
Figure 7b is an explanatory diagram showing the state in the low temperature phase.
The figure is an explanatory diagram showing the distal end of an ultrasound endoscope that accommodates the fourth embodiment of the present invention, and FIG. 8 is an explanatory diagram showing the distal end of an ultrasound endoscope that accommodates the fifth embodiment of the present invention. FIG. 9 is a perspective view showing a sixth embodiment of the present invention,
FIG. 10 is a sectional view showing the distal end of an ultrasonic endoscope that accommodates a seventh embodiment of the present invention. 21...insertion part, 22...housing, 23,
41... Frame body, 24, 81... Balloon, 25,
42...Array type ultrasonic transducer, 26, 27...
Disc, 28, 43, 44, 66... Shape memory alloy, 29... Heater, 31... Lead wire (bundle),
33,94...Inlet, 34,93...(Ultrasonic) transmission medium, 35,95...Outlet, 45...
Rotating axis (rotating axis), 61...Thermistor, 64...
...Polymer piezoelectric array, 65,88...Printed circuit board, 66A,82A...Bending portion, 67,8
3... Heating element, 71, 86... Holder, 72...
...Earth electrode, 74,80...Base, 89...
Piezoelectric element.

Claims (1)

[Claims] 1. An ultrasonic probe that has a single or multiple ultrasonic transducers and is capable of transmitting and receiving ultrasonic beams in a limited direction, the outer shape of which changes depending on temperature. An ultrasonic wave characterized by fixing an ultrasonic vibrator via a memory alloy and providing means for heating and cooling the shape memory alloy, thereby making it possible to transmit and receive the ultrasonic wave in directions other than the limited directions. probe. 2. The ultrasonic probe according to claim 1, wherein the ultrasonic probe is formed using an array type ultrasonic transducer in which a large number of piezoelectric elements are arranged adjacent to each other in one direction. probe. 3. Claims characterized in that the shape memory alloy is attached to at least one end of the array type ultrasonic transducer in the arrangement direction, and the outer shape is twisted and deformed by transfer. Second
Ultrasonic probe as described in section. 4. Each end of the shape memory alloy is attached to both sides of the transmitting/receiving surface of the ultrasonic vibrator which can be rotated, and expands and contracts in the folding direction due to transfer, thereby rotating the ultrasonic vibrator. The ultrasonic probe according to claim 1, wherein the ultrasonic probe is configured to be able to 5. The shape memory alloy has one surface fixed to the back side of the ultrasonic transducer, and is bent so as to form a right angle or an acute angle with that surface, so that the bending angle changes upon transfer. An ultrasonic probe according to claim 1, characterized in that: 6. The ultrasonic probe according to claim 1, wherein the shape memory alloy is constructed using a plurality of shape memory alloys having different transition temperatures. 7. The ultrasonic probe according to claim 1, wherein the heating means is configured by supplying power to a heating element. 8. The ultrasonic probe according to claim 1, wherein the cooling means is formed by injecting or circulating an ultrasonic transmission medium.