JP3524183B2 - Ultrasonic probe - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is provided with a piezoelectric type actuator which is small in size and can be operated with a large amount of displacement and generated force.
The present invention also relates to an ultrasonic probe that mechanically scans an ultrasonic transducer to display a tomographic image of a subject.

[0002]

2. Description of the Related Art In recent years, a fine driving mechanism has been developed due to the progress of fine processing technology. In particular, in the field of medical devices, along with an increasing need for minimally invasive treatment that significantly reduces the burden on patients, diagnostic and therapeutic devices that function in a narrow body are being developed.

In such a field, realization of a compact, high-speed and highly flexible actuator is desired.

One example is an ultrasonic endoscope. An ultrasonic endoscope is inserted into the body cavity of the stomach, ureter, bile duct, blood vessel, etc., and an ultrasonic transducer attached to the tip sends an ultrasonic beam into the subject to capture its reflected waves. However, this ultrasonic transducer must be mechanically rotated or deflected in order to form a tomographic image. Currently, most ultrasonic endoscopes employ a method in which the rotation of an external motor is transmitted to an ultrasonic transducer at the tip by a shaft that passes through a catheter. By this rotational movement, the transmission / reception direction of the ultrasonic beam is moved in the direction orthogonal to the propagation direction of the ultrasonic wave (beam scanning), and two-dimensional echo information in the space where the beam scanning is performed is obtained. CRT based on this echo information
An image can be displayed as a tomographic image on a display such as. Conventionally, most of the ultrasonic tomography devices are displayed as a two-dimensional image except for special ones, but inside the body cavity, the orientation of the probe can be freely set so that the ultrasonic probe can be operated from the body surface. It is very difficult to change the fault plane for observation.

A three-dimensional tomographic image can be obtained by moving the ultrasonic probe in the direction perpendicular to the beam scanning plane and storing the echo information in the memory in the apparatus at the coordinates corresponding to the beam scanning. it can. For example, Japanese Patent Application Laid-Open No. 5-233339 discloses a system in which the shaft of a rotating rotor is rotated by a support mechanism having an axis orthogonal to the shaft.
Further, Japanese Patent Application Laid-Open No. 62-120844 discloses a method of rotating the rotating shaft of a rotating transducer head in a plane orthogonal to the ultrasonic wave radiation surface. In addition to this, JP-A-2-
Japanese Patent Laid-Open No. 246948 and Japanese Patent Laid-Open No. 5-244491 disclose a three-dimensional tomographic image by transmitting transducers by forming a two-dimensional array and giving a phase difference between individual elements without using such a mechanism. A method of obtaining an image is disclosed. However, it is difficult to reduce the size and weight of the mechanism that incorporates the motor. Further, in the case of an arrayed probe, in order to effectively deflect the ultrasonic beam, a large number of divisions (at least 1
6 × 16 = 256) is considered necessary, and there are many difficult problems to realize, such as increase in wiring space and increase in crosstalk between wirings, in addition to the difficulty of manufacturing, and it is intended to be used in a body cavity. Not suitable for.

Various methods have been devised for obtaining a three-dimensional tomographic image in an ultrasonic probe used by being inserted into a body cavity. For example, as disclosed in JP-A-57-9439, by rotating a vibrator, radial scanning is performed on a plane perpendicular to the long axis, and further, by moving the vibrator unit in the long axis direction. There is a method for obtaining a cylindrical three-dimensional tomographic image. Further, as disclosed in Japanese Patent Laid-Open No. 63-115546, there is also a method of moving the observation surface by inclining the surface of the vibrator that performs radial scanning. The scanning mechanism for the purpose of obtaining an image in the front in the insertion direction uses a shape memory alloy (example: Japanese Patent Application Laid-Open No. 5-237113) as well as one that converts the rotation of the shaft into rotational movement by a cam or the like. : Japanese Patent Application Laid-Open No. 4-266746), one that utilizes the generation of bubbles by heat (Example: Japanese Patent Laid-Open No. 4-354946), and one that uses an electromagnet (Example: Japanese Patent Laid-Open No. 5-2371).
No. 11, Japanese Patent Laid-Open No. 5-2444694), various methods in which the actuator itself alternately changes the direction of force have been devised. If the entire scanning mechanism is rotated about the insertion direction, a front three-dimensional tomographic image can be obtained. In addition, a method (Japanese Utility Model Laid-Open No. 63-130008) in which an ultrasonic transducer is fixed to the free end of a bimorph type actuator and the actuator is bent and displaced to perform ultrasonic beam scanning has been devised.

[0007]

However, JP-A-57-57
According to the method disclosed in Japanese Patent No. 9439 or Japanese Patent Laid-Open No. 63-115546, the side of the probe can be observed, but the front part to be inserted cannot be observed. In addition, since it is continuously rotated, an expensive sliding contact such as a slip ring is required to supply electric energy to the vibrator. In the drive system using a shaft as disclosed in Japanese Patent Laid-Open No. 237113/1993, in addition to the problem that the image is blurred due to the vibration generated by the rotation of the shaft, the volume occupied by the shaft may cause, for example, a laser fiber. There is a problem that it becomes difficult to reduce the diameter when incorporating a therapeutic means. Since the method of generating bubbles and using a shape memory alloy basically uses heat, it has disadvantages in its cooling method, stability, responsiveness, and the like. The method using electromagnets also uses windings and iron cores, and it is difficult to reduce the size.In addition, the gap between the stator and rotor must be set with high accuracy in order to effectively generate driving force. It can be said that it is difficult to reduce the diameter. Although the method of fixing the ultrasonic transducer to the free end of the bimorph type actuator has a simple configuration, the bending displacement of the bimorph type actuator is so small that beam scanning can be performed only in a minute spatial region.

[0008]

To achieve such an object, a plurality of bimorph type actuator elements in which the directions of displacement of independently movable free ends are orthogonal to each other, and the displacement of the free ends are A piezoelectric actuator having a movable portion that is synthesized and displaced, and is provided in two orthogonal directions.
And a ultrasonic wave provided in the rotating part.
A vibrator and a connection for transmitting the displacement of the movable part to the rotating part.
An ultrasonic probe having a connection part .

Further, it is preferable to have a plurality of bimorph type actuator elements in which the directions of displacement of the free ends are orthogonal to each other, and a movable part which is displaced by combining the displacements of the free ends.

It is preferable that the bimorph type actuator elements in which the displacement directions of the free ends are the same are arranged substantially in parallel.

The movable portion is provided at least for each of the shaft members arranged substantially in parallel with the plurality of bimorph type actuator elements, and for each of the independently movable free ends, and in the long axis direction of the shaft members. And a plurality of support members provided separately from each other, and the shaft member is supported by holes provided in the plurality of support members.

The movable portion has a groove portion into which each of the free ends is fitted, and the free end is slidable in a direction orthogonal to the displacement of the free end in the groove portion. .

Further, the connection between the fixing material and the signal line is
It is preferable to connect by soldering or a conductive adhesive, and in the case of soldering, it is preferable to use one having a melting point sufficiently lower than the Curie temperature of the piezoelectric body used in the bimorph type actuator element.

Further, an elongated hole is formed in the center of the support member so as to match the displacement direction of the connected bimorph type actuator element, and the shaft member is inserted into the elongated hole. The minor axis length is about the diameter of the shaft material, and the major axis length is set longer than the displacement amount of the bimorph type actuator element which is displaced in the other direction.

Further, it is preferable that a hole is formed at the center of the fixing member, and the inner diameter of the hole is large enough not to affect the operation of the shaft member.

What achieves such an object is as follows.
Using the piezoelectric actuator, a rotating unit that can rotate in two orthogonal directions, an ultrasonic transducer provided in the rotating unit, and a connection for transmitting displacement of the movable unit to the rotating unit. And an ultrasonic probe having a section.

The connecting portion has a contact having a spherical tip and a receiving member with which the tip of the contact comes into contact, and the contact and the receiving member are attracted by a magnetic force of a permanent magnet.

[0018]

In the piezoelectric type actuator of the present invention, a plurality of bimorph type actuator elements are arranged in substantially parallel directions, and the directions of displacement of their free ends operate independently in directions orthogonal to each other. Further, these displacements are combined in the movable portion, and the displacement in any direction is possible.

As one mode of the movable part, in the one having a shaft member arranged in parallel with the bimorph type actuator element, the shaft member is composed of a plurality of support members provided for each independently movable free end. It is supported by the hole. Since the displacements of these support members operate in the directions orthogonal to each other, the displacements of the tip end of the shaft member are combined and can be displaced in any direction.

In one aspect of the movable part, in which the free ends each have a groove portion fitted therein, the free end is slidable in the groove portion in a direction orthogonal to the displacement of the free end. . Therefore, the free end that is displaced in a certain direction is not affected by the displacement of the free end that is orthogonal to it. As a result, the movable portion can be displaced in any direction by combining these displacements.

In the ultrasonic probe of the present invention, a plurality of bimorph type actuator elements are arranged in substantially parallel directions, and the displacement directions of their free ends operate independently in directions orthogonal to each other. Furthermore, in the movable part, these displacements are combined and displaced in an arbitrary direction. This displacement is transmitted to the rotating portion provided with the ultrasonic transducer by the connecting portion.
The rotating portion has a structure capable of rotating in two orthogonal directions, and rotates in any direction in response to the displacement of the movable portion.

The connecting portion according to one aspect of the present invention has a contact having a spherical tip and a receiving member with which the tip of the contact abuts, and these are flexibly connected by an attraction force by a magnetic force. Therefore, the linear displacement of the movable portion can be smoothly converted into the rotational movement of the rotating portion.

[0023]

【Example】

(Embodiment 1) FIG. 1 is a perspective view showing an embodiment of the piezoelectric actuator of the present invention. FIG. 2 is a sectional view showing a mounting example of a fixed end of an embodiment of the piezoelectric actuator of the present invention. FIG. 3 is a perspective view showing a configuration of a bimorph type actuator element and a supporting material of the piezoelectric type actuator of the present invention. FIG. 4 is a plan view showing the displacement of the piezoelectric actuator of the present invention in the X-axis direction. FIG. 5 is a plan view showing the displacement of the piezoelectric actuator of the present invention in the Y-axis direction. FIG. 6 is a diagram showing voltage-displacement characteristics of the bimorph type actuator element of the piezoelectric type actuator of the present invention. FIG. 7 is a diagram showing time-displacement characteristics of the bimorph type actuator element of the piezoelectric type actuator of the present invention. FIG. 8 is a diagram showing time-voltage characteristics of the bimorph type actuator element of the piezoelectric type actuator of the present invention.

As shown in FIG. 1, a pair of bimorph-type actuator elements 2 that are displaced in the X-axis direction and a pair of bimorph-type actuator elements 20 that are displaced in the Y-axis direction are arranged in axial symmetry, and the shaft is made of a shaft material. 21 is provided. One end (fixed end) of the bimorph type actuator element is fixed to a fixing member 3 having a hole 31 in the center and a shaft member inserted in the hole 31, and the free end of the other end is in the X-axis direction. The supporting member 4 is attached to the bimorph type actuator element 2 which is displaced.
Bimorph type actuator element 20 which is displaced in the axial direction
Each of the support members 40 is provided in the
The long hole 41 in the axial direction is formed in the supporting member 40 in the long hole 4 in the Y-axis direction.
2 is provided, and the other end of the shaft member 21 is provided with another fixing member 30 fixed to a housing (not shown).

As shown in FIG. 2, in this embodiment, the bimorph type actuator elements 2 and 20 are of the parallel type, that is, the surface side electrodes have the same potential, and can be soldered to the metal fixing material 3. It is fixed.

In this way, electrical connection can be made at the same time as mechanical fixing. In this case, the potential of the fixing material 3 is set to a common potential of 0 [V], and the potential of the internal electrode of each bimorph type actuator element, that is, the potential of the shim material is given to each element that is independently displaced, so that the bimorph type actuator element can be driven. It will be possible.

As shown in FIG. 3, at the center of the supporting member 4, there is provided an elongated hole 41 whose major axis coincides with the X-axis direction, and a supporting member 40.
There is an elongated hole 42 whose long axis coincides with the Y-axis direction in the center of
The shaft member 21 penetrates these elongated holes 41 and 42, and also penetrates the central hole portion 31 of the fixing member 3, and its end is used as an output end.

As shown in FIGS. 4 and 5, the long hole 4 of the support member 4 is formed.
1 becomes the point of action in the X-axis direction, and the shaft member 21 is displaced in the X-axis direction. Further, the elongated hole 42 of the support member 40 serves as an action point in the Y-axis direction, and displaces the shaft member 21 in the Y-axis direction. Assuming that the displacement in the X-axis direction is Ux and the displacement in the Y-axis direction is Uy, the end of the shaft member 21 is fitted to the fixing member 30 and thus serves as a fulcrum, and the output end of the shaft member 21 is Wx in the X-axis direction. = Ux · (Z
x2 + Zx1) / Zx1, Wy = Uy · (Z
A displacement of (y2 + Zx1) / Zy1 is generated. Shaft material 21
The displacement at the output end of is a combination of the displacements of Wx and Wy.

The displacements Ux and Uy can be changed by the voltage applied to the bimorph type actuator element.

As shown in FIG. 6, when the voltage Vx or Vy applied to the bimorph type actuator element is increased in the + direction, the displacement Ux or Uy is increased in the + direction,
It can be seen that the displacement increases in the-direction if the displacement increases in one direction. That is, by adjusting Vx and Vy, Ux and U
y can be set independently, and the output end of the movable member can be displaced to any position within the operating range.

As shown in FIG. 7, the voltage-displacement characteristic of the bimorph type actuator element generally has a hysteresis (history) characteristic. Therefore, even if the voltage is increased from V1 to V2 and then lowered to V1 again, it does not return to the original position U1 but becomes the position of U1 ′.

Therefore, when operating the piezoelectric actuator of the present invention, it is necessary to control the hysteresis characteristics in consideration. For example, as shown in FIG.
In order to perform the displacement characteristic, a voltage that changes with time as shown in FIG. 8 may be applied.

According to the structure of this embodiment, Zy2 /
The displacement amount can be enlarged or reduced depending on the ratio of Zy1, Zx2 / Zx1, and the like. However, it should be noted that the force generated at the output end decreases in inverse proportion to the magnification of displacement.

(Embodiment 2) FIG. 9 is a perspective view showing an embodiment of the piezoelectric actuator of the present invention. Figure 10
FIG. 6 is a plan view showing displacement in the X-axis direction of the piezoelectric actuator of the present invention. FIG. 11 is a plan view showing the displacement of the piezoelectric actuator of the present invention in the Y-axis direction.

As shown in FIG. 9, a pair of bimorph type actuator elements 2 displacing in the X-axis direction and a pair of bimorph type actuator elements 20 displacing in the Y-axis direction are arranged in axial symmetry, and the shaft is made of a shaft material. 21 is provided and is inserted into a hole 31 provided at the center of the fixing member 3. The fixed ends of the bimorph type actuator elements 2 and 20 are fixed to the fixing material 3, and the free end of the other end is displaced in the X axis direction. The support material 4 is displaced in the bimorph type actuator element 2 in the Y axis direction. The bimorph type actuator element 20 is provided with a support member 40, and the support members 4 and 40 are provided with round holes 43 and 44 having a diameter such that the shaft member 21 can be swung.

As shown in FIGS. 10 and 11, in the X-axis direction, the round hole 43 of the support member 4 serves as a fulcrum, and the round hole 43 of the support member 4 serves as an action point in the X-axis direction. When the support member 4 is displaced by Ux, the output end of the shaft member 21 is displaced by Wx = Ux (1 + Z2 / Z1) in the X-axis direction. Shaft material 21
The displacement at the output end of is a combination of the displacements of Wx and Wy.

In the y direction, the round hole 44 of the support 40 is
Is the fulcrum, and the round hole 44 of the support member 40 is the point of action in the Y-axis direction. When the support member 40 is displaced by Uy,
The output end of the shaft member 21 is Wy = -Uy · Z2 / Z in the Y-axis direction.
Displace by 1.

Further, according to the structure of this embodiment as in the first embodiment, the displacement amount can be expanded or reduced depending on the ratio of Z2 / Z1. However, it should be noted that the force generated at the output end decreases in inverse proportion to the magnification of displacement.

(Embodiment 3) FIG. 12 is a perspective view showing an embodiment of the piezoelectric actuator of the present invention. FIG.
FIG. 3 is a perspective view showing a movable member of the piezoelectric actuator of the present invention. FIG. 14 is a perspective view showing an embodiment of the piezoelectric actuator of the present invention.

As shown in FIG. 12, a pair of bimorph type actuator elements 2 which are displaced in the X axis direction and a pair of bimorph type actuator elements 20 which are displaced in the Y axis direction.
Are arranged in axial symmetry. A shaft member 21 is provided on the shaft, and the shaft member 21 is inserted into a hole 31 provided at the center of the fixing member 3. The fixed ends of the bimorph type actuator elements 2 and 20 are fixed to the fixed member 3, and the movable member 32 is provided at the free end of the other end.

As shown in FIG. 13, the movable member 32 has an X
The bimorph type actuator element 2 provided with the grooves 33 and 34 in the axial direction and the Y-axis direction and displaced in the X-axis direction is
Of the bimorph type actuator element 20 which is displaced in the Y-axis direction is inserted in the groove 34 in the Y-axis direction.

The widths of the grooves 33 and 34 are set to about the thickness of the bimorph type actuator elements 2 and 20, and are set so as to slide in the direction orthogonal to the displacement of the bimorph type actuator elements 2 and 20 with as little friction as possible. It

Therefore, the bimorph-type actuator element 2 which is displaced in the X-axis direction and the bimorph-type actuator element 20 which is displaced in the Y-axis direction are not affected by the displacement of the other one, and the displacement of the free end is caused by the movable member 32. Can be told.

As a result, the output end 35 of the movable member 32 can be displaced in a combined direction of the displacements of these bimorph type actuator elements 2 and 20 in the X-axis direction or the Y-axis direction.

(Embodiment 4) As shown in FIG. 14, for either one of the bimorph type actuator elements,
Two side-by-side actuators may be configured by one bimorph type actuator element 2, 20. If you do this,
Wiring to the electrodes of the bimorph element can be reduced, which is advantageous in manufacturing.

Here, the other components are the same as those shown in FIG.

In the above description, the parallel type is used as the bimorph type actuator element, but the same effect can be obtained by using the series type. At that time, since the drive voltage is applied between the surface electrodes on both sides, the material around the fixed end of the bimorph type actuator element or the fixing material 3 is made insulative so that the surface electrodes are not short-circuited. There is a need.

Further, in the series type, the intermediate shim material is not always necessary, and the removed shim material may be used depending on the desired characteristics of the actuator.

In the above description, the number of bimorph elements that can operate independently is one or two, but the embodiment of the present invention is not limited to this.

(Embodiment 5) FIG. 15 is a plan view showing an embodiment of the piezoelectric actuator of the present invention. As shown in FIG. 15, a structure in which bimorph type actuator elements 20 are stacked in the thickness direction is shown. A plurality of bimorph type actuator elements 20 are provided on the fixing member 3 at predetermined intervals.
Are fixed in parallel. This distance may be narrow as long as the elements do not touch each other. At the free ends of the plurality of bimorph type actuator elements 20, the support member 4 is provided.
Are glued together. In this case, the adhesive 36 is preferably a flexible adhesive such as silicone or urethane.
By adopting a structure in which the bimorph type actuator element for one sheet in the above-mentioned embodiment is replaced with this element group, the generated force at the output end can be increased in proportion to the number of superposed sheets. Since the bimorph element has a thickness of about several hundreds of microns, even if the bimorph elements are stacked in the thickness direction, a large space does not increase.

(Embodiment 6) In Embodiments 1 to 3, the directions in which the bimorph element is independently displaced are two directions of X and Y, but in addition to this, bimorphs which are displaced in other directions are combined. The form is also possible.

FIG. 16 is a plan view showing an embodiment of the piezoelectric actuator of the present invention. FIG. 17 is a cross-sectional view taken along the line AA ′ of an embodiment of the piezoelectric actuator of the present invention.

As shown in FIG. 16, in addition to the bimorph-type actuator element 2 which is displaced in the X-axis direction and the bimorph-type actuator element 20 which is displaced in the Y-axis direction, a bimorph-type actuator element which is inclined by 45 degrees with respect to these elements. 22 and 23 are provided.

As shown in FIG. 17, considering the case where the axial center at the position of the free end is displaced from the position of the axial point 24 to the position of the axial point 24 ', each bimorph type actuator element 2, 20, 22, It is understood that the positions of 23 should be the positions of the broken lines.

With such a structure, the generated force can be increased, and the difference in the generated force depending on the direction of displacement can be alleviated, and a smooth generated force can be obtained in all directions.

(Embodiment 7) Second Invention FIG. 18 is a sectional view showing an embodiment of the ultrasonic probe of the present invention. FIG. 19 is a perspective view of the ultrasonic probe of the present invention with the housing of the same embodiment removed.

As shown in FIGS. 18 and 19, the piezoelectric type actuator 1 is the piezoelectric type actuator shown in the first embodiment, and includes a bimorph type actuator element 20 which is displaced in the X axis direction and a bimorph type actuator element which is displaced in the Y axis direction. The piezoelectric actuator 1 is fixed in the housing 5 with the fixing members 3 and 30, the output end is connected to the connecting portion 51 attached to the swinging portion 6, and the rotating portion is It is composed of a gimbal mechanism having a biaxial degree of freedom and a probe head portion, the probe head portion is supported by the gimbal mechanism, and the ultrasonic transducer 7 is bonded to the tip (FIG. 19).
In order to make the explanation easier to understand, the actuator part and the rotating part are drawn separately.

In order to propagate the ultrasonic waves emitted from the ultrasonic transducer 7, the inside of the housing 5 (from the fixing member 3 to the acoustic window 5)
Up to 2), a liquid that propagates ultrasonic waves is enclosed.

As the liquid, for example, a chlorofluorocarbon compound such as physiological saline solution, silicone oil, or fluorinate can be used. When a liquid having a low insulating property such as physiological saline solution is used, a bimorph type actuator element is used. 2,
It is necessary to consider the insulation of the electric system such as 20, the ultrasonic transducer 7 and its electrode wiring.

The signal lines 70 and 71 to the ultrasonic transducer 7 are
This is performed through the wiring holes provided in the fixing materials 3 and 30, but in the fixing material 30, the wiring holes are sealed so that the liquid does not leak.

The signal lines 70 and 71 have a coil-like structure so that they can be expanded and contracted in order to prevent stress caused by the rotation of the probe head. A tube 75 made of a flexible resin is provided behind the fixing member 30 and is connected to an ultrasonic diagnostic apparatus main body (not shown). The inside of the tube 75 is a transmission / reception signal line 72 (coaxial cable) or an actuator drive line 7.
3, 74 and the actuator common line pass through.

However, in this embodiment, the fixing members 3 and 30 and the housing 5 are made of metal and are electrically connected to the common electrode (shim member) of the bimorph type actuator elements 2 and 20. Therefore, the common actuator line is shared with one side of the transmission / reception signal line 72 (for example, the shield line side).

The output end of the actuator portion is displaced substantially linearly in the X-axis and Y-axis directions, and the connecting portion 51 plays a role of converting this linear displacement into a rotational movement.

As shown in FIG. 20, the connecting portion 51 uses a gimbal mechanism, and the shafts 53 and 54 of the gimbal mechanism are inserted into the probe head portion. As the actuator output end 55 moves, The probe head is
It rotates as shown in FIG.

Although FIG. 21 shows only one direction,
The same applies to the direction orthogonal to this. Although this method is well known, it is difficult to miniaturize it and its cost is high because it is mechanically complicated.

As shown in FIG. 22, a cylindrical groove portion 56 is provided on the back surface of the probe head, and a thin metal plate material 57 is embedded in the groove portion 56. Actuator output end 5
5 is inserted into a round hole provided at the center of the plate member 57. The probe head unit rotates as shown in FIG. 23 in accordance with the operation of the actuator output end 55.

This method has a simple structure and is advantageous in terms of downsizing and cost, but the plate member 57 must be thinned in order to provide a sufficient deflection angle to the probe head section. Further, as the actuator rotates, the actuator output end 55 moves the plate member 57.
Since the cross-sectional area of the portion penetrating the hole changes, a gap is required between the output end and the round hole. Therefore, in order to improve the accuracy of the deflection angle, the output end must be thin. Further, as the actuator output end 55 slides in the round hole of the plate member 57 with the rotation, the plate member 57 is greatly worn.

FIG. 2 shows the structure of the connecting portion which solves the above problems.
4 to 26.

As shown in FIG. 24, the actuator output end 55 has a pipe shape, and a slider 58 is provided therein.
, And a permanent magnet 59 is provided on the slider 58, and its tip is processed into a spherical surface (convex surface). The tip of the permanent magnet 59 is attracted to the bearing portion 510 of the receiving member 500 provided on the probe head side. The bearing portion 510 is processed into a spherical surface (concave surface) having the same radius of curvature as the spherical surface at the tip of the permanent magnet 59.

However, the range of the spherical surface of the bearing 510 is π-2θ with respect to the deflection angle θmax as shown in FIG.
Must be less than or equal to max. With respect to the displacement of the actuator output end 55, the bearing portion 510 always maintains the attracted state, so that the probe head rotates as shown in FIG.

Although the permanent magnet 59 is provided on the slider 58 side in this embodiment, the permanent magnet 59 may be provided on the receiving member 500 side or both sides. Next, a specific example of ultrasonic beam scanning by the ultrasonic probe 10 of the present invention will be described.

FIG. 27 is a perspective view showing an example of scanning the ultrasonic beam of the ultrasonic probe of the present invention. FIG. 28 is a diagram showing the scanning displacement of the ultrasonic beam of the ultrasonic probe of the present invention. FIG. 29 is a perspective view showing an example of scanning an ultrasonic beam of the ultrasonic probe of the present invention. FIG. 30 is a diagram showing the scanning displacement of the ultrasonic beam of the ultrasonic probe of the present invention. Figure 3
FIG. 1 is a perspective view showing an example of scanning an ultrasonic beam of an ultrasonic probe of the present invention. FIG. 32 is a diagram showing the scanning displacement of the ultrasonic beam of the ultrasonic probe of the present invention.

As shown in FIGS. 27 and 28, the horizontal axis represents time (t) and the vertical axis represents the displacement (θ) of the free end of the bimorph type actuator that operates independently. The directions are taken as two coordinate axes, the X axis and the Y axis, and their displacement amounts are Ux and Uy. Since the movable portion is displaced by combining these displacements, its position can be represented by (Ux, Uy).

The displacement of the movable part is transmitted to the rotating part through the connecting part. Since this rotating portion can rotate in two directions orthogonal to each other, the angles θx and θy corresponding to Ux and Uy, respectively.
Only deflect. Ux and Uy can be controlled by the magnitude of the voltage applied to the bimorph type actuator. That is, when the voltage of the bimorph type actuator element that generates the displacement of the x-axis is smoothly changed from −Vx to + Vx, the angle of the rotating portion is smoothly deflected from −θx to + θx. During this time, by transmitting and receiving K times with the ultrasonic transducer, one tomographic image composed of K echo data can be obtained.

Similarly, when the voltage of the bimorph type actuator element which causes the displacement of the Y-axis is smoothly changed from −Vy to + Vy, the angle of the rotating portion is smoothly deflected from −θy to + θy. Here, within one cycle of the voltage change of the bimorph type actuator element displaced in the Y-axis direction, X
If the voltage change of the bimorph type actuator element that is displaced in the axial direction is performed N times, the ultrasonic wave emitting direction of the ultrasonic wave oscillator fixed to the rotating portion is as shown in FIGS.
A region obtained by cutting out the space of the subject at an angle of 2θx2θy is scanned with N tomographic planes, and three-dimensional echo data of a tomographic image is obtained.

Since the ultrasonic probe 10 of the present invention can deflect the ultrasonic beam in an arbitrary direction by the voltage applied to the actuator, it is spirally scanned as shown in FIGS. Alternatively, as shown in FIGS. 31 and 32, ultrasonic beam scanning can be performed on a curved tomographic plane.

As shown in FIGS. 29 and 30, the voltage of the bimorph type actuator element (θx side) is a sine wave, and its amplitude is smoothly increased or decreased from 0 to 2V. Further, the voltage of the bimorph type actuator element (on the θy side) also has a similar sine wave, but the phase is advanced by 90 degrees with respect to the voltage in the X-axis direction. As a result, the output end of the actuator makes a circular motion (spiral motion) with a gradually increasing radius, and a spiral ultrasonic beam scanning is realized. Others are as described in FIG. 28.

In this case, in order to send the ultrasonic beam into the space of the subject at a constant density, the period of the sine wave is fixed, and the ultrasonic wave is increased as the deflection angle from the center line of the spiral increases. A method of shortening the sound wave transmission / reception cycle, a method of keeping the ultrasonic wave transmission / reception cycle constant, and lengthening the cycle of the sine wave as the amplitude increases may be implemented.

As shown in FIGS. 31 and 32, both the bimorph type actuator element (θx side) and (θy side) repeatedly increase and decrease the voltage in the same cycle. for that reason,
Echo data of the same tomographic plane is always obtained. The shape and inclination of the tomographic plane can be freely manipulated by appropriately changing the voltage waveform applied to each actuator. Others are as described in FIG. 28.

In the above description, the actuator 1 is
Although the one shown in the first embodiment is taken as an example, the same effect can be obtained by using the actuator shown in any of the other embodiments.

[0081]

According to the piezoelectric actuator used in the ultrasonic probe of the present invention, the independently movable free ends are displaced in directions orthogonal to each other and parallel to each other. A plurality of bimorph-type actuator elements, and a movable part that is displaced by combining the displacements of the free ends.

The movable portion is provided at least for each of the shaft members arranged substantially parallel to the plurality of bimorph type actuator elements and for each of the independently movable free ends, and the shaft members are arranged in the long axis direction. And a plurality of support members provided separately from each other, and the shaft member is supported by holes provided in the plurality of support members.

The movable portion has a groove portion into which each of the free ends is fitted, and the free end is slidable in a direction orthogonal to the displacement of the free end.

The movable part has a free end that is displaced in one direction of the plurality of bimorph type actuator elements and a fixed end of another bimorph type actuator element that is displaced in a direction orthogonal to the displacement of the free ends. Since they are connected, it is possible to realize an ultrasonic probe that can be instantaneously displaced in an arbitrary direction without using a complicated mechanism. Further, since the structure is simple, compact and low-cost ultra
A sound wave probe can be realized.

In addition, the displacement directions of the free ends that can be independently operated are orthogonal to each other, and the displacement of the free ends is combined with a plurality of bimorph type actuator elements arranged in substantially parallel directions. A movable part, a rotating part that can rotate in two orthogonal directions, an ultrasonic transducer provided in the rotating part, and a connecting part that transmits displacement of the movable part to the rotating part. The connecting portion has a contact member having a spherical tip at the tip and a receiving member with which the tip of the contact abuts, and the contact member and the receiving member are attracted by a magnetic force of a permanent magnet. An ultrasonic probe capable of obtaining a three-dimensional tomographic image can be realized with a simple structure. Moreover, since the scanning surface can be freely moved or fixed by the voltage applied to the bimorph type actuator, the number of cross sections to be scanned can be arbitrarily changed or fixed at any position. In particular, the bimorph type actuator is suitable for application to a probe having a small diameter such as a probe in a body cavity because it can be easily manufactured with an elongated shape. Furthermore, since a sliding contact for transmitting an electric signal for driving the ultrasonic vibrator is not required, the cost of the device can be reduced and the durability can be improved.

Further, since the connecting portion is composed of a contactor having a spherical tip and a receiving member with which the tip of the contact abuts, and these are attracted by magnetic force, the linear movement is changed to the rotational movement with a simple structure. The conversion can be realized, and the stable rotating operation can be obtained at all times, which contributes to downsizing of the device, cost reduction, and high image quality.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a piezoelectric actuator of the present invention.

FIG. 2 is a cross-sectional view showing a mounting example of a fixed end of an embodiment of the piezoelectric actuator of the present invention.

FIG. 3 is a perspective view showing a configuration of a bimorph type actuator element and a supporting member of the piezoelectric type actuator of the present invention.

FIG. 4 is a plan view showing displacement in the X-axis direction of the piezoelectric actuator of the present invention.

FIG. 5 is a plan view showing displacement in the Y-axis direction of the piezoelectric actuator of the present invention.

FIG. 6 is a diagram showing voltage-displacement characteristics of the bimorph type actuator element of the piezoelectric type actuator of the present invention.

FIG. 7 is a diagram showing time-displacement characteristics of the bimorph type actuator element of the piezoelectric type actuator of the present invention.

FIG. 8 is a diagram showing time-voltage characteristics of the bimorph type actuator element of the piezoelectric type actuator of the present invention.

FIG. 9 is a perspective view showing an embodiment of the piezoelectric actuator of the present invention.

FIG. 10 is a plan view showing displacement of the piezoelectric actuator of the present invention in the X-axis direction.

FIG. 11 is a plan view showing displacement in the Y-axis direction of the piezoelectric actuator of the present invention.

FIG. 12 is a perspective view showing an embodiment of the piezoelectric actuator of the present invention.

FIG. 13 is a perspective view showing a movable member of the piezoelectric actuator of the present invention.

FIG. 14 is a perspective view showing an embodiment of the piezoelectric actuator of the present invention.

FIG. 15 is a perspective view showing an embodiment of the ultrasonic actuator of the present invention.

FIG. 16 is a perspective view showing an embodiment of the ultrasonic actuator of the present invention.

FIG. 17 is a cross-sectional view taken along the line AA ′ of the embodiment of the ultrasonic actuator of the present invention.

FIG. 18 is a perspective view showing an embodiment of the ultrasonic probe of the present invention.

FIG. 19 is a perspective view of the ultrasonic probe of the present invention with the housing removed.

FIG. 20 is a perspective view showing an example of a connecting portion of the ultrasonic probe of the present invention.

FIG. 21 is a cross-sectional view showing the rotation of the connecting portion of the ultrasonic probe of the present invention.

FIG. 22 is a perspective view showing an example of a connecting portion of the ultrasonic probe of the present invention.

FIG. 23 is a cross-sectional view showing the rotation of the connecting portion of the ultrasonic probe of the present invention.

FIG. 24 is a perspective view showing an embodiment of a connecting portion of the ultrasonic probe of the present invention.

FIG. 25 is a cross-sectional view showing the rotation of the connecting portion of the ultrasonic probe of the present invention.

FIG. 26 is a cross-sectional view showing details of rotation of the connecting portion of the ultrasonic probe of the present invention.

FIG. 27 is a perspective view showing an example of scanning an ultrasonic beam of the ultrasonic probe of the present invention.

FIG. 28 is a diagram showing scanning displacement of an ultrasonic beam of the ultrasonic probe of the present invention.

FIG. 29 is a perspective view showing an example of scanning an ultrasonic beam of the ultrasonic probe of the present invention.

FIG. 30 is a diagram showing scanning displacement of an ultrasonic beam of the ultrasonic probe of the present invention.

FIG. 31 is a perspective view showing an example of scanning with an ultrasonic beam of the ultrasonic probe of the present invention.

FIG. 32 is a diagram showing scanning displacement of an ultrasonic beam of the ultrasonic probe of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Piezoelectric actuator 10 Ultrasonic probe 2 Bimorph type actuator element 20 displaced in the Y-axis direction Bimorph type actuator element 21 displaced in the X-axis direction Shaft members 22, 23 Bimorph type actuator element 24 Insulation sleeve 25 Soldering 3, 30 Fixed Material 31 Hole 32 Movable Part 33 X-Axis Groove 34 Y-Axis Groove 35 Output End 36 Adhesive 4, 40 Support Material 41 X-Axis Long Hole 42 Y-Axis Long Hole 43, 44 Round Hole 5 Housing 51 Connection 52 Acoustic windows 53, 54 Gimbal mechanism shaft 55 Actuator output end 56 Groove 57 Plate 58 Slider 59 Permanent magnet 500 Bearing 510 Bearing 6 Swing 7 Ultrasonic transducer 70, 71 Signal line 72 Transmission / reception signal lines 73, 74 Actuator drive line 75 Resin tube

Claims (5)

(57) [Claims] 1. A piezoelectric actuator having a plurality of bimorph type actuator elements which are independently movable and whose displacement directions are orthogonal to each other, and a movable part which is displaced by combining the displacements of the free ends. Equipped and orthogonal 2
And a rotation part that is rotatable in the direction
Transmits the displacement of the sound wave oscillator and the movable part to the rotating part.
An ultrasonic probe having a connecting portion. 2. The ultrasonic probe according to claim 1, wherein the direction of the free end of the displacement is the same bimorph type actuator device, characterized by comprising a substantially parallel arrangement. 3. The movable part is provided at least for each of the independently movable free ends of a shaft member arranged substantially parallel to the plurality of bimorph type actuator elements, and in the long axis direction of the shaft member. 3. A plurality of supporting members provided separately from each other, wherein the shaft member is supported by holes provided in the plurality of supporting members. Ultrasonic probe . 4. The movable portion has a groove portion into which each of the free ends is fitted, and the free end is slidable in a direction orthogonal to the displacement of the free end in the groove portion. The ultrasonic probe according to any one of claims 1 to 3, characterized in that
Child . 5. The connecting portion has a contact having a spherical tip and a receiving member with which the tip of the contact abuts, and the contact and the receiving member are attracted by a magnetic force of a permanent magnet. The ultrasonic probe according to claim 1 , wherein: