JPH05244691A - Ultrasonic probe - Google Patents

Abstract

PURPOSE:To reduce an accessory circuit scale, and to attain a low cost by dividing each electrode provided at the both main faces of a disk being an electrostrictive material into more than three fans, circularly dividing it into plural parts from a center, and using it as a vibrator. CONSTITUTION:The electrode provided at one main face of a disk 2 being the electric distortion material is divided into four fans, and divided into plural parts from the center, so that electrodes 110e, 111a-111d, 112a-112d, 113a-113d, and 114a-114d can be formed. In the electrode on the other main face, a circular area sharing the center of an electrode 120 is divided into fine parts by equal angles, so that electrodes 121 and 122 can be formed. A piezoelectric vibrator 3 is a circle interfit with the circular opening of the center of the electric distortion vibrator 2, and the diameter of the electrodes 110e and 120 is equal to that of the vibrator 3. Thus, the are a where a piezoelectricity is induced by a bias voltage is designated as a pair of fans, a ultrasonic scanning by a phased array system is operated, and the operation of obtaining a tomographic image information is successively operated while rotating the fan designation are a in the vibrator, so that a three-dimensional ultrasonic wave can be measured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic diagnostic apparatus for medical use, a non-destructive inspection apparatus, or the like for measuring an internal image of a living body or a structure by transmitting and receiving ultrasonic waves and measuring a motion of a fluid applying the Doppler effect. The present invention relates to a sound wave measuring device, and more particularly, to a structure of an ultrasonic probe which is an ultrasonic wave transmitting / receiving unit.

[0002]

2. Description of the Related Art In a conventional electronic scanning type ultrasonic measuring device, a device for obtaining a tomographic image of the inside of a subject in real time by B-mode echography has been put into practical use. In the three-dimensional measurement of the inside of the subject using this device, the examiner changes the position and orientation of the ultrasonic probe by hand or mechanically scans and accumulates tomographic image information of the target site. Later, the stereoscopic information inside the subject was reconstructed. However, in the mechanical scanning method, when the subject includes a moving part such as the heart of the human body, the subject moves during the mechanical scanning time and the real-time property is significantly reduced. From this point, an electronic scanning type ultrasonic measuring device and an ultrasonic probe therefor which can obtain three-dimensional information in real time are required.

An electronic scanning ultrasonic probe for three-dimensional measurement is known in which an ultrasonic transducer is divided into two-dimensional directions, as disclosed in Japanese Patent Laid-Open No. 60-20400. In this technique, independent electrodes are formed and wired for each of the ultrasonic transducers arranged in a two-dimensional array. However, with this configuration, the number of channels increases sharply as compared with the conventional tomographic image measuring apparatus, so that it is difficult to realize it because it becomes difficult to dramatically expand the circuit scale and implement it. As a method for avoiding this sudden increase in the number of channels, a method in which an electrostrictive material is used for a vibrator and electrodes are matrix-selected is disclosed in Japanese Patent Laid-Open No. 56-11374.

Piezoelectric materials, which have been widely used as materials for ultrasonic transducers, utilize the property of generating a voltage by mechanical displacement due to the reception of ultrasonic waves, thereby utilizing the electroacoustic conversion part of an ultrasonic probe. Is used for. On the other hand, the electrostrictive material has a property that the voltage changes due to mechanical displacement only under a bias electric field. Further, since the electromechanical coupling coefficient greatly changes depending on the strength of the bias electric field, the electrostrictive material can be regarded as a piezoelectric material whose conversion efficiency can be controlled by the bias electric field.

[0005]

In the prior art disclosed in Japanese Patent Laid-Open No. 60-20400, since the finely divided two-dimensional transducers are individually wired, the number of divisions of the ultrasonic transducers increases. It was difficult to realize because the circuit scale increased rapidly and implementation became difficult.

Further, when three-dimensional measurement is performed using a rectangular two-dimensional array transducer as a sound source, the directivity when radiating into or receiving from the measurement area is perpendicular to the center of the transducer surface. It was axisymmetric with respect to rotation through 90 ° or 180 °. This method has a problem in that, when three-dimensional information is rotated and displayed, the non-uniformity of resolution varies depending on the display orientation. For this reason, an ultrasonic wave which has an axially symmetric resolution even for rotations of a small angle of 90 degrees or less and which can obtain a polygonal prism or a truncated pyramid-shaped measurement region having a polygonal surface composed of four or more sides on the bottom surface I needed a probe.

Further, when the circular electrode is divided into fan-shaped portions with a minute angle, the central portion becomes extremely finely processed, which is unnecessarily fine when dividing the sound source.

Further, in each of the transducers in the ultrasonic probe, it is not necessary to use the electrostrictive material to induce the piezoelectricity by the bias voltage in the portion that always transmits and receives the ultrasonic wave by utilizing the piezoelectricity. , High sensitive piezoelectric must be used.

[0009]

In order to enable the measurement of rotational symmetry at a small angle described above, the first and second main surfaces of a disk of an electrostrictive material whose piezoelectricity is induced by a bias voltage are provided. The second electrode is divided into three or more sectors, and the electrodes on one or both of the first and second principal surfaces are divided into concentric circles from the center to form a transducer for ultrasonic transmission and reception. ..

In order to reduce the division in the vicinity of the center of the ultrasonic probe, in the concentric division of the electrodes on each main surface, the central portion within the minimum radius is made into one circle.

In order to reduce the area of the portion to which the bias voltage of the ultrasonic probe is applied, the portion sandwiched by the circular electrodes having the smallest radius on each main surface is made of a piezoelectric material.

In order to realize an ultrasonic measuring device using the ultrasonic probe, the electrode group on one main surface is connected to the transmitting / receiving circuit and the bias voltage applying means is connected to the electrode group on the other main surface.

In order to produce the ultrasonic probe, the back braking material is divided along a part or all of the division of the electrodes on at least one main surface in the angular direction, and the divided section of the back braking material is divided. Used for wiring.

[0014]

A wave transmitting circuit and a wave receiving circuit are connected to each of the divided electrodes on the first main surface. Each of the divided electrodes on the second main surface is connected to a bias voltage applying circuit or is grounded.

Among the divided electrodes on the second main surface, those which are connected between the bias voltage applying circuit and the divided electrodes on the first main surface facing each other have piezoelectricity in the electrostrictive material. And defines the position of the acoustic aperture that effectively induces the ultrasonic wave in the plane of the transducer.

From among the fan-shaped divided electrodes on the second main surface, two groups of fan-shaped divided electrodes are continuously and symmetrically selected in the plane. By inputting and outputting the phased array type ultrasonic transmission / reception signals in this state, a rectangular or fan-shaped tomographic plane can be measured in a plane including the center line of the selected region and perpendicular to the transducer plane.
Furthermore, if the connection position of the electrode to the bias voltage applying circuit is moved so that the center lines of the selected regions of the two groups rotate sequentially,
Since the tomographic plane rotates about a line that passes through the center of the circular oscillator and is perpendicular to the oscillator plane, a cylindrical or truncated cone-shaped three-dimensional imaging region can be obtained.

In the manufacture of the ultrasonic probe, if the back braking material is also divided along the dividing line in the angular direction of the vibrator, wiring can be easily performed at a position along the cross section using a flexible printed wiring board or the like.

[0018]

EXAMPLE A first example according to the present invention will be described below. A cross-sectional view including a transducer portion of the ultrasonic probe of the present invention is shown in FIG. The electrostrictive oscillator 2 and the piezoelectric oscillator 3 were used as oscillator materials. As shown in FIG. 1A, the electrostrictive oscillator 2 has a sector shape in which a circular opening is provided in the center of a disk and the disk is divided into four. The piezoelectric vibrator 3 has a circular shape that fits into a circular opening in the center of the electrostrictive vibrator 2. The thicknesses of the vibrators 2 and 3 were processed so that the resonance frequencies were the same.

The material of the electrostrictive oscillator is Pb (Mg _1/3 Nb _2/3 )
In relaxation type ferroelectrics such as O ₃ -PbTiO ₃ based solid solution ceramics, a ceramic composition whose phase transition temperature to the ferroelectric is relatively near room temperature, or a porcelain plate of which is divided into a number of fine columns vertically and horizontally. A composite material was used in which the space was filled with resin or the like. The piezoelectric vibrator 3 is composed of a lead zirconate titanate (PZT) based porcelain composition which has been widely used from the past, or the above-mentioned composite material.

An electrode (coating) is formed on each main surface of this vibrator. When the oscillator material was porcelain, the electrodes were formed by baking silver, and when it was a composite material, the electrodes were formed by electroless plating of copper, nickel, or the like.

The electrodes on the first main surface of the vibrators 2 and 3 are shown in FIG.
It was divided as shown in (a). The center electrode 110e has the same diameter as the piezoelectric vibrator 3. Electrodes 111a to 111d, 11
2a to 112d, 113a to 113d, 114a to 11
4d is a concentric division of 110e, which is further divided into four equal parts at the central angle.

The electrodes on the second main surface of the vibrator were divided as shown in FIG. 1 (b). The center electrode 120 has the same diameter as the piezoelectric vibrator 3. The electrodes 121 and 122 are the electrodes 120.
And a ring-shaped region sharing the center of the electrode 120 is further finely divided into equal angles at the central angle. However, any one of the minute divisions at the same angle was made to coincide with the equal angle four divisions shown in FIG. 1 (c) is shown, and 111 indicates any of 111a to 111d, and the same applies to 112, 113, 114.

In this way, only the electrostrictive vibrator 2 having electrodes formed on both principal surfaces was cut into four pieces along the four-divided positions of the equiangular electrodes shown in FIG. 1 (a). FIG. 5 shows a method of wiring the transducer and a method of assembling the ultrasonic probe.

FIGS. 5 (a) and 5 (b) show wiring to one of the four divided pieces of the electrostrictive vibrator shown in FIG. 1 (a). Electrode 11
The electrostrictive oscillator 2 including 1a, 112a, 113a, 114a is bonded to the back braking material (backing) 41. The cross-sectional shape of the back braking member 41 is the same as that of the fan-shaped electrostrictive vibrator 2. Wiring was performed using flexible printed wiring boards 51a, 51b, 51c for each electrode provided on the electrostrictive vibrator 2. 51a and 51c are connected to a bias voltage applying circuit for inducing piezoelectricity in the electrostrictive oscillator 2, and 51b
Is connected to an ultrasonic transmitting / receiving circuit. In Fig. 5 (a) and (b), the conductor of the flexible printed wiring board is connected to the cross section of the electrode, but if it is difficult to connect by soldering etc., connect the conductor to the main surface of the vibrator. You may connect in an extended form.

The electrostrictive vibrator having the wiring and the adhesive thus bonded was manufactured for the other three electrostrictive vibrators and assembled as an ultrasonic probe as shown in FIG. 5 (c). The cylindrical back braking member 40 has the same outer diameter as the piezoelectric vibrator 3. The lead 52 was connected to the electrodes 110e and 120, and the piezoelectric vibrator 3 was bonded to the back braking material 40. Four of the back braking members 41, to which the electrostrictive oscillator 2 was wired and bonded, were bonded so as to surround the cylindrical back braking member 40. The acoustic matching layer 53 and the acoustic lens 54 were adhered so as to cover the entire surface of the circular vibrator formed thereby. A flexible printed wiring board is adhered to the side surface of the back braking member 41, but if the thickness of the flexible printed wiring board expands the gap between the four vibrators in the assembly shown in FIG. A recess may be provided on the side surface of the braking member 41 so that the thickness of the wiring board is less likely to affect it.

The acoustic matching layer 53 is formed by mixing epoxy resin with fine particles of tungsten oxide. The thickness was made to correspond to a quarter wavelength of the center frequency of the ultrasonic probe.
Further, the acoustic impedance of the acoustic matching layer of the portion bonded to the electrostrictive oscillator 2 and the acoustic impedance of the portion bonded to the piezoelectric oscillator 3 may be changed. That is, a region having the same diameter as the piezoelectric vibrator 3 but different acoustic impedance is formed in the central portion of the acoustic matching layer 53. At this time, the thickness can be made equal by selecting the acoustic impedance of the material so that the sound velocities of the respective parts become equal.

A copper electrode film (not shown) is formed on the main surface of the acoustic matching layer 53 which is not in contact with the vibrator surface by electroless plating and is grounded to provide a shield for preventing electric shock.

The acoustic lens 54 has a shape obtained by cutting a part of a sphere with a flat surface, and the bottom surface is the same circular shape as the acoustic matching layer 53. The acoustic lens material was formed by mixing silicon rubber with fine silica powder. The speed of sound in this material is about 900 m / s, which is slower than the speed of sound in water.

FIG. 6 (a) shows the layer structure of the ultrasonic probe schematically shown in section in the assembly procedure of FIG. 5 (c). When the electrostrictive oscillator 2 and the piezoelectric oscillator 3 are made of a flexible composite material and are supported by the back braking members 40 and 41, the oscillator surface can be concave. As a result, the configuration as shown in FIG. 6B can be obtained by omitting the acoustic lens 54 and using the protective film 61. With this configuration, the acoustic lens 54 of FIG.
Since the configuration can be omitted, it is possible to prevent the decrease in sensitivity caused by the attenuation due to the acoustic lens material.
In FIG. 6, 110 to 115 and 121 to 124 are shown in FIG.
Alternatively, it is similar to that described in FIG.

Next, the operation of the ultrasonic probe having such a configuration will be described. FIGS. 3A and 3B show an example of a selection method when the electrodes shown in FIGS. 1A and 1B are in operation. First, the electrodes in the shaded area in FIG. 3A are connected to the ultrasonic wave transmitting / receiving circuit. These are the electrodes 111a, 111c, 112a, 112c, 113a, 11 of FIG.
3c, 114a, 114c, 110e. Further, among the electrodes in FIG. 3B, the electrodes in the shaded area are connected to the bias voltage applying circuit, and the other electrodes in FIG. 3B are grounded.

In this connected state, the piezoelectricity is induced by the bias electric field, and the region in the plane of the transducer connected to the ultrasonic wave transmitting / receiving circuit is as shown in FIG. 3 (c). Elements 30 and 31a to 35 effective for transmission and reception are provided in the ultrasonic probe.
a, 31b to 35b are formed. The area effective for transmitting and receiving ultrasonic waves can move the electrode selection position in FIG. 3B to a rotationally symmetric position around an axis passing through the center of the circle.

When the moved region includes the four-division line of FIG. 3 (a) inside, all the electrodes of FIG. 3 (a) are connected to the ultrasonic wave transmitting / receiving circuit. For example, in FIG. 1A, the two areas selected in FIG. 3B are 111a to 114a and 111d to 111d.
When the dividing line between 114d and the dividing line between 111c and 114c with 111b to 114b is covered, 111a to
The same transmission signal group is transmitted to the electrodes 114a and 111d to 114d, and the reception signals are also added for each electrode at the same radial position.

Similarly, 111b to 114b and 111c to 1
The signal on the electrode of 14c is also processed. In this method,
The electrode selection area of (b) sequentially moves to reach the position as shown in FIG. 1 (a) every ¼ rotation, and the number of electrodes involved in transmission / reception of signals from the ultrasonic transmission / reception circuit becomes about half.

The same operation can be performed even if all the electrodes shown in FIG. 3A are always used to transmit / receive a transmission / reception signal. In this case, the same transmission signal group is transmitted in each of vertically and horizontally divided FIG. 3 (a), and the received signals are also added for each electrode at the same radial position, and the divided position for dividing the same is shown in FIG. 1 when the electrode selection area in (b) reaches 1/4 rotation
/ 4 turn. In any of these cases, a group of electrodes 121 and 122 selected in FIG. 3 (b) must be selected from the inside of two fan shapes having a central angle of 90 degrees, which are symmetrical to each other by 180 degrees.

The number of equal divisions of the area of FIG.
Then, the central angle of the fan-shaped region in FIG. 3B where the selection of electrodes is allowed is (180-360 ÷ N) degrees.

If the isolation between the piezoelectric induced region and the non-induced region due to the bias voltage is insufficient due to the material characteristics of the electrostrictive oscillator 2 and the like, the division number N in FIG.
Can be increased so that transmission and reception are not performed through the electrodes (channels) in the regions where the selected regions in FIG. 3B do not overlap.

The element 3 thus formed
It is also possible to use 0, 31a to 35a and 31b to 35b to perform tomographic image imaging by the phased array method in the same manner as in the conventional sector scanning ultrasonic probe.

As shown in FIG. 4 (a), an ultrasonic beam B for scanning is formed in the subject by using the element group R, and the focal point of the ultrasonic beam B is moved in the distance direction from R or the array direction of the element group is arranged. Ultrasonic pulses are transmitted and received while being deflected in the (longitudinal direction). Information on the tomographic plane S can be obtained based on the intensity distribution of the reflected echo and the Doppler information.

When the element group R is moved while being sequentially rotated by the selection method of FIG. 3, the ultrasonic beam B and the tomographic plane S to be formed are also rotated around the rotation axis C, so that it is shown in FIG. 4B. Information in such a stereoscopic imaging region V is obtained. In the case of scanning the tomographic plane S in this case, if the ultrasonic scanning is performed densely as the distance from the rotation axis C increases, the scanning density in the region can be made uniform.

As the imaging method, not only the tomographic plane S is sequentially rotated, but also only the two orthogonal cross sections are imaged, and the rotational position and the superposition of the element group R necessary for scanning a part of the three-dimensional area are used. It is also possible to send and receive sound waves.

FIG. 7 shows an example of the apparatus configuration when an image is picked up using the ultrasonic probe of the present invention. X and Y are electrode groups corresponding to FIGS. 1 (a) and 1 (b), respectively. For convenience of illustration, Y has the number of divisions in the angular direction in FIG. 1 (b) reduced.

The electrode group X is connected to the variable delay lines 71a to 71e. These can be realized, for example, by configuring the terminations of a large number of LC delay line groups with taps to connect to a multiplexer circuit and select the multiplexer circuit according to an external input. The control circuit 77 sequentially sets the delay times according to the phased array method. Variable delay line 7
Each of 1a to 71e also has a function of adding the received signals from the elements that it has at that time.

Each of the variable delay lines 71a to 71e is a driver 73 for transmitting ultrasonic waves and an adder 74.
To the coupler 72 via the coupler 72. The adder 74 may include an amplifier. The output of the adder 74 is converted into a digital signal by the A / D converter 81 and held in the memory circuit 78. The storage circuit 78 can be configured by a buffer memory that holds signal data corresponding to one ultrasonic pulse reception signal that has been A / D converted at high speed, and a DRAM that can hold them in sequentially designated storage areas.

The electrode group Y is connected to the matrix switch 76 except for the central electrode. The matrix switch 76 is connected to the DC amplifier 75 that applies a bias voltage and the ground point. The control circuit 77 designates the bias potential of each electrode as the output of the DC amplifier 75 or the ground point. The arithmetic unit 79 converts the tomographic image information and the stereoscopic image information into data for display based on the signal held in the memory circuit 78 and outputs the data to the display unit 80. These operations are defined by the control circuit 77.

The arithmetic unit 79 and the display unit 80 are, for example,
It may be a microcomputer equipped with a microprocessor and a CRT for output from the terminal. In addition, the control circuit 77
Can also be composed of a microprocessor and a ROM.

The following operations are possible as an example for performing image pickup with such a configuration.

First, the memory circuit 7 is output by the output of the control circuit 77.
The buffer memory 8 is refreshed and the initial storage address of the DRAM is initialized. The control circuit 77 sends a selection control signal to the matrix switch 76 in order to specify the acoustic opening in the ultrasonic probe for transmitting and receiving ultrasonic waves.
Output to. As a result, a bias voltage is applied to a part of the electrode group Y as shown in FIG. 3B, and the rest is grounded.

The control circuit 77 outputs a signal voltage to the DC amplifier 75, and a predetermined DC bias voltage is output to the connection point of the matrix switch 76. Matrix switch 76
According to the connection state of, the piezoelectricity induced by the bias voltage is induced in a part of the electrostrictive oscillator 2. The circular electrode at the center is always connected to the ground point and remains selected, and since the piezoelectric vibrator 3 is sandwiched between the facing electrodes, this portion always operates as a vibrator.

In order to transmit the ultrasonic pulse so as to converge it to one point in the subject, the control circuit 77 provides the variable delay lines 71a to 71e connected to the electrode group X with delay times according to the phased array method. Set. These operations can be realized by designating selection of a predetermined tap by the multiplexer circuit in the above-mentioned configuration. In many cases, the same delay time group is set for each of the two electrodes that divide the electrode group X excluding the central circle portion vertically or horizontally.

The driver 73 outputs a transmission pulse signal to the electrostrictive vibrator 2 via the coupler 72 and the variable delay lines 71a to 71e according to the trigger input from the control circuit 77. The coupler 72 transmits the transmission pulse signal to the variable delay lines 71a to 71e.
It is connected only to the side and not to the adder 74. Figure 3 (c)
The element group as described above is excited by the transmitted pulse signal voltage, and the ultrasonic wave is transmitted toward the convergence point in the subject. As a result, the echo is reflected from the acoustic impedance interface in the subject.

Immediately after the ultrasonic wave transmission signal is transmitted, the control circuit 77 changes the delay time of the variable delay lines 71a to 71e to the setting for receiving the wave. Immediately after the transmission, a delay time distribution corresponding to a small focal length for phasing addition of received signals from a short distance inside the subject is set, and then gradually changed to a larger focal length as time passes. .. These are set according to the propagation speed of sound waves in the subject. Immediately after the wave transmission, the coupler 72 includes a driver 73 and variable delay lines 71a to 71e.
Connect only between.

Each variable delay line adds the received signals from the connected elements, and its output is the adder 74 for the entire signal.
Will be input. Adder 7 from short distance to long distance
The received echo signal output from the A.D.4 is the A / D converter 81.
Is converted into a digital signal via and is output to the storage device 78.

In the memory circuit 78, after the signal data corresponding to one A / D converted ultrasonic pulse reception signal is held in the buffer memory, they are successively stored in a memory area such as a DRAM of a designated address. The operation of storing the reception signal is continued until the echo is received from the portion corresponding to the deepest part in the subject.

Next, in order to transmit the ultrasonic pulse so as to converge on another point in the subject, a series of transmission / reception operations are performed again. In this case, the delay time is set in a direction different from the previous transmission / reception deflection direction, and the reception signal data is held in the storage circuit 78 again.

When a large number of such scans are repeated, the received signal of the entire B-mode image corresponding to the tomographic plane S in FIG. 4A based on the element arrangement in the ultrasonic probe set at the time of transmitting waves. The data is held in the memory circuit 78.

The control circuit 77 outputs a new selection control signal to the matrix switch 76 in order to rotate the arrangement of the elements in the ultrasonic probe. As a result, as shown in FIG. 3B, a part of the electrode group Y in which the piezoelectricity is induced rotates. Ultrasonic transmission / reception scanning is performed at the element position, and the reception signal data of the entire B-mode image at the new rotated position is held in the storage circuit 78.

The operation of holding the received signal data of the entire B-mode image in the memory circuit 78 is performed by the matrix switch 76.
It is repeated according to the rotation of the element arrangement in the ultrasonic probe by the selection of. When the rotation reaches 180 degrees, the storage circuit 78 retains the entire information in the truncated cone-shaped imaging area as shown by V in FIG. 4B.

When a series of ultrasonic scanning is completed, the arithmetic unit 79 performs arithmetic processing for imaging various measured quantities based on the received data held in the memory circuit 78 by the output of the control circuit 77. The various measurement quantities may be echo reflection intensity, Doppler information, and the like. The arithmetic processing refers to, for example, detection processing of RF signals accumulated in the storage circuit 78, filter processing, gain correction processing, coordinate conversion processing, contour extraction processing, and the like. The measured amount visualized by brightness modulation or the like is displayed on the display device 80.
Displayed to the inspector.

A second embodiment of the present invention will be described with reference to FIG. A disk-shaped electrostrictive oscillator 21 was used as the oscillator material. The method of forming the electrostrictive material and the electrode is the same as in the first embodiment. The electrode on the first main surface was divided as shown in FIG. Electrodes 110a to 110d, 111a to 111d, 1
12a to 112d, 113a to 113d, 114a to 114
Reference numerals d and 115a to 115d denote concentric circles divided into four equal parts at the central angle. FIG. 2C shows a cross-sectional view, and 110 indicates any of 110a to 110d, and 111, 112, 113, 114, 11
The same applies to 5. The electrodes on the second main surface of the vibrator were divided as shown in FIG. 2 (b). Electrodes 122 and 123
Are divided into concentric circles and then finely divided into equal angles at the central angle. However, any of the minute divisions at the same angle was made to coincide with the equal angle four divisions shown in FIG.

The electrostrictive vibrator 21 having electrodes formed on both principal surfaces in this manner was cut into four pieces along the four-divided positions of the equiangular electrodes shown in FIG. 1 (a). The method of wiring to the vibrator and the method of assembling the ultrasonic probe are similar to those in FIG. 5 showing the assembling in the first embodiment. There is no piezoelectric vibrator 3 in the central portion of FIG.
The back braking member 42 has a shape having a fan shape obtained by dividing an ordinary cylinder into four on the bottom surface. An extremely thin flexible printed wiring board was adhered between the electrostrictive vibrator 21 and the back braking material 42 to connect to the electrodes 123 and 124 in FIG. 2 and extend along the radial side surfaces of the fan. This replaces the wiring to the electrode 121 by the flexible printed wiring board 51a in FIG.

The operation when imaging or measuring is performed using the ultrasonic probe of this configuration is the same except that the central piezoelectric vibrator 3 in the first embodiment is not provided.
As an example of the device configuration when performing imaging or measurement, it is conceivable that only a part of FIG. 7 is modified. In FIG. 7, the circular electrode at the center of the electrode group X is omitted from the configuration, and the variable delay line 71e is also omitted. As the central circular electrode is divided into four, the number of electrodes connected to 71a to 71d increases by one. The central electrode of the electrode group Y is also omitted. Except for this change, the operation when imaging or measuring is the same as in the first embodiment.

In the first and second embodiments of the present invention described above, the number of divisions in the radial direction and the angular direction of the electrode on the main surface in FIGS. 1 (a) (b) and 3 (a) (b). Is not limited to the number of this embodiment, and can be increased.
The shape of the acoustic lens in FIGS. 5 and 6 does not have to be a part of a sphere as in this embodiment. Further, there are many conceivable measurement device configurations for obtaining three-dimensional information using the ultrasonic probe of the present invention, not limited to the case of the present embodiment.

[0063]

According to the present invention, the two-dimensional array ultrasonic probe conventionally required for three-dimensional imaging can be realized with a relatively small number of channels. Conventionally according to the present invention
The number of channels required for about 00 channels was reduced to about 200 channels, and the scale of the attached circuit could be significantly reduced, and the cost could be reduced.

By using the ultrasonic probe of the present invention in an ultrasonic measuring device, it is possible to easily extend the measurement information, which has been mainly based on a tomographic image, to a three-dimensional area. This makes it possible to three-dimensionally understand the structure and Doppler information inside the subject.

[Brief description of drawings]

FIG. 1A is a plan view and FIG. 1C is a sectional view showing an electrode structure of an ultrasonic probe according to a first embodiment of the present invention.

FIG. 2A is a plan view and FIG. 2C is a sectional view showing an electrode structure of an ultrasonic probe according to a second embodiment of the present invention.

FIG. 3 is a plan view showing a method for selecting the aperture position of the ultrasonic probe according to the present invention.

FIG. 4 is an explanatory diagram showing a three-dimensional imaging method using an ultrasonic probe according to the present invention.

FIG. 5 is a perspective view showing the assembly of the ultrasonic probe according to the present invention.

FIG. 6 is a sectional view of an ultrasonic probe according to the present invention.

FIG. 7 is a block diagram showing a circuit configuration of an apparatus for performing measurement using the ultrasonic probe according to the present invention.

[Explanation of symbols]

110-115 ... Signal side electrode, 120-122 ... Bias side electrode, 2 ... Electrostrictive oscillator, 3 ... Piezoelectric oscillator, 40-4
1 ... Rear braking material.

Front page continuation (72) Inventor Yuichi Sanwa 1-280, Higashi Koigokubo, Kokubunji, Tokyo Inside the Central Research Laboratory, Hitachi, Ltd.

Claims (6)

[Claims] 1. An electrostrictive material in which piezoelectricity is induced by a bias voltage in an ultrasonic probe including a vibrator as a means for converting ultrasonic waves and electric energy, and a backside braking material holding the vibrator. The first and second electrodes provided on both main surfaces of the disk are divided into three or more sectors, and one or both of the first and second electrodes are divided into a plurality of concentric circles from the center. An ultrasonic probe characterized by being used as a vibrator. 2. The ultrasonic probe according to claim 1, wherein, in dividing the electrodes on the both principal surfaces, the first and second electrodes in a region within a minimum radius of concentric division are circular electrodes. 3. The ultrasonic probe according to claim 2, wherein a portion of the vibrator sandwiched by the circular electrodes is made of a piezoelectric material. 4. The method according to claim 1, 2 or 3, wherein one of the first and second electrodes is 4 in the angular direction.
An ultrasonic probe divided into the above even numbers. 5. The ultrasonic probe according to claim 1, comprising any one of the ultrasonic probes, wherein an electrode group on one main surface of the transducer of the ultrasonic probe is used as a transmission / reception circuit. connection,
An ultrasonic measuring device in which a bias voltage inducing means capable of selecting each electrode is connected to an electrode group on the other main surface. 6. The rear braking material according to claim 1, 2, 3 or 4, wherein the back braking material is divided into substantially the same shape as a part or all of the division of the electrodes on at least one main surface of the vibrator in the angular direction. A method for manufacturing an ultrasonic probe, in which a bias voltage supply line or a signal line is wired using the cross section of the backside braking material that has been formed.