JPH11317999A - Ultrasonic wave vibrator and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To focus an ultrasonic wave beam and to form a focus without the use of an acoustic lens that much attenuates the ultrasonic wave and has a large power loss. SOLUTION: A laminate 24 formed by sequentially stacking a 1st flexible cable 14, a piezoelectric diaphragm 16, a 2nd flexible cable 18, 1st and 2nd matching layers 20, 22 is placed on an upper face of a backing material 12 having a recessed shape on its upper face. A pressing plate 28 with a shape corresponding to an upper face shape of the backing material 12 is pressed from its upper part to connect the flexible cables 14, 18 and an electrode of the piezoelectric diaphragm 16 and the laminate 24 is curved in response to the upper face shape of the backing material 12 to focus an ultrasonic wave beam depending on the shape of the laminate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic oscillator and a method of manufacturing the same, and more particularly to an ultrasonic oscillator for improving an ultrasonic beam focusing method and a method of manufacturing the same.

[0002]

2. Description of the Related Art Ultrasonic diagnostic apparatuses for transmitting and receiving ultrasonic waves to and from a living body as a subject to observe the living body have become widespread. An ultrasonic transducer used for an ultrasonic probe connected to the diagnostic device generally has a laminated structure. For example, focusing on a piezoelectric vibrator that actually generates ultrasonic waves,
A backing material for mechanically damping and widening the frequency band is arranged on the rear surface. on the other hand,
On the front surface of the piezoelectric vibrating plate, two matching layers each corresponding to λ / 4 are arranged. The matching layer, by performing matching between the acoustic impedance of the piezoelectric diaphragm and the acoustic impedance of a living body as a subject,
The transmission of ultrasonic waves is improved. A plurality of electrodes are formed on the front and back surfaces of the piezoelectric vibrating plate. For example, a negative lead wire (flexible cable if necessary) is connected to the front surface side, and a positive lead wire (necessary Flexible cable) is connected according to
A predetermined voltage is applied to the front and back surfaces of the piezoelectric vibrating plate to transmit an ultrasonic wave, and a signal is transmitted by a reflected wave reflected from a living body or the like.

When transmitting and receiving an ultrasonic beam by the ultrasonic transducer, it is necessary to focus the ultrasonic beam. In this case, the focus in the arrangement direction of the vibrating elements constituting the piezoelectric vibrating plate is set by delaying a transmission wave applied to each vibrator during transmission, and delaying a reception wave of each vibrator during reception. (Electronic focus). On the other hand, for focusing of the ultrasonic beam in a direction orthogonal to the arrangement direction of the vibration elements, a focal point is formed at a predetermined position using an acoustic lens, and the resolution in a direction perpendicular to the electronic scanning direction is improved. Since the acoustic lens is in direct contact with the living body, the acoustic lens has a convex shape in order to maintain close contact with the living body.
In this case, since the sound speed in the living body is about 1530 m / sec,
The material of the acoustic lens needs to have a sound speed lower than that of a living body. Generally, a silicone rubber having a sound speed of about 1000 m / sec is used.

[0004]

However, acoustic lenses using silicone rubber have a large temperature dependence of sound speed,
There is a problem that the focus position varies depending on the use environment. Further, an acoustic lens made of silicone rubber has a problem that attenuation at a high frequency is large. This attenuation tends to increase particularly toward the center of the acoustic lens, and there is a problem that the ultrasonic beam characteristics are deteriorated, so that the original performance of the ultrasonic vibrator cannot be sufficiently exhibited.

On the other hand, when the vibrator surface is formed into a concave shape having a curvature instead of using an acoustic lens, there is a problem in that the connection between the electrode of the vibrating element and the lead lead becomes difficult in shape. There is.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to focus an ultrasonic beam and form a focal point without using an acoustic lens having the above problems. And a method of manufacturing the same.

[0007]

In order to achieve the above-mentioned object, the present invention provides a structure in which a sheet-like first flexible cable is provided on an upper surface of a hard backing material having an upper surface having a predetermined curvature. , A piezoelectric diaphragm and a sheet-like second
A laminating step of sequentially laminating a flexible cable and one or more matching layers to form a laminated body, and applying pressure from above or below the laminated body to form the laminated body into a shape along the top surface shape of the backing material. And a deformation step of pressing and deforming the body.

The piezoelectric vibrating plate has a plurality of vibrating elements arranged in a scanning direction, and the backing material has a predetermined curvature in a direction orthogonal to the arrangement direction. Further, the first flexible cable and the second flexible cable are connected to a piezoelectric vibrating plate, and apply a driving voltage of the piezoelectric vibrating plate and transmit a signal by the received reflected ultrasonic beam.

According to this structure, since the piezoelectric vibrating plate and the matching layer are pressed and formed in a shape corresponding to the curved surface of the backing material, the ultrasonic beam transmitted and received from the piezoelectric vibrating plate is directed in the direction corresponding to the curvature. Can be focused. Also,
Since the laminate is pressed and deformed with the piezoelectric diaphragm sandwiched between the first and second sheet-like flexible cables, the connection between the curved piezoelectric diaphragm and each flexible cable can be easily performed.

[0010] In order to achieve the above object, according to the present invention, in the above-described manufacturing method, the deforming step includes:
The stacked body is pressed and deformed by a pressing plate having a pressing surface having a shape corresponding to the top surface shape of the backing material.

According to this structure, the laminate can be easily pressed and deformed by a uniform pressing force.

In order to achieve the above object, according to the present invention, in the above-mentioned manufacturing method, the first flexible cable and one of the two surfaces of the piezoelectric vibrating plate and the second flexible cable are connected to the piezoelectric vibrating plate. The connection between the other electrode of the two surfaces of the plate is performed simultaneously with the pressing deformation of the laminate.

According to this structure, the work of connecting the electrodes can be performed easily and quickly.

In order to achieve the above object, the present invention further comprises a step of interposing an adhesive between the backing material and the laminate and between the laminates of the laminate, And a curing step of curing the adhesive while maintaining the pressed state in the step.

According to this configuration, an ultrasonic vibrator having a laminated body having a shape corresponding to the curved surface of the backing material can be easily manufactured in a series of continuous manufacturing steps.

In order to achieve the above object, according to the structure of the present invention, in the above-mentioned manufacturing method, after the curing step, a groove forming step of forming a groove in the laminated body in order to divide it into an arrayed vibrator. It is characterized by including.

According to this configuration, it is possible to easily produce an array type of vibrator including wirings and the like.

In order to achieve the above object, the present invention comprises a hard backing material having an upper surface having a predetermined curvature, a piezoelectric vibrating plate curved along the shape of the upper surface of the backing material, One or more matching layers curved along the curved shape of the piezoelectric vibrating plate, and a sheet-like flexible cable is closely arranged on the front and back surfaces of the piezoelectric vibrating plate.

According to this structure, the ultrasonic beam transmitted and received from the piezoelectric diaphragm can be focused in a direction corresponding to the curvature. Further, since the laminate is pressed and deformed with the piezoelectric vibrating plate sandwiched between the first and second sheet-like flexible cables, the connection between the bending piezoelectric vibrating plate and each flexible cable can be easily performed.

In order to achieve the above object, the present invention provides a vibrator comprising: a piezoelectric vibrating plate;
A groove is formed in the matching layer to form an arrayed vibrator.

According to this configuration, it is possible to easily produce an array type of vibrator including wirings and the like.

In order to achieve the above object, the present invention is characterized in that the groove is filled with an adhesive.

According to this configuration, it is possible to obtain a curved shape while maintaining the strength of the piezoelectric vibrating plate or the matching layer in which the groove is formed.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention (hereinafter referred to as embodiments) will be described below with reference to the drawings. FIG. 1 shows a state in which the ultrasonic transducer 10 of the present embodiment is pressed and deformed.

First, the configuration of the ultrasonic vibrator 10 will be described. In the case of the present embodiment, the ultrasonic vibrator 10 includes a first flexible cable 14, a piezoelectric vibrating plate 16, a second flexible cable 18, a first matching layer 20, and a backing material 12 having a concavely curved upper surface. A laminate 24 in which the second matching layers 22 are sequentially laminated is formed, and a thermosetting adhesive is interposed between the members. In the present embodiment, an example having a double matching layer will be described, but the number of matching layers can be arbitrarily changed.

The backing material 12 is formed of a hard material obtained by mixing a metal such as tungsten mainly with an epoxy resin, for example, and has a curved upper surface in a scanning direction of an ultrasonic beam transmitted and received by the piezoelectric vibrating plate 16. A concave surface is formed with a predetermined curvature (for example, a curvature radius of 20 mm; curvature ≒ focal length) in a direction perpendicular to the direction. The backing material 12 has a function of mechanically damping the ultrasonic vibration from the piezoelectric vibration plate 16 on the back surface side of the piezoelectric vibration plate 16 to widen the frequency band.

On the concave curved surface of the backing material 12,
A first flexible cable 14 made of a thin sheet-like flexible wiring board is arranged, and can be connected to one or a plurality of electrodes (not shown) formed on the lower surface of the piezoelectric vibration plate 16. Similarly, one or a plurality of electrodes (not shown) are formed on the piezoelectric vibrating plate 16 so that the second flexible cable 18 can be connected thereto. After hardening by, it can be cut by grooving to divide it as an element). In the case of this embodiment, the first flexible cable 14 functions as a thin signal lead,
The flexible cable 18 functions as a ground lead thin plate, applies a predetermined drive voltage to the piezoelectric vibrating plate 16, and sends out a signal based on an ultrasonic beam reflected by a living body to an ultrasonic diagnostic apparatus (not shown).

The piezoelectric vibrating plate 16 may be a single type vibrating element or an array type in which a plurality of vibrating elements are arranged in an array. In the present embodiment, the ultrasonic beam in the vibrating element array direction is controlled by delay control. The description is made by taking an array type vibrating element capable of focusing as an example. As shown in FIG. 2A, the piezoelectric vibrating plate 16 has a plurality of strip-shaped vibrating elements 16 arranged in the direction of arrow A in the figure.
a. Then, focusing in the direction of arrow A can be performed by delaying the transmission / reception wave of each vibration element 16a.

The piezoelectric diaphragm 16 used in this embodiment is
As shown in FIG. 2A, a plurality of cutout grooves 2 are arranged in a direction (direction of arrow B in the figure) orthogonal to the arrangement direction of the vibrating elements 16a.
6 is formed, and by applying an external force in the direction of arrow C in the figure, the sheet can be curved as shown in FIG. At this time, the strength can be maintained by filling the notch groove 26 with an adhesive such as silicone rubber which can maintain flexibility even during curing. Note that FIG.
FIG. 2B shows a state in which the state of FIG. Further, a composite piezoelectric material can be used as the piezoelectric diaphragm 16.

Further, the second flexible cable 1
8, a first matching layer 20 having a thickness corresponding to λ / 4,
The second matching layer 22 is disposed, and the acoustic impedance of the piezoelectric diaphragm 16 and the like is matched with the acoustic impedance of a living body as a subject, thereby improving the transmission of ultrasonic waves.

Next, a description will be given of a method of manufacturing the ultrasonic vibrator 10 having the above-described components.

First, the backing material 12 is placed on a fixing jig (not shown) and an adhesive (for example,
A thermosetting adhesive). Subsequently, the first flexible cable 14 is laminated, and an adhesive is applied to the upper surface thereof,
The piezoelectric vibrating plate 16 is laminated, an adhesive is applied to the upper surface thereof,
The second flexible cables 18 are stacked and arranged. Then, an adhesive is again applied to the upper surface of the second flexible cable 18. Further, the first matching layer 20, the adhesive, the second
The laminated body 24 is formed by laminating in order of the matching layer 22, and the laminating step is completed. At this time, the piezoelectric diaphragm 16 has a flat shape as shown in FIG. Similarly, the first and second flexible cables 14 and 18 and the first and second matching layers 20 and 22 also have a flat shape. That is, the laminate 24 has a flat shape.

Subsequently, a pressure device (not shown) is provided.
The laminate 24 is pressed down from above by a press plate 28 that can be moved up and down. The lower surface (pressing surface) of the pressure plate 28 has a substantially semi-cylindrical shape having a convex shape corresponding to the upper surface shape of the backing material 12, and the laminated body 24 is pressed down from above the laminated body 24 with a uniform predetermined pressure. can do. As a result, the laminated body 24 is curved as shown in FIG. 1 according to the upper surface shape of the backing material 12 and the lower surface shape of the pressure plate 28, and the mutual members are in close contact with each other. At this time, an excess portion of the adhesive applied between the members is extruded from each of the adhesive layers to form an adhesive layer having an optimum thickness.

Then, the adhesive is cured while the pressing plate 28 presses the laminate 24. For example, when a thermosetting adhesive is used as the adhesive, it is put into a thermosetting furnace or the like while maintaining the above-mentioned pressed state, and is subjected to a hardening treatment for a predetermined time. Thereafter, when the pressing is released, the ultrasonic transducer 10 having the curved surface is completed.

As described above, by bending the laminated body 24 according to the preset curved surface shape of the backing material 12, the ultrasonic beam transmitted and received by the piezoelectric diaphragm 16 can be converted into an arrow shown in FIG. Focusing can be performed in the B direction, and the ultrasonic beam can be focused without using an acoustic lens. Further, the first and second flexible cables 14 and 18 have a sheet shape, and can be easily brought into close contact with the front and back surfaces of the piezoelectric vibrating plate 16, and are provided with electrodes formed on the curved piezoelectric vibrating plate 16. The first and second flexible cables 1
Since the positioning connection with 4, 18 can be easily and collectively performed, the production becomes easy.

In addition, since focusing can be performed without using an acoustic lens as in the related art, the output power is less attenuated with respect to the input power, so that the ultrasonic probe can be driven efficiently and more than necessary. Since no input power is required, the temperature rise on the probe surface can be reduced. The same effect can be expected at the time of reception. Further, the direction of the ultrasonic beam can be easily determined according to the shape of the upper surface of the backing material, and the beam characteristics can be easily improved.

In the present embodiment, the case where the upper surface of the backing material has a concave shape has been described as an example. However, a convex shape may be used if necessary. In the present embodiment,
Although an example in which a plurality of notch grooves are formed to bend the piezoelectric vibration plate has been described, even if the grooves are completely separated in a direction along the grooves, the bending and connection with the flexible cable can be easily performed as in the present embodiment. Can be done. Further, after the adhesive is cured in the present embodiment, it is also possible to grooving with a dicing saw and to divide the arrayed vibration elements.

[0038]

According to the present invention, it is possible to easily manufacture an ultrasonic vibrator including a piezoelectric vibrating plate having a curved shape, focus an ultrasonic beam without using an acoustic lens, and form a focal point. It can be performed.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram illustrating a configuration of an ultrasonic vibration manufacturing method and an ultrasonic vibrator according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram illustrating a piezoelectric diaphragm of the ultrasonic transducer according to the embodiment of the present invention.

[Explanation of symbols]

10 ultrasonic transducer, 12 backing material, 14 first
Flexible cable, 16 piezoelectric diaphragm, 18 second
Flexible cable, 20 first matching layer, 22 second
Matching layer, 24 laminate, 26 notch groove, 28 pressure plate.

Claims (8)

[Claims] 1. A sheet-like first flexible cable, a piezoelectric vibrating plate, a sheet-like second flexible cable, and one or more matching layers are provided on an upper surface of a hard backing material having an upper surface having a predetermined curvature. And a deformation step of applying pressure from above or below the laminate and pressing and deforming the laminate into a shape along the top surface shape of the backing material. A method for manufacturing an ultrasonic vibrator, comprising: 2. The manufacturing method according to claim 1, wherein in the deforming step, the laminate is pressed and deformed by a pressing plate having a pressing surface having a shape corresponding to an upper surface shape of the backing material. Manufacturing method of ultrasonic transducer. 3. The manufacturing method according to claim 1, wherein one of the two surfaces of the first flexible cable and the piezoelectric vibration plate and one of the two surfaces of the second flexible cable and the piezoelectric vibration plate. A method of manufacturing an ultrasonic vibrator, wherein the connection between the other electrode is performed simultaneously with the pressing deformation of the laminate. 4. The method according to claim 1, further comprising the step of interposing an adhesive between the backing material and the laminate, and between the laminates. A curing step of curing the adhesive while maintaining the pressed state of the deforming step. 5. The method according to claim 4, further comprising, after the curing step, a groove forming step of forming a groove in the laminated body to divide the laminated body into array vibrators. Manufacturing method. 6. A hard backing material having an upper surface with a predetermined curvature, a piezoelectric diaphragm curved along the upper surface shape of the backing material, and at least one layer curved along the curved shape of the piezoelectric diaphragm. An ultrasonic vibrator, comprising: a matching layer; and a sheet-like flexible cable disposed in close contact with the front and back surfaces of the piezoelectric vibrating plate. 7. The ultrasonic vibrator according to claim 6, wherein grooves are formed in said piezoelectric vibrating plate and said matching layer to form an arrayed vibrator. 8. The ultrasonic vibrator according to claim 7, wherein said groove is filled with an adhesive.