JPH0218093B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION BACKGROUND OF THE INVENTION A. Technical Field The present invention relates to an ultrasound probe and a method for manufacturing the same.

B. Prior art and its problems Ultrasonic probes are generally widely used as probes in ultrasonic diagnostic devices that can observe tomographic images of living organisms in real time, and ultrasonic flaw detection devices for non-destructive testing. It's being used.

Ultrasonic probes use ultrasonic waves for information purposes, so in addition to a transducer that generates ultrasonic waves to increase directivity and S/N ratio, there is also a transducer that matches the acoustic impedance of the object. It has a laminated structure including a matching layer, an acoustic lens that converges the sound waves generated by the vibrator, and a backing material that absorbs the free vibrations of the vibrator and the ultrasonic waves emitted from the back surface. Conventionally, each component of a probe, such as the backing material, vibrator, matching layer, and acoustic lens, was manufactured separately and then glued together in a predetermined order using an adhesive to manufacture the probe. That's what I was doing. However, this method requires an extremely large number of processing and bonding processes, such as when manufacturing an electronic scanning ultrasound probe in which many transducers are arranged one-dimensionally in an array, making the manufacturing process complicated. Therefore, there was a drawback that the characteristics of the probe deteriorated due to the accumulation of variations in processing and assembly accuracy in each process.

In addition, when cutting transducers into strips to make an array in order to facilitate one-dimensional arrangement of transducers, if the backing material attached to the back side of the transducer is rubber-based (silicone rubber, etc.), The material alone lacks mechanical strength and is not suitable for the base used to cut the vibrator with a scribing dicer. Proposals have been made to bond retaining plates such as the above, but the disadvantage is that the process of adhering and peeling off the retaining plates increases, making the work cumbersome and time-consuming.

A linear scanning type probe, in which transducers are arranged in a straight line, cannot scan curved parts such as the chest or neck of the human body, and in order to scan these curved or free surfaces, non-linear A scanning type probe is required, but there is a manufacturing problem in that it is extremely difficult to process and cut the curved surface of the vibrator, which has hindered its practical use.

Purpose of the Invention Therefore, the present invention provides a method for manufacturing an ultrasonic probe with good characteristics and high stability by shortening the manufacturing process, and a method for manufacturing such an ultrasonic probe. The purpose is to provide.

According to the present invention, electrodes are attached to both main surfaces of a flat piezoelectric material, lead wires are connected to the electrodes, and an acoustic matching layer is provided on one main surface of the piezoelectric material to form a vibrator body. The main body of the vibrator is cut into parts leaving at least a part of the matching layer to form a multi-element array, and the divided main body of the vibrator is divided into a mold hole for acoustic lens molding and a mold hole for backing molding. A mold that communicates with each other is set so that the one and the other main surfaces face the acoustic lens molding mold hole and the backing molding mold hole, respectively, and a fluid acoustic material is injected into the mold. Then, the periphery of the transducer body is molded to form an ultrasonic probe in which the acoustic lens part and the backing part are integrated.

According to one aspect of the present invention, in the method of manufacturing an ultrasound probe, the transducer body is set into a mold so that the longitudinal axis of the transducer body is substantially vertical.

According to the present invention, the following ultrasonic probe is provided. In other words, in this ultrasonic probe, electrodes are attached to both main surfaces of a flat piezoelectric material, lead wires are connected to these electrodes, and an acoustic matching layer is provided on one main surface of the piezoelectric material. The vibrator body has an array shape divided into a plurality of elements with at least a part of the matching layer remaining, and the vibrator body divided in this way is molded to cover the periphery. An acoustic lens portion is integrally formed on the one principal surface side of the vibrator body, and a backing portion is integrally formed on the other principal surface side of the acoustic material.

According to one aspect of the present invention, the ultrasonic probe is a conductive pattern in which lead wires are formed on a flexible substrate.

According to another aspect of the present invention, the matching layer in the ultrasonic probe is formed of a flexible member, and the array-shaped transducer body divided into a plurality of elements is held and molded on a curved surface. be.

According to another aspect of the present invention, the back surface of the backing portion of the ultrasonic probe has a rough surface.

According to another aspect of the present invention, the matching layer in the ultrasonic probe has multiple layers each having a different acoustic impedance.

According to another aspect of the invention, an ultrasound probe includes:
Molded with an integrated case.

DETAILED DESCRIPTION OF THE INVENTION Next, an ultrasonic probe and a method for manufacturing an ultrasonic probe according to the present invention will be described in detail with reference to the accompanying drawings.

As shown in the embodiment shown in the center of FIG. 1, a piezoelectric material 10 made of ceramic, polymer, or ceramic composite polymer is formed into a flat rectangular shape as a whole.
Then, a conductive material such as silver is deposited by vapor deposition, printing, etc., and electrodes 12 and 14 are provided on the main surfaces located at the top and bottom of the figure. In the case of an array type probe, as shown in FIG. 1, one of the two electrodes 12 is
It is folded back to the other main surface on which the electrode 14 is located via the side surface 16 to facilitate connection with a lead wire to be described later. The electrodes 12 and 14 are electrically separated by a longitudinally extending slit 18.

Next, lead wires are connected to the electrodes 12 and 14 attached to the piezoelectric material 10, but in the case of an array type, a substrate made of a flexible insulating material is used. That is, as shown in the lower part of FIG. 1, an opening 22 having a width at least a little smaller than the rectangle of the piezoelectric material 10 is provided in the upper part of a flexible substrate 20 made of polyimide or the like, which is entirely formed into a rectangular flat plate. ,
A first conductive pattern 24 and a second conductive pattern 26 having shapes as shown in the figure are formed around this opening 22. Both patterns are formed by depositing a foil of a conductive material, such as copper, on the main surface of the substrate 20. The first conductive pattern 24 has an opening 22
The second conductive pattern 26 includes an extending portion 28 along one long side of the opening 22 and a lead portion 30 connected to an external circuit. and a large number of lead parts 34 connected to external circuits. First conductive pattern 2
4 serves as a common electrode lead wire for a large number of ultrasonic transducers 40 (see FIG. 2) included in the ultrasonic probe 60 (see FIG. 7). The conductive patterns 26 form the lead wires of individual electrodes of a large number of ultrasonic transducers. Therefore, in this example, the lead portions 34 of the second conductive pattern 26 are provided in correspondence with the number of transducers included in the completed ultrasound probe. Furthermore, a cover film made of polyimide or the like is applied so as to cover the lead portion except for the extension portion.

Next, as shown in the upper part of FIG.
A matching material 36 is prepared as a matching layer, which is formed into a rectangular shape that is slightly longer and much wider than the rectangle shown in FIG. This matching material 36 has a predetermined thickness, and after being completed as an ultrasonic probe, it alleviates the difference in acoustic impedance between the object and the transducer and suppresses reflections occurring at the boundary with the object. This is to effectively output ultrasonic waves to the load side. When the probe is a nonlinear array with a curved surface, the alignment material 36 is preferably a flexible polymer film or the like, for example, a polymer composite material in which a ceramic with high acoustic impedance or dungsten powder is added to a polymer. Can be used. This alignment material 36 also functions as a holding stand when cutting the piezoelectric material 10.

By the way, according to the method of manufacturing an ultrasound probe according to the present invention, the piezoelectric material 10 provided with the electrodes 12 and 14 is placed in the orientation shown in the center of FIG. The opening 22 is connected to the piezoelectric material 1.
Place it so that it overlaps with the 0 rectangle. In this state, the respective lead portions 28 and 32 of the first and second conductive patterns 24 and 26 and the portions of the electrodes 12 and 14 that are in contact with these, respectively, are joined by soldering or the like. In this case, it is advantageous in terms of process to heat the substrate 20 from the back side. As a result, the electrodes 12 and 14 are connected to the first and second electrodes, respectively.
This means that the lead portions 30 and 34 of the conductive patterns 24 and 26 are electrically connected.

Next, on the piezoelectric material 10 mounted on the substrate 20 in this way, an alignment material 36 shown in the upper part of FIG.
is placed so that it is aligned with the upper main surface (electrode 12 side) of the piezoelectric material 10, and
(see figure). The alignment material 36 is bonded only to the main surface of the piezoelectric material 10, using an adhesive such as epoxy resin.

Next, in the case of an array type, as shown in FIG. 2, with the matching material 36 on the lower side, both sleeves of the substrate 20 are pressed against the matching material 36, and the piezoelectric material 10 is cut with a thin grinding wheel such as a scribing dicer. Cuts 38 are made in the width direction to equally divide the piezoelectric material 10 in the longitudinal direction.

As shown in FIGS. 2 to 4, the cut 38 extends through the substrate 20 and the respective extensions 28 and 32 of the first and second conductive patterns 24 and 26 attached to the substrate 20. From the electrode 14 of the piezoelectric material 10 to the piezoelectric material 10 and the electrode 12,
The alignment material 20 is slightly cut into the alignment material 20 until its tip completely separates the extension portion 32 (the tip position of arrow A in FIG. 1) and its lower side completely separates the electrode 12. ing. Further, the interval, that is, the pitch between two adjacent notches 38 is equal to the arrangement pitch of the plurality of lead portions 34 of the second conductive pattern 26, and one notch 38 is positioned approximately at the center of the two adjacent lead portions 34. Thus, adjacent lead portions 34 are electrically disconnected from each other. The tip 41 of the cut 38 must not reach the end 36 of the first conductive pattern 24 (which in this example is also the end of the flexible substrate 20), and the first conductive pattern 24 It is continuous without being divided by (see arrow B in Figure 1).
As a result, a main body portion of the ultrasonic probe including a large number of ultrasonic transducers 40 is formed.

Next, as described above, the piezoelectric material 10 is sandwiched between the substrate 20 and the matching material 36, and cuts 38 are made as necessary to form a large number of vibrators 40 in the vibrator body 3.
7, both long and short sleeve parts 42 and 44 of the board 20
The vibrator 40 and the matching material 3 are placed in a mold 46 shown in FIGS. 5 and 6 while being bent upward in a U-shape in FIG.
6. Install it so that no distortion occurs. Type 46
is for linear scanning, and consists of a flat plate base 48 and a box-shaped frame 50 separate from the base 48. A mold hole 52 for an acoustic lens with a partially circular cross section is bored in the upper surface of the base 48. is provided. On the other hand, the frame 50 is formed wider and longer than the piezoelectric material 10;
The internal space surrounded by the hole 54 forms a punching mold hole 54. When setting the vibrator main body 37 in this mold 46, the alignment material 36 is placed flat on the stand 48,
The piezoelectric material 10 is positioned directly above the acoustic lens mold hole 52, and then the frame 50 is mounted on the stand 48. At this time, the width of the alignment material 36 is adjusted using the groove 55 provided at the lower end of the frame 50. Position and fix by holding down the part that extends in the direction. When the vibrator main body 37 is attached to the mold 46, the first conductive pattern 24 on the substrate 20
The sleeve 44 on the extended portion 28 side is lower than the upper end of the frame 50, and is therefore buried together with the mold described later. Further, the lead portion 30 on the substrate 20,
The sleeve 42 on the 34 side protrudes further upward from the upper end of the frame 50, and when molded, it protrudes to the outside and can be easily connected to a connector (not shown). The longitudinal end of the acoustic lens mold cavity 52 in the mold 46 extends to the outside of the matching material 36, as shown in FIG. 6, and communicates with the bucking mold cavity 54. Therefore, when the inside of the mold is molded, the two holes 52 and 54 are filled with this molding material and are integrated.

After the vibrator body 37 has been attached to the mold 46, a casting resin made of a fluid acoustic material is injected into the mold 46 (see arrow C in FIG. 6) and solidified to form the vibrator body. Mold around 37,
At this time, the acoustic lens section 56 is attached to the matching material 36 side of the transducer body 37 (the front side of the completed probe), and the bucking section 58 is attached to the substrate 20 side of the transducer body 37 (the rear side of the completed probe). The vibrator body 37 is integrally formed and embedded and fixed within the molded portion (see FIGS. 7 to 9). Acoustic lens section 56
is for contacting the subject and converging the ultrasonic waves, and preferably has an acoustic impedance close to that of the subject (1.5×10 ⁵ g/cm ² ·s for a living body). The bucking part 58 increases the ultrasonic output to the front load by reflecting the ultrasonic waves emitted in the opposite direction to the ultrasonic output direction of the probe, that is, to the back side, thereby improving the sensitivity of the probe. It serves as a reflective material to improve the response of the probe, or as an absorbing material that sharpens the ultrasonic pulse by absorbing the ultrasonic waves radiated to the back surface. For this reason, it is desirable that the backing material has a high absorption rate and low acoustic impedance; for example, it is preferable that the echo from the back side of the backing material be about -80 dB. Therefore, silicone rubber and the like are suitable materials that function as both an acoustic lens and a backing material. Note that the cross-sectional shape of the acoustic lens mold hole 52 is similar to that of the acoustic lens portion 56 formed by molding.
The curvature r is set so that r=F(1-v _p /C) F: focal length v _p : sound speed in the subject C: sound speed of the mold member.

When the casting resin is completely solidified, the mold part is removed from the mold 46, and the unnecessary portion of the matching material 36 shown by the two-dot chain line in FIGS. 7 and 8 is cut off. As a result, the ultrasonic probe 60 including the acoustic lens section 56 and the backing section 58 is completed.

FIG. 10 shows another example of the configuration of the matching material 36.
In the same figure, the matching materials are the first matching material 36A and the second matching material 36A.
The acoustic impedance of each of the matching materials 36A and 36B is changed in stages to improve the matching and improve the output efficiency and responsiveness of ultrasonic waves. . Two matching materials 3
6A and 36B are bonded with adhesive in advance and then joined to the piezoelectric material 10. In the case of an array type, the notch 38 in the transducer body is cut to a part of the first matching material 36A or to a part of the second matching material 36B on the transducer side, as shown in FIG. 11 or 12. do.

In FIG. 13, the back surface of the bucking part 58 is
An example is shown in which the value is 9. As shown in Fig. 14, the vibrator 40
This is a diffuse reflection of ultrasound waves emitted from the back toward the back, reducing noise components caused by back echoes.
When injecting the acoustic material into the mold, the bucking part 58
Since the back side of the is open, it is possible to easily form a rough surface by pressing a mold material with a rough surface. Difficulties such as forming surfaces are eliminated.

FIG. 15 shows an example in which a case 62 of an ultrasonic probe is attached together when molding the periphery of the transducer main body 37A. The case 62 is open at a portion corresponding to the acoustic lens mold hole 52, and is box-shaped as a whole. This case 62 is molded into mold 4 before resin injection.
Place it inscribed on the inner surface of 6A. A vibrator main body 37A in which the width of the matching material 36 is the same as the inner width of the case 62 and the length of the matching material 36 is slightly shorter than the inner length of the case 62 is placed in the mold 46A, and the sleeve of the matching material 36 is placed in the mold 46A. 64 to the case 6 using the mounting bracket 66.
The case 62 is fixed to the inner opening edge 68 with screws, and then resin is injected to integrate the case 62 on the outer surface of the mold part, thereby shortening the process.

Views A in FIGS. 16 and 17 to A in FIG. 19 show various modifications of the completed ultrasonic probe. FIG. 16 shows a single probe 72 in which only one vibrator 70 is provided, and the entire probe has a cylindrical shape.
The single probe 72 has a simple electrical configuration;
The electrodes of the vibrator 70 are attached only to both main surfaces without being folded back, and wire-shaped lead wires are connected. A matching material 71 may be attached to this vibrator 70 to form a vibrator body. 17 shows curved array type ultrasonic probes 74, 76 with fan-shaped ends, and FIG. 18 shows curved array type ultrasonic probes 74 with fan-shaped ends. In both cases, the scanning range is expanded by arranging transducer arrays 78 and 80 in a convex shape, as shown in FIG. As a manufacturing method of these ultrasonic probes 74, 76, the first
As shown in FIG. 7B and FIG. Molding is carried out with the transducer arrays 78 and 80 held in the curved shape by pressing the extended portions of the matching material 36 with the curved grooves of the frames 50B and 50C. View A in FIG. 19 shows a curved array type ultrasonic probe 82 having a circular arc shape. As shown in Figure C, the transducer array 84 is arranged in a concave shape to increase the scanning line density in the deep part of the subject and improve resolution, as well as to make good contact with curved parts of the subject such as the neck. As shown in FIG. B, this method of manufacturing the ultrasonic probe 82 is such that the upper surface of the base 48D of the mold 46D is an upwardly convex curved surface, and the matching material 36 is connected to the frame 50D.
It is made by holding it in a curved shape to eliminate distortion, and then applying a mold to it. In FIG. 17B to FIG. 19B, if a notch 85 is made in the sleeve 42 of the substrate 20, the array can be easily curved.

FIG. 20 shows an example in which molding is performed using a vertical mold. If the main surface of the vibrator body 37 (the main surface of the alignment material 36) is placed in the mold 46 with the horizontal axis facing downward and the horizontal axis is horizontal, the alignment material 36 will bend due to the weight of the vibrator body 37 and the weight of the mold material. This will cause distortion in the vibrator. In FIG. 20, the vibrator body 37
By attaching it to the mold 86 with its horizontal axis perpendicular, the deflection of the alignment material 36 is reduced and the flatness of the vibrator surface is improved. The vibrator body 37 is made of matching material 36
is pressed by the L-shaped frame 88 and the plate frame 90 against the underframe 92 in which the acoustic lens mold hole 52 is provided, and the substrate 2
A sleeve 42 provided with a lead portion of 0 is pressed against and fixed to a plate frame 90 by an L-shaped frame 88. Since the acoustic lens mold hole 52 is located vertically, the mold material is densely poured by its own weight during the casting operation, so there is an effect that no undesirable air bubbles remain in the acoustic lens portion.

Specific effects of the invention According to the ultrasonic probe and the method for manufacturing an ultrasonic probe of the present invention, the formation of an acoustic lens and a backing material, the adhesion of a transducer and a backing, and the bonding of a matching material and an acoustic lens. Bonding is done simultaneously in a single process. Therefore, the number of steps required for manufacturing can be significantly shortened, and product costs can be reduced. Furthermore, by sandwiching the vibrator between the matching material and the substrate, relatively large strength can be obtained, so that it can be easily divided into arrays without requiring any extra steps. Further, by making the matching material flexible, a probe having an arbitrary curved surface can be easily manufactured. Furthermore, since the connection between the vibrator and the external circuit is made using a substrate, highly accurate mechanical dimensions can be obtained, and the use of such a substrate also provides good compatibility with molding operations.

The ultrasonic probe provided in this way avoids the accumulation of variations by shortening the manufacturing process, reduces acoustic impedance discontinuities within the probe, and has a A material with low acoustic impedance is interposed, which reduces interference between vibrators during vibration, improves and stabilizes the characteristics of the probe, and has the effect of increasing water resistance and mechanical strength. .

[Brief explanation of drawings]

FIG. 1 is an assembled perspective view illustrating the manufacturing process of the vibrator body, FIG. 2 is a perspective view illustrating the process of cutting the vibrator, and FIGS. 3 and 4 are the same as in FIG.
5 is a partially cutaway perspective view illustrating the molding process of the probe,
Figure 6 is a sectional view taken along the - line in Figure 5;
The figure is an external perspective view showing the completed ultrasonic probe after being demolded after molding, and Figures 8 and 9 are -
10 to 12 show a modified example in which the matching layer is multilayered, and FIG. 10 is a partially cutaway perspective view, and FIG. 11 and FIG.
Fig. 2 is a partial sectional view, Fig. 13 is a needle perspective view showing a modification of the bucking part, and Fig. 14 is a - of Fig. 13.
15 is a partially assembled perspective view showing an embodiment in which a case is integrated with an ultrasonic probe and molded, and FIGS. 16 to 19 are modified examples of the ultrasonic probe. Figure A in Figures 16 and 17 to Figure A in Figure 19 are perspective views showing completed probes, and Figures B in Figure 17 to Figure B in Figure 19 show the molding process. The configuration diagrams to be explained, Figure C in Figure 17 to Figure C in Figure 19 are explanatory diagrams of the operation of the probe, respectively, Figure 20 is a perspective view showing another example of the molding process, and Figure 21 is a diagram showing the operation of the probe. FIG. 21 is a plan view of the embodiment shown in FIG. 20; Explanation of symbols of main parts, 10...Piezoelectric material, 1
2, 14... Electrode, 20... Substrate, 36, 36
A, 36B... matching material, 37, 37A, 37B,
37C... Vibrator body, 38... Notch, 46,
46A, 46B, 46C, 46D, 86... type,
52... Mold hole for acoustic lens, 54... Mold hole for bucking, 56... Acoustic lens section, 58... Bucking section, 62... Case.

Claims (1)

[Claims] 1. Electrodes are attached to both main surfaces of a flat piezoelectric material, lead wires are connected to the electrodes, and an acoustic matching layer is provided on one main surface of the piezoelectric material to generate vibrations. The vibrator body has an array shape divided into a plurality of elements with at least a part of the matching layer remaining, and the divided vibrator body is molded to cover the periphery thereof. An ultrasonic probe characterized in that an acoustic lens part is integrally formed on the one principal surface side of the transducer body and a bucking part is integrally formed on the other principal surface side of an acoustic material. 2. The ultrasonic probe according to claim 1, wherein the lead wire is a conductive pattern formed on a flexible substrate. 3. The matching layer is formed of a flexible member, and the array-shaped vibrator body divided into a plurality of elements is molded while being held on a curved surface. The ultrasonic probe according to item 2. 4. The ultrasonic probe according to claim 1, wherein the back surface of the bucking portion has a rough surface. 5. The ultrasonic probe according to claim 1, wherein the matching layer has multiple layers each having a different acoustic impedance. 6. A step of depositing patterns for forming electrodes and lead wires connected to the electrodes on both main surfaces of a flat piezoelectric material, and providing an acoustic matching layer on one main surface of the piezoelectric material to form a vibrator body. forming the vibrator body using the matching layer as a holding member;
a step of cutting the matching layer leaving at least a part of it and dividing it so as to form a multi-element array, and forming lead wires for a common electrode and lead wires for individual electrodes; A mold in which a lens molding mold hole and a bucking molding mold hole are in communication with each other is arranged such that one main surface side faces the acoustic lens molding mold hole and the other main surface side faces the bucking molding mold hole. and a step of injecting a fluid acoustic material into the mold and molding the periphery of the vibrator body to integrally form an acoustic lens part and a backing part. Probe manufacturing method. 7. The method of manufacturing an ultrasonic probe according to claim 6, wherein the transducer body is set in the mold so that its longitudinal axis is substantially vertical. .