JP7706352B2 - Ultrasonic probe and manufacturing method thereof. - Google Patents

Description

The present invention relates to an ultrasonic probe that has improved directionality and chemical resistance, and a method for manufacturing the same.

One example of an ultrasonic probe is disclosed in Patent Document 1. Fig. 7 is a side view of a conventional ultrasonic probe 160 disclosed in Patent Document 1.
The ultrasonic probe 160 comprises a backing material (backing material) 161 for absorbing and attenuating ultrasonic waves emitted from the back of a piezoelectric element 162, piezoelectric elements 162 made of, for example, piezoelectric ceramics arranged in an array on the backing material with a predetermined gap (air space) 166, a first acoustic matching layer 163 for efficiently propagating ultrasonic waves laminated on the upper surface of the piezoelectric element 162 and arranged in the same manner as the piezoelectric elements, a similar second acoustic matching layer 164, an adhesive 165 for bonding the acoustic matching layer and the acoustic lens, and an acoustic lens 167 for focusing ultrasonic waves (paragraph 0002 of Patent Document 1).

In the ultrasonic probe 160 disclosed in Patent Document 1, the second acoustic matching layer 164 and the acoustic lens 167 are bonded together with an adhesive gel-like material. Compared to liquid adhesives, the gel-like material has extremely low fluidity and therefore does not seep into the gap 166 between the piezoelectric elements 162, preventing crosstalk and a decrease in sensitivity while also achieving a wide directional characteristic (Summary of Patent Document 1).

JP 10-253604 A

Incidentally, when an ultrasonic probe is used, echo jelly is applied to the area to be examined, and the echo jelly adheres to the ultrasonic probe. When wiping off the echo jelly or for disinfection before and after use, for example, alcohol is used, but if chemicals or the like get into the inside of the ultrasonic probe, there is a risk of causing a decrease in sensitivity. Therefore, the ultrasonic probe needs to be resistant to chemicals, and for example, a resin film made of polyimide needs to be incorporated into the structure of the ultrasonic probe. In that case, a typical laminate structure is formed by bonding a resin film onto an acoustic matching layer, and bonding an acoustic lens onto this resin film.
However, when the acoustic matching layer and the resin film are bonded with a gel-like material, even if the gel-like material has no fluidity, some displacement is expected to occur. Therefore, when using a gel-like material, there are cases where the resin film cannot be fixed in a constant state without wrinkles or air bubbles. As a result, there are cases where the acoustic lens on the resin film cannot be fixed in a constant state. Furthermore, there is a possibility that the gel-like adhesive will get into the gaps between the elements when the resin film is fixed and pressurized.
The object of this application is to provide an ultrasonic probe having a novel structure and a manufacturing method thereof, which improves directionality by completely maintaining a specified gap between individual vibration parts consisting of a laminated section having a piezoelectric ceramic and an acoustic matching layer in this order, and which allows resin films to be stably laminated in a constant fixed state and has chemical resistance.

In order to achieve this object, the ultrasonic probe of the present invention includes a backing material on a base, a transducer array configured by arranging a large number of individual vibration units, each of which is a laminated unit having a piezoelectric ceramic and an acoustic matching layer in this order, on the backing material in a first direction with a predetermined gap therebetween, and a resin film provided on the acoustic matching layer of the transducer array as a protective film for the transducer array,
The acoustic matching layer and the resin film are bonded to each other by a sheet-like adhesive layer.

When implementing the invention of this ultrasonic probe, it is preferable that the sheet-shaped adhesive layer is made of a photocurable adhesive film. This type of film has no fluidity, so even when pressure or temperature is applied when bonding the acoustic matching layer and the resin film, the adhesive does not flow into the gap. Furthermore, because it is in a sheet form, wrinkles and air bubbles are less likely to occur when bonding the acoustic matching layer and the resin film. As such a sheet-shaped adhesive layer, for example, a photocurable adhesive film in which a special acrylate is blended as a reactive plasticizer in a photosensitive acrylic polymer is preferable. Specifically, but not limited to, a photocurable adhesive film (product name: Aronix UVP) manufactured by Toagosei Co., Ltd. can be mentioned.

When implementing this ultrasonic probe invention, the resin film provided on the upper part of the photocurable adhesive film is made of a material that has a certain degree of transparency to the wavelength required for curing the photocurable adhesive film and is resistant to the above-mentioned echo jelly and alcohol, etc., and is preferably, but not limited to, polyphenylene sulfide (hereinafter referred to as PPS).

According to the method for manufacturing an ultrasonic probe of this application, the method includes the steps of stacking a backing material on a base, stacking a piezoelectric ceramic layer and a layer for forming an acoustic matching layer on the backing material, the piezoelectric ceramic layer being longitudinally aligned in a first direction;
cutting the piezoelectric ceramic layer and the layer for forming the acoustic matching layer at a predetermined pitch along the first direction and in the lamination direction to form a transducer array in which a large number of laminated portions of the piezoelectric ceramic layer and the acoustic matching layer are arranged;
laminating a member for a photocurable adhesive film on the acoustic matching layer of the transducer array formed;
laminating a resin film as a protective film for the transducer array on the sheet-like member;
a step of irradiating the structure having the resin film laminated thereon with light;
The present invention is characterized by comprising:

According to the ultrasonic probe of the present invention, the acoustic matching layer and the resin film as the protective film are bonded by a sheet-like adhesive layer, so that an ultrasonic probe can be realized in which there are substantially no wrinkles or bubbles between the acoustic matching layer and the resin film, and the gaps between the individual vibration parts are perfectly maintained. Therefore, an ultrasonic probe with wide directivity and in which the protective film is laminated on the acoustic matching layer in a certain fixed state can be realized.
Furthermore, according to the method for manufacturing an ultrasonic probe of the present invention, since the above-mentioned specified steps are used, it is possible to easily manufacture an ultrasonic probe that is substantially free of wrinkles or air bubbles between the acoustic matching layer and the resin film and in which the gaps between the individual vibration parts are completely maintained.

1A is a side view showing an overview of an ultrasonic probe according to an embodiment of the present invention, and FIG. 1B is a side view showing an overview of an ultrasonic probe according to a comparative example. 1A and 1B are process diagrams for explaining an embodiment of the invention of a method for manufacturing an ultrasonic probe. 2A and 2B are process diagrams continuing from FIG. 2 for explaining an embodiment of the method for manufacturing an ultrasonic probe according to the present invention. 5A to 5C are process diagrams continuing from FIG. 3 for explaining the embodiment of the invention of the method for manufacturing an ultrasonic probe. 5A to 5C are process diagrams continuing from FIG. 4 for explaining the embodiment of the method for manufacturing an ultrasonic probe according to the present invention. 1 is a characteristic diagram showing an overview of the directivity of an ultrasonic probe according to an embodiment of the present invention and the directivity of an ultrasonic probe according to a comparative example. FIG. 1 is a side view showing an overview of a conventional ultrasonic probe.

Embodiments of the ultrasonic probe and its manufacturing method of the present invention will be described below with reference to the drawings. Note that the drawings used in the description are merely schematic illustrations to enable understanding of these inventions. In addition, in the drawings used in the description, similar components are indicated with the same numbers, and their explanation may be omitted. Furthermore, the shapes, materials, etc. described in the following description are merely preferred examples within the scope of this invention. Therefore, the present invention is not limited to the following embodiments.

1. Configuration of Ultrasonic Probe Fig. 1 is a side view showing an outline of an ultrasonic probe 10 according to an embodiment.
In the following description of the embodiment, an ultrasonic probe equipped with an acoustic lens will be described. The acoustic lens has the effect of converging ultrasonic waves, and is preferably equipped in the ultrasonic probe. The same applies to the following embodiments of the manufacturing method.
The ultrasonic probe 10 of the embodiment includes a base 20, a backing material 30, an individual vibration section 110, a transducer array 40a in which the individual vibration sections are arranged in an array, a sheet-like adhesive layer 70, a resin film 80, and an acoustic lens 100. Each of the components will be specifically described below.
The base 20 plays a role in maintaining the strength of the ultrasonic probe during the manufacturing stage and during the product stage.
The backing material 30 has a role of absorbing and attenuating ultrasonic waves that leak backward out of the ultrasonic waves generated by the piezoelectric ceramics 40 .
The individual vibration portion 110 includes a piezoelectric ceramic 40, a first acoustic matching layer 50, and a second acoustic matching layer 60, in this order.
A large number of individual vibrating parts 110 are arranged on a backing material 30 along a first direction (direction P in the figure) with a predetermined gap 90 therebetween, thereby forming a transducer array 40a.
The acoustic matching layer may have a configuration other than the first and second acoustic matching layers, that is, a configuration in which only the first acoustic matching layer is laminated, or a configuration in which the third or more acoustic matching layers are laminated.
The resin film 80 has chemical resistance and is adhered onto the acoustic matching layer 60 in the transducer array 40a by a sheet-like adhesive layer 70.
The acoustic lens 100 is for converging ultrasonic waves, and is adhered onto the resin film 80 .
The piezoelectric ceramic 40 generates ultrasonic waves when vibrated by applying a voltage to the piezoelectric ceramic 40. The acoustic matching layers 50 and 60 are for efficiently propagating the ultrasonic waves.
Moreover, the sheet-like adhesive layer 70 according to the present invention has no fluidity. In this embodiment, the adhesive layer 70 is formed of a sheet-like photocurable pressure-sensitive adhesive film.
The resin film 80 has a property of transmitting light when the sheet-shaped photocurable adhesive film is cured, and a property as a protective film. In this embodiment, PPS is used as the resin film 80. Since PPS has a certain degree of transparency to the wavelength required for curing the sheet-shaped photocurable adhesive film, it does not inhibit the curing of the sheet-shaped photocurable adhesive film by light irradiation. Moreover, since PPS has chemical resistance, it serves as a so-called protective layer for the transducer array 40a, and can prevent a decrease in sensitivity when chemicals or the like enter the inside of the ultrasonic probe.

In the embodiment of the present invention, the adhesive layer 70 is configured not with a liquid adhesive but with a sheet-shaped photocurable adhesive film. The photocurable adhesive film, which is the material of the adhesive layer 70, can be cured by light irradiation and has adhesiveness before curing, but after light irradiation, it solidifies like a general adhesive and has the property of being stable against chemicals and the surrounding environment.
As a result, the adhesive does not flow into the gap 90, the independence of the individual vibration parts 110 is ensured, and an ultrasonic probe with wide directivity is obtained. Moreover, since it is in a sheet form, it is less likely to wrinkle, and air bubbles are less likely to remain between the acoustic matching layer and the resin film, so that the resin film can be laminated on the acoustic matching layer in a certain fixed state.

2. An embodiment of the manufacturing method of the ultrasonic probe according to the present invention will now be described. Figures 2 to 5 are process diagrams for this purpose, and are process diagrams shown by side views corresponding to Figure 1 for each process.
First, a backing material 30x made of, for example, a rubber material mixed with iron powder is laminated on a base 20x made of, for example, aluminum, and then a piezoelectric ceramic layer 40x made of, for example, lead zirconate titanate and a layer 50x for forming an acoustic matching layer made of, for example, epoxy resin are laminated on the backing material with the first direction being the longitudinal direction (FIG. 2(A)).
Next, the piezoelectric ceramic layer 40x and the layer 50x for forming the acoustic matching layer are cut at a predetermined pitch along the first direction P and in the stacking direction, for example by a dicing saw, to form a transducer array 40a in which a large number of individual vibration parts 110 of the piezoelectric ceramic layer 40x and the acoustic matching layers 50, 60 are arranged (Figure 2 (B)).
Next, ARONIX UVP (thickness t=10 μm) 70x, which is a member for a sheet-like photocurable adhesive film, is laminated on the acoustic matching layer 60 of the transducer array 40a thus formed (FIG. 3(A)).
Next, a resin film 80 made of PPS is laminated on the ARONIX UVP as a protective film for the transducer array (FIG. 3(B)).
Next, the structure in which the PPS (thickness t=9.36 μm) is laminated is irradiated with light 131 from a metal halide lamp 130 to harden the ARONIX UVP, thereby obtaining a sheet-like adhesive layer 70 according to the present invention (FIG. 4).
Next, an acoustic lens 100 made of, for example, silicone rubber is adhered onto the PPS (FIG. 5).

According to the manufacturing method of the above embodiment, by using a sheet-shaped photocurable adhesive film, it is possible to prevent the adhesive from flowing into voids, and because it is in sheet form, the amount of adhesive applied is uniform on the adhesive surface, the position can be easily fixed, wrinkles and air bubbles are less likely to occur, workability is improved, and since there is no need to heat or pressurize during curing, no residual stress remains in the ultrasonic probe, and deterioration of characteristics and defects during the manufacturing stage can be reduced.

3. Experimental Results Next, the experimental results will be described. As an example, an ultrasonic probe having the configuration described in the above embodiment was prepared. Also, as a comparative example, an ultrasonic probe having the same configuration as the example was prepared, except that the adhesive for laminating the resin film was a liquid silicone adhesive instead of the Aronix UVP used in the example.
The ultrasonic probes of the example and the comparative example all have a center frequency of 2.5 MHz.

The directivity of ultrasound along the direction of the vibration array for each of the ultrasonic probes of the embodiment and the comparative example was measured using a known measurement method. Figure 6 is a characteristic diagram showing the directivity of the ultrasonic probe of the comparative example and the directivity of the ultrasonic probe of the embodiment obtained by the above measurement. In Figure 6, the vertical axis indicates the sound pressure level, and the semicircular axis indicates the angle.

Focusing on the directivity 140 of the ultrasonic probe of the embodiment and the directivity 150 of the ultrasonic probe of the comparative example, at the point where the sound pressure level reaches half, i.e., -6 dB, the directivity angle of the ultrasonic probe of the comparative example is about 70 deg., and the directivity angle of the ultrasonic probe of the embodiment is about 115 deg.
When comparing the beam angles of the ultrasonic probes at the point where the sound pressure level reaches half, i.e., -6 dB, the beam angle of the ultrasonic probe of the embodiment is about 45 deg. wider than that of the ultrasonic probe of the comparative example.
Thus, by maintaining the gap between the individual vibration portions, the ultrasonic probe of the embodiment can obtain a wider directivity than the ultrasonic probe using the liquid adhesive of the comparative example.
Furthermore, visual observation revealed that the Examples had fewer wrinkles and air bubbles than the Comparative Examples, and more specifically, the Examples had substantially no wrinkles or air bubbles.

10: Ultrasonic probe of the present invention 20: Base 20x: Base 30: Backing material 30x: Backing material 40: Piezoelectric ceramic 40x: Piezoelectric ceramic 40a: Transducer array 50: First acoustic matching layer 50x: First acoustic matching layer 60: Second acoustic matching layer 60x: Second acoustic matching layer 70: Sheet-like adhesive 70x: Sheet-like adhesive 80: Resin film 80x: Resin film 90: Gap 90x: Gap 100: Acoustic lens 100x: Acoustic lens 110: Individual vibration part 120: Ultrasonic probe of comparative example 121: Base 122: Backing material 123: Piezoelectric ceramic 123a: Transducer array 124: First acoustic matching layer 125: Second acoustic matching layer 126: Liquid adhesive 127: Acoustic lens 128: Individual vibration part 130: Light irradiation lamp 131: Light 140: Directivity of ultrasonic probe of the embodiment 150: Directivity of ultrasonic probe of the comparative example

Claims (2)

An ultrasonic probe comprising: a transducer array in which a large number of individual vibration units, each of which is a laminated portion having a piezoelectric ceramic and an acoustic matching layer in this order, are arranged in a first direction with a predetermined gap therebetween; and a resin film provided on the acoustic matching layer of the transducer array as a protective film for the transducer array, wherein the acoustic matching layer and the resin film are bonded to each other with a photocurable adhesive film in which an acrylate is blended as a plasticizer in a photosensitive acrylic polymer ;
11. An ultrasonic probe, wherein the resin film is made of polyphenylene sulfide . Laminating a backing material on a base;
laminating a piezoelectric ceramic layer and a layer for forming an acoustic matching layer on a backing material, the piezoelectric ceramic layer being longitudinally aligned in a first direction;
cutting the piezoelectric ceramic layer and the layer for forming the acoustic matching layer at a predetermined pitch along the first direction and in the lamination direction to form a transducer array in which a large number of laminated portions of the piezoelectric ceramic layer and the acoustic matching layer are arranged;
laminating a member for a photocurable adhesive film on the acoustic matching layer in the transducer array formed above , the member being made of a photosensitive acrylic polymer mixed with acrylate as a plasticizer ;
laminating polyphenylene sulfide as a resin film as a protective film for the transducer array on the laminated member for the photocurable adhesive film ;
a step of irradiating the structure having the resin film laminated thereon with light;
A method for manufacturing an ultrasonic probe comprising the steps of:

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