Ultrasonic probe and method for manufacturing the same.

Abstract

To provide an ultrasonic probe that is improved in directivity and has chemical resistance, and a method of manufacturing the same.SOLUTION: An ultrasonic probe 10 comprises: a vibrator array 40a constituted by arraying many individual vibration parts 110, each consisting of a lamination part comprising a piezoelectric ceramic 40, a first acoustic matching layer 50 and a second acoustic matching layer 60 in this order, in a first direction with predetermined gaps 90; and a resin film 80 which is provided on the second acoustic matching layers as a protective film for the vibrator array. The second acoustic matching layers and the resin film are bonded together with a sheet-type adhesion layer 70. The sheet type adhesion layer is formed of a photocuring adhesive film, and the resin film is formed of polyphenylene sulfide.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an ultrasonic probe having improved directivity and chemical resistance, and a method for manufacturing the same.

Background Art

[0002] As an example of an ultrasonic probe, there is one 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 includes a backing material (backing material) 161 for absorbing and attenuating ultrasonic waves emitted from the back surface of the piezoelectric element 162, piezoelectric elements 162 made of, for example, piezoelectric ceramics arranged in an array with a predetermined gap (void) 166 on the backing material, a first acoustic matching layer 163 laminated on the upper surface of the piezoelectric element 162 and arranged in the same manner as the piezoelectric elements for efficiently propagating ultrasonic waves, 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 converging ultrasonic waves (paragraph 0002 of Patent Document 1).

[0003] In the ultrasonic probe 160 disclosed in Patent Document 1, the second acoustic matching layer 164 and the acoustic lens 167 are joined with a gel-like material having adhesiveness. Since the gel-like material has extremely low fluidity compared to a liquid adhesive, it does not enter the gap 166 between the piezoelectric elements 162, preventing the occurrence of crosstalk and a decrease in sensitivity and obtaining a wide directivity characteristic (summary of Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Incidentally, when using an ultrasonic probe, an echo jelly is applied to the examination site, so 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. However, when chemicals or the like penetrate into the ultrasonic probe, it may cause a decrease in sensitivity. Therefore, the ultrasonic probe requires chemical resistance, and for example, it is necessary to incorporate a resin film made of polyimide into the structure of the ultrasonic probe. In that case, typically, a laminated structure is formed by adhering a resin film onto an acoustic matching layer and then adhering an acoustic lens onto this resin film. However, when the acoustic matching layer and the resin film are adhered with a gel-like material, even if the gel-like material has no fluidity, some displacement is considered to occur. Therefore, in the case of a gel-like material, there may be a situation where the resin film cannot be fixed in a constant state without wrinkles and bubbles. Due to this influence, it is considered that the acoustic lens on the resin film may also not be fixed in a constant state. Furthermore, when fixing and pressing the resin film, there is also a possibility that the gel-like adhesive may enter the gap between the elements. The object of this application is to provide a novel-structured ultrasonic probe and its manufacturing method, which can obtain an improved directivity by completely maintaining a predetermined gap between individual vibration parts each composed of a laminated part having a piezoelectric ceramic and an acoustic matching layer in this order, can stably laminate a resin film in a certain fixed state, and has chemical resistance.

Means for Solving the Problems

[0006] To achieve this object, according to the ultrasonic probe of the present invention, a backing material is provided on a base, and individual vibration parts each composed of a laminated part having a piezoelectric ceramic and an acoustic matching layer in this order are arranged in a large number in a first direction with a predetermined gap to form a vibrator array, and a resin film as a protective film for the vibrator array provided on the acoustic matching layer of the vibrator array. In the ultrasonic probe comprising: It is characterized in that the adhesion between the acoustic matching layer and the resin film is performed with a sheet-like adhesive layer.

[0007] In carrying out the invention of this ultrasonic probe, it is preferable that the sheet-like adhesive layer is composed of a photocurable adhesive film. Since this type of film has no fluidity, the inflow of the adhesive into the voids is not caused even by the pressure or temperature when adhering the acoustic matching layer and the resin film. Moreover, since it is sheet-like, wrinkles and bubbles are less likely to occur when adhering the acoustic matching layer and the resin film. As such a sheet-like 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 thereto, for example, a photocurable adhesive film (trade name: Aronix UVP) manufactured by Toagosei Co., Ltd. can be mentioned.

[0008] In carrying out the invention of this ultrasonic probe, the resin film provided on the upper part of the photocurable adhesive film has a certain transmittance with respect to the wavelength necessary for the curing of the photocurable adhesive film, and is made of a material having resistance to the above-mentioned echo jelly, alcohol, etc. Although not limited thereto, for example, polyphenylene sulfide (hereinafter referred to as PPS) is preferable.

[0009] According to the manufacturing method of the ultrasonic probe of this application, a step of laminating a backing material on a base, and laminating a piezoelectric ceramic layer having a longitudinal direction in the first direction and a layer for forming an acoustic matching layer on the backing material; A step of 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 vibrator array in which a plurality of laminated portions of the piezoelectric ceramic layer and the acoustic matching layer are arranged; A step of laminating a member for the photocurable adhesive film on the acoustic matching layer of the formed vibrator array; A step of laminating a resin film as a protective film for the vibrator array on the sheet-like member; A step of irradiating light to the structure laminated with the resin film; It is characterized by including.

Effect of the Invention

[0010] According to the ultrasonic probe of the present invention, since the adhesion between the acoustic matching layer and the resin film as the protective film is performed by the sheet-like adhesive layer, there are substantially no wrinkles or air bubbles between the acoustic matching layer and the resin film, and the ultrasonic probe can realize the ultrasonic probe in which the gaps between the individual vibration parts are completely maintained. Therefore, a wide directivity can be achieved, and a protective film can realize an ultrasonic probe laminated on the acoustic matching layer in a fixed state. Moreover, according to the method for manufacturing an ultrasonic probe of the present invention, since the above-described predetermined steps are used, an ultrasonic probe in which there are substantially no wrinkles or air bubbles between the acoustic matching layer and the resin film and the gaps between the individual vibration parts are completely maintained can be easily manufactured.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

[0012] Hereinafter, embodiments of the ultrasonic probe and its manufacturing method of the present invention will be described with reference to the drawings. Each drawing used in the description only schematically shows the inventions to the extent that they can be understood. Also, in each drawing used in the description, the same components are denoted by the same numbers, and the description thereof may be omitted. In addition, the shapes, materials, etc. described in the following description are merely preferred examples within the scope of the present invention. Therefore, the present invention is not limited only to the following embodiments.

[0013] 1. Configuration of the ultrasonic probe FIG. 1 is a side view showing an overview of the ultrasonic probe 10 of the embodiment. In this case, the description of the embodiment is made for an ultrasonic probe provided with an acoustic lens. The acoustic lens has the effect of converging ultrasonic waves and is preferably provided in the ultrasonic probe. The same applies to the embodiments of the manufacturing method hereinafter. The ultrasonic probe 10 of the embodiment includes a base 20, a backing material 30, an individual vibration part 110, a transducer array 40a in which the individual vibration parts are arranged in an array, a sheet-like adhesive layer 70, a resin film 80, and an acoustic lens 100. Hereinafter, each component will be specifically described. The base 20 has the role of maintaining the strength in the manufacturing stage and the product stage of the ultrasonic probe. The backing material 30 has the role of absorbing and attenuating the ultrasonic waves that leak backward among the ultrasonic waves emitted by the piezoelectric ceramics 40. The individual vibration part 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 the individual vibration parts 110 are arranged on the backing material 30 along the first direction (P direction in the figure) with a predetermined gap 90, thereby constituting the transducer array 40a. Regarding the acoustic matching layer, a configuration other than the first acoustic matching layer and the second acoustic matching layer, that is, a configuration in which only the first acoustic matching layer is laminated or a configuration in which three or more acoustic matching layers are laminated may be used. The resin film 80 has chemical resistance and is adhered onto the acoustic matching layer 60 in the oscillator 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 ceramics 40 emits ultrasonic waves by applying a voltage to cause vibration. The acoustic matching layers 50 and 60 are for efficiently propagating ultrasonic waves. Also, the sheet-like adhesive layer 70 according to the present invention has no fluidity. In this embodiment, the adhesive layer 70 is constituted by a sheet-like photocurable adhesive film. Also, the resin film 80 has physical properties of transmitting light when curing the sheet-like photocurable adhesive film and physical properties as a protective film. In this embodiment, PPS is used as the resin film 80. Since PPS has a certain transmittance with respect to the wavelength necessary for curing the sheet-like photocurable adhesive film, it does not inhibit the curing of the sheet-like photocurable adhesive film by light irradiation. Moreover, since PPS has chemical resistance, it can serve as a so-called protective layer of the oscillator array 40a and prevent a decrease in sensitivity when chemicals or the like enter the ultrasonic probe.

[0014] In the embodiment of the present invention, the adhesive layer 70 is constituted by a sheet-like photocurable adhesive film instead of a liquid adhesive. The photocurable adhesive film, which is the material of the adhesive layer 70, can be cured by light irradiation. It has adhesiveness before curing, but solidifies like a general adhesive after light irradiation and has characteristics of being stable against chemicals and the surrounding environment. As a result, the inflow of the adhesive into the void 90 does not occur, the independence of the individual vibrating portions 110 is ensured, and an ultrasonic probe with a wide directivity is obtained. Moreover, since it is sheet-like, it is not likely to wrinkle, and it is also difficult for air bubbles 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.

[0015] 2. Embodiment of the manufacturing method Next, embodiments of the invention of a method for manufacturing an ultrasonic probe will be described. FIGS. 2 to 5 are process diagrams therefor, and are process diagrams shown by side views corresponding to FIG. 1 for each process. First, for example, a backing material 30x made of a rubber material mixed with iron powder is laminated on a base 20x made of aluminum, and 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, an 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 an acoustic matching layer are cut along the first direction P at a predetermined pitch and, for example, by a dicing saw in the stacking direction to form a transducer array 40a in which a large number of individual vibration portions 110 of the piezoelectric ceramic layer 40x and the acoustic matching layers 50, 60 are arranged (FIG. 2(B)). Next, an 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 formed transducer array 40a (FIG. 3(A)). Next, a PPS, which is a resin film 80, is laminated on the Aronix UVP as a protective film for the transducer array (FIG. 3(B)). Next, the structure laminated with the PPS (thickness t = 9.36 μm) is irradiated with light 131 by a metal halide lamp 130 to cure 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 on the PPS (FIG. 5).

[0016] According to the manufacturing method of the above-described embodiment, by using a sheet-like photocurable adhesive film, it is possible to prevent the adhesive from flowing into the voids, and since it is sheet-like, the application amount of the adhesive is uniform on the adhesive surface, the position fixing is easy, wrinkles and bubbles are less likely to enter, the workability is improved, and since there is no need to heat and pressurize during curing, no residual stress remains in the ultrasonic probe, and deterioration of characteristics and defects during the manufacturing stage can be reduced.

[0017] 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. As a comparative example, an adhesive for laminating a resin film was made into a liquid silicone adhesive instead of the Aronix UVP used in the example, and an ultrasonic probe having the same configuration as that of the example was prepared except for this. Note that the ultrasonic probes in both the example and the comparative example have a center frequency of 2.5 MHz.

[0018] The directivity of the ultrasonic waves along the direction of the vibration array of each of the ultrasonic probes in the example and the comparative example was measured by a well-known measurement method. FIG. 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 example obtained by the above measurement. In FIG. 6, the vertical axis represents the sound pressure level, and the semi-circular axis represents the angle.

[0019] Focusing on the directivity 140 of the ultrasonic probe of the example and the directivity 150 of the ultrasonic probe of the comparative example, at the time when the sound pressure level reaches -6 dB at which it becomes half, 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 example is about 115 deg. When comparing the directivity angles of the respective ultrasonic probes at the time when the sound pressure level reaches -6 dB at which it becomes half, the directivity angle of the ultrasonic probe of the example is about 45 deg. wider than that of the ultrasonic probe of the comparative example. From this, by maintaining the gaps between the individual vibrating parts, the ultrasonic probe of the example can obtain a wider directivity than the ultrasonic probe using the liquid adhesive of the comparative example. Also, as a result of visual observation, it was found that there are fewer wrinkles and bubbles in the example than in the comparative example, specifically, there are substantially no wrinkles and bubbles in the example.

Explanation of Reference Numerals

[0020] 10: Ultrasonic probe of the present invention 20: Base 20x: Base 30: Backing material 30x: Backing material 40: Piezoelectric ceramics 40x: Piezoelectric ceramics 40a: Array of vibrators 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: Void 90x: Void 100: Acoustic lens 100x: Acoustic lens 110: Individual vibration part 120: Ultrasonic probe of comparative example 121: Base 122: Backing material 123: Piezoelectric ceramics 123a: Array of vibrators 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 example 150: Directivity of ultrasonic probe of comparative example

Claims

1. An ultrasonic probe comprising: an array of oscillators configured by arranging a plurality of individual oscillators each comprising a piezoelectric ceramic and a stacked portion having an acoustic matching layer in this order, in a first direction with a predetermined gap therebetween; and a resin film provided on the acoustic matching layer of the oscillator array and serving as a protective film for the oscillator array. The adhesion between the acoustic matching layer and the resin film is effected using a photocurable adhesive film in which an acrylate is blended as a plasticizer in a photosensitive acrylic polymer. The ultrasonic probe, wherein the resin film is polyphenylene sulfide.

2. A step of laminating a backing material on a base; A step of laminating a piezoelectric ceramic layer having a longitudinal direction in a first direction and a layer for forming an acoustic matching layer on the backing material; A step of cutting the piezoelectric ceramic layer and the layer for forming an acoustic matching layer at a predetermined pitch along the first direction and in the stacking direction to form an array of oscillators in which stacked portions of the piezoelectric ceramic layer and the acoustic matching layer are arranged in a plurality; A step of laminating, as a member for a photocurable adhesive film, a member in which an acrylate is blended as a plasticizer in a photosensitive acrylic polymer on the acoustic matching layer in the formed oscillator array; On the laminated member for the photocurable adhesive film A step of laminating polyphenylene sulfide as a resin film serving as a protective film for the oscillator array; A step of irradiating the structure laminated with the resin film with light; A method for manufacturing an ultrasonic probe, comprising the above steps.

Images