Ultrasonic probe, ultrasonic diagnostic apparatus, and method for manufacturing ultrasonic probe

Abstract

Provided is an ultrasonic probe capable of coping with high-frequency driving, a manufacturing method therefor, and an ultrasonic diagnostic apparatus. The ultrasonic probe (100) includes an acoustic matching portion (20) disposed on a plurality of piezoelectric elements (10), and a conductive member (30Fr) disposed on the plurality of piezoelectric elements (10) adjacent to the acoustic matching portion (20), the conductive member (30Fr) including a multilayer conductive layer disposed on a front side in a front-rear direction FR of the acoustic matching portion (20), the multilayer conductive layer including a plurality of first conductive layers (32F) respectively joined to second conductive portions (13) of the piezoelectric elements (10), and a second conductive layer (31F) stacked on the plurality of first conductive layers (32F) and electrically connected to the plurality of first conductive layers (32F), a ratio of a thickness HF in an up-down direction UD to a width D1 in a left-right direction LR in the first conductive layers (32F) being 1.6 or less.

Description

Technical Field

[0001] This invention relates to an ultrasonic probe, an ultrasonic diagnostic device, and a method for manufacturing an ultrasonic probe. Background Technology

[0002] In the medical field, ultrasound diagnostic devices that utilize ultrasound imaging are already in practical use. These devices send an ultrasound beam from an ultrasound probe to the subject, receive the ultrasound echoes from the subject using the probe, and then electrically process the received signals to generate an ultrasound image.

[0003] In the field of ultrasound diagnostics, the demand for high-resolution ultrasound images is greater than ever before, as the scope of observation expands. To acquire high-resolution ultrasound images, high-frequency ultrasound transmission and reception are required. However, if the spacing between piezoelectric elements is not reduced according to the ultrasound frequency, the generation of grating lobes will affect the quality of the ultrasound image.

[0004] Patent document 1 describes an ultrasonic probe designed to suppress the decrease in sensitivity when the spacing between piezoelectric elements becomes narrower.

[0005] Previous technical documents

[0006] Patent documents

[0007] Patent Document 1: International Publication No. 2018 / 070159 Summary of the Invention

[0008] The technical problem to be solved by the invention

[0009] Patent Document 1 describes the key point that when the driving frequency of the piezoelectric element exceeds 15 MHz, the element spacing is preferably less than 150 μm. However, it does not mention further high-frequency driving.

[0010] The purpose of this invention is to provide an ultrasonic probe capable of handling high-frequency driving, its manufacturing method, and an ultrasonic diagnostic device.

[0011] means for solving technical problems

[0012] An ultrasonic probe according to one aspect of the present invention has a plurality of piezoelectric elements arranged in a first direction. The ultrasonic probe includes: a support member supporting the plurality of piezoelectric elements; an acoustic matching portion disposed on the plurality of piezoelectric elements; and a conductive member adjacent to the acoustic matching portion and disposed on the plurality of piezoelectric elements. The plurality of piezoelectric elements are each composed of a laminate in which a first conductive portion, a piezoelectric body portion, and a second conductive portion are sequentially stacked on top of the support member. The conductive member includes a multilayer conductive layer disposed on at least one end in a second direction, which intersects the first direction of the acoustic matching portion. The multilayer conductive layer includes: a plurality of first conductive layers, which are respectively bonded to the second conductive portions of the piezoelectric elements; and a second conductive layer stacked on the plurality of first conductive layers and electrically connected to the plurality of first conductive layers. The thickness of the first conductive layer is 1.6 or less in ratio to its length (i.e., width) in the first direction.

[0013] An ultrasonic diagnostic apparatus according to one aspect of the present invention includes the aforementioned ultrasonic probe.

[0014] According to one aspect of the present invention, a method for manufacturing an ultrasonic probe includes a plurality of piezoelectric elements arranged in a first direction, wherein the length (i.e., width) of the piezoelectric elements in the first direction is a predetermined value, a direction intersecting the first direction is designated as a second direction, and a direction perpendicular to both the first and second directions is designated as a third direction. The method for manufacturing the ultrasonic probe comprises the following steps: fixing a sheet-like laminate, formed by sequentially stacking a first conductive portion, a piezoelectric portion, and a second conductive portion perpendicular to the third direction, onto a support member; and fixing the laminate to the support member. An acoustic matching portion is formed in a portion of the upper surface on the opposite side of the component side in the second direction; a first conductive layer with a thickness of 1.6 times or less in the third direction is formed on at least one end of the acoustic matching portion on the upper surface of the laminate in the second direction; the laminate having the acoustic matching portion and the first conductive layer formed thereon is divided into a plurality of piezoelectric elements in the first direction by cutting; and a second conductive layer is formed on the first conductive layer after being divided into the plurality of piezoelectric elements, spanning the plurality of first conductive layers.

[0015] Invention Effects

[0016] According to the present invention, an ultrasonic probe capable of high-frequency driving, a method for manufacturing the same, and an ultrasonic diagnostic device can be provided. Attached Figure Description

[0017] Figure 1 This is a plan view showing a schematic structure of an ultrasonic probe 100, an embodiment of the ultrasonic probe of the present invention.

[0018] Figure 2 yes Figure 1 A schematic diagram of the cross section viewed from direction AA.

[0019] Figure 3 yes Figure 1 Schematic diagrams of cross sections in the BB and CC directions.

[0020] Figure 4 yes Figure 1 A schematic diagram of the cross-section viewed from the DD direction.

[0021] Figure 5 It is a planar schematic diagram showing the state after the first process is completed.

[0022] Figure 6 yes Figure 5 A schematic diagram of the cross section viewed from A1-A1.

[0023] Figure 7 yes Figure 5 Schematic diagrams of cross sections in the A2-A2 and A3-A3 directions.

[0024] Figure 8 It is a planar schematic diagram showing the state after the second process has ended, following the first process.

[0025] Figure 9 yes Figure 8 A schematic diagram of the cross section viewed from A1-A1.

[0026] Figure 10 yes Figure 8 A schematic diagram of the cross section viewed from A4-A4.

[0027] Figure 11 It is a planar schematic diagram showing the state after the third process, which follows the second process.

[0028] Figure 12 yes Figure 11 A schematic diagram of the cross section viewed from A1-A1.

[0029] Figure 13 yes Figure 11 Schematic diagrams of cross sections in the A2-A2 and A3-A3 directions.

[0030] Figure 14 This is a planar schematic diagram showing the state after the fourth process, which follows the third process.

[0031] Figure 15 yes Figure 14 Schematic diagrams of cross sections in the A2-A2 and A3-A3 directions.

[0032] Figure 16 yes Figure 14 A schematic diagram of the cross section viewed from A4-A4.

[0033] Figure 17 This is a planar schematic diagram showing the state after the fifth process, which follows the fourth process.

[0034] Figure 18 yes Figure 17 Schematic diagrams of cross sections in the A2-A2 and A3-A3 directions.

[0035] Figure 19 yes Figure 17 A schematic diagram of the cross section viewed from A4-A4.

[0036] Figure 20 This is a planar schematic diagram showing the state after the completion of the seventh process, which follows the fifth process.

[0037] Figure 21 This is a diagram showing a first modified example of the ultrasonic probe 100, which is related to... Figure 1 A schematic diagram of the cross section corresponding to the view in direction AA.

[0038] Figure 22 This is a diagram showing a second modified example of the ultrasonic probe 100, which is related to... Figure 1 A schematic diagram of the cross section corresponding to the view in direction AA.

[0039] Figure 23 This is a graph showing the verification results of the ultrasonic probe. Detailed Implementation

[0040] Figure 1 This is a plan view showing a schematic structure of an ultrasonic probe 100, an embodiment of the ultrasonic probe of the present invention. Figure 2 yes Figure 1 A schematic diagram of the cross section viewed from direction AA. Figure 3 yes Figure 1 Schematic diagrams of cross sections in the BB and CC directions. Figure 4 yes Figure 1 A cross-sectional schematic diagram of the DD direction. The ultrasound probe 100 is an image generation device included in the ultrasound diagnostic apparatus. The ultrasound diagnostic apparatus includes: a device for generating and recording ultrasound images while bringing the ultrasound probe 100 close to the outer surface of the subject, and a device for generating and recording ultrasound images while bringing the ultrasound probe 100, which is built into the front end of the insertion part of the endoscope, close to the organs of the subject, etc.

[0041] In this instruction manual, Figure 1 The right-hand direction on the paper is recorded as the forward direction Fr of the ultrasonic probe 100. Figure 1The leftward direction on the paper is recorded as the rearward direction Rr of the ultrasonic probe 100; these directions are collectively referred to as the front-rear direction FR. Furthermore, Figure 1 The top direction on the paper is recorded as the right direction R of the ultrasonic probe 100. Figure 1 The downward direction on the paper is recorded as the left direction L of the ultrasonic probe 100, and these directions are collectively referred to as the left-right direction LR. Furthermore, the direction perpendicular to the front-back direction FR and the left-right direction LR is recorded as the up-down direction UD. In the up-down direction UD, from... Figure 1 The direction from the front of the paper towards the inside is recorded as the downward direction D of the ultrasonic probe 100, which will... Figure 1 The direction of the inner side of the paper facing forward is recorded as the upward direction U of the ultrasonic probe 100.

[0042] [Overall structure of the ultrasonic probe]

[0043] The ultrasonic probe 100 includes: a backing material 50; a front FPC (Flexible Printed Circuits) 60Fr and a rear FPC 60Rr (reference) supported by the backing material 50. Figure 1 ); Multiple ( ) supported by backing material 50 and arranged in the left-right direction LR. Figure 1 (In the example, there are 8) piezoelectric elements 10 (reference) Figure 3 and Figure 4 ); an acoustic matching part 20 corresponding to and disposed thereon each piezoelectric element 10 (reference) Figure 4 ); the first conductive layer 32F and the first conductive layer 32R (reference) corresponding to each piezoelectric element 10 and disposed thereon Figure 3 ); and a second conductive layer 31F and a second conductive layer 31R (reference) disposed together with all piezoelectric elements 10. Figure 1 and Figure 3 The first conductor layer 32F, the first conductor layer 32R, the second conductor layer 31F, and the second conductor layer 31R are each composed of conductive materials such as metals or metal compounds.

[0044] like Figure 1 and Figure 2 As shown, the front FPC60Fr and the rear FPC60Rr are arranged at intervals in the front-to-back direction FR and are fixed to the backing material 50 by an adhesive such as epoxy resin. Figure 1 As shown, an electrode pattern forming region 61Fr is provided at the rear end of the front FPC60Fr. Furthermore, an electrode pattern forming region 61Rr is provided at the front end of the rear FPC60Rr.

[0045] like Figure 3As shown in the CC cross section, in the electrode pattern forming region 61Fr, the line electrodes 72 corresponding to each piezoelectric element 10 are arranged along the left-right direction LR. Furthermore, as... Figure 3 As shown in the BB cross section, in the electrode pattern forming region 61Rr, the line electrodes 71 corresponding to each piezoelectric element 10 are arranged along the left-right direction LR.

[0046] like Figure 3 and Figure 4 As shown, multiple piezoelectric elements 10 are arranged at a predetermined spacing P along the left-right direction LR above a backing material 50. Each piezoelectric element 10 is composed of a laminate consisting of a first conductive portion 12 made of conductive material, a piezoelectric body portion 11 made of piezoelectric material, and a second conductive portion 13 made of conductive material, which are sequentially stacked above the backing material 50. The first conductive portion 12 is fixed to the surface (lower surface) of the piezoelectric body portion 11 on the backing material 50 side by means of vapor deposition or the like, and the second conductive portion 13 is fixed to the surface (upper surface) of the piezoelectric body portion 11 on the side opposite to the backing material 50 side by means of vapor deposition or the like. The first conductive portion 12 functions as a signal electrode of the piezoelectric element 10. The second conductive portion 13 functions as a grounding electrode for obtaining a reference potential relative to the potential of the first conductive portion 12.

[0047] like Figure 2 and Figure 3 As shown, the first conductive portion 12 of the piezoelectric element 10 is disposed above the corresponding wire electrodes 71 and 72, and is electrically connected to these wire electrodes 71 and 72 via a conductive material such as silver (not shown). Connectors (not shown) for connecting to the wire electrodes 71 and 72 are provided on the front FPC60Fr and rear FPC60Rr, and are electrically connected to the main body of the ultrasonic diagnostic device. Therefore, the potential of the first conductive portion 12 of the piezoelectric element 10 can be controlled or acquired from the main body of the ultrasonic diagnostic device via the wire electrodes 71 and 72.

[0048] like Figure 2 As shown, the acoustic matching portion 20, the first conductive layer 32F, and the first conductive layer 32R are disposed on the second conductive portion 13 of the corresponding piezoelectric element 10. The acoustic matching portion 20 is fixed to the second conductive portion 13 by adhesive or the like. The first conductive layer 32F is disposed adjacent to the acoustic matching portion 20 on the front side of the acoustic matching portion 20. The first conductive layer 32R is disposed adjacent to the acoustic matching portion 20 on the rear side of the acoustic matching portion 20. The first conductive layer 32F and the first conductive layer 32R corresponding to each piezoelectric element 10 are electrically connected to the second conductive portion 13 of that piezoelectric element 10, and function as grounding electrodes.

[0049] The portion comprising the piezoelectric element 10 and its corresponding acoustic matching portion 20, the first conductive layer 32F, and the first conductive layer 32R is described as a detection unit. A gap is formed between each detection unit and adjacent detection units, separating these detection units from each other through this gap. Furthermore, as... Figure 3 and Figure 4 As shown, insulating filler material 40 is filled in the gaps between adjacent detection units, thereby fixing the positions of multiple detection units.

[0050] The width D1 of the detection unit in the left-right direction LR is uniform in the up-down direction UD. In other words, the widths of the piezoelectric element 10, acoustic matching part 20, first conductive layer 32F, and first conductive layer 32R constituting the detection unit are the same in the left-right direction LR. The width D2 of the insulating filler material 40 in the left-right direction LR is uniform in the up-down direction UD. The sum of widths D1 and D2 constitutes the arrangement spacing P of the plurality of piezoelectric elements 10. From the viewpoint of acquiring high-resolution ultrasonic images and suppressing the generation of grating noise, reducing this arrangement spacing P is effective.

[0051] like Figure 1 and Figure 3 As shown, the second conductive layer 31F is an elongated rectangular shape extending in the left-right direction LR, spanning the eight first conductive layers 32F and disposed on the first conductive layers 32F disposed on each piezoelectric element 10. That is, the second conductive layer 31F is electrically connected to the first conductive layer 32F corresponding to each piezoelectric element 10, and functions as a grounding electrode.

[0052] like Figure 1 and Figure 3 As shown, the second conductive layer 31R is an elongated rectangular shape extending in the left-right direction LR, spanning the eight first conductive layers 32R and disposed on the first conductive layers 32R disposed on each piezoelectric element 10. That is, the second conductive layer 31R is electrically connected to the first conductive layer 32R corresponding to each piezoelectric element 10, functioning as a grounding electrode. The second conductive layers 31F and 31R are connected to ground (not shown).

[0053] like Figure 1 and Figure 2As shown, a first conductive layer 32F corresponding to the piezoelectric element 10 and a second conductive layer 31F disposed on the first conductive layer 32F constitute a conductive member 30Fr with a multilayer structure disposed adjacent to the acoustic matching portion 20 corresponding to the piezoelectric element 10 on the second conductive portion 13 of the piezoelectric element 10. Furthermore, a first conductive layer 32R corresponding to the piezoelectric element 10 and a second conductive layer 31R disposed on the first conductive layer 32R constitute a conductive member 30Rr with a multilayer structure disposed adjacent to the acoustic matching portion 20 corresponding to the piezoelectric element 10 on the second conductive portion 13 of the piezoelectric element 10.

[0054] [Detailed information on the components of an ultrasonic probe]

[0055] The backing material 50 supports multiple piezoelectric elements 10 and absorbs ultrasonic waves emitted downwards (D) from the piezoelectric elements 10. The backing material 50 is formed, for example, from a rubber material such as ferrite rubber.

[0056] The piezoelectric body 11 of the piezoelectric element 10 is formed of a piezoelectric material. Examples of piezoelectric materials include piezoelectric ceramics such as PZT (lead zirconate titanate) or polymer materials such as PVDF (polyvinylidene fluoride).

[0057] The acoustic matching section 20 is used to match the acoustic impedance of the piezoelectric body section 11 of the piezoelectric element 10 and the test body, so that ultrasonic waves can easily enter the test body. The acoustic matching section 20 can be formed of a material having an acoustic impedance value that is smaller than that of the piezoelectric body section 11 and larger than that of the test body. Furthermore, the acoustic matching section 20 can also be formed by stacking multiple layers formed of such a material. For example, by stacking an acoustic matching layer made of a material having an acoustic impedance lower than that acoustic matching layer on the acoustic matching layer disposed on the second conductive section 13 of the piezoelectric element 10, a layer structure in which the acoustic impedance gradually decreases from the piezoelectric body section 11 to the test body is formed.

[0058] The first conductive layer 32F, the first conductive layer 32R, the second conductive layer 31F, and the second conductive layer 31R are not limited to any conductive material, but are preferably made of silver. The first conductive layer 32F, the first conductive layer 32R, the second conductive layer 31F, and the second conductive layer 31R are preferably formed of a conductive material having an acoustic impedance value that is smaller than that of the piezoelectric part 11 and larger than that of the test object.

[0059] The insulating filler material 40 is formed from an insulating resin material or the like. Examples of resin materials include silicone resin or epoxy resin.

[0060] Although Figure 1The illustration is omitted, but in the ultrasonic probe 100, sometimes an acoustic lens is fixed on the upper surface of the conductive part 30Fr, the conductive part 30Rr, the acoustic matching part 20 and the insulating filling material 40.

[0061] [Operation of the ultrasonic probe]

[0062] By applying pulsed or continuous wave voltages between the first conductive portion 12 of the plurality of piezoelectric elements 10 and the conductive members 30Rr and 30Fr connected to the second conductive portion 13 of the plurality of piezoelectric elements 10, each piezoelectric portion 11 expands and contracts to generate pulsed or continuous wave ultrasonic waves. If these ultrasonic waves are incident on the test body via the acoustic matching portion 20, they are combined to form an ultrasonic beam, which propagates within the test body. If the ultrasonic echo propagating and reflected within the test body is incident on each piezoelectric portion 11 via the acoustic matching portion 20, each piezoelectric portion 11 deforms, generating a signal voltage between the first conductive portion 12 and the second conductive portion 13 based on this deformation. The signal voltage generated in the plurality of piezoelectric elements 10 is extracted from the first conductive portion 12 of each piezoelectric element 10 and the conductive members 30Fr and 30Rr, and is received as a received signal, from which an ultrasonic image is generated.

[0063] [Preferred configurations of the first conductive layer 32R and the first conductive layer 32F]

[0064] As described above, reducing the spacing P is effective from the viewpoint of acquiring high-resolution ultrasonic images and suppressing grating noise. The gap between the aforementioned detection units is formed by cutting with a dicing saw as described in the manufacturing process below. Currently, the lower limit of the width of the dicing blade mounted on the dicing saw is approximately 15 μm. That is, in Figure 3 and Figure 4 If the width D2 shown is not less than 15μm, then in order to reduce the spacing P, the width D1 of the detection unit needs to be reduced.

[0065] If the width D1 decreases, then, for example, the bonding area between the piezoelectric element 10 and the acoustic matching portion 20, and the bonding area between the piezoelectric element 10 and the backing material 50, will decrease. Therefore, in order to mitigate the thermal strain caused by the difference in the coefficients of thermal expansion between the components constituting the detection unit, it is effective to avoid placing the ultrasonic probe 100 in a high-temperature environment during the manufacturing process. Furthermore, to ensure the performance of the ultrasonic probe 100, it is also important to avoid exposing the ultrasonic probe 100 to a high-temperature environment during the manufacturing process. Thus, when the ultrasonic probe 100 is not placed in a high-temperature environment during the manufacturing process, the hardness of the first conductive layer 32R and the first conductive layer 32F in the detection unit is sometimes less than the hardness of the acoustic matching portion 20 and the piezoelectric element 10.

[0066] Furthermore, in the detection unit, the volume of the first conductive layer 32R can be smaller than the volumes of the acoustic matching portion 20 and the piezoelectric element 10, respectively, and the volume of the first conductive layer 32F can also be smaller than the volumes of the acoustic matching portion 20 and the piezoelectric element 10, respectively. Therefore, if the width D1 becomes smaller, the bonding area between the first conductive layer 32R, the first conductive layer 32F and other constituent elements becomes smaller.

[0067] Thus, by reducing the width D1, if the bonding area between the first conductive layer 32R and the first conductive layer 32F and other constituent elements becomes smaller, or if the hardness of the first conductive layer 32R and the first conductive layer 32F becomes smaller, then during the cutting process used to form the detection unit, the first conductive layer 32R and the first conductive layer 32F will tilt to the left and right in the LR direction due to the force exerted by the cutting blade and the water flow used to cool and remove cutting chips, and be dragged by it. The acoustic matching part 20 and the piezoelectric element 10 may also tilt.

[0068] The verification results showed that by increasing the length (i.e., the thickness) of the first conductive layer 32F in the vertical direction UD, the [the following text is incomplete and requires further context: "to achieve the desired effect"]. Figure 3 The thickness HF shown is the length (i.e., the width) of the first conductor layer 32F in the left-right direction LR. Figure 3 When the ratio (HF / D1) of the width D1 shown is 1.6 or less (in other words, when the thickness HF is 1.6 times or less than the width D1), the tilting of the first conductive layer 32F in the left-right direction LR can be suppressed even if the width D1 becomes smaller or the hardness of the first conductive layer 32F becomes smaller. Specifically, it is known that by making the ratio (HF / D1) 1.6 or less, even if the width D1 is set to a small value such as 25 μm or more and less than 40 μm (equivalent to driving an ultrasonic probe 100 of 20 MHz to 23 MHz), the tilting of the first conductive layer 32F in the left-right direction LR can be suppressed. Furthermore, it is known that by making the ratio (HF / D1) 1.6 or less, even if the Shore D hardness (the hardness measured by the D-type tester specified in JIS (Japanese Industrial Standard) Z 2246) of the first conductive layer 32F is in the range of 80 or more and 85 or less, that is, even if the ultrasonic probe 100 is not placed in a high-temperature environment during the manufacturing process, the tilting of the first conductive layer 32F in the left-right direction LR can be suppressed.

[0069] Similarly, it was found that by increasing the length, i.e. the thickness, in the vertical direction UD of the first conductor layer 32R ( Figure 3 The thickness HR shown is the length (i.e., the width) of the first conductor layer 32R in the left-right direction LR. Figure 3When the ratio (HR / D1) of the thickness HR is 1.6 or less (in other words, when the thickness HR is 1.6 times or less than the width D1), the tilting of the first conductive layer 32R in the left-right direction LR can be suppressed even if the width D1 is small or the hardness of the first conductive layer 32R is small. Specifically, it is known that by making the ratio (HR / D1) 1.6 or less, even if the width D1 is set to a small value such as 25 μm or more and less than 40 μm (equivalent to driving an ultrasonic probe 100 of 20 MHz to 23 MHz), the tilting of the first conductive layer 32R in the left-right direction LR can be suppressed. Furthermore, it is known that by making the ratio (HR / D1) 1.6 or less, even if the Shore D hardness of the first conductive layer 32R is in the range of 80 or more and 85 or less, that is, even if the ultrasonic probe 100 is not placed in a high-temperature environment during the manufacturing process, the tilting of the first conductive layer 32R in the left-right direction LR can be suppressed.

[0070] In addition, considering the materials and structures typically used for the acoustic matching part 20, the Shore D hardness of the acoustic matching part 20 is greater than 85.

[0071] From the viewpoints of conductivity and ease of manufacture, the first conductive layer 32F and the first conductive layer 32R are preferably composed of heat-cured silver paste. For example, LOCTITE ABLESTIK 2902 silver paste manufactured by LOCTITE Corporation is preferred, but it is not limited to this. When calcination conditions of 65°C for 2 hours are used to obtain sufficient conductivity, the Shore D hardness of this silver paste is 80.

[0072] [Manufacturing process of ultrasonic probes]

[0073] The ultrasonic probe 100 described above is manufactured by sequentially performing the following first to seventh processes. See below for reference. Figures 5 to 20 The manufacturing process of the ultrasonic probe 100 will be described below. First, an overview of each process is given, followed by examples of each process.

[0074] <First Process>

[0075] (summary)

[0076] A sheet-like piezoelectric element 10S perpendicular to the vertical direction UD is formed, and the formed piezoelectric element 10S is bonded to the front FPC substrate 60Fr and the rear FPC substrate 60Rr using a conductive material. Then, the bonded body of the front FPC substrate 60Fr, the rear FPC substrate 60Rr and the piezoelectric element 10S is fixed to the backing material 50 using an adhesive Ad. Figure 5 It is a planar schematic diagram showing the state after the first process is completed. Figure 6 yes Figure 5 A schematic diagram of the cross section viewed from A1-A1. Figure 7 yes Figure 5 Schematic cross-sectional views along A2-A2 and A3-A3. The piezoelectric element 10S is the substrate of multiple piezoelectric elements 10, such as... Figure 6 and Figure 7 As shown, it is a laminate formed by stacking the first conductive part 12S, the piezoelectric part 11S and the second conductive part 13S.

[0077] (Example)

[0078] Using "C91H" manufactured by Fuji Ceramics Corporation as the piezoelectric material, the piezoelectric material was ground to a thickness of 60 μm using a grinding wheel to form the piezoelectric body 11S in the piezoelectric element 10S. On one side of the piezoelectric body 11S, a first conductive part 12S made of titanium and gold films was formed by sputtering. On the other side of the piezoelectric body 11S, a second conductive part 13S made of titanium and gold films was formed by sputtering. After the piezoelectric element 10S thus formed was trimmed to the desired size using a cutting saw, it was ultrasonically cleaned and plasma cleaned to complete the sheet-like piezoelectric element 10S.

[0079] Furthermore, LOCTITEABLESTIK 2902 silver paste manufactured by LOCTITE Corporation was applied to the electrode pattern forming area 61Fr of the front FPC substrate 60Fr and the electrode pattern forming area 61Rr of the rear FPC substrate 60Rr using a dispenser. With the first conductive portion 12S in contact with the silver paste, a piezoelectric element 10S was placed, and the silver paste was cured by heat treatment (2 hours at 65°C), thus bonding the piezoelectric element 10S to the front FPC substrate 60Fr and the rear FPC substrate 60Rr.

[0080] <Second Process>

[0081] (summary)

[0082] like Figure 8 As shown, in Figure 5 The piezoelectric element 10S shown has a sheet-like acoustic matching portion 20S formed in the central part of the front-rear direction FR on the upper surface of the upper surface, which is perpendicular to the vertical direction UD. Figure 9 yes Figure 8 A schematic diagram of the cross section viewed from A1-A1. Figure 10 yes Figure 8 A schematic cross-sectional view from A4-A4. Figure 10 In the example shown, the acoustic matching part 20S is a stack of a first layer 21, a second layer 22, and a third layer 23.

[0083] (Example)

[0084] A first layer 21 with a thickness of 25 μm was formed using a mixture of epoxy resin “Epotek-330” manufactured by Epoxy Technology and iron powder with a particle size of 5 μm.

[0085] A second layer 22 with a thickness of 30 μm was formed using a mixture of epoxy resin “Epotek-330” manufactured by Epoxy Technology and alumina powder with a particle size of 5 μm.

[0086] A third layer 23 with a thickness of 20 μm was formed using epoxy resin “Epotek-330” manufactured by Epoxy Technology.

[0087] On the upper surface of the piezoelectric element 10S after the first process, DER (registered trademark) 332 is coated with epoxy resin, a first layer 21 is disposed thereon, DER (registered trademark) 332 is coated on the first layer 21, a second layer 22 is disposed thereon, DER (registered trademark) 332 is coated on the second layer 22, and a third layer 23 is disposed thereon. Then, pressure is applied from the third layer 23 side to form the three-layer structure sound matching part 20S and to bond the sound matching part 20S to the piezoelectric element 10S.

[0088] <Third Process>

[0089] (summary)

[0090] exist Figure 8 The adjacent region on the upper surface of the piezoelectric element 10S in the state shown is coated with a conductive material in front of the acoustic matching portion 20S. Figure 8 The adjacent area behind the acoustic matching portion 20S on the upper surface of the piezoelectric element 10S shown is coated with a conductive material, which is then cured by heat treatment, such as... Figure 11 As shown, a first conductive layer 32FS extending in the left-right direction LR and a first conductive layer 32RS extending in the left-right direction LR are formed. Figure 12 yes Figure 11 A schematic diagram of the cross section viewed from A1-A1. Figure 13 yes Figure 11 Schematic diagrams of cross sections in the A2-A2 and A3-A3 directions.

[0091] In the third process, so that Figure 13 The first conductive layer 32RS is formed such that its length, or thickness HR, in the vertical direction UD is less than 1.6 times the aforementioned width D1, which is determined by the design value of the ultrasonic probe 100. Furthermore, to make... Figure 13The first conductive layer 32FS is formed such that the length, i.e. the thickness HF, in the vertical direction UD of the first conductive layer 32FS is less than 1.6 times the aforementioned width D1, which is determined by the design value of the ultrasonic probe 100.

[0092] (Example)

[0093] Next to the front side of the acoustic matching section 20S of the piezoelectric element 10S after the second process, silver paste "LOCTITE ABLESTIK 2902" manufactured by LOCTITE Corporation was applied using a distributor.

[0094] Next to the acoustic matching section 20S of the piezoelectric element 10S after the second process, silver paste "LOCTITE ABLESTIK 2902" manufactured by LOCTITE Corporation was applied using a distributor.

[0095] Then, the silver paste was cured by heat treatment (2 hours at 65°C) to form the first conductor layer 32FS and the first conductor layer 32RS.

[0096] <Fourth Process>

[0097] (summary)

[0098] The piezoelectric element 10S, which has an acoustic matching part 20S, a first conductive layer 32FS, and a first conductive layer 32RS formed on its upper surface through a third process, is divided into multiple piezoelectric elements 10 by cutting in the left-right direction LR. Figure 14 This is a plan view showing the state after the fourth process is completed. For example... Figure 14 As shown, by moving the cutting blade from the rear direction Rr to the front direction Fr, the piezoelectric element 10S forming the acoustic matching part 20S, the first conductive layer 32FS, and the first conductive layer 32RS are cut. By repeatedly cutting while changing the position of the cutting blade in the left-right direction LR, a state is obtained in which multiple detection units of width D1 are arranged at a spacing P in the left-right direction LR. Figure 14 The cutting area 40a shown represents the area cut by the cutting blade.

[0099] Figure 15 yes Figure 14 Schematic diagrams of cross sections in the A2-A2 and A3-A3 directions. Figure 16 yes Figure 14 A schematic cross-sectional view from A4-A4. (See diagram below.) Figure 15 and Figure 16 As shown, the cutting region 40a reaches the backing material 50. This also provides electrical isolation between the multiple wire electrodes 71 and between the multiple wire electrodes 72.

[0100] (Example)

[0101] The piezoelectric element 10S, which has an acoustic matching part 20S, a first conductive layer 32FS, and a first conductive layer 32RS formed on its upper surface through a third process, is divided into multiple parts in the left-right direction LR by cutting, forming 256 piezoelectric elements 10. The cutting conditions are as follows.

[0102] Cutting conditions:

[0103] spacing( Figure 14 The spacing between the elements (P) is 40 μm.

[0104] Number of cuts: 280

[0105] Feed rate: 1.5 mm / sec

[0106] Speed: 30,000 rpm

[0107] Cutting blade:

[0108] 15μm width

[0109] Z09-SD2500-Y1-60 51.0×0.015 (Manufactured by DISCO Corporation)

[0110] Cutting saw:

[0111] DAD 323 (manufactured by DISCO Corporation)

[0112] Furthermore, the first conductive layer 32FS and the first conductive layer 32RS have low Shore D hardness, which reduces the load applied to the cutting blade during cutting and extends the blade's life. Moreover, the soft first conductive layer 32FS and the first conductive layer 32RS can also handle debris during cutting.

[0113] <Fifth Process>

[0114] (summary)

[0115] The cutting area 40a formed in the fourth process is filled with insulating filler material 40. Figure 17 This is a planar schematic diagram showing the state after the fifth process is completed. Figure 18 yes Figure 17 Schematic diagrams of cross sections in the A2-A2 and A3-A3 directions. Figure 19 yes Figure 17 A schematic diagram of the cross section viewed from A4-A4.

[0116] (Example)

[0117] In the cutting zone 40a formed in the fourth process, silicone resin "RTV630" manufactured by Momentive Corporation is filled. The filling is performed by evacuating the vacuum chamber using a rotary pump for about 10 minutes to ensure that there are no air bubbles inside the cutting zone 40a.

[0118] <Sixth Process>

[0119] (summary)

[0120] Will Figure 17 The upper surfaces of the first conductive layers 32F and 32R are activated. The upper surfaces of the plurality of first conductive layers 32F arranged in the left-right direction LR and the insulating filler material 40 located between them are activated by cutting with a cutting blade. Similarly, the upper surfaces of the plurality of first conductive layers 32R arranged in the left-right direction LR and the insulating filler material 40 located between them are activated by cutting with a cutting blade.

[0121] In the sixth process, the thickness of the first conductive layer 32F and the first conductive layer 32R in the vertical direction UD is ( Figure 15 The upper surfaces of the first conductor layer 32F and the first conductor layer 32R are slightly cut to a degree that makes the thicknesses HR and HF substantially unchanged. That is, after the sixth process, the thicknesses of the first conductor layer 32F and the first conductor layer 32R are substantially the same as those after the third process (less than 1.6 times the width D1). Furthermore, this sixth process is not necessary and can be omitted.

[0122] (Example)

[0123] The upper surfaces of the first conductor layer 32F and the first conductor layer 32R were activated by cutting the fifth process using a cutting saw used in the fourth process.

[0124] <Seventh Process>

[0125] (summary)

[0126] like Figure 20 As shown, a second conductive layer 31F is formed across the upper surface of the plurality of activated first conductive layers 32F. Furthermore, a second conductive layer 31R is formed across the upper surface of the plurality of activated first conductive layers 32R.

[0127] (Example)

[0128] The upper surfaces of the multiple activated first conductor layers 32F were coated with LOCTITE ABLESTIK 2902 silver paste manufactured by LOCTITE Corporation using a dispenser.

[0129] The upper surfaces of the multiple activated first conductor layers 32R were coated with LOCTITE ABLESTIK 2902 silver paste manufactured by LOCTITE Corporation using a dispenser.

[0130] Then, the silver paste was cured by heat treatment (2 hours at 65°C) to form the second conductive layer 31F and the second conductive layer 31R.

[0131] Then, the upper surfaces of the second conductor layer 31F and the second conductor layer 31R are cut using a cutting saw used in the fourth process, so that the upper surfaces of the second conductor layer 31F and the second conductor layer 31R are aligned with the upper surface of the acoustic matching part 20.

[0132] [First Variation]

[0133] Figure 21 This is a diagram showing a first modified example of the ultrasonic probe 100, which is related to... Figure 1 A schematic diagram of the cross section corresponding to the view in direction AA. Figure 21 The modified example shown omits the first conductive layer 32R in the multilayer conductive component 30Rr, and only forms the second conductive layer 31R on the rear side of the acoustic matching portion 20. Otherwise, it is consistent with... Figure 2 Same. In manufacturing Figure 21 When using the ultrasonic probe of the modified example shown, in the third process described above ( Figure 11 The first conductor layer 32RS is not formed in the process, and the fourth process is carried out. Figure 14 ) and the fifth process ( Figure 17 Then, in the seventh step, a second conductive layer 31R is formed across multiple piezoelectric elements 10 on the rear side of the acoustic matching section 20.

[0134] [Second variation]

[0135] Figure 22 This is a diagram showing a second modified example of the ultrasonic probe 100, which is related to... Figure 1 A schematic diagram of the cross section corresponding to the view in direction AA. Figure 22 In the modified example shown, the multilayer conductive member 30Rr is removed, and the acoustic matching portion 20 is formed in the region where the multilayer conductive member 30Rr is formed. Otherwise, with... Figure 2 Same. In manufacturing Figure 22 When using the ultrasonic probe of the modified example shown, in the second process described above ( Figure 8 In the third process, the acoustic matching part 20S is formed in the region where the first conductive layer 32RS is formed, and then, in the third process ( Figure 11 Only the first conductor layer 32FS is formed in the process, and then the fourth process is performed. Figure 14 ) and the fifth process ( Figure 17 Then, in the seventh step, a second conductive layer 31F is formed on the front side of the acoustic matching part 20.

[0136] [Verification Result]

[0137] Figure 23 This is a diagram showing the verification results of an ultrasonic probe manufactured according to the embodiments of the above manufacturing process. The following describes... Figure 23 The contents of Examples 1 to 4, Reference Examples 1 and 2, and Comparative Examples 1 and 2 are shown.

[0138] (Example 1)

[0139] Made with Figures 1-4 The structure shown corresponds to an ultrasonic probe driven by a 23MHz motor. The total number of piezoelectric elements 10 is 256, and the width D1 of each piezoelectric element 10 is 25μm. The ratio (HR / D1) of the first conductive layer 32R formed in the third process is 0.4, and the ratio (HF / D1) of the first conductive layer 32F formed in the third process is also 0.4.

[0140] (Example 2)

[0141] The ratio (HF / D1) of the first conductive layer 32F formed in the third process was changed to 1.4. Otherwise, an ultrasonic probe was fabricated in the same manner as in Example 1.

[0142] (Example 3)

[0143] Made Figure 22 The ultrasonic probe shown is a modified example. The total number of piezoelectric elements 10 is 256, and the width D1 of each piezoelectric element 10 is 25 μm. The ratio (HF / D1) of the first conductive layer 32F formed in the third process is 1.4.

[0144] (Example 4)

[0145] The ratio (HF / D1) of the first conductive layer 32F formed in the third process was changed to 1.6. Otherwise, an ultrasonic probe was fabricated in the same manner as in Example 1.

[0146] (Refer to Example 1)

[0147] The width D1 of the piezoelectric element 10 was changed to 40 μm, the ratio (HR / D1) of the first conductive layer 32R formed in the third process was changed to 2.6, and the ratio (HF / D1) of the first conductive layer 32F formed in the third process was changed to 2.6. Otherwise, an ultrasonic probe was fabricated in the same manner as in Example 1.

[0148] (See Example 2 for reference)

[0149] The width D1 of the piezoelectric element 10 was changed to 63 μm, the ratio (HR / D1) of the first conductive layer 32R formed in the third process was changed to 2.3, and the ratio (HF / D1) of the first conductive layer 32F formed in the third process was changed to 2.3. Otherwise, an ultrasonic probe was fabricated in the same manner as in Example 1.

[0150] (Comparative Example 1)

[0151] The ratio (HF / D1) of the first conductive layer 32F formed in the third process was changed to 1.8. Otherwise, an ultrasonic probe was fabricated in the same manner as in Example 1.

[0152] (Comparative Example 2)

[0153] The ratio (HF / D1) of the first conductive layer 32F formed in the third process was changed to 1.7. Otherwise, an ultrasonic probe was fabricated in the same manner as in Example 1.

[0154] Figure 23 The “tilt / pour rate” shown represents the proportion of 256 detection units that are tilted or tilted in the left or right direction. Figure 23 The "OK" rating shown indicates that there is no tilting or tilting of the detection unit, and it is a good product with no performance problems. Figure 23 The "NG" rating shown indicates that the detection unit has tipped over or tilted and cannot be used as a product.

[0155] By comparing Examples 1-4 with Comparative Examples 1 and 2, it can be seen that if the ratio (HF / D1) exceeds 1.6, tipping or tilting occurs. Furthermore, as shown in the results of Example 1, no tipping or tilting occurs when both the ratio (HR / D1) and the ratio (HF / D1) are set to 0.4. Therefore, it can be concluded that the tipping or tilting in Comparative Examples 1 and 2 is due to the value of the ratio (HF / D1). From this verification result, it can be seen that by keeping the ratio (HF / D1) below 1.6, tipping or tilting can be prevented. Additionally, since the first conductive layer 32F and the first conductive layer 32R are formed from the same material and through the same manufacturing process, tipping or tilting can also be prevented by keeping the ratio (HR / D1) below 1.6.

[0156] Based on the results of Reference Examples 1 and 2, even when the width D1 is large, tilting or overturning does not occur even if the ratios (HF / D1) and (HR / D1) exceed 1.6. One reason for this is that the bonding areas of the first conductor layer 32F and the first conductor layer 32R with other constituent elements become larger. However, even with such a large width D1, if the ratios (HF / D1) and (HR / D1) are kept below 1.6, tilting or overturning becomes even less likely. Therefore, regardless of the size of the width D1, setting the ratios (HF / D1) and (HR / D1) to 1.6 or less is effective in preventing tilting or overturning. Figure 23 The results show that by setting the ratio (HF / D1) and the ratio (HR / D1) to below 1.6, tilting or tipping can be prevented even when the width D1 is set to a value less than 40 μm. As a result, it is possible to efficiently manufacture ultrasonic probes capable of handling high-frequency drives.

[0157] This specification describes at least the following items. Additionally, the components corresponding to the above embodiments are shown in parentheses, but the specification is not limited thereto. (1)

[0159] An ultrasonic probe has a plurality of piezoelectric elements (piezoelectric elements 10) arranged in a first direction (left-right direction LR), the ultrasonic probe (ultrasonic probe 100) comprising:

[0160] Support component (backing material 50) that supports the aforementioned plurality of piezoelectric elements;

[0161] An acoustic matching section (acoustic matching section 20) is disposed on the plurality of piezoelectric elements; and

[0162] Conductive components (conductive component 30Fr, conductive component 30Rr) are adjacent to the aforementioned acoustic matching portion and disposed on the aforementioned plurality of piezoelectric elements.

[0163] The aforementioned piezoelectric elements are each composed of a laminate in which a first conductive portion (first conductive portion 12), a piezoelectric body portion (piezoelectric body portion 11), and a second conductive portion (second conductive portion 13) are sequentially stacked on top of the aforementioned support member.

[0164] The aforementioned conductive component includes a multilayer conductive layer disposed at at least one end of the acoustic matching portion in a second direction (front-back direction FR) that intersects the first direction.

[0165] The aforementioned multilayer conductive layer includes: a plurality of first conductive layers (first conductive layer 32F, first conductive layer 32R), which are respectively bonded to the second conductive portion of the piezoelectric element; and a second conductive layer (second conductive layer 31F, second conductive layer 31R), which is stacked on the plurality of first conductive layers and electrically connected to the plurality of first conductive layers.

[0166] In the first conductor layer described above, the ratio of the thickness (HF, HR) to the length (D1) in the first direction is 1.6 or less. (2)

[0168] According to the ultrasonic probe described in (1), wherein,

[0169] The first conductive layer is formed by heat-curing silver paste with a Shore D hardness of 80 or higher and 85 or lower. (3)

[0171] According to the ultrasonic probe described in (1) or (2), wherein,

[0172] The width of the first conductive layer is 25 μm or more and less than 40 μm. (4)

[0174] According to any one of (1) to (3) of the ultrasonic probe, wherein,

[0175] The length (i.e., width) of each of the aforementioned piezoelectric elements in the first direction is the same as the width of the aforementioned first conductive layer. (5)

[0177] According to any one of (1) to (4) of the ultrasonic probe, wherein,

[0178] The aforementioned conductive components are disposed on both ends in the second direction. (6)

[0180] According to any one of (1) to (5) of the ultrasonic probe, wherein,

[0181] The Shore D hardness of the first conductive layer is less than the Shore D hardness of the acoustic matching part. (7)

[0183] An ultrasonic diagnostic device comprising the ultrasonic probe described in any one of (1) to (6). (8)

[0185] A method for manufacturing an ultrasonic probe, the ultrasonic probe having a plurality of piezoelectric elements (piezoelectric elements 10) arranged in a first direction (left-right direction LR), wherein the length, i.e., the width, of the piezoelectric elements in the first direction is a predetermined value (D1).

[0186] The direction intersecting the first direction is designated as the second direction (front-back direction FR), and the direction perpendicular to both the first and second directions is designated as the third direction (up-down direction UD).

[0187] The manufacturing method of the ultrasonic probe (ultrasonic probe 100) includes the following steps:

[0188] A sheet-like laminate (piezoelectric element 10S) formed by sequentially stacking a first conductive part (first conductive part 12S), a piezoelectric part (piezoelectric part 11S), and a second conductive part (second conductive part 13S) perpendicular to the third direction described above is fixed to a support member (backing material 50) (first process, Figure 5 );

[0189] A sound matching portion (sound matching portion 20S) is formed in a portion of the upper surface of the above-mentioned laminate on the side opposite to the side of the above-mentioned support member in the second direction (second process). Figure 8 );

[0190] A first conductor layer (first conductor layer 32FS, first conductor layer 32RS) with a thickness (HF, HR) of less than 1.6 times the predetermined value in the third direction is formed on at least one end side of the acoustic matching portion in the second direction on the upper surface of the above-mentioned laminate. (Third process) Figure 11 );

[0191] The laminate containing the acoustic matching portion and the first conductive layer is cut into multiple pieces in the first direction to form multiple piezoelectric elements (fourth process). Figure 14 );as well as

[0192] A second conductive layer (second conductive layer 31F, second conductive layer 31R) spanning the plurality of first conductive layers is formed on the first conductive layers (first conductive layer 32F, first conductive layer 32R) after they have been divided into the plurality of first conductive layers (seventh process). Figure 20 ).

[0193] The various embodiments have been described above with reference to the accompanying drawings, but the present invention is not limited to these examples. Those skilled in the art will readily conceive of various modifications or alterations within the scope of the patented technical solutions, and these should also be understood to fall within the technical scope of the present invention. Furthermore, the constituent elements of the above embodiments can be combined arbitrarily without departing from the spirit of the invention.

[0194] Furthermore, this application is based on Japanese patent application filed on April 1, 2021 (Japanese Patent Application 2021-063176), the contents of which are incorporated herein by reference.

[0195] Symbol Explanation

[0196] 10S, 10 - Piezoelectric element; 11S, 11 - Piezoelectric body; 12S, 12 - First conductive part; 13S, 13 - Second conductive part; 20S, 20 - Acoustic matching part; 21 - First layer; 22 - Second layer; 23 - Third layer; 30Fr, 30Rr - Conductive component; 31F, 31R - Second conductive layer; 32F, 32FS, 32RS, 32R - First conductive layer; 40a - Cutting area; 40 - Insulating filler material; 50 - Backing material; 60Fr - Front FPC; 60Rr - Rear FPC; 61Fr, 61Rr - Electrode pattern forming area; 71, 72 - Wire electrode; 100 - Ultrasonic probe.

Claims

1. An ultrasonic probe having a plurality of piezoelectric elements arranged in a first direction, the ultrasonic probe comprising: A support component that supports the plurality of piezoelectric elements; An acoustic matching section is disposed on the plurality of piezoelectric elements in the third direction; as well as A conductive component, which is adjacent to the acoustic matching portion in the second direction and disposed on the plurality of piezoelectric elements in the third direction, The second direction is the direction that intersects with the first direction. The third direction is a direction perpendicular to the first direction and the second direction. The plurality of piezoelectric elements are each composed of a laminate in which a first conductive portion, a piezoelectric body portion, and a second conductive portion are sequentially stacked on top of the support member. The conductive component includes a multilayer conductive layer disposed at at least one end in the second direction of the acoustic matching portion. The conductive layer of the multilayer structure includes: Multiple first conductive layers, each of which is bonded to the second conductive portion of the piezoelectric element; and a second conductor layer, which is stacked on the plurality of first conductor layers and electrically connected to the plurality of first conductor layers. In the first conductive layer, the ratio of the length (thickness) in the third direction to the length (width) in the first direction is 1.6 or less.

2. The ultrasonic probe according to claim 1, wherein, The first conductive layer is formed from heat-cured silver paste with a Shore D hardness of 80 or higher and 85 or lower.

3. The ultrasonic probe according to claim 1 or 2, wherein, The width of the first conductive layer is greater than 25 μm and less than 40 μm.

4. The ultrasonic probe according to claim 1 or 2, wherein, The length, i.e. the width, of each of the plurality of piezoelectric elements in the first direction is the same as the width of the first conductive layer.

5. The ultrasonic probe according to claim 1 or 2, wherein, The conductive components are disposed on both ends in the second direction.

6. The ultrasonic probe according to claim 1 or 2, wherein, The Shore D hardness of the first conductive layer is less than the Shore D hardness of the acoustic matching part.

7. An ultrasonic diagnostic apparatus comprising an ultrasonic probe according to any one of claims 1 to 6.

8. A method for manufacturing an ultrasonic probe, the ultrasonic probe having a plurality of piezoelectric elements arranged in a first direction, wherein the length, i.e., the width, of the piezoelectric elements in the first direction is a predetermined value. The direction intersecting the first direction is designated as the second direction, and the direction perpendicular to both the first and second directions is designated as the third direction. The manufacturing method of the ultrasonic probe includes the following steps: A sheet-like laminate, which is perpendicular to the third direction and consists of a first conductive part, a piezoelectric part, and a second conductive part stacked sequentially, is fixed to the support member. An acoustic matching portion is formed in a portion of the upper surface of the laminate on the side opposite to the support member side in the second direction; A first conductive layer with a thickness of less than 1.6 times the predetermined value is formed on at least one end side of the acoustic matching portion in the second direction on the upper surface of the laminate. The laminate containing the acoustic matching portion and the first conductive layer is cut into multiple portions in the first direction to form the multiple piezoelectric elements; and A second conductive layer is formed across the plurality of first conductive layers after the first conductive layers have been divided into the plurality of first conductive layers.

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