Ultrasonic probe

Abstract

Provided is an ultrasonic probe in which reliability is not impaired even when the number of channels of a piezoelectric element is increased, and in which an acoustic design does not need to be changed. A flexible circuit board (2) is disposed between a backing material (1) and a plurality of piezoelectric elements (4), each of the plurality of piezoelectric elements (4) is configured from a laminate (L) in which a signal electrode layer (4A), a piezoelectric body part (4B), and a ground electrode layer (4C) are laminated in this order in the lamination direction, the signal electrode layer is electrically connected to the flexible circuit board, the flexible circuit board is longer than the piezoelectric body part in the elevation direction (D2), and the ground electrode layer is electrically connected to the piezoelectric body part in the elevation direction (D2). A first member (5) comprising an adhesive in which abrasive grains are dispersed is disposed at the end of the laminate in the elevation direction, and the ground electrode layer is electrically connected to the flexible circuit board via a metal foil (6) extending from the surface of the laminate along the surface and side surfaces of the first member.

Description

Technical Field

[0001] The present invention relates to an ultrasonic probe in which a plurality of piezoelectric elements are arranged in an array along an azimuth direction. Background Art

[0002] Ultrasonic diagnostic devices that use ultrasonic imaging have long been in practical use in the medical field. Typically, such devices transmit an ultrasonic beam from an ultrasonic probe toward a subject, receive ultrasonic echoes from the subject using the ultrasonic probe, and electronically process the received signals to generate an ultrasonic image.

[0003] Ultrasonic probes typically have multiple piezoelectric elements arranged in an array along the so-called azimuth direction on a backing material. Patent Documents 1 and 2 disclose ultrasonic probes in which a flexible circuit board is arranged between the backing material and the multiple piezoelectric elements to extract signals from the multiple piezoelectric elements.

[0004] The signal electrode layer of the piezoelectric elements, which are located opposite the flexible printed circuit board, is connected to the flexible printed circuit board, extracting signals from the piezoelectric elements. Furthermore, a metal foil is connected to the ground electrode layer of the piezoelectric elements, which are located on the opposite side of the signal electrode layer, grounding the piezoelectric elements.

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2001-276060

[0006] Patent Document 2: Japanese Patent Application Laid-Open No. 2001-298795

[0007] However, due to the recent increase in high frequencies, the number of channels in piezoelectric elements has increased, leading to narrower pitches and a wider field of view. This has necessitated the need for a flexible printed circuit board that is long in the elevation direction to extract signals. The length of the flexible printed circuit board in the elevation direction tends to be longer than the length of the piezoelectric element.

[0008] In this way, if the length of the flexible circuit board in the elevation direction is longer than the piezoelectric element, a gap is likely to be generated between the metal foil connected to the ground electrode layer of the piezoelectric element and the end of the piezoelectric element in the elevation direction. When multiple piezoelectric elements are divided by cutting using a cutting blade, the cutting blade will shake and cause damage to the piezoelectric element, which may damage the reliability of the ultrasonic probe.

[0009] If the piezoelectric element is lengthened in the elevation direction in conjunction with a flexible printed circuit, the frequency band shape will change, and the acoustic design will need to be changed.

[0010] Furthermore, if the number of channels of the piezoelectric element increases, the cutting blade used for cutting is easily worn, and the cut cross-section of the piezoelectric element is damaged, thereby possibly impairing the reliability of the ultrasonic probe. Summary of the Invention

[0011] The present invention has been made to solve such conventional problems, and an object of the present invention is to provide an ultrasonic probe that does not impair reliability even when the number of channels of a piezoelectric element is increased, and that does not require a change in acoustic design.

[0012] The above-mentioned object can be achieved according to the following configuration.

[0013] [1] An ultrasonic probe comprising a plurality of piezoelectric elements arranged in an array along an azimuth direction on a backing material, wherein:

[0014] A flexible circuit board is arranged between the backing material and the plurality of piezoelectric elements.

[0015] Each of the plurality of piezoelectric elements is composed of a stacked body in which a signal electrode layer, a piezoelectric body portion, and a ground electrode layer are sequentially stacked in a stacking direction on the surface of a flexible circuit board.

[0016] The signal electrode layer is electrically connected to the flexible circuit board.

[0017] In the elevation direction, the flexible circuit board is longer than the piezoelectric body.

[0018] A first member composed of an adhesive in which abrasive grains are dispersed is disposed at an end portion of the stack in the elevation direction.

[0019] The ground electrode layer is electrically connected to the flexible printed circuit via a metal foil extending from the surface of the laminate along the surface of the first member and the side surface of the first member in the elevation angle direction.

[0020] [2] The ultrasonic probe according to [1], wherein:

[0021] The first members are respectively arranged at both ends of the stacked body in the elevation angle direction.

[0022] [3] The ultrasonic probe according to [1] or [2], wherein:

[0023] The sound attenuation rate of the first member is equal to or higher than the sound attenuation rate of the backing material.

[0024] [4] The ultrasonic probe according to any one of [1] to [3], wherein:

[0025] The first member is formed of a glassy binder or a ceramic binder in which abrasive grains selected from white alumina abrasive, green silicon carbide, and resinoid are dispersed.

[0026] [5] The ultrasonic probe according to any one of [1] to [4], wherein:

[0027] A second member is arranged between the first member and an end portion of the stacked body in the elevation angle direction. The second member has an acoustic attenuation rate greater than that of the first member.

[0028] [6] The ultrasonic probe according to [5], wherein:

[0029] The second member is made of a cushioning material.

[0030] [7] The ultrasonic probe according to [6], wherein:

[0031] The cushioning material is made of silicone resin or epoxy resin.

[0032] [8] The ultrasonic probe according to any one of [1] to [7], wherein:

[0033] A dematching layer is disposed between the flexible printed circuit board and the plurality of piezoelectric elements. The acoustic impedance of the dematching layer is higher than the acoustic impedance of the piezoelectric body.

[0034] Effects of the Invention

[0035] According to the present invention, a flexible circuit board is arranged between a backing material and a plurality of piezoelectric elements. The plurality of piezoelectric elements are each composed of a laminate in which a signal electrode layer, a piezoelectric body portion, and a ground electrode layer are sequentially laminated in a lamination direction on the surface of the flexible circuit board. The signal electrode layer is electrically connected to the flexible circuit board. The flexible circuit board is longer than the piezoelectric body portion in the elevation direction. A first member composed of an adhesive in which abrasive grains are dispersed is arranged at an end portion of the laminate in the elevation direction. The ground electrode layer is electrically connected to the flexible circuit board via a metal foil extending from the surface of the laminate along the surface of the first member and along the side surfaces of the first member in the elevation direction. This allows for the realization of an ultrasonic probe that can achieve an increase in the number of channels of the piezoelectric elements without compromising reliability and without requiring a change in acoustic design. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a perspective view showing a portion of the ultrasonic probe according to the first embodiment of the present invention.

[0037] Figure 2 It is a cross-sectional view of the ultrasonic probe according to the first embodiment of the present invention.

[0038] Figure 3 It is a cross-sectional view of an ultrasonic probe according to Embodiment 2 of the present invention.

[0039] Figure 4 It is a cross-sectional view of an ultrasonic probe according to Embodiment 3 of the present invention.

[0040] Figure 5 It is a cross-sectional view of an ultrasonic probe according to Embodiment 4 of the present invention.

[0041] Explanation of symbols

[0042] 1-backing material, 2-flexible circuit board, 3-dematching layer, 4-piezoelectric element, 4A-signal electrode layer, 4B-piezoelectric body, 4C-ground electrode layer, 5-first component, 6-metal foil, 7-acoustic matching layer, 8-filler, 9-second component, D1-azimuth direction, D2-elevation direction, G-groove, L-laminate, B-cutting blade. DETAILED DESCRIPTION

[0043] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0044] The following description of the components and elements is based on representative embodiments of the present invention, but the present invention is not limited to these embodiments.

[0045] In addition, in this specification, the numerical range expressed with "to" means the range including the numerical values ​​described before and after "to" as the lower limit and the upper limit.

[0046] In this specification, “same” and “identical” include a range of error generally allowed in the technical field.

[0047] Implementation Method 1

[0048] Figure 1 2 shows the structure of an ultrasonic probe according to Embodiment 1 of the present invention. The ultrasonic probe includes a backing material 1, a flexible printed circuit board 2 disposed on the backing material 1, a dematching layer 3 disposed on the flexible printed circuit board 2, and a plurality of piezoelectric elements 4 disposed on the dematching layer 3.

[0049] The flexible wiring board 2 is formed longer than the dematching layer 3 and the piezoelectric element 4 in the elevation angle direction D2 . A pair of first members 5 formed on the flexible wiring board 2 are arranged at both ends of the dematching layer 3 and the piezoelectric element 4 in the elevation angle direction D2 .

[0050] The ultrasonic probe further includes a metal foil 6 disposed on the plurality of piezoelectric elements 4 and the pair of first components 5, and an acoustic matching layer 7 disposed on the metal foil 6. The metal foil 6 is bent rearward toward the backing material 1 at the corners of the pair of first components 5 and extends along the side surfaces of each first component 5 in the elevation direction D2 to the side surfaces of the backing material 1.

[0051] Furthermore, the direction from the backing material 1 toward the acoustic matching layer 7 is referred to as “front,” and the direction from the acoustic matching layer 7 toward the backing material 1 is referred to as “rear.”

[0052] The plurality of piezoelectric elements 4 are arranged in an array along the azimuth direction D1, with grooves G formed between each of the piezoelectric elements 4. The grooves G are formed to extend from the acoustic matching layer 7 to the surface of the flexible printed circuit board 2. As a result, the dematching layer 3, the pair of first members 5, and the acoustic matching layer 7 are also divided into multiple pieces along the azimuth direction D1, similar to the plurality of piezoelectric elements 4. Furthermore, the metal foil 6 disposed above the plurality of piezoelectric elements 4 and on the side surfaces of the pair of first members 5 is also divided into multiple pieces along the azimuth direction D1, in accordance with the plurality of piezoelectric elements 4.

[0053] Furthermore, the interior of the groove G is filled with a filler 8 .

[0054] The backing material 1 absorbs ultrasonic waves emitted backward from the plurality of piezoelectric elements 4 and is formed by dispersing fillers such as ferrite, tungsten, and manganese in a base material such as rubber, epoxy resin, and polyurethane resin.

[0055] The flexible circuit board 2 is used to lead out electrodes of the plurality of piezoelectric elements 4 and has a multilayer structure in which a plurality of wiring layers are formed.

[0056] The dematching layer 3 is used to reflect ultrasonic waves emitted backward from the plurality of piezoelectric elements 4 forward. It is formed of a material having an acoustic impedance higher than the acoustic impedance of the piezoelectric body, which will be described later, constituting the piezoelectric elements 4, such as tungsten, tungsten carbide, tungsten oxide, or tantalum.

[0057] Acoustic matching layer 7 is a layer used to match the acoustic impedance of the plurality of piezoelectric elements 4 with that of the subject, thereby facilitating the entry of ultrasonic waves into the subject. It can be formed from a material having an acoustic impedance lower than that of the piezoelectric body portion of piezoelectric element 4 but higher than that of the subject. Furthermore, acoustic matching layer 7 can have a multilayer structure such that the acoustic impedance decreases gradually from piezoelectric element 4 toward the subject.

[0058] The filler 8 is used to fix the positions and postures of the dematching layer 3 , the piezoelectric element 4 , and the acoustic matching layer 7 adjacent to each other in the azimuth direction D1 , and is made of, for example, silicone resin, epoxy resin, or the like.

[0059] like Figure 2 As shown, each piezoelectric element 4 is formed of a stacked body L in which a signal electrode layer 4A, a piezoelectric body portion 4B, and a ground electrode layer 4C are stacked in this order toward the front (in the stacking direction) on the surface of the dematching layer 3 .

[0060] The piezoelectric body 4B is formed from a known piezoelectric material. It expands and contracts when a voltage is applied, emitting ultrasonic waves. It also expands and contracts when so-called ultrasonic echoes propagate from the outside, generating electrical signals. Examples of piezoelectric materials include piezoelectric ceramics such as PZT (lead zirconate titanate) and polymer materials such as PVDF (polyvinylidene fluoride).

[0061] The signal electrode layer 4A is used to apply a voltage to the piezoelectric element 4B and extract the electrical signal generated by the expansion and contraction of the piezoelectric element 4B due to the propagation of ultrasonic echoes. Furthermore, the signal electrode layer 4A is electrically connected to the wiring layer (not shown) of the flexible printed circuit board 2 via the conductive dematching layer 3. Specifically, the dematching layer 3 includes electrode layers (not shown) on the surface facing the multiple piezoelectric elements 4 and the surface facing the flexible printed circuit board 2. The signal electrode layer 4A of each piezoelectric element 4 is electrically connected to the wiring layer (not shown) of the flexible printed circuit board 2 by utilizing the electrode layers disposed on both surfaces of the dematching layer 3 and the conductivity of the dematching layer 3 itself.

[0062] The ground electrode layer 4C is used to set the reference potential of the piezoelectric body portion 4B to a predetermined ground potential, and is in contact with and electrically connected to the metal foil 6 disposed on the upper portion of the piezoelectric element 4 .

[0063] The pair of first members 5 are each formed of an adhesive in which abrasive grains are dispersed. Specifically, the first members 5 can be formed of a glass adhesive or a ceramic adhesive in which abrasive grains such as white alumina abrasive, green silicon carbide, or a resinous substance are dispersed.

[0064] Furthermore, since the first member 5 contacts the side surface of the piezoelectric element 4 in the elevation angle direction D2 , its acoustic attenuation rate is preferably equal to or higher than that of the backing material 1 in order to suppress the influence on the acoustic characteristics of the piezoelectric element 4 .

[0065] The abrasive grains contained in the first member 5 are used for performing a grinding process on the dicing blade B used when dividing the piezoelectric elements 4 into a plurality of elements.

[0066] The height of the pair of first members 5 from the surface of the flexible printed circuit board 2 toward the front is equivalent to the combined thickness of the dematching layer 3 and the piezoelectric element 4. The surface of the first member 5 facing the front is flush with the surface of the ground electrode layer 4C of the piezoelectric element 4. Therefore, the metal foil 6 extends flat from the piezoelectric element 4 to the first member 5, bends rearward at the corner of the first member 5, and extends rearward along the side surface of the first member 5 in the elevation angle direction D2.

[0067] The ultrasonic probe according to the first embodiment of the present invention includes the pair of first members 5 . Therefore, even if the flexible printed circuit 2 is formed to be longer than the dematching layer 3 and the piezoelectric element 4 in the elevation angle direction D2, a gap is not generated between the ends of the dematching layer 3 and the piezoelectric element 4 in the elevation angle direction D2.

[0068] Therefore, it is possible to prevent the piezoelectric elements 4 from being damaged by vibration of the dicing blade B during dicing to separate the piezoelectric elements 4. Furthermore, there is no need to lengthen the dematching layer 3 and the piezoelectric elements 4 in the elevation direction D2 to accommodate the flexible printed circuit board 2, and no need to change the acoustic design.

[0069] Furthermore, the height of the first member 5 corresponds to the combined thickness of the dematching layer 3 and the piezoelectric element 4. Therefore, when the dematching layer 3 and the piezoelectric element 4 are cut using the dicing blade B, the first member 5 is also cut by the dicing blade B. However, the first member 5 is formed from a material containing abrasive grains. As a result, each time the dematching layer 3 and the piezoelectric element 4 are cut, the abrasive grains contained in the first member 5 abrade the dicing blade B. This prevents damage to the cut cross-section of the piezoelectric element 4 due to wear of the dicing blade B.

[0070] This can improve the reliability of the ultrasonic probe.

[0071] The ultrasonic probe according to the first embodiment of the present invention can be manufactured as follows.

[0072] First, the flexible printed circuit board 2 and the dematching layer 3 are bonded to the surface of the backing material 1 in this order using an adhesive or the like. Then, a laminate L including the signal electrode layer 4A, the piezoelectric body portion 4B, and the ground electrode layer 4C laminated in this order is bonded to the surface of the dematching layer 3 using an adhesive or the like.

[0073] Furthermore, a pair of first members 5 are arranged and bonded to the flexible wiring board 2 so as to be adjacent to the dematching layer 3 and both end portions of the laminate L in the elevation angle direction D2 .

[0074] Furthermore, metal foil 6 is bonded to the surfaces of the laminate L and the pair of first members 5. Furthermore, the metal foil 6, which is bent at the corners of the pair of first members 5, is bonded to the side surfaces of the first members 5, the flexible circuit board 2, and the backing material 1. An acoustic matching layer 7 is then bonded to the metal foil 6.

[0075] In this state, the dicing blade B is relatively moved in the elevation direction D2 while rotating, thereby dicing the dematching layer 3 , the laminate L, and the acoustic matching layer 7 into multiple parts in the azimuth direction D1 , thereby forming multiple piezoelectric elements 4 .

[0076] At this time, a pair of first parts 5 are also divided into multiple parts along the azimuth direction D1 in conjunction with multiple piezoelectric elements 4, and the metal foil 6 arranged on the upper part of the piezoelectric element 4 and the side parts of the pair of first parts 5 are also divided into multiple parts along the azimuth direction D1 in conjunction with multiple piezoelectric elements 4.

[0077] As the pair of first members 5 are divided by the dicing blade B, the dicing blade B is subjected to a grinding process by the abrasive grains contained in the first member 5 every time dicing is performed.

[0078] Finally, the filler 8 is filled in the groove G formed by cutting, thereby manufacturing Figure 1 Ultrasound probe shown.

[0079] Furthermore, in the first embodiment described above, the metal foil 6 connected to the ground electrode layer 4C of the plurality of piezoelectric elements 4 extends along the side surface of each first member 5 in the elevation angle direction D2 to the side surface of the backing material 1. However, the present invention is not limited to this. Alternatively, the metal foil 6 may be bent along the front or back surface of the flexible printed circuit board 2 and connected to a ground wiring layer (not shown) of the flexible printed circuit board 2. In this case, the metal foil 6 does not need to extend to the side surface of the backing material 1.

[0080] Furthermore, the acoustic matching layer 7 disposed on the metal foil 6 is also divided into multiple pieces along the azimuth direction D1 to match the multiple piezoelectric elements 4, but this is not limiting. For example, prior to disposing the acoustic matching layer 7, dicing may be performed to divide the dematching layer 3, the laminate L, the pair of first members 5, and the metal foil 6 into multiple pieces along the azimuth direction D1. A single acoustic matching layer 7 extending long in the azimuth direction D1 may then be disposed on the multiple pieces of piezoelectric elements 4 and the metal foil 6.

[0081] Implementation Method 2

[0082] Figure 3 2 shows the structure of an ultrasonic probe according to Embodiment 2 of the present invention. This ultrasonic probe is similar to the ultrasonic probe of Embodiment 1, except that second members 9 are disposed between the pair of first members 5 and the opposite ends of the dematching layer 3 and the piezoelectric element 4 in the elevation angle direction D2. The remaining components are the same as those of the ultrasonic probe of Embodiment 1.

[0083] Specifically, the ultrasonic probe according to the second embodiment includes a flexible printed circuit board 2 disposed on a backing material 1, a dematching layer 3 disposed on the flexible printed circuit board 2, and a plurality of piezoelectric elements 4 disposed on the dematching layer 3. A pair of first components 5 are disposed at both ends of the dematching layer 3 and the piezoelectric elements 4 in the elevation angle direction D2, via a pair of second components 9 formed on the flexible printed circuit board 2.

[0084] A metal foil 6 is arranged on the plurality of piezoelectric elements 4 , the pair of second members 9 , and the pair of first members 5 , and an acoustic matching layer 7 is arranged on the metal foil 6 .

[0085] The pair of second members 9 have the same height as the first member 5 and have a higher sound attenuation rate than the first member 5. Specifically, the second members 9 can be formed using a buffer material made of silicone resin or epoxy resin, similar to the filler 8 filling the groove G.

[0086] In this way, by placing the second component 9 having an acoustic attenuation rate greater than that of the first component 5 between the piezoelectric element 4 and the first component 5, the influence of direct contact with the first component 5 on the acoustic characteristics of the piezoelectric element 4 can be suppressed, thereby further improving the reliability of the ultrasonic probe.

[0087] In the ultrasonic probe according to the second embodiment, even if the flexible printed circuit board 2 is formed longer than the dematching layer 3 and the piezoelectric elements 4 in the elevation angle direction D2, no gap is generated between the ends of the dematching layer 3 and the piezoelectric elements 4 in the elevation angle direction D2. This prevents the piezoelectric elements 4 from being damaged by vibration of the dicing blade B during dicing of the plurality of piezoelectric elements 4. Furthermore, there is no need to lengthen the dematching layer 3 and the piezoelectric elements 4 in the elevation angle direction D2 in accordance with the flexible printed circuit board 2, and no change in the acoustic design is required.

[0088] Furthermore, each time the dematching layer 3 and the piezoelectric element 4 are cut, the dicing blade B is polished by the abrasive grains contained in the first member 5 , thereby preventing the cut cross section of the piezoelectric element 4 from being damaged due to wear of the dicing blade B.

[0089] Implementation 3

[0090] Figure 4 2 shows the structure of an ultrasonic probe according to Embodiment 3 of the present invention. Unlike the ultrasonic probe of Embodiment 1, this ultrasonic probe is configured such that, instead of disposing a pair of first members 5 at both ends of the dematching layer 3 and piezoelectric element 4 in the elevation angle direction D2, the first member 5 formed on the flexible printed circuit board 2 is disposed only at one end of the dematching layer 3 and piezoelectric element 4 in the elevation angle direction D2. The remaining components are the same as those of the ultrasonic probe of Embodiment 1.

[0091] Specifically, the ultrasonic probe according to Embodiment 3 includes a flexible printed circuit board 2 disposed on a backing material 1, a dematching layer 3 disposed on the flexible printed circuit board 2, and a plurality of piezoelectric elements 4 disposed on the dematching layer 3. A first member 5 is disposed at one end of the dematching layer 3 and the piezoelectric elements 4 in the elevation angle direction D2. Furthermore, a metal foil 6 is disposed on the plurality of piezoelectric elements 4 and the first member 5, and an acoustic matching layer 7 is disposed on the metal foil 6.

[0092] In the ultrasonic probe according to Embodiment 3, even if the flexible printed circuit board 2 is formed longer than the dematching layer 3 and the piezoelectric element 4 in the elevation direction D2, no gap is generated at the ends of the dematching layer 3 and the piezoelectric element 4 in the elevation direction D2. This prevents the piezoelectric elements 4 from being damaged by vibration of the dicing blade B during dicing of the plurality of piezoelectric elements 4. Furthermore, there is no need to lengthen the dematching layer 3 and the piezoelectric element 4 in the elevation direction D2 in accordance with the flexible printed circuit board 2, and no change in the acoustic design is required.

[0093] Furthermore, each time the dematching layer 3 and the piezoelectric element 4 are cut, the dicing blade B is polished by the abrasive grains contained in the first member 5 , thereby preventing the cut cross section of the piezoelectric element 4 from being damaged due to wear of the dicing blade B.

[0094] In addition, in order to prevent the piezoelectric element 4 from being damaged due to the vibration of the cutting blade B during cutting, Figure 4 As shown, the dicing blade B is preferably relatively moved along the elevation angle D2 from one end of the dematching layer 3 and the piezoelectric element 4 where the first member 5 is arranged toward the other end where the first member 5 is not arranged.

[0095] Furthermore, the third embodiment may be applied to the ultrasonic probe of the second embodiment, and the second member 9 and the first member 5 may be arranged only at one end of the dematching layer 3 and the piezoelectric element 4 in the elevation angle direction D2.

[0096] Implementation 4

[0097] Figure 5 2 shows the structure of an ultrasonic probe according to a fourth embodiment of the present invention. This ultrasonic probe is different from the ultrasonic probe of the first embodiment, except that the matching layer 3 is omitted and a plurality of piezoelectric elements 4 are directly arranged on the surface of the flexible printed circuit board 2. The remaining components are the same as those of the ultrasonic probe of the first embodiment.

[0098] Specifically, the ultrasonic probe according to the fourth embodiment includes a flexible printed circuit 2 disposed on a backing material 1, a plurality of piezoelectric elements 4 disposed on the flexible printed circuit 2, and a pair of first members 5 disposed at both ends of the piezoelectric elements 4 in the elevation angle direction D2. Furthermore, a metal foil 6 is disposed on the plurality of piezoelectric elements 4 and the pair of first members 5, and an acoustic matching layer 7 is disposed on the metal foil 6.

[0099] In the ultrasonic probe according to the fourth embodiment, even if the flexible printed circuit board 2 is formed to be longer than the piezoelectric elements 4 in the elevation angle direction D2, no gap is generated at the ends of the piezoelectric elements 4 in the elevation angle direction D2. This prevents the piezoelectric elements 4 from being damaged by vibration of the dicing blade B during dicing of the plurality of piezoelectric elements 4. Furthermore, there is no need to lengthen the piezoelectric elements 4 in the elevation angle direction D2 to accommodate the flexible printed circuit board 2, and no changes are required to the acoustic design.

[0100] Furthermore, each time the piezoelectric element 4 is cut, the dicing blade B is polished by the abrasive grains contained in the first member 5 , thereby preventing the cut cross section of the piezoelectric element 4 from being damaged due to wear of the dicing blade B.

[0101] However, if a plurality of piezoelectric elements 4 are arranged on the surface of the dematching layer 3 as in the first embodiment, ultrasonic waves emitted backward from the piezoelectric elements 4 can be reflected forward by the dematching layer 3 , thereby forming a high-performance ultrasonic probe.

[0102] Furthermore, it is also possible to apply the fourth embodiment to the ultrasonic probe of the second embodiment or the third embodiment and omit the matching layer 3 .

Claims

1. An ultrasonic probe comprising a plurality of piezoelectric elements arranged in an array along an azimuth direction on a backing material, wherein: A flexible circuit board is arranged between the backing material and the plurality of piezoelectric elements. The plurality of piezoelectric elements are each composed of a stacked body in which a signal electrode layer, a piezoelectric body portion, and a ground electrode layer are sequentially stacked in a stacking direction on the surface of the flexible circuit board. The signal electrode layer is electrically connected to the flexible circuit board, In the elevation angle direction, the flexible circuit board is longer than the piezoelectric body. A first member composed of an adhesive in which abrasive grains are dispersed is disposed at an end portion of the stack in the elevation angle direction. The ground electrode layer is electrically connected to the flexible printed circuit via a metal foil extending from the surface of the laminate along the surface of the first member and the side surface of the first member in the elevation angle direction.

2. The ultrasonic probe according to claim 1, wherein: The first members are respectively arranged at both ends of the stacked body in the elevation angle direction.

3. The ultrasonic probe according to claim 1, wherein: The sound attenuation rate of the first member is equal to or greater than the sound attenuation rate of the backing material.

4. The ultrasonic probe according to claim 1, wherein: The first member is formed of a glassy binder or a ceramic binder in which any one of white alumina abrasive, green silicon carbide, and a resinous substance is dispersed as the abrasive grains.

5. The ultrasonic probe according to claim 1, wherein A second member is disposed between the end portion of the stacked body in the elevation angle direction and the first member, and the second member has a higher sound attenuation rate than the first member. The ultrasonic probe according to claim 5 , wherein: The second member is made of a cushioning material.

7. The ultrasonic probe according to claim 6, wherein: The buffer material is made of silicone resin or epoxy resin.

8. The ultrasonic probe according to any one of claims 1 to 7, wherein: A dematching layer is disposed between the flexible circuit board and the plurality of piezoelectric elements. The acoustic impedance of the dematching layer is higher than the acoustic impedance of the piezoelectric body.

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