Ultrasound probe

Abstract

This ultrasonic probe comprises at least one piezoelectric element that sends / receives ultrasonic waves. The at least one piezoelectric element includes: a piezoelectric body formed by the sol-gel process; and at least one electrode that contains a conductive elastomer and that contacts the piezoelectric body.

Description

Technical Field

[0001] This disclosure relates to ultrasonic probes. Bu Related thereto.

Background Art

[0002] In medical diagnosis of living bodies and non-destructive inspection of structures, etc., ultrasonic measurement using an ultrasonic probe is utilized as a method for non-invasively and non-destructively inspecting internal structures. A general ultrasonic probe has a piezoelectric element that mutually converts an electrical signal due to a voltage change and mechanical vibration of ultrasonic waves. Also, a general piezoelectric element has a piezoelectric body, an upper electrode disposed on the upper surface of the piezoelectric body, and a lower electrode disposed on the lower surface of the piezoelectric body.

[0003] Such an ultrasonic probe is desired to have flexibility so that highly accurate measurement can be performed on a curved structure. Therefore, the piezoelectric element included in the ultrasonic probe is desired to have flexibility.

[0004] The piezoelectric body included in the piezoelectric element described in Patent Document 1 is formed by a sol-gel method so as to ensure the flexibility of the ultrasonic probe. Also, the upper electrode included in the piezoelectric element is formed by a conductive paste or a metal vapor deposition method.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] Piezoelectric materials formed by the sol-gel method are porous, resulting in significant surface irregularities. Therefore, when forming metal film electrodes on the piezoelectric material using the vapor deposition method, it is difficult to form the electrodes thick enough, and the surface of the piezoelectric material cannot be adequately covered. As a result, the conductivity of the electrodes deteriorates, leading to unstable operation of the ultrasonic probe. [Means for solving the problem]

[0007] To solve the above problems, an ultrasonic device according to one aspect of this disclosure B The beam comprises at least one piezoelectric element for transmitting and receiving ultrasonic waves, the at least one piezoelectric element comprising a piezoelectric body, at least one electrode in contact with the piezoelectric body and containing a conductive elastomer, another electrode in contact with the side of the piezoelectric body opposite to the at least one electrode, and a backing material in contact with the side of the other electrode opposite to the piezoelectric body, the backing material containing an elastomer. Furthermore, the piezoelectric material is porous. Furthermore, ultrasonic pulse according to one aspect of this disclosure B The device comprises at least one piezoelectric element for transmitting and receiving ultrasonic waves, the at least one piezoelectric element comprising a piezoelectric body, at least one electrode in contact with the piezoelectric body and containing a conductive elastomer, and a housing for protecting the piezoelectric element, the housing containing an elastomer. Furthermore, the piezoelectric material is porous. [Effects of the Invention]

[0009] According to this disclosure, a flexible ultrasound probe can be provided. [Brief explanation of the drawing]

[0010] [Figure 1] This is a plan view showing an ultrasonic probe according to the first embodiment. [Figure 2] Figure 1 is a cross-sectional view of the ultrasonic probe shown. [Figure 3] This diagram shows the flow of the manufacturing method for the ultrasonic probe according to the first embodiment. [Figure 4]This is a plan view showing an ultrasonic probe according to the second embodiment. [Figure 5] Figure 4 shows the ultrasonic probe viewed in the X2 direction. [Figure 6] Figure 4 shows the ultrasonic probe viewed in the Y1 direction. [Modes for carrying out the invention]

[0011] Preferred embodiments relating to this disclosure will be described below with reference to the attached drawings. Furthermore, the scope of this disclosure is not limited to these embodiments unless otherwise stated in the following description.

[0012] 1. First Embodiment 1-1. Ultrasound probe 100 Figure 1 is a plan view showing the ultrasonic probe 100 of the first embodiment. Figure 2 is a cross-sectional view of the ultrasonic probe 100 shown in Figure 1. Note that the dimensions and scale of each part of the ultrasonic probe 100 shown in Figure 2 differ appropriately from the actual dimensions and are shown schematically for ease of understanding. The actual thickness of the ultrasonic probe 100 is much thinner than the thickness shown in Figure 2. Also, Figure 2 corresponds to the cross-section along line AA in Figure 1.

[0013] In the following explanation, for convenience, we will use mutually orthogonal X, Y, and Z axes as appropriate. Furthermore, one direction along the X-axis will be denoted as the X1 direction, and the direction opposite to the X1 direction will be denoted as the X2 direction. Similarly, one direction along the Y-axis will be denoted as the Y1 direction, and the direction opposite to the Y1 direction will be denoted as the Y2 direction. One direction along the Z-axis will be denoted as the Z1 direction, and the direction opposite to the Z1 direction will be denoted as the Z2 direction. In the following explanation, viewing in the Z1 or Z2 direction will be referred to as a "planar view." Also, the Z1 direction will be considered upward, and the Z2 direction will be considered downward.

[0014] The ultrasonic probe 100 shown in FIGS. 1 and 2 is used for ultrasonic measurements such as medical diagnosis of living bodies and non-destructive inspection of structures. Ultrasonic measurement is a method of measuring the presence or position of an object by transmitting an ultrasonic signal from the ultrasonic probe 100 toward the object and receiving the ultrasonic signal reflected by the object with the ultrasonic probe 100. Ultrasonic waves have the property of reflecting at the interface between different objects. The greater the difference in acoustic impedance between objects, the greater the reflectivity of ultrasonic waves. The presence or position of the object is measured based on the reflectivity. According to such ultrasonic measurement, the internal structure can be inspected non-invasively and non-destructively.

[0015] The ultrasonic probe 100 has flexibility. This flexible ultrasonic probe 100 has excellent adhesion to curved surfaces such as the neck, chest, abdomen, arm, and finger. Therefore, the ultrasonic probe 100 has excellent adhesion not only to the flat surface of the object but also to the curved surface. By using such an ultrasonic probe 100, the measurable range of the object can be expanded.

[0016] The ultrasonic probe 100 includes a piezoelectric element 2, a flexible wiring board 3, a backing material 4, and a housing 5. As shown in FIG. 2, the ultrasonic probe 100 has a lower surface 101 and an upper surface 102. The upper surface 102 is the surface that contacts the object. The ultrasonic probe 100 transmits and receives ultrasonic waves from the upper surface 102.

[0017] 1-1a. Piezoelectric Element 2 The piezoelectric element 2 shown in FIGS. 1 and 2 transmits and receives ultrasonic waves. The piezoelectric element 2 has a function of mutually converting an electrical signal due to a voltage change and the mechanical vibration of ultrasonic waves.

[0018] The piezoelectric element 2 includes a lower electrode 21, a piezoelectric body 22, and an upper electrode 23. The piezoelectric body 22 is located between the lower electrode 21 and the upper electrode 23 and contacts them. In the state where the ultrasonic probe 100 is in contact with the object, the lower electrode 21 is located farther from the object than the upper electrode 23. Also, the lower electrode 21 is another electrode that contacts the surface of the piezoelectric body 22 opposite to the upper electrode 23.

[0019] In the example shown in Figure 1, the shape of the lower electrode 21 in plan view is rectangular. The lower electrode 21 is flexible. The material of the lower electrode 21 is a metal, such as stainless steel. Because the material of the lower electrode 21 is metal, it is thinner than, for example, an elastomer, and it is possible to ensure the minimum hardness necessary for the ultrasonic probe 100 to be practical. Note that the material of the lower electrode 21 may be a metal other than stainless steel, or a non-metallic material such as carbon.

[0020] As shown in Figure 2, the lower electrode 21 has a lower surface 211 and an upper surface 212. The piezoelectric element 22 is in contact with the upper surface 212. The thickness of the lower electrode 21 is preferably, for example, 10 μm to 200 μm, and more preferably 50 μm to 100 μm. By having a thickness within the above range, the flexibility of the ultrasonic probe 100 is suppressed while ensuring the minimum hardness necessary for practical use, compared to when the thickness is outside the range.

[0021] As shown in Figure 1, the piezoelectric element 22 has a nearly circular shape in plan view. However, this shape may also be a polygon other than a circle, such as a quadrilateral. In the illustrated example, the planar area of ​​the piezoelectric element 22 is smaller than the planar area of ​​the lower electrode 21. The piezoelectric element 22 overlaps with the lower electrode 21 in plan view.

[0022] The piezoelectric material 22 is a sol-gel film formed by the sol-gel method. Such a piezoelectric material 22 is porous. By forming the piezoelectric material 22 by the sol-gel method, a piezoelectric material 22 with excellent flexibility can be obtained. Examples of materials for the piezoelectric material 22 include piezoelectric ceramics such as lead zirconate titanate (PZT).

[0023] As shown in Figure 2, the piezoelectric body 22 has a lower surface 221 and an upper surface 222. The lower surface 221 is in contact with the lower electrode 21, and the upper surface 222 is in contact with the upper electrode 23. The thickness of the piezoelectric body 22 is preferably, for example, 10 μm to 200 μm, and more preferably 50 μm to 100 μm. Having a thickness within the above range makes it easier to deform the piezoelectric body 22 and easier to form the piezoelectric body 22 by the sol-gel method compared to when the thickness is outside the range.

[0024] As shown in Figure 1, the upper electrode 23 has a nearly circular shape in plan view. However, this shape may also be a polygon other than a circle, such as a quadrilateral. In the illustrated example, the planar area of ​​the upper electrode 23 is smaller than the planar area of ​​the lower electrode 21 and the planar area of ​​the piezoelectric element 22. The upper electrode 23 overlaps with the lower electrode 21 and the piezoelectric element 22 in plan view.

[0025] The upper electrode 23 is an electrode containing a conductive elastomer. Preferably, the conductive elastomer contains a binder and a conductive filler. Examples of the binder include rubber or thermoplastic elastomers such as silicone rubber and urethane rubber. Examples of the conductive filler include metal particles such as silver powder, conductive carbon, and plated fillers such as silver-plated filler. The conductive filler may be in powder, particulate, or fibrous form.

[0026] Because the upper electrode 23 contains a conductive elastomer, the upper electrode 23 is a thin film and has excellent flexibility. Therefore, the ability of the upper electrode 23 to follow the deformation of the piezoelectric body 22 can be improved. Furthermore, by using a conductive elastomer, an upper electrode 23 of sufficient thickness can be formed on the upper surface 222 of the piezoelectric body 22. Therefore, a flexible ultrasonic probe 100 with good conductivity can be provided.

[0027] Furthermore, because the upper electrode 23 has excellent flexibility, even if the upper electrode 23 is bent, the decrease in the conductivity of the upper electrode 23 is suppressed. If the upper electrode 23 is a metal film, the flexibility of the material itself is low, so if the curvature of the upper electrode 23 is reduced or the upper electrode 23 is repeatedly bent, there is a risk that the upper electrode 23 will break. However, in this embodiment, the upper electrode 23 is not a metal film and has excellent flexibility, so even if the curvature of the upper electrode 23 is reduced or the upper electrode 23 is repeatedly bent, the risk of damage such as cracks occurring in the upper electrode 23 can be reduced. Therefore, the decrease in conductivity due to the occurrence of minute cracks in the upper electrode 23 is suppressed. For this reason, by including a conductive elastomer in the upper electrode 23, the durability of the ultrasonic probe 100 can be improved.

[0028] Furthermore, among the conductive elastomers mentioned above, it is preferable that the conductive elastomer includes silicone rubber. Silicone rubber has low ultrasonic attenuation. Therefore, by using silicone rubber for the upper electrode 23, it is possible to provide an ultrasonic probe 100 with higher accuracy compared to, for example, the case where urethane rubber is used.

[0029] Furthermore, among the conductive fillers mentioned above, silver filler is particularly preferred as the conductive filler. Specifically, for example, a silica core using silica as the core material can be used as a silver-plated filler. Silver has excellent conductivity. Therefore, by using silver filler as the conductive filler, it is possible to provide an upper electrode 23 with excellent conductivity. In addition, the conductive filler may include, for example, two or more fillers with different average particle sizes. In particular, the performance of the upper electrode 23 can be improved by including two or more silver fillers with different average particle sizes in the upper electrode 23.

[0030] The mixing ratio of conductive filler to 100 phr binder is not particularly limited, but is preferably 50 phr to 600 phr, and more preferably 100 phr to 400 phr. When the mixing ratio is within the above range, it is easier to form an upper electrode 23 that is more conductive and less prone to damage compared to when it is outside the range.

[0031] When two or more conductive fillers with different average particle sizes are included, the average diameter of the two conductive fillers is not particularly limited, but it is preferable that one is 4 μm or more and 8 μm or less, and the other is 5 μm or more and 15 μm or less. When the average diameter is above the lower limit, the conductive fillers are less likely to aggregate compared to when it is below the lower limit. Also, when the average diameter is below the upper limit, the upper electrode 23 is less likely to be damaged even by bending with a small curvature compared to when it exceeds the upper limit.

[0032] Furthermore, the conductive elastomer may contain a curing agent and a dispersant in addition to the aforementioned binder and conductive filler. Other materials besides those mentioned above may also be included, to the extent that the properties of the upper electrode 23 do not change significantly. The mixing ratio of the curing agent to 100 phr of binder is, for example, 10 phr or less. The mixing ratio of the dispersant to 100 phr of binder is, for example, 20 phr or less. In addition, two or more types of curing agents and dispersants may be used.

[0033] As shown in Figure 2, the upper electrode 23 has a lower surface 231 and an upper surface 232. The lower surface 231 is in contact with the piezoelectric element 22. The upper surface 232 is in contact with the housing 5. The thickness of the upper electrode 23 is preferably, for example, 5 μm to 200 μm, and more preferably 10 μm to 100 μm. Having a thickness within the above range makes it easier to deform the upper electrode 23, suppresses ultrasonic attenuation, and makes it easier to achieve uniformity in the thickness of the upper electrode 23, compared to when the thickness is outside the range.

[0034] As described above, the piezoelectric element 2 has a flexible lower electrode 21, a piezoelectric body 22 formed by the sol-gel method, and an upper electrode 23 containing a conductive elastomer. Therefore, the piezoelectric element 2 is flexible. The flexibility of the piezoelectric element 2 ensures the flexibility of the ultrasonic probe 100. Thus, the ultrasonic probe 100 can be applied not only to the flat surface of the object but also to curved surfaces. This expands the range of application of the ultrasonic probe 100. Furthermore, because the piezoelectric element 2 has excellent flexibility, it is less prone to damage such as cracks, thus improving the durability of the ultrasonic probe 100.

[0035] 1-1b. Flexible wiring board 3 The flexible wiring board 3 is connected to the piezoelectric element 2. The flexible wiring board 3 has a film-like insulating substrate, wiring 31 arranged within the insulating substrate, and wiring 32 arranged within the insulating substrate. In Figure 2, wirings 31 and 32 are schematically shown. The insulating substrate is made of a resin such as polyimide. Wirings 31 and 32 are made of a metal such as copper. Wiring 31 is connected to the lower electrode 21. Wiring 32 is connected to the upper electrode 23.

[0036] 1-1c. Backing material 4 The backing material 4 is positioned below the lower electrode 21. The backing material 4 also contacts the lower surface 211 of the lower electrode 21, which is the side opposite to the piezoelectric element 22. The backing material 4 is flexible. The backing material 4 attenuates the ultrasonic waves radiated downward from the piezoelectric element 2, suppressing unwanted vibrations. Because the presence of the backing material 4 suppresses unwanted vibrations, the resolution can be improved compared to when the backing material 4 is absent. In addition, the presence of the backing material 4 reduces multiple reflections between the lower surface 101 of the ultrasonic probe 100 and the lower surface 211 of the piezoelectric element 2.

[0037] In the illustrated example, the shape of the backing material 4 in plan view is a rectangle. However, the shape of the backing material 4 in plan view may be other shapes, such as a circle. Furthermore, the planar area of ​​the backing material 4 is larger than the planar area of ​​the piezoelectric element 22, and the backing material 4 overlaps with the piezoelectric element 22 in plan view. Because the planar area of ​​the backing material 4 is larger than that of the piezoelectric element 22, it can effectively attenuate the ultrasonic waves radiated downward from the piezoelectric element 22 compared to the case where the planar area is smaller.

[0038] The material of the backing material 4 is preferably an elastomer. The use of an elastomer ensures the flexibility of the backing material 4. Specifically, the material of the backing material 4 is preferably butyl rubber. Butyl rubber has greater ultrasonic attenuation than, for example, silicone rubber. Therefore, using butyl rubber for the backing material 4 allows for sufficient ultrasonic attenuation even with a thin thickness. Furthermore, the backing material 4 is preferably free of inorganic particles. By not including inorganic particles, the flexibility of the backing material 4 can be increased compared to when inorganic particles are included.

[0039] As shown in Figure 2, the backing material 4 has a lower surface 401 and an upper surface 402. The lower surface 401 is in contact with the housing 5. The upper surface 402 is in contact with the piezoelectric element 2. The thickness of the backing material 4 is preferably, for example, 0.1 mm or more and 1.0 mm or less, and more preferably 0.2 mm or more and 0.8 mm or less. When the thickness is within the above range, the backing material 4 is particularly flexible compared to when it is outside the range, and the ultrasonic attenuation function of the backing material 4 is particularly effective.

[0040] 1-1d. Enclosure 5 The housing 5 shown in Figure 1 covers the piezoelectric element 2 and the backing material 4. A portion of the flexible wiring board 3 is located inside the housing 5, while the rest is exposed from the housing 5. The housing 5 is also flexible. The housing 5 has the function of protecting the piezoelectric element 2 and other components.

[0041] The material of the housing 5 is preferably an elastomer. The elastomer material provides the housing 5 with excellent flexibility, shock absorption, and waterproofing to protect the piezoelectric element 2. Furthermore, it is preferable to use an elastomer with low ultrasonic attenuation for the housing 5. By including an elastomer with low ultrasonic attenuation in the housing 5, the housing 5 functions not only as a protective layer for the piezoelectric element 2, but also as an acoustically matching layer.

[0042] The acoustic matching layer is used to reduce the reflection of ultrasound caused by the difference in acoustic impedance between the piezoelectric element 2 and the object. When the object is a living organism, the acoustic impedance of the piezoelectric element 2 and the living organism differ significantly. Therefore, the presence of the housing 5, which functions as an acoustic matching layer, can reduce the reflection of ultrasound caused by the difference in acoustic impedance between the piezoelectric element 2 and the living organism. Thus, by the housing 5 functioning as an acoustic matching layer, the acoustic impedance matching is improved, and the amount of ultrasound transmitted to the object can be increased.

[0043] Furthermore, the material of the housing 5 is preferably silicone rubber. Silicone rubber has lower ultrasonic attenuation than urethane rubber and the like. Therefore, by including silicone rubber in the housing 5, it can be suitably used as an acoustic matching layer. In addition, by including silicone rubber in the housing 5, the housing 5 can function as an acoustic lens by being given an appropriate shape. Acoustic lenses are used to focus ultrasonic waves and improve resolution. Therefore, the presence of housing 5, which functions as an acoustic lens, can improve resolution compared to when housing 5 is not present. Also, silicone rubber has excellent biocompatibility and is easy to apply to medical diagnosis of living organisms. Furthermore, silicone rubber and living organisms have similar acoustic impedances. Therefore, when the target object is a living organism, using silicone rubber can increase the amount of ultrasonic waves transmitted to the target object and improve resolution. In addition, if the upper electrode 23 contains silicone rubber, including silicone rubber in the housing 5 can improve their adhesion.

[0044] Furthermore, it is preferable that the housing 5 does not contain inorganic particles. By not containing inorganic particles, the flexibility of the housing 5 can be increased compared to when inorganic particles are included. In addition, since the housing 5 and the aforementioned backing material 4 are elastomers that do not contain inorganic particles, the flexibility of the ultrasound probe 100 is less likely to be impaired. As a result, adhesion to various parts of the living body is particularly high, enabling diagnosis of a wide range of areas of the living body.

[0045] In the illustrated example, the shape of the housing 5 in plan view is rectangular. However, the shape of the housing 5 in plan view may be other shapes, such as circular. Furthermore, the planar area of ​​the housing 5, i.e., the planar area of ​​the ultrasonic probe 100, is not particularly limited, but for example, 50 mm². 2 The above is 10,000 mm. 2 The following applies:

[0046] As shown in Figure 2, the lower surface 101 of the ultrasonic probe 100 corresponds to the lower surface of the housing 5, and the upper surface 102 corresponds to the upper surface of the housing 5. The thickness of the ultrasonic probe 100 is preferably, for example, 0.1 mm or more and 10 mm or less, and more preferably 0.5 mm or more and 2 mm or less. By having a thickness within the above range, it is possible to provide an ultrasonic probe 100 that is more flexible and easier to handle compared to when the thickness is outside the range.

[0047] 1-2. Method for manufacturing an ultrasonic probe 100 Figure 3 is a diagram showing the flow of the manufacturing method of the ultrasonic probe 100 according to the first embodiment. As shown in Figure 3, the manufacturing method of the ultrasonic probe 100 includes a piezoelectric element formation step S10, a wiring formation step S20, a backing material formation step S30, and a housing formation step S40. The piezoelectric element formation step S10 includes a lower electrode preparation step S11, a piezoelectric body formation step S12, and an upper electrode formation step S13.

[0048] In piezoelectric element formation step S10, the piezoelectric element 2 is formed. Specifically, first, in lower electrode preparation step S11, the lower electrode 21 is prepared. Specifically, for example, a stainless steel substrate with a thickness of 50 μm is prepared.

[0049] In piezoelectric body formation step S12, a piezoelectric body 22 is formed on the lower electrode 21 by the sol-gel method. By forming the piezoelectric body 22 by the sol-gel method, a flexible and thin piezoelectric body 22 can be easily formed. Specifically, for example, a sol-gel film with a thickness of about 100 μm is formed on the lower electrode 21.

[0050] In the upper electrode formation step S13, the upper electrode 23 is formed by coating a conductive elastomer onto the piezoelectric body 22, for example, by a screen method, and curing it. Specifically, for example, first, a conductive elastomer is formed by mixing 100 phr of binder "KE-106" manufactured by Shin-Etsu Chemical Co., Ltd., 150 phr of silver filler "FA-2-3" manufactured by DOWA Electronics, 150 phr of silver filler "G-35" manufactured by DOWA Electronics, 10 phr of curing agent "CAT-RG" manufactured by Shin-Etsu Chemical Co., Ltd., 10 phr of "KF-6015" manufactured by Shin-Etsu Chemical Co., Ltd., and 10 phr of "KF-6106" manufactured by Shin-Etsu Chemical Co., Ltd. Next, the conductive elastomer is coated onto the piezoelectric body 22 to a thickness of 50 μm to 100 μm and cured at 150°C for 30 minutes. Furthermore, when applying conductive elastomer in a nearly circular shape when viewed from above, the diameter should be, for example, between 6 mm and 9 mm.

[0051] By using a conductive elastomer, the conductive elastomer can be applied to the piezoelectric body 22 without the material of the upper electrode 23 penetrating into the interior of the piezoelectric body 22. Furthermore, by using a conductive elastomer, an upper electrode 23 of sufficient thickness can be formed on the piezoelectric body 22. As a result, an ultrasonic probe 100 with good conductivity can be obtained.

[0052] Furthermore, the conductive elastomer contains a binder, which is a rubber or thermoplastic elastomer such as silicone rubber or urethane rubber, and a conductive filler. The hardening of the binder prevents the movement of the conductive filler. By using a conductive elastomer, it is possible to form an upper electrode 23 that is less susceptible to damage such as cracks even when deformed, and in which a decrease in conductivity is suppressed.

[0053] The piezoelectric element 2 is formed by the above process. As described above, the piezoelectric element 2 has a piezoelectric body 22 formed by the sol-gel method and an upper electrode 23 formed using a conductive elastomer. Therefore, the piezoelectric element 2 is flexible. The flexibility of the piezoelectric element 2 ensures the flexibility of the ultrasonic probe 100. Therefore, the ultrasonic probe 100 can be applied not only to the flat surface of the object but also to curved surfaces. This expands the range of application of the ultrasonic probe 100. Furthermore, because the ultrasonic probe 100 has excellent flexibility, it is less prone to damage such as cracks, thus improving the durability of the ultrasonic probe 100.

[0054] In the wiring formation process S20, a flexible wiring board 3 connected to the piezoelectric element 2 is formed. Specifically, for example, the flexible wiring board 3 has areas where conductive material such as copper is exposed. In this case, first, for example, an anisotropic conductive film that functions as an adhesive is temporarily pressed onto the area in question. More specifically, for example, an anisotropic conductive film "MF-331" manufactured by Hitachi Chemical is temporarily pressed onto a 1.5 mm square exposed copper area at 80°C for 3 seconds.

[0055] Subsequently, the wiring 32 of the flexible wiring board 3 and the upper electrode 23 are heat-pressed together. If the upper electrode 23 is made of silicone rubber, it is preferable to irradiate the surface of the upper electrode 23 with ultraviolet light to modify the surface before heat-pressing. Specifically, for example, the surface of the upper electrode 23 is modified by irradiating it with vacuum ultraviolet light for 30 seconds using an excimer lamp. Then, the wiring 32 and the upper electrode 23 are heat-pressed together using an FPC alignment heat-pressing device at 140°C for 10 seconds. In addition, the wiring 31 of the flexible wiring board 3 and the lower electrode 21 are heat-pressed together. Specifically, for example, the wiring 31 and the lower electrode 21 are heat-pressed together using an FPC alignment heat-pressing device at 140°C for 10 seconds.

[0056] In the backing material formation process S30, the backing material 4 is formed. Specifically, the backing material 4 is formed on the lower surface 211 of the lower electrode 21 by pressing and attaching it to the lower surface 211. When the backing material 4 contains butyl rubber and the housing 5 contains silicone rubber, it is preferable to use an adhesive butyl rubber tape for the backing material 4. Specifically, for example, the butyl rubber tape "NO.5938" manufactured by Maxell Sliontec is attached as the backing material 4.

[0057] In the housing formation process S40, the housing 5 is formed. For example, the housing 5 is formed by bonding a sheet containing a self-adhesive elastomer to the upper surface 232 of the upper electrode 23 and the lower surface 401 of the backing material 4 using an adhesive. Specifically, for example, a sheet of self-adhesive silicone rubber is bonded to the upper surface 232 and the lower surface 401 using an adhesive. Also, for example, the thickness of the sheet in contact with the upper surface 232 of the upper electrode 23 is thinner than the thickness of the sheet in contact with the lower surface 401 of the backing material 4, taking into consideration the amount of ultrasound transmitted to the object. For example, a sheet of self-adhesive silicone rubber with a thickness of 0.4 mm is bonded to the upper surface 232, and a sheet of self-adhesive silicone rubber with a thickness of 0.6 mm is bonded to the lower surface 401.

[0058] Furthermore, for example, when the housing 5 is formed using a sheet containing silicone rubber, since silicone rubber is difficult to adhere, it is preferable to irradiate the surface of the sheet with ultraviolet light to modify the surface before bonding the sheets together. Specifically, for example, the surface of the sheet is modified by irradiating it with vacuum ultraviolet light for 30 seconds using an excimer lamp.

[0059] Furthermore, the bonding temperature between the sheet on the upper surface 232 and the sheet on the lower surface 401 is room temperature, the pressure is 1.2 MPa, and the bonding time is 30 minutes. When bonding the sheets together, pressure may be applied through a foam sheet. Alternatively, for example, after bonding the sheets together, they may be left for about 24 hours to reach practical strength.

[0060] The ultrasonic probe 100 is manufactured as described above. According to the method described above, a flexible ultrasonic probe 100 with good resolution can be easily manufactured.

[0061] 2. Second Embodiment The following describes a second embodiment of this disclosure. For elements whose operation and function are the same as those of the first embodiment described above, the reference numerals used in the description of the above embodiment will be reused, and detailed descriptions of each will be omitted as appropriate.

[0062] 2-1. Ultrasonic probe 100A Figure 4 is a plan view showing the ultrasonic probe 100A of the second embodiment. Figure 5 is a view of the ultrasonic probe 100A of Figure 4 in the X2 direction. Figure 6 is a view of the ultrasonic probe 100A of Figure 4 in the Y1 direction. Note that the dimensions and scale of the parts of the ultrasonic probe 100A shown in Figures 4, 5, and 6 differ appropriately from the actual dimensions and are shown schematically for ease of understanding. Also, Figure 5 corresponds to the cross section along line BB in Figure 4. Figure 6 corresponds to the cross section along line CC in Figure 4.

[0063] As shown in Figures 4, 5, or 6, the ultrasonic probe 100A of the second embodiment differs from the ultrasonic probe 100 of the first embodiment in that it has a plurality of piezoelectric elements 2A.

[0064] The ultrasonic probe 100A comprises a piezoelectric structure 200, a flexible wiring board 3, a backing material 4, and a housing 5. The piezoelectric structure 200 includes a plurality of piezoelectric elements 2A. In the example shown in Figure 4, the ultrasonic probe 100A has seven piezoelectric elements 2A, but the number of piezoelectric elements 2A is not limited to this and may be between 2 and 6, or 8 or more. Specifically, for example, the ultrasonic probe 100A may have a large number of piezoelectric elements 2A, such as 128.

[0065] As shown in Figures 4, 5, or 6, the piezoelectric structure 200 has a lower electrode 21, a piezoelectric body 22, and a plurality of upper electrodes 23A. The lower electrode 21 is integrally provided in common with the plurality of piezoelectric elements 2A. The piezoelectric body 22 is also integrally provided in common with the plurality of piezoelectric elements 2A.

[0066] The multiple upper electrodes 23A correspond to "multiple electrodes." The multiple upper electrodes 23A are provided in a one-to-one correspondence with the multiple piezoelectric elements 2A. The shape of each upper electrode 23A in plan view is rectangular. However, this shape may be a polygon other than a rectangle, or a circle. In plan view, the multiple upper electrodes 23A are spaced apart from each other and arranged in a line along the Y-axis. The distance between the centers of the multiple upper electrodes 23A, i.e., the pitch, is not particularly limited, but is, for example, about 0.5 mm.

[0067] Note that the multiple upper electrodes 23A do not have to be arranged in a single row as shown in Figure 4; for example, they may be arranged in multiple rows, or they may be arranged randomly.

[0068] Furthermore, wiring 31 is connected to the lower electrode 21, and wiring 32 is connected to multiple upper electrodes 23.

[0069] As described above, this embodiment has multiple piezoelectric elements 2A. Multiple upper electrodes 23A are provided in a one-to-one correspondence with multiple piezoelectric elements 2A, and a piezoelectric body 22 is provided integrally with multiple piezoelectric elements 2A. Therefore, only the portion of the piezoelectric body 22 to which voltage is applied can be vibrated. In particular, the piezoelectric body 22 is formed by the sol-gel method and is porous and thin. Therefore, even if the piezoelectric body 22 is not provided for each piezoelectric element 2A, if an upper electrode 23A is provided for each piezoelectric element 2A, only the portion of the piezoelectric body 22 to which voltage is applied can be accurately vibrated. Thus, even if the piezoelectric body 22 is not divided, the piezoelectric body 22 can be utilized for each upper electrode 23A. Furthermore, since the piezoelectric body 22 is formed by the sol-gel method, it is flexible and is provided integrally with multiple piezoelectric elements 2A. Therefore, it has excellent conformability to the bending of curved objects.

[0070] For example, multiple piezoelectric elements 2A are required to display images using the ultrasound probe 100 for medical purposes. For instance, by having multiple piezoelectric elements 2A, the ultrasound probe 100 can be used as a phased array probe.

[0071] 2-2. Manufacturing method of ultrasonic probe 100A In this embodiment as well, similar to the first embodiment, the method for manufacturing the ultrasonic probe 100A includes the steps shown in Figure 3.

[0072] First, in the lower electrode preparation step S11, the lower electrode 21 is prepared. Specifically, for example, a stainless steel substrate with a flat area of ​​25 mm × 84 mm and a thickness of 50 μm is prepared.

[0073] In piezoelectric body formation step S12, a piezoelectric body 22 is formed on the lower electrode 21 by the sol-gel method. Specifically, for example, a sol-gel film with a planar area of ​​15 mm × 80 mm and a thickness of approximately 100 μm is formed on the lower electrode 21. This sol-gel film is the piezoelectric body 22.

[0074] In the upper electrode formation step S13, the upper electrode 23 is formed by applying a conductive elastomer onto the piezoelectric body 22, for example, by a screen method, and curing it. For example, the conductive elastomer is applied onto the piezoelectric body 22 and cured at 150°C for 30 minutes. Specifically, the conductive elastomer is applied to a rectangular pattern with a planar area of ​​4.5 mm × 0.25 mm and a thickness of approximately 50 μm. For example, 128 rectangular patterns are formed. The 128 rectangular patterns are formed at a pitch of, for example, 0.5 mm.

[0075] In this embodiment as well, a flexible ultrasonic probe 100A with good resolution can be easily manufactured, similar to the first embodiment.

[0076] Although the present disclosure has been described above based on preferred embodiments, the present disclosure is not limited to the embodiments described above. Furthermore, the configuration of each part of the present disclosure can be replaced with any configuration that performs a similar function to the embodiments described above, and any configuration can be added.

[0077] In the embodiment described above, there is one piezoelectric element 2, but there may be multiple piezoelectric elements 2. That is, the ultrasonic probe 100 may be an array probe. [Explanation of Symbols]

[0078] 2...Piezoelectric element, 3...Flexible wiring board, 4...Backing material, 5...Housing, 21...Lower electrode, 22...Piezoelectric body, 23...Upper electrode, 31...Wiring, 32...Wiring, 100...Ultrasonic probe, 101...Bottom surface, 102...Top surface, 211...Bottom surface, 212...Top surface, 221...Bottom surface, 222...Top surface, 231...Bottom surface, 232...Top surface, 401...Bottom surface, 402...Top surface.

Claims

1. It comprises at least one piezoelectric element that transmits and receives ultrasonic waves, The at least one piezoelectric element is Piezoelectric material and At least one electrode, which is in contact with the piezoelectric material and includes a conductive elastomer, Another electrode in contact with the surface of the piezoelectric body opposite to the at least one electrode, The other electrode comprises a backing material that contacts the side of the electrode opposite to the piezoelectric element, The aforementioned backing material includes an elastomer, The piezoelectric material is porous. An ultrasonic probe characterized by the following features.

2. It comprises at least one piezoelectric element that transmits and receives ultrasonic waves, The at least one piezoelectric element is Piezoelectric material and At least one electrode, which is in contact with the piezoelectric material and includes a conductive elastomer, The device includes a housing that protects the piezoelectric element, The housing includes an elastomer, The piezoelectric material is porous. An ultrasonic probe characterized by the following features.

3. The conductive elastomer includes silicone rubber. The ultrasonic probe according to claim 1 or 2.

4. The conductive elastomer includes a conductive filler. The ultrasonic probe according to claim 1 or 2.

5. The conductive filler is a silver filler. The ultrasonic probe according to claim 4.

6. The backing material includes butyl rubber, The ultrasonic probe according to claim 1.

7. The backing material does not contain inorganic particles. The ultrasonic probe according to claim 1 or 6.

8. The housing includes silicone rubber, The ultrasonic probe according to claim 2.

9. The housing does not contain inorganic particles. The ultrasonic probe according to claim 2 or 8.

10. The aforementioned at least one piezoelectric element is a plurality of piezoelectric elements, The aforementioned at least one electrode is a plurality of electrodes, The plurality of electrodes are provided in a one-to-one correspondence with the plurality of piezoelectric elements. The ultrasonic probe according to claim 1 or 2, wherein the piezoelectric body is integrally provided in common with the plurality of piezoelectric elements.

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