Ultrasound probe

Abstract

This suppresses defects such as delamination of the piezoelectric material caused by external forces acting on the piezoelectric material from the wiring board in the thickness direction. [Solution] The ultrasonic probe 100 comprises a piezoelectric body 20, an insulating layer 30, a first electrode 40, and a wiring board 60. The piezoelectric body 20 includes a first surface 21. The insulating layer 30 includes a covering portion 31 that covers a part of the first surface 21 and a peripheral portion 32 that does not overlap the piezoelectric body 20 in a plan view. The first electrode 40 includes an electrode portion 41 that contacts the first surface 21 and a terminal portion 42 that contacts the surface of the peripheral portion 32. The wiring board 60 is bonded to the terminal portion 42 of the first electrode 40 and the peripheral portion 32 of the insulating layer 30.

Description

Technical Field

[0001] The present disclosure relates to an ultrasonic probe. Background Art

[0002] Ultrasonic probes that transmit and receive ultrasonic waves using a piezoelectric element having a laminated structure in which a piezoelectric body is interposed between a first electrode and a second electrode have been conventionally proposed. For example, Patent Document 1 discloses an ultrasonic probe including a piezoelectric body formed by a sol-gel method, an upper electrode in contact with an upper surface of the piezoelectric body, and a lower electrode in contact with a lower surface of the piezoelectric body. A flexible wiring board for applying a voltage to the upper electrode is bonded to an end portion of the upper electrode located on the surface of the piezoelectric body. Prior Art Documents Patent Documents

[0003] Patent Document 1 International Publication No. 2023 / 140166 Specification Summary of the Invention Problem to be Solved by the Invention

[0004] In a configuration in which the wiring board is bonded to the upper electrode on the surface of the piezoelectric body, an external force in the thickness direction of the piezoelectric body can act from the wiring board to the upper electrode and the piezoelectric body. Problems such as peeling of the piezoelectric body may occur due to the external force acting on the piezoelectric body from the wiring board. In consideration of the above circumstances, an object of one aspect of the present disclosure is to suppress problems such as peeling of the piezoelectric body caused by the external force acting on the piezoelectric body from the wiring board. Means for Solving the Problem

[0005] An ultrasonic probe according to one aspect of the present disclosure comprises a piezoelectric body including a first surface; an insulating layer including a covering portion that covers a part of the first surface and a peripheral portion that does not overlap the piezoelectric body in a plan view; a first electrode including an electrode portion that contacts the first surface and a terminal portion that contacts the surface of the peripheral portion; and a wiring board joined to the terminal portion of the first electrode and the peripheral portion of the insulating layer. [Brief explanation of the drawing]

[0006] [Figure 1] This is a plan view of the ultrasonic probe in the embodiment. [Figure 2] This is a cross-sectional view of line II-II in Figure 1. [Figure 3] This is a magnified plan view of multiple first electrodes. [Figure 4] This is a cross-sectional view of an ultrasonic probe related to proportionality. [Figure 5] This is a process diagram illustrating the manufacturing procedure for ultrasonic probes. [Modes for carrying out the invention]

[0007] The embodiments for implementing this disclosure will be described with reference to the drawings. Note that the dimensions and scale of the elements in each drawing may differ from those of the actual product. Furthermore, the embodiments described below are illustrative examples of embodiments that may be envisioned when implementing this disclosure. Therefore, the scope of this disclosure is not limited to the embodiments exemplified below.

[0008] A: Embodiment Figure 1 is a plan view of an ultrasonic probe 100 in one embodiment of the present disclosure. Figure 2 is a cross-sectional view taken along line II-II in Figure 1. In the following description, we assume three mutually orthogonal axes (X-axis, Y-axis, Z-axis). One direction along the X-axis is denoted as the X1 direction, and the direction opposite to the X1 direction is denoted as the X2 direction. Similarly, mutually opposite directions along the Y-axis are denoted as the Y1 direction and the Y2 direction, and mutually opposite directions along the Z-axis are denoted as the Z1 direction and the Z2 direction. Furthermore, observing any element of the ultrasonic probe 100 with a line of sight along the Z-axis is referred to as "planar view".

[0009] The ultrasound probe 100 of this embodiment is used for ultrasound measurement for medical observation of the inside of a living body. Ultrasound measurement is a method of observing the internal structure of a living body by, for example, transmitting ultrasound from the ultrasound probe 100 to the living body and receiving the ultrasound reflected from inside the living body with the ultrasound probe 100. Ultrasound measurement using the ultrasound probe 100 allows for non-invasive examination of the internal structure of a living body.

[0010] The ultrasound probe 100 is flexible. The ultrasound probe 100 is used in a curved state to conform to the curved surfaces of various parts of the body, such as the neck, chest, abdomen, arm, wrist, or fingers. As illustrated in Figures 1 and 2, the ultrasound probe 100 comprises a piezoelectric unit 10, a wiring board 60, a support member 71, and a protective cover 72. In Figure 1, for convenience, the portion of the protective cover 72 located in the Z1 direction of the piezoelectric unit 10 is shown as broken.

[0011] The piezoelectric unit 10 is a flattened inspection unit for transmitting and receiving ultrasonic waves. The piezoelectric unit 10 converts between a voltage-varying drive signal and the mechanical vibration of ultrasonic waves. Specifically, the piezoelectric unit 10 transmits ultrasonic waves in the Z1 direction and receives ultrasonic waves arriving from the Z1 direction. As illustrated in Figures 1 and 2, the piezoelectric unit 10 comprises a piezoelectric body 20, an insulating layer 30, and a plurality of first electrodes 40 and second electrodes 50.

[0012] The piezoelectric element 20 is a structure that mutually converts drive signals and mechanical vibrations through the piezoelectric effect. The piezoelectric element 20 is formed from a piezoelectric material such as lead zirconate titanate (PZT). The piezoelectric element 20 is a flexible porous material that deforms under external force. The method of manufacturing the piezoelectric element 20 is arbitrary, but for example, it is formed by the sol-gel method. That is, the piezoelectric element 20 is a sol-gel film formed by the sol-gel method. The formation of the piezoelectric element 20 by the sol-gel method is disclosed, for example, in Japanese Patent Publication No. 7092277. The piezoelectric element 20 is composed of multiple layers stacked by, for example, repeated film-forming processes. The film thickness of the piezoelectric element 20 is, for example, 10 μm or more and 200 μm or less (more preferably 50 μm or more and 100 μm or less). Note that the manufacturing method and dimensions of the piezoelectric element 20 are not limited to the above examples and may be changed as desired. Furthermore, the piezoelectric element 20 is not limited to a porous material. Elements of any material having a piezoelectric effect and flexibility can be used as the piezoelectric element 20.

[0013] The piezoelectric element 20 is a plate-like member formed in a rectangular shape with an elongated length in the direction of the X axis when viewed from above. The piezoelectric element 20 includes a first surface 21 and a second surface 22 parallel to the XY plane. The first surface 21 is the main surface of the piezoelectric element 20 facing in the Z1 direction. The second surface 22 is the main surface of the piezoelectric element 20 facing in the Z2 direction. That is, the second surface 22 is the surface of the piezoelectric element 20 opposite to the first surface 21.

[0014] The second electrode 50 is a flat, plate-shaped conductive member (lower electrode) located in the Z2 direction of the piezoelectric body 20. The second electrode 50 is formed in a long rectangular shape in the X-axis direction when viewed from above. The second electrode 50 is made of a metal material such as stainless steel. The second electrode 50 is formed to a plate thickness that allows for both appropriate mechanical strength and appropriate flexibility. The plate thickness of the second electrode 50 is, for example, 10 μm or more and 200 μm or less (more preferably 50 μm or more and 100 μm or less).

[0015] The second electrode 50 includes a front surface 51 and a back surface 52 parallel to the XY plane. The front surface 51 is the main surface of the second electrode 50 facing in the Z1 direction. The back surface 52 is the main surface of the second electrode 50 facing in the Z2 direction. The piezoelectric body 20 is formed on a part of the front surface 51 of the second electrode 50. That is, the piezoelectric body 20 and the second electrode 50 overlap each other in a plan view.

[0016] As illustrated in Figures 1 and 2, the second electrode 50 includes an electrode portion 53 and an overhang portion 54 in a plan view. The electrode portion 53 is the part of the second electrode 50 that overlaps with the piezoelectric body 20 in a plan view. That is, the electrode portion 53 contacts the second surface 22 of the piezoelectric body 20. On the other hand, the overhang portion 54 is the part that extends from the periphery of the piezoelectric body 20 in a plan view. That is, the overhang portion 54 does not overlap with the piezoelectric body 20 in a plan view. Specifically, the overhang portion 54 is a rectangular frame-shaped portion that surrounds the electrode portion 53 in a plan view.

[0017] The insulating layer 30 is a film formed of an insulating material, such as a resin material. The insulating layer 30 is formed in the Z1 direction of the piezoelectric body 20 and the second electrode 50. Specifically, the insulating layer 30 is continuous from the first surface 21 of the piezoelectric body 20 to the front surface 51 of the second electrode 50. The insulating layer 30 is formed of a resin material such as acrylic resin, polyvinyl chloride (PVC), polyethylene (PE), polyurethane (PU), or silicone resin. The method of manufacturing the insulating layer 30 is arbitrary, but for example, the insulating layer 30 is formed by attaching an insulating sheet molded into a predetermined planar shape. However, the method of manufacturing the insulating layer 30 is arbitrary. For example, the insulating layer 30 may be formed by coating and curing an insulating material using various printing technologies. The insulating layer 30 may also be formed by a combination of attaching an insulating sheet and coating an insulating material.

[0018] The thickness of the insulating layer 30 is, for example, 1 μm or more and 100 μm or less (more preferably 5 μm or more and 20 μm or less). The thickness of the insulating layer 30 is less than the thickness of the piezoelectric element 20. However, configurations in which the thickness of the insulating layer 30 exceeds the thickness of the piezoelectric element 20, or configurations in which the thickness of the insulating layer 30 is equivalent to the thickness of the piezoelectric element 20, are also conceivable.

[0019] The insulating layer 30 includes a covering portion 31, a peripheral edge portion 32, and a stepped portion 33. The covering portion 31, the peripheral edge portion 32, and the stepped portion 33 are formed continuously with each other. That is, the covering portion 31, the peripheral edge portion 32, and the stepped portion 33 constitute a single mutually continuous film body.

[0020] The covering portion 31 is a portion that covers a part of the first surface 21 of the piezoelectric body 20. Specifically, the covering portion 31 covers a portion of the first surface 21 of the piezoelectric body 20 near the peripheral edge E2 extending along the X-axis in the Y2 direction. As described above, the covering portion 31 of the insulating layer 30 overlaps the piezoelectric body 20 in a plan view.

[0021] The peripheral edge portion 32 is a portion formed on the overhang portion 54 of the second electrode 50. That is, the peripheral edge portion 32 overlaps the overhang portion 54 of the second electrode 50 in a plan view. Specifically, the peripheral edge portion 32 covers an elongated region along the X-axis in the Y2 direction on the front surface 51 of the overhang portion 54. As described above, the peripheral edge portion 32 of the insulating layer 30 is in contact with the overhang portion 54 of the second electrode 50. As mentioned above, the overhang portion 54 of the second electrode 50 is a portion that overhangs in the Y2 direction from the peripheral edge E2 of the piezoelectric body 20 in a plan view. Therefore, the peripheral edge portion 32 of the insulating layer 30 does not overlap the piezoelectric body 20 in a plan view. According to the configuration in which the peripheral edge portion 32 of the insulating layer 30 is in contact with the overhang portion 54 of the second electrode 50 as described above, the peripheral edge portion 32 of the insulating layer 30 can be supported by the second electrode 50.

[0022] As can be understood from the above description, the peripheral edge portion 32 is located more toward the Z2 direction than the covering portion 31 in the Z-axis direction. As exemplified in FIG. 2, the stepped portion 33 of the insulating layer 30 is a portion that connects the covering portion 31 and the peripheral edge portion 32. Specifically, the stepped portion 33 covers the side surface (peripheral edge E2) of the piezoelectric body 20 between the covering portion 31 and the peripheral edge portion 32 in a plan view.

[0023] The multiple first electrodes 40 are flat plates (upper electrodes) located in the Z1 direction of the piezoelectric body 20 and the second electrode 50. Each first electrode 40 is formed from a low-resistance conductive material such as copper or silver. The manufacturing method of the first electrodes 40 is arbitrary, but each first electrode 40 is formed by, for example, applying and curing a silver paste. For applying the silver paste, printing techniques such as screen printing can be used. The conductive material used to form the first electrodes 40 can be changed as desired. For example, the first electrodes 40 may be formed from various conductive elastomers in which a conductive filter is dispersed in an elastic material such as epoxy resin, acrylic resin, urethane resin, polyester resin, cellulose resin, silicone rubber, or urethane rubber.

[0024] The film thickness of each first electrode 40 is, for example, 5 μm or more and 50 μm or less (more preferably 10 μm or more and 20 μm or less). The film thickness of the first electrode 40 is greater than the film thickness of the insulating layer 30. However, configurations in which the film thickness of the first electrode 40 is less than the film thickness of the insulating layer 30, or configurations in which the film thickness of the first electrode 40 is equal to the film thickness of the insulating layer 30, are also conceivable.

[0025] Figure 3 is an enlarged plan view of the multiple first electrodes 40. As illustrated in Figures 1 and 3, the multiple first electrodes 40 are arranged with a gap between them in the direction of the X-axis in a plan view. The pitch of the arrangement of the multiple first electrodes 40 (hereinafter referred to as "arrangement pitch P") is constant. For example, the arrangement pitch P is 0.1 mm or more and 10.0 mm or less (more preferably 0.5 mm or more and 1.0 mm or less). The piezoelectric body 20 is a single film formed continuously in the direction of the X-axis across the multiple first electrodes 40. Similarly, the insulating layer 30 is also a single film formed continuously in the direction of the X-axis across the multiple first electrodes 40. The X-axis can also be expressed as the axis along the direction in which the multiple first electrodes 40 are arranged.

[0026] Each first electrode 40 is formed in an elongated shape extending in the direction of the Y axis in a plan view. Each first electrode 40 includes an electrode portion 41, a terminal portion 42, and a connecting portion 43 in a plan view. The electrode portion 41, the terminal portion 42, and the connecting portion 43 constitute a single conductive film that is continuous with each other. The planar shapes of the multiple first electrodes 40 are substantially the same.

[0027] The electrode portion 41 of each first electrode 40 is the part that overlaps with the first surface 21 of the piezoelectric body 20 in a plan view. Specifically, the electrode portion 41 is formed in the region of the first surface 21 that is not covered by the insulating layer 30. Therefore, the electrode portion 41 is in contact with the first surface 21 of the piezoelectric body 20. The electrode portion 41 is formed in an elongated shape along the Y axis.

[0028] As described above, a laminated structure is formed in which the piezoelectric body 20 is interposed between the electrode portion 41 of the first electrode 40 and the electrode portion 53 of the second electrode 50. The portion in which the electrode portion 41 of the first electrode 40, the piezoelectric body 20, and the electrode portion 53 of the second electrode 50 are laminated in the Z-axis direction functions as a piezoelectric element that transmits and receives ultrasonic waves. That is, a displacement (vibration) corresponding to the voltage between the electrode portion 41 and the electrode portion 53 is generated in the piezoelectric body 20. The Z-axis can also be expressed as the axis along the direction in which the electrode portion 41, the piezoelectric body 20, and the electrode portion 53 are laminated.

[0029] The terminal portion 42 of each first electrode 40 is the portion that contacts the surface of the peripheral portion 32 of the insulating layer 30. As described above, the peripheral portion 32 of the insulating layer 30 does not overlap with the piezoelectric body 20 in a plan view. Therefore, while the electrode portion 41 of each first electrode 40 overlaps with the piezoelectric body 20 in a plan view, the terminal portion 42 of each first electrode 40 does not overlap with the piezoelectric body 20 in a plan view. As can be understood from the above explanation, in the region that does not overlap with the piezoelectric body 20 in a plan view, a laminated structure is formed in which the terminal portion 42 of the first electrode 40, the peripheral portion 32 of the insulating layer 30, and the protruding portion 54 of the second electrode 50 are stacked in the Z-axis direction.

[0030] The connecting portion 43 of each first electrode 40 is a portion that connects the electrode portion 41 and the terminal portion 42. The connecting portion 43 rides from the first surface 21 of the piezoelectric body 20 onto the covering portion 31 of the insulating layer 30 in plan view, and extends to the peripheral edge portion 32 via the covering portion 31 and the stepped portion 33. A portion of the connecting portion 43 that has reached the peripheral edge portion 32 is connected to the terminal portion 42. Therefore, as illustrated in FIGS. 1 to 3, the connecting portion 43 of each first electrode 40 overlaps in plan view with the peripheral edge E1 of the insulating layer located on the first surface 21 of the piezoelectric body 20 and the peripheral edge E2 of the piezoelectric body covered by the insulating layer 30.

[0031] As illustrated in FIG. 3, the line width Wb of the terminal portion 42 of each first electrode 40 is less than the line width Wa of the electrode portion 41 of the first electrode 40 (Wb<Wa). The line width Wa is a dimension of the electrode portion 41 in the X-axis direction. The line width Wb is a dimension of the terminal portion 42 in the X-axis direction. For example, in a configuration where the arrangement pitch P is 1.0 mm, the line width Wa of the electrode portion 41 is, for example, 500 µm or more and 950 µm or less (more preferably 800 µm or more and 900 µm or less). Since the arrangement pitch P of each first electrode 40 is constant, the interval Db between the respective terminal portions 42 of the first electrodes 40 adjacent to each other in the X-axis direction is greater than the interval Da between the respective electrode portions 41 (Db>Da). The interval Da between the respective electrode portions 41 is, for example, 50 µm or more and 500 µm or less (more preferably 100 µm or more and 200 µm or less). On the other hand, the interval Db between the respective terminal portions 42 is, for example, 100 µm or more and 900 µm or less (more preferably 400 µm or more and 600 µm or less).

[0032] Further, the line width Wc of the connecting portion 43 of each first electrode 40 is less than the line width Wa of the electrode portion 41 of said first electrode 40 (Wc<Wa). The line width Wc of the connecting portion 43 is the dimension of the connecting portion 43 in the X-axis direction. The line width Wb of the terminal portion 42 and the line width Wc of the connecting portion 43 are substantially the same (Wb=Wc). As described above, the arrangement pitch P of the first electrodes 40 is constant, so the distance Dc between the respective connecting portions 43 of the first electrodes 40 that are adjacent to each other in the X-axis direction is greater than the distance Da between the respective electrode portions 41 (Dc>Da). The distance Db between the respective terminal portions 42 and the distance Dc between the respective connecting portions 43 are substantially the same (Db=Dc). For example, in a configuration where the arrangement pitch P is 1.0 mm, the distance Dc between the respective connecting portions 43 is, for example, not less than 100 μm and not more than 900 μm (more preferably not less than 400 μm and not more than 600 μm).

[0033] In a configuration where the distance D (Da, Db, Dc) between the respective first electrodes 40 is excessively small, there is a possibility that the mutually adjacent first electrodes 40 are short-circuited. Further, in a configuration where the distance Da between the respective electrode portions 41 is excessively large, it is difficult to sufficiently maintain the sensitivity of the ultrasonic probe 100. According to the distance D within the range exemplified in the above description, it is possible to achieve both suppression of short-circuiting of the first electrodes 40 and sufficient sensitivity at a high level. However, the specific dimensions and magnitude relationships of each line width W (Wa, Wb, Wc) and each distance D (Da, Db, Dc) are not limited to the above examples and may be arbitrarily changed.

[0034] The wiring substrate 60 illustrated in FIGS. 1 and 2 is a mounting component for transmitting a drive signal supplied from an external device to the piezoelectric unit 10. The wiring substrate 60 includes an insulating base material 61, a plurality of wirings 62, and a plurality of wirings 63. Note that illustration of each wiring 62 is omitted in FIG. 1.

[0035] The insulating substrate 61 is a flexible layered or film-like flat plate material. That is, the wiring board 60 is an elastically deformable flexible printed circuit board (FPC). The multiple wirings 62 and 63 are conductor patterns formed on the surface of the insulating material facing the Z2 direction. As illustrated in Figure 1, each wiring 63 is located near both ends of the insulating substrate 61 in the X-axis direction. In a plan view, the multiple wirings 62 are located between the multiple wirings 63.

[0036] The ends of the wiring board 60 are joined to the piezoelectric unit 10. For joining the wiring board 60 to the piezoelectric unit 10, for example, an anisotropic conductive film 65 (ACF) is used. The anisotropic conductive film 65 is an adhesive in which a large number of conductive particles are dispersed. Note that in Figure 1, the anisotropic conductive film 65 is conveniently shaded.

[0037] Specifically, the wiring board 60 is joined to the terminal portions 42 of each first electrode 40 of the piezoelectric unit 10 and to the peripheral portions 32 of the insulating layer 30. That is, with the terminal portions 42 of the first electrode 40 and each wiring 62 of the wiring board 60 electrically connected by the conductive particles of the anisotropic conductive film 65, the insulating substrate 61 of the wiring board 60 is joined to the peripheral portions 32 of the insulating layer 30 by the adhesive of the anisotropic conductive film 65. Specifically, the wiring board 60 is installed so that its edges overlap the peripheral portions 32 of the insulating layer 30 in a plan view. Therefore, the wiring board 60 does not overlap the electrode portions 41 and connecting portions 43 of each first electrode 40 with the peripheral portions 32 and stepped portions 33 of the insulating layer 30 in a plan view. In other words, the wiring board 60 is not directly joined to the electrode portions 41 located on the first surface 21 of the piezoelectric body 20 among the first electrodes 40. Each wire 63 in Figure 1 is joined to the second electrode 50 by an anisotropic conductive film 65. Each wire 63 is, for example, grounded.

[0038] The support member 71 is a backing material installed on the back surface 52 of the second electrode 50. Specifically, the support member 71 is a plate-shaped member that overlaps the entire area of ​​the piezoelectric body 20 in a plan view. The support member 71 is made of an elastic material such as butyl rubber or silicone rubber. The support member 71 attenuates the ultrasonic waves radiated from the piezoelectric body 20 in the Z2 direction. Note that the support member 71 may be omitted.

[0039] The protective cover 72 is a structure that protects the piezoelectric unit 10. Specifically, the protective cover 72 is an insulating housing that covers the entire piezoelectric unit 10 (piezoelectric body 20, insulating layer 30, first electrode 40 and second electrode 50) and the support member 71. A portion of the wiring board 60 near the end joined to the piezoelectric unit 10 is housed in the protective cover 72, while the other portion of the wiring board 60 is exposed from the protective cover 72. The protective cover 72 is formed of an elastic material such as silicone rubber or urethane rubber. The protective cover 72 can protect the piezoelectric body 20, the insulating layer 30, the first electrode 40 and the second electrode 50. Note that the protective cover 72 may be omitted.

[0040] Figure 4 is a cross-sectional view of a configuration (hereinafter referred to as "proportional configuration") that is in comparison to the embodiment described above. In the proportional configuration, the connecting portion 43 and terminal portion 42 between the insulating layer 30 and the first electrode 40 in the embodiment are omitted.

[0041] In a proportional configuration, the wiring board 60 is joined to the first surface 21 of the piezoelectric body 20 and the electrode portion 41 of each first electrode 40. As illustrated by the arrows in Figure 4, an external force in the Z1 direction may act on the first electrode 40 and the piezoelectric body 20 from the wiring board 60. Therefore, in a proportional configuration, there is a possibility that the first electrode 40 may detach from the first surface 21 of the piezoelectric body 20 due to the external force in the Z1 direction, or that the piezoelectric body 20 may be damaged. For example, in a configuration in which the piezoelectric body 20 is composed of multiple layers, the external force in the Z1 direction acting on the first surface 21 may cause each layer of the piezoelectric body 20 to detach.

[0042] In contrast to proportionality, in this embodiment, the wiring board 60 is joined to the terminal portion 42 of the first electrode 40 and the peripheral portion 32 of the insulating layer 30. The peripheral portion 32 and the terminal portion 42 do not overlap with the piezoelectric body 20 in a plan view. Therefore, no external force in the Z1 direction acts on the first surface 21 of the piezoelectric body 20 and the electrode portion 41 of each first electrode 40 via the wiring board 60. In other words, the external force acting on the piezoelectric body 20 from the wiring board 60 is reduced. Therefore, according to this embodiment, compared to proportionality, damage to the piezoelectric body 20 caused by external forces acting from the wiring board 60 can be suppressed.

[0043] Furthermore, in this embodiment, the line width Wb of the terminal portion 42 of each first electrode 40 is less than the line width Wa of the electrode portion 41. Therefore, it is easy to secure the spacing Db of the terminal portions 42 on each first electrode 40. As a result of securing sufficient spacing Db of the terminal portions 42, the possibility of short circuits between the terminal portions 42 of each first electrode 40 can be reduced.

[0044] For example, when the first electrode 40 is formed by printing technology, the liquid conductive material of the first electrode 40 may wet and spread in the X-axis direction at the stepped portion of the insulating layer 30. Therefore, adjacent first electrodes 40 are prone to short circuits. In particular, steps are formed in the portion of the first electrode 40 that overlaps with the periphery E1 of the insulating layer 30 or the periphery E2 of the piezoelectric body 20 in a plan view (connecting portion 43). Therefore, the connecting portions 43 of adjacent first electrodes 40 are particularly prone to short circuits. Therefore, a configuration in which the line width Wb of the terminal portion 42 is less than the line width Wa of the electrode portion 41, thereby ensuring a spacing Db between each terminal portion 42, is particularly effective in suppressing short circuits between each first electrode 40.

[0045] B: Manufacturing method Figure 5 is a flowchart of the procedure for manufacturing the ultrasonic probe 100. In the first step S1, the second electrode 50 is prepared. In step S2, following step S1, a piezoelectric body 20 is formed on the front surface 51 of the second electrode 50. As mentioned above, the piezoelectric body 20 is formed, for example, by the sol-gel method.

[0046] In step S3, following step S2, an insulating layer 30 is formed extending from the first surface 21 of the piezoelectric body 20 to the peripheral edge 32 of the second electrode 50. In step S4, following step S3, a plurality of first electrodes 40 are formed. Each first electrode 40 extends in the Y-axis direction from the first surface 21 of the piezoelectric body 20 to the peripheral edge 32 of the insulating layer 30. The piezoelectric unit 10 is manufactured through the above steps (S1 to S4).

[0047] In step S5, following step S4, the wiring board 60 is joined to the peripheral portion 32 of the insulating layer 30 and the terminal portion 42 of each first electrode 40. In step S6, following step S5, a support member 71 is joined to the back surface 52 of the second electrode 50. Note that step S6, in which the support member 71 is installed, may be performed at any point between steps S1 and S5. In step S7, following step S6, a protective cover 72 is formed to house the piezoelectric unit 10, the support member 71, and a part of the wiring board 60. The ultrasonic probe 100 is manufactured through the above steps (S1 to S7).

[0048] C: Variant The following are examples of specific modifications that may be added to the embodiments exemplified above. Two or more embodiments may be arbitrarily selected from the following examples and merged as appropriate, provided they do not contradict each other.

[0049] (1) In the above-described embodiment, a configuration in which the piezoelectric body 20 is continuous across a plurality of first electrodes 40 was illustrated, but the piezoelectric body 20 may be formed individually, spaced apart from each other, for each first electrode 40 (i.e., for each piezoelectric element). Similarly, in the above-described embodiment, a configuration in which the insulating layer 30 is continuous across a plurality of first electrodes 40 was illustrated, but the insulating layer 30 may be formed individually, spaced apart from each other, for each first electrode 40 (i.e., for each piezoelectric element).

[0050] Furthermore, in the above-described embodiment, since the piezoelectric element 20 is continuous across multiple first electrodes 40, the manufacturing process of the ultrasonic probe 100 is simplified compared to an embodiment in which the piezoelectric element 20 is divided for each first electrode 40. Similarly, in the above-described embodiment, since the insulating layer 30 is continuous across multiple first electrodes 40, the manufacturing process of the ultrasonic probe 100 is simplified compared to an embodiment in which the insulating layer 30 is divided for each first electrode 40.

[0051] Furthermore, in the configuration in which the piezoelectric body 20 is divided into first electrodes 40, the insulating layer 30 is formed across the first surface 21 of the piezoelectric body 20 and the gap between each piezoelectric body 20. As a result, stress may concentrate in specific parts of the insulating layer 30, potentially causing damage to the insulating layer 30. In the above-described configuration, the piezoelectric body 20 and the insulating layer 30 are continuous across multiple first electrodes 40. Therefore, localized stress concentration in the insulating layer 30 is suppressed, and consequently, the possibility of damage to the insulating layer 30 can be reduced.

[0052] (2) In the above-described embodiment, an example was given in which the line width Wb of the terminal portion 42 of the first electrode 40 is less than the line width Wa of the electrode portion 41. However, the line width W of the first electrode 40 may be constant throughout the entire longitudinal direction of the first electrode 40. For example, the line width Wa of the electrode portion 41 and the line width Wb of the terminal portion 42 (and the line width Wc of the connecting portion 43) may be the same. Similarly, the spacing Da of each electrode portion 41 and the spacing Db of each terminal portion 42 (and the spacing Dc of each connecting portion 43) may be the same.

[0053] (3) With respect to each element of the ultrasonic probe 100 according to the embodiment (piezoelectric body 20, insulating layer 30, first electrode 40, second electrode 50, wiring board 60, support member 71, protective cover 72), conditions such as dimensions, materials, or manufacturing methods are not limited to the examples in the above embodiment and may be changed as desired.

[0054] (4) In the above-described embodiment, a configuration in which multiple first electrodes 40 are installed is illustrated, but a single first electrode 40 may be formed. The first electrode 40 includes an electrode portion 41, a terminal portion 42, and a connecting portion 43, similar to the above-described embodiment. The planar shape of the first electrode 40 may be arbitrarily changed. For example, the electrode portion 41 of the first electrode 40 may be any planar shape such as a circular shape or a polygonal shape.

[0055] (5) In the above-described embodiment, an example was given in which the peripheral edge 32 of the insulating layer 30 is formed on the second electrode 50 (protruding portion 54). However, the element on which the peripheral edge 32 of the insulating layer 30 is formed is not limited to the second electrode 50. For example, in a configuration in which the second electrode 50 or the piezoelectric body 20 is formed on an insulating substrate, the peripheral edge 32 of the insulating layer 30 may be formed on the surface of the insulating substrate.

[0056] (6) In the above-described embodiment, an ultrasonic probe 100 used for observing living organisms was given as an example, but the uses of the ultrasonic probe 100 are not limited to the above examples and may be changed as appropriate. For example, the ultrasonic probe 100 can also be used for non-destructive testing of structures such as buildings. The object to be observed by the ultrasonic probe 100 (e.g., living organisms or structures) may be changed as appropriate.

[0057] (7) The notation "nth" (where n is a natural number) in this application is used solely as a formal and convenient label to distinguish each element in notation and has no substantive meaning whatsoever. Therefore, there is no room for restrictive interpretation of the position or manufacturing order of each element based on the notation "nth".

[0058] D: Note From the forms exemplified above, the following configuration can be understood, for example.

[0059] An ultrasonic probe according to one aspect of the present disclosure (Aspect 1) comprises a piezoelectric body including a first surface, an insulating layer including a covering portion that covers a part of the first surface and a peripheral portion that does not overlap the piezoelectric body in a plan view, a first electrode including an electrode portion that contacts the first surface and a terminal portion that contacts the surface of the peripheral portion, and a wiring board joined to the terminal portion of the first electrode and the peripheral portion of the insulating layer. In the above aspect, the wiring board is joined to the terminal portion of the first electrode and the peripheral portion of the insulating layer. The peripheral portion and the electrode portion do not overlap the piezoelectric body. Therefore, no external force acts on the first surface of the piezoelectric body and the electrode portion of each first electrode via the wiring board. That is, the external force acting on the piezoelectric body from the wiring board is reduced. Therefore, compared to a configuration in which the wiring board is joined to the first surface of the piezoelectric body and the electrode portion of each first electrode, damage to the piezoelectric body caused by external forces acting from the wiring board can be suppressed.

[0060] In a specific example of Embodiment 1 (Embodiment 2), a second electrode is further provided, the piezoelectric body further includes a second surface opposite to the first surface, the second electrode includes an electrode portion that contacts the second surface of the piezoelectric body and a protruding portion that extends from the periphery of the piezoelectric body in a plan view, and the periphery of the insulating layer contacts the protruding portion. In the above embodiment, the periphery of the insulating layer contacts the protruding portion of the second electrode. Therefore, the periphery of the insulating layer can be supported by the second electrode.

[0061] In a specific example of Embodiment 2 (Embodiment 3), a protective cover is further provided that covers the piezoelectric element, the insulating layer, the first electrode, and the second electrode. In the above embodiment, the piezoelectric element, the insulating layer, the first electrode, and the second electrode can be protected by the protective cover.

[0062] In any specific example of Embodiments 1 to 3 (Embodiment 4), the device comprises a plurality of first electrodes including the first electrode, the plurality of first electrodes are arranged with intervals between them, each of the plurality of first electrodes includes an electrode portion and a terminal portion, and the line width of the terminal portion is less than the line width of the electrode portion. In the above embodiment, the line width of the terminal portion is less than the line width of the electrode portion in each of the plurality of first electrodes. Therefore, it is easy to ensure the spacing between the terminal portions of each first electrode. As a result of ensuring sufficient spacing between the terminal portions, the possibility of a short circuit occurring in the terminal portions of each first electrode can be reduced.

[0063] In a specific example of Embodiment 4 (Embodiment 5), each of the plurality of first electrodes includes a connecting portion that connects the electrode portion and the terminal portion, and in a plan view, the connecting portion of each of the plurality of first electrodes overlaps with the periphery of the insulating layer located on the first surface and the periphery of the piezoelectric material covered by the insulating layer, and the line width of the connecting portion is less than the line width of the electrode portion. Since a step is formed in the portion of the first electrode that overlaps with the periphery of the insulating layer or the periphery of the piezoelectric material in a plan view, the connecting portions of adjacent first electrodes are prone to short-circuiting each other. The configuration in which the line width of the connecting portion that overlaps with the periphery of the insulating layer and the periphery of the piezoelectric material of each first electrode is less than the line width of the electrode portion is particularly effective in reducing the possibility of short-circuiting each connecting portion.

[0064] In any specific example (6) of embodiments 1 to 5, the piezoelectric material is continuous across the plurality of first electrodes, and the insulating layer is continuous across the plurality of first electrodes. In the above embodiments, since the piezoelectric material is continuous across the plurality of first electrodes, the manufacturing process of the ultrasonic probe is simplified compared to a configuration in which the piezoelectric material is separated for each first electrode. Similarly, since the insulating layer is continuous across the plurality of first electrodes, the manufacturing process of the ultrasonic probe is simplified compared to a configuration in which the insulating layer is separated for each first electrode. Furthermore, in a configuration in which the piezoelectric material is separated for each first electrode, the insulating layer is formed across the first surface of the piezoelectric material and the space between each piezoelectric material, which can lead to stress concentration in specific parts of the insulating layer and the possibility of damage to the insulating layer. With a configuration in which the piezoelectric material and insulating layer are continuous across the plurality of first electrodes, localized stress concentration in the insulating layer is suppressed, and as a result, the possibility of damage to the insulating layer can be reduced. [Explanation of Symbols]

[0065] 100... Ultrasonic probe, 10... Piezoelectric unit, 20... Piezoelectric body, 21... First surface, 22... Second surface, 30... Insulating layer, 31... Covering part, 32... Peripheral part, 33... Stepped part, 40... First electrode, 41... Electrode part, 42... Terminal part, 43... Connecting part, 50... Second electrode, 51... Front surface, 52... Back surface, 53... Electrode part, 54... Protruding part, 60... Wiring board, 61... Insulating base material, 62... Wiring, 63... Wiring, 65... Anisotropic conductive film, 71... Support member, 72... Protective cover.

Claims

1. A piezoelectric material including the first surface, An insulating layer including a covering portion that covers a part of the first surface and a peripheral portion that does not overlap the piezoelectric body in a plan view, A first electrode including an electrode portion that contacts the first surface and a terminal portion that contacts the surface of the peripheral edge, A wiring board is joined to the terminal portion of the first electrode and the peripheral edge portion of the insulating layer. An ultrasound probe equipped with the following features.

2. Further comprising a second electrode, The piezoelectric material further includes a second surface opposite to the first surface, The second electrode includes an electrode portion that contacts the second surface of the piezoelectric body and an overhang portion that extends from the periphery of the piezoelectric body in a plan view. The peripheral edge of the insulating layer is in contact with the protruding portion. An ultrasonic probe according to claim 1.

3. A protective cover covering the piezoelectric element, the insulating layer, the first electrode, and the second electrode. The ultrasonic probe according to claim 2, further comprising:

4. It comprises a plurality of first electrodes, including the first electrode, The plurality of first electrodes are arranged with intervals between them. Each of the plurality of first electrodes includes the electrode portion and the terminal portion, The wire width of the terminal portion is less than the wire width of the electrode portion. An ultrasonic probe according to claim 1.

5. Each of the plurality of first electrodes includes a connecting portion that connects the electrode portion and the terminal portion. The connecting portion of each of the plurality of first electrodes overlaps in plan view with the peripheral edge of the insulating layer located on the first surface and the peripheral edge of the piezoelectric material covered by the insulating layer. The line width of the connecting portion is less than the line width of the electrode portion. The ultrasonic probe according to claim 4.

6. The piezoelectric material is continuous across the plurality of first electrodes, The insulating layer is continuous across the plurality of first electrodes. An ultrasonic probe according to claim 1.

Images