JP2021168427A - Ultrasonic transducer - Google Patents

Abstract

To provide an ultrasonic transducer which can easily attain reduction of the size in the thickness direction of a piezoelectric material and securing of an elastic force in the thickness direction in a spring electrode at the same time.SOLUTION: An ultrasonic transducer T includes: a spring electrode 30, which is conductive and is also in contact with a first conductive layer 11 as a contact target; and a support unit 50, which faces the contact target and holds the spring electrode between the support unit and the contact target. The spring electrode has a coil spring 32, which is wound around a center axial line X extending in the thickness direction, the outer diameter of the coil spring becoming smaller in a place closer to one side in the thickness direction or closer to another side in the thickness direction. The ultrasonic transducer T is held while the spring electrode is being pushed against the contact target from one side in the thickness direction.SELECTED DRAWING: Figure 3

Description

The present invention relates to an ultrasonic transducer.

Patent Document 1 discloses an ultrasonic transducer. In the ultrasonic transducer disclosed in Patent Document 1, conductive layers are arranged on both sides of a plate-shaped transducer body, and a linear cylindrical coil spring is in contact with one of the conductive layers.

U.S. Pat. No. 8,904,881

The ultrasonic transducer of Patent Document 1 employs a configuration in which one end of a coil formed linearly is brought into contact with a conductive layer arranged on the surface of the transducer body. However, in a configuration in which a linear cylindrical coil spring is brought into contact with the conductive layer as in the ultrasonic transducer of Patent Document 1, "reducing the space in the thickness direction of the element in which vibration is generated" and "the coil spring is It is difficult to achieve both "to fully exert elastic force".

The present invention has been completed based on the above circumstances, and provides an ultrasonic transducer that can easily reduce the size of the piezoelectric body in the thickness direction and secure the elastic force in the thickness direction in the spring electrode. The purpose is to do.

The ultrasonic transducer, which is one of the present inventions,
A piezoelectric body, a first conductive layer arranged on the first surface on one side in the thickness direction of the piezoelectric body, and a second conductive layer arranged on the second surface on the other side in the thickness direction of the piezoelectric body. , And a piezoelectric element that generates ultrasonic waves in response to a voltage applied between the first conductive layer and the second conductive layer.
An acoustic transmission unit that transmits ultrasonic waves generated by the piezoelectric element,
Have,
An ultrasonic transducer in which the surface of the piezoelectric element on the side of the second conductive layer is fixed to the acoustic transmission portion.
A spring electrode that conducts contact with the first conductive layer, or a conductor portion electrically connected to any of the first conductive layer and the second conductive layer, and conducts contact with the contact target.
A support portion that is arranged to face the contact object and sandwiches the spring electrode between the contact object and the support portion.
Have,
The spring electrode has a coil spring that is wound around a central axis extending in the thickness direction and whose outer diameter decreases toward one side in the thickness direction or the other side in the thickness direction.
The spring electrode is held in a state of being pressed against the contact object from one side in the thickness direction.

In this ultrasonic transducer, the spring electrode is wound around a central axis extending in the thickness direction of the piezoelectric body, and the outer diameter becomes smaller toward one side in the thickness direction or the other side in the thickness direction. Has. In this ultrasonic transducer, even if the size of the coil spring in the thickness direction is reduced, the elastic force for pushing in the thickness direction can be easily secured. Therefore, in this ultrasonic transducer, it is easy to achieve both the size reduction in the thickness direction and the securing of the elastic force in the thickness direction in the spring electrode, and it is possible to improve the electrical connection while reducing the size.

The ultrasonic transducer may include an inner electrode as a spring electrode. The inner electrode targets the first conductive layer or the first conductor portion electrically connected to the first conductive layer as a contact target, and the coil spring forming a part of itself is in a compressed state between the contact target and the support portion. It may be arranged and held in a state where the contact object is pushed to the other side in the thickness direction.

In this ultrasonic transducer, it is easy to achieve both the size reduction in the thickness direction and the securing of the elastic force in the thickness direction in the inner electrode configured as the spring electrode. In particular, in this ultrasonic transducer, the distance between the support portion and the piezoelectric body can be easily reduced, and the force with which the spring electrode pushes the contact object can be easily secured.

When the inner electrode is the spring electrode, the inner electrode has a first conductor portion as a contact target, and a coil spring forming a part of itself is arranged in a compressed state between the first conductor portion and the support portion. The first conductor portion may be held in a state of being pushed to the other side in the thickness direction.

In an ultrasonic transducer having a piezoelectric element in which conductive layers are arranged on both sides of the piezoelectric body, the electrodes need to be electrically connected to the conductive layer. However, when the electrodes are connected to the conductive layer by soldering, there is a concern that the oscillation characteristics of the piezoelectric element may change depending on the amount of solder used for soldering. On the other hand, if the inner electrode configured as the spring electrode is held in a state where the first conductor portion is pushed to the other side in the thickness direction as in the ultrasonic transducer described above, soldering is performed. You don't have to. Therefore, this ultrasonic transducer can solve the problem that the oscillation characteristics of the piezoelectric element change due to the amount of solder.

In the ultrasonic transducer described above, the coil spring of the inner electrode may have a configuration in which the outer diameter decreases toward the other side in the thickness direction.

In this ultrasonic transducer, the outer diameter of the coil spring of the inner electrode is gradually suppressed toward the other side in the thickness direction. Therefore, this ultrasonic transducer can further reduce the size of the inner electrode on the piezoelectric element side.

In the ultrasonic transducer described above, the coil spring of the inner electrode may have a configuration in which the outer diameter increases toward the other side in the thickness direction.

In this ultrasonic transducer, the outer diameter of the coil spring of the inner electrode gradually increases toward the other side in the thickness direction, so that the size of the support portion side of the inner electrode can be relatively reduced.

Any of the above ultrasonic transducers may include an outer electrode as a spring electrode. Then, the contact target may include an annular member having conductivity, being electrically connected to the second conductive layer, and being formed in an annular shape. The outer electrode may be held in a state where the annular member is pushed to the other side in the thickness direction.

In this ultrasonic transducer, it is easy to achieve both the size reduction in the thickness direction and the securing of the elastic force in the thickness direction in the outer electrode configured as the spring electrode. Moreover, this ultrasonic transducer has a configuration in which the outer electrode is pressed against the conductive annular member, so that an electrical connection can be stably secured.

The annular member may be directly or indirectly fixed to the peripheral portion of the piezoelectric element in the acoustic transmission portion via another member, and the annular member may be fixed to the annular member in the thickness direction of the first conductive layer. An annular conductor portion may be provided on the side in a state of being insulated from the first conductive layer. The outer electrode may be held in a state of being pressed against the annular conductor portion from one side in the thickness direction.

This ultrasonic transducer can stably hold the annular member by utilizing the peripheral portion of the piezoelectric element in the acoustic transmission portion. Further, in this ultrasonic transducer, in the annular member thus stably held, an annular conductor portion insulated from the first conductive layer is provided at a position on one side of the first conductive layer in the thickness direction. The outer electrode can be received by the annular conductor portion. Therefore, this ultrasonic transducer has "electrical connection between the outer electrode and the annular conductor portion at a position on one side in the thickness direction of the first conductive layer" and "reliable insulation of the outer electrode with respect to the first conductive layer". Can be compatible with each other.

Any of the above ultrasonic transducers may include an inner electrode and an outer electrode as spring electrodes. The outer electrode may be configured to contact an annular member having conductivity and being formed in an annular shape. Then, the annular member may be directly or indirectly fixed to the peripheral portion of the piezoelectric element in the acoustic transmission portion via another member. Then, in the annular member, an annular conductor portion may be provided on one side of the first conductive layer in the thickness direction in a state of being insulated from the first conductive layer. Then, the outer electrode may be held in a state of being pressed against the annular conductor portion from one side in the thickness direction. The annular conductor portion may be provided with an opening at one end on one side in the thickness direction of the annular conductor portion. Then, the support portion may have a protruding portion that protrudes to the other side in the thickness direction and is inserted into the opening. Then, the end portion of the coil spring of the inner electrode on one side in the thickness direction may be supported inside the annular member by the end surface of the protruding portion on the protruding side.

In this ultrasonic transducer, both the electrical connection to the first conductive layer and the electrical connection to the second conductive layer can be secured by interposing the spring electrode. Further, this ultrasonic transducer can stably hold the annular member by utilizing the peripheral portion of the piezoelectric element in the acoustic transmission portion. Further, in this ultrasonic transducer, in the annular member thus stably held, an annular conductor portion insulated from the first conductive layer is provided at a position on one side of the first conductive layer in the thickness direction. The outer electrode can be received by the annular conductor portion. Therefore, this ultrasonic transducer has "electrical connection between the outer electrode and the annular conductor portion at a position on one side in the thickness direction of the first conductive layer" and "reliable insulation of the outer electrode with respect to the first conductive layer". Can be compatible with each other. Moreover, a protrusion provided on the other side of the support portion in the thickness direction is inserted into the opening provided on one end of the annular conductor portion in the thickness direction, and the coil spring of the inner electrode is formed. One end in the thickness direction is supported by the protruding end surface of the protruding portion. Therefore, in this ultrasonic transducer, the inner electrode and the annular conductor portion are less likely to come into contact with each other, and the insulating property between the inner electrode and the annular conductor portion is further enhanced.

In the ultrasonic transducer having the end face on the protruding side, an annular wall portion protruding to the other side in the thickness direction may be formed on the end face on the protruding side. Then, the annular wall portion may be arranged so as to surround the end portion of the coil spring on one side in the thickness direction.

In this ultrasonic transducer, the relative movement of the inner electrode is more reliably regulated at the end face on the protruding side, so that the insulation between the inner electrode and the annular conductor portion is further enhanced.

In the ultrasonic transducer having the annular conductor portion, the outer peripheral surface of the annular conductor portion may have a tapered surface whose diameter decreases toward one side in the thickness direction. The coil spring of the outer electrode may be arranged along the tapered surface on the outside of the annular conductor portion, and may have a configuration in which the inner diameter becomes smaller toward one side in the thickness direction, and is pressed against the tapered surface. It may be a configuration that is held in a state.

In this ultrasonic transducer, both the tapered surface of the annular conductor portion and the coil spring of the outer electrode are aligned so that the inner diameter becomes smaller toward one side in the thickness direction, and the coil spring of the outer electrode has this shape. It is pressed against the tapered surface and held. In this ultrasonic transducer, the inside of the coil spring of the outer electrode is easily supported stably by the tapered surface, and the coil spring of the outer electrode is less likely to be displaced, so that the electrical connection between the outer electrode and the annular conductor is stable. Easy to maintain.

In the ultrasonic transducer having the tapered surface, the support portion may have a covering portion which is arranged to face the tapered surface and covers the coil spring of the outer electrode from the side opposite to the tapered surface. The facing surface facing the tapered surface in the covering portion may have a second tapered surface that is arranged along the coil spring and whose diameter decreases toward one side in the thickness direction.

In this ultrasonic transducer, the portion (covered portion) of the support portion that covers the coil spring of the outer electrode can be brought closer to the coil spring in accordance with the tapered coil spring. Therefore, in this ultrasonic transducer, the thickness of the covering portion can be secured to be larger, and the strength of the supporting portion in the vicinity of the covering portion can be further increased.

In the ultrasonic transducer having the tapered surface, the outer electrode may have a terminal extending from one end of the coil spring on one side in the thickness direction toward the support portion and being held by the support portion.

Since this ultrasonic transducer has a configuration in which the terminal extends from the end of the coil spring whose diameter is reduced toward the central axis toward the support portion, it is advantageous in arranging the terminal near the central axis in the support portion.

In the ultrasonic transducer, which is one of the present inventions, the coil spring tends to exert an elastic force while reducing the space in the thickness direction of the piezoelectric body.

FIG. 1 is a perspective view illustrating the ultrasonic transducer of the first embodiment. FIG. 2 is an exploded perspective view of the ultrasonic transducer of FIG. FIG. 3 is a cross-sectional view of the ultrasonic transducer of FIG. FIG. 4 is a cross-sectional perspective view showing a cross-sectional configuration in which the ultrasonic transducer of FIG. 1 is cut at a predetermined position. FIG. 5 is an enlarged view of a part of the cross-sectional view of FIG. FIG. 6 is a cross-sectional view of the ultrasonic transducer of the second embodiment. FIG. 7 is a cross-sectional view of the ultrasonic transducer of another embodiment.

<First Embodiment>
The following description relates to the ultrasonic transducer T of the first embodiment.
The ultrasonic transducer T of the first embodiment shown in FIG. 1 is used in a medical or industrial ultrasonic device. The ultrasonic transducer T is, for example, a disposable product (disposable product). The ultrasonic transducer T transmits and receives ultrasonic waves.

As shown in FIG. 2, the ultrasonic transducer T includes a support portion 50, an outer electrode 40, an inner electrode 30, an annular member 70, a surrounding member 80, a piezoelectric element 10, a conductive sheet 102, an acoustic transmission layer 20, and a case 90. .. The ultrasonic transducer T is electrically connected to a control device (not shown) and may receive an electrical signal from this control device. Further, the ultrasonic transducer T may transmit an electric signal to the control device. In the configuration of FIG. 2, the sound transmission layer 20 and the case 90 correspond to an example of the sound transmission unit.

In the following description, as shown in FIG. 3, the thickness direction of the piezoelectric body 14 is the vertical direction. One side of the piezoelectric body 14 in the thickness direction is the lower side, and the other side of the piezoelectric body 14 in the thickness direction is the upper side. FIG. 3 schematically shows a cross section of the ultrasonic transducer T cut along the central axis X.

The piezoelectric element 10 is an element that generates ultrasonic waves. The piezoelectric element 10 has a piezoelectric body 14, a first conductive layer 11, and a second conductive layer 12. The piezoelectric element 10 has a plate shape having a predetermined thickness. The piezoelectric element 10 has a disk shape in which the outer edge of the upper surface 11A and the outer edge of the lower surface 12B are both circular and the outer peripheral surface is a cylindrical surface. The piezoelectric element 10 has a columnar shape centered on the central axis X.

The piezoelectric body 14 is made of PZT (lead zirconate titanate) or the like. The piezoelectric body 14 has a disk shape having a predetermined thickness. The upper surface 14A, which is one surface of the piezoelectric body 14 in the thickness direction, corresponds to an example of the first surface. The lower surface 14B, which is the other surface of the piezoelectric body 14 in the thickness direction, corresponds to an example of the second surface.

The first conductive layer 11 is arranged on the upper surface 14A of the piezoelectric body 14. The second conductive layer 12 is arranged on the lower surface 14B of the piezoelectric body 14. The first conductive layer 11 and the second conductive layer 12 are electrode layers having conductivity formed by vapor deposition of gold or silver, copper, tin or the like, plating, sputtering, printing of paste, baking or the like. The first conductive layer 11 is a first electrode on the upper surface side of the piezoelectric element 10. The second conductive layer 12 is a second electrode on the lower surface side of the piezoelectric element 10. The lower surface 12B of the second conductive layer 12 is one main surface (lower surface) of the piezoelectric element 10. The lower surface of the piezoelectric element 10 (lower surface 12B of the second conductive layer 12) is fixed to the acoustic transmission layer 20 via an adhesive 120 (see FIG. 5). The upper surface 11A of the first conductive layer 11 is the other main surface (upper surface) of the piezoelectric element 10. The upper surface 11A and the lower surface 12B of the piezoelectric element 10 are parallel. Both the upper surface 11A and the lower surface 12B are planes orthogonal to the central axis X. The first conductive layer 11 is arranged so as to cover the entire upper surface 14A of the piezoelectric body 14. The second conductive layer 12 is arranged so as to cover the entire lower surface 14B of the piezoelectric body 14.

The first conductive layer 11 is electrically connected to the substrate 110 by an inner electrode 30, which will be described later. The second conductive layer 12 is electrically connected to the substrate 110 by a conductive sheet 102, a conductor portion 88, an annular member 70, and an outer electrode 40, which will be described later. The piezoelectric element 10 can perform an operation of transmitting an electric signal to a control device (not shown) via the first conductive layer 11 and the second conductive layer 12. Further, the piezoelectric element 10 can perform an operation of receiving an electric signal from the control device. The piezoelectric element 10 generates ultrasonic waves in response to an AC voltage applied between the first conductive layer 11 and the second conductive layer 12.

The acoustic transmission layer 20 is a member that transmits ultrasonic waves generated by the piezoelectric element 10. The acoustic transmission layer 20 is arranged on the lower side of the piezoelectric element 10. The sound transmission layer 20 has a disk shape. The upper surface of the acoustic transmission layer 20 is adhered to the lower surface of the piezoelectric element 10 via an adhesive 120 (FIG. 5). The acoustic transmission layer 20 has an acoustic impedance having a magnitude intermediate between the acoustic impedance of the piezoelectric element 10 and the acoustic impedance of the bottom wall 91 which is an acoustic lens.

The upper surface, which is the plate surface on one side of the acoustic transmission layer 20, is a support surface that supports the lower surface 12B of the piezoelectric element 10, and is also a support surface that supports the lower end portion of the enclosing member 80. The upper surface of the sound transmission layer 20 is a flat surface having a circular outer edge. The area of the upper surface of the acoustic transmission layer 20 is larger than the area of the lower surface of the piezoelectric element 10. The outer diameter of the upper surface of the acoustic transmission layer 20 is larger than the outer diameter of the lower surface of the piezoelectric element 10. The acoustic transmission layer 20 has a columnar shape centered on the central axis X. The acoustic transmission layer 20 and the piezoelectric element 10 are laminated in a coaxial positional relationship centered on the central axis X. The lower end of the enclosing member 80 is fixed to the peripheral portion of the piezoelectric element 10 in the acoustic transmission layer 20 by an adhesive 120 (FIG. 5).

The case 90 has a bottom wall 91 and a peripheral wall 92. The bottom wall 91 and the peripheral wall 92 are integrally formed of the same material. The bottom wall 91 has a substantially disk shape and has a circular shape when viewed from above. The bottom wall 91 covers the entire lower surface of the case 90. The upper end side of the case 90 (the side opposite to the bottom wall 91) is open. A piezoelectric element 10, an acoustic transmission layer 20, a surrounding member 80, an annular member 70, and the like are housed inside the case 90.

The bottom wall 91 of the case 90 is an acoustic lens that focuses ultrasonic waves. The bottom wall 91 of the case 90 and the acoustic transmission layer 20 are adhered to each other by an adhesive 120 (FIG. 5). The bottom wall 91 of the case 90 and the acoustic transmission layer 20 are laminated in a coaxial positional relationship centered on the central axis X. By interposing the sound transmission layer 20 between the bottom wall 91 of the case 90 and the piezoelectric element 10, ultrasonic waves are efficiently propagated to the bottom wall 91. The peripheral wall 92 of the case 90 is connected over the entire circumference of the outer edge of the bottom wall 91, and is arranged in a cylindrical shape upward from the bottom wall 91. The inner peripheral surface 92A of the peripheral wall 92 is a cylindrical inner surface. A support portion 50, which will be described later, is fixed to the upper end portion of the peripheral wall 92.

The support portion 50 functions as a lid portion and is arranged so as to close the opening formed at the upper end portion of the case 90. The support portion 50 also functions as a substrate holding portion for holding the substrate 110. Details of the support portion 50 will be described later.

As shown in FIG. 4, the surrounding member 80 is a member that surrounds the outer peripheral side of the piezoelectric element 10. The surrounding member 80 is arranged between the outer peripheral surface 10A of the piezoelectric element 10 and the inner peripheral surface 92A of the peripheral wall 92. The surrounding member 80 is fixed in a configuration supported on the upper surface of the acoustic transmission layer 20. The surrounding member 80 forms a continuous annular shape over the entire circumference. As shown in FIG. 5, the surrounding member 80 has an insulator portion 85 and a conductor portion 88. The insulator portion 85 and the conductor portion 88 are integrated by insert molding.

The insulator portion 85 is made of an insulator such as a synthetic resin material. The insulator portion 85 includes an inner insulator portion 86 arranged on the inner peripheral side of the surrounding member 80, and an overhanging portion 87 projecting outward from the conductor portion 88. The inner insulator portion 86 forms a portion on the inner peripheral side of the surrounding member 80. The inner insulator portion 86 is continuous with the entire circumference of the surrounding member 80. The overhanging portion 87 is provided on the outer peripheral peripheral portion on the outermost outer peripheral side of the surrounding member 80. The overhanging portion 87 is continuous with the entire circumference of the surrounding member 80. The overhanging portion 87 is made of a material that is softer than the material that forms the case 90. The overhanging portion 87 is annular when viewed from above. The overhanging portion 87 projects in a flange shape from the lower end portion of the inner insulator portion 86, and projects toward the peripheral wall 92 side of the case 90.

The conductor portion 88 is made of a conductor such as metal. The conductor portion 88 is electrically connected to the second conductive layer 12 of the piezoelectric element 10 via the conductive sheet 102. The conductor portion 88 has a continuous annular shape all around. The conductor portion 88 surrounds the outer peripheral side of the piezoelectric element 10. The conductor portion 88 is held at a position separated from the piezoelectric element 10 by the insulator portion 85. The conductor portion 88 includes a first conductive connection portion 89A, a second conductive connection portion 89B, and a buried portion 89C. The annular member 70 is electrically connected to the first conductive connection portion 89A while being in contact with the first conductive connection portion 89A. The conductive sheet 102 is electrically connected to the second conductive connection portion 89B while being in contact with the second conductive connection portion 89B. The buried portion 89C is embedded inside the insulator portion 85.

The first conductive connection portion 89A is a fitting portion into which the annular member 70 is fitted. The first conductive connection portion 89A covers the outer peripheral surface of the insulator portion 85. The first conductive connection portion 89A is located above the upper surface 87A of the overhanging portion 87. The first conductive connection portion 89A is inclined along the inclined surface 85A provided on the upper end side and the outer peripheral side of the insulator portion 85. The outer peripheral surface of the first conductive connecting portion 89A is exposed to the outside at a position above the overhanging portion 87. The first conductive connection portion 89A is formed in a cylindrical shape, and is configured so that the inner diameter and the outer diameter become smaller as the distance from the piezoelectric element 10 increases (upward). The first conductive connection portion 89A is inclined so that the opening on the inner peripheral side becomes narrower toward the upper side. The outer peripheral surface of the first conductive connection portion 89A has a contact portion 89D that comes into contact with the annular member 70. The contact portion 89D is inclined with respect to the direction of the central axis of the surrounding member 80 (that is, the direction of the central axis X (FIG. 3) and the fitting direction between the surrounding member 80 and the annular member 70). Specifically, the surface (outer peripheral surface) of the contact portion 89D is inclined outward (radial outer side centered on the central axis X (FIG. 3)) toward the lower side, and the diameter increases toward the lower side. It has a cylindrical tapered surface.

The buried portion 89C is connected to the lower end of the first conductive connecting portion 89A. The upper part of the buried portion 89C is inclined at the same slope as the first conductive connecting portion 89A. The lower part of the buried portion 89C is substantially parallel to the central axis of the surrounding member 80. An insulator portion 85 is provided on the inner peripheral side of the buried portion 89C, and an overhanging portion 87 is provided on the outer peripheral side of the buried portion 89C.

The second conductive connection portion 89B is provided on the lower surface of the surrounding member 80. The second conductive connecting portion 89B is bent from the lower end of the embedded portion 89C to the outer peripheral side. The second conductive connecting portion 89B is located below the overhanging portion 87 and is exposed to the outside. The upper surface of the second conductive connection portion 89B is located at the same height as the lower surface of the overhanging portion 87.

The conductive sheet 102 has a strip shape that crosses the inner peripheral side of the surrounding member 80. The conductive sheet 102 extends in a predetermined direction along the direction of a plane orthogonal to the central axis X (FIG. 3). Since the conductive sheet 102 has a band shape, the contact pressure with the second conductive layer 12 is increased as compared with the conductive sheet having a circular shape having the same size as the second conductive layer 12 of the piezoelectric element 10. Both ends of the conductive sheet 102 in the longitudinal direction are electrically connected while being in contact with the second conductive connecting portion 89B. The conductive sheet 102 and the second conductive connecting portion 89B are joined by resistance welding.

The annular member 70 is a member that has conductivity, is electrically connected to the second conductive layer 12, and is formed in an annular shape. The annular member 70 is formed of a conductive material such as metal. The central axis of the annular member 70 coincides with the above-mentioned central axis X (FIG. 3). The direction of the central axis of the annular member 70 is the direction along the central axis X. The annular member 70 is attached so as to be fitted to the surrounding member 80 by relatively moving in the direction of the central axis of the surrounding member 80. The annular member 70 is in contact with the first conductive connecting portion 89A and is electrically connected in a state of being fitted with the surrounding member 80. The annular member 70 has a cylindrical shape in which the axial direction (direction of the central axis X) is smaller than the radial direction (radial direction orthogonal to the central axis X). The annular member 70 has a cylindrical portion 72 and an umbrella-shaped portion 76. The umbrella-shaped portion 76 corresponds to an example of the annular conductor portion. The tubular portion 72 is provided below the annular member 70. The lower end of the tubular portion 72 constitutes an opening at the lower end of the annular member 70. The umbrella-shaped portion 76 is provided on the upper portion of the annular member 70. The upper end of the umbrella-shaped portion 76 constitutes an opening at the upper end of the annular member 70. The cross-sectional shape of the tubular portion 72 and the umbrella-shaped portion 76 (the cross-sectional shape in the direction orthogonal to the central axis of the annular member 70) is circular. The tubular portion 72 and the umbrella-shaped portion 76 are formed coaxially.

The radial dimension of the tubular portion 72 is constant over a predetermined axial region of the tubular portion 72. The radial dimension of the tubular portion 72 is larger than the radial dimension of the upper end of the first conductive connecting portion 89A. The radial dimension of the tubular portion 72 is smaller than the radial dimension of the lower end of the first conductive connecting portion 89A. The lower end of the tubular portion 72 comes into contact with the intermediate portion (contact portion 89D) of the first conductive connecting portion 89A in the vertical direction. The lower end of the tubular portion 72 is separated upward from the upper surface 87A of the overhanging portion 87 in the fitted state of the annular member 70 and the surrounding member 80. The end face of the lower end of the tubular portion 72 is a contact end face 74 that comes into contact with the first conductive connecting portion 89A when the annular member 70 and the surrounding member 80 are fitted. The contact end surface 74 is curved in an arc shape toward the outside of the tubular portion 72 in the radial direction. The contact end face 74 is continuous over the entire circumference of the tubular portion 72. An opening 72B is formed at the lower end of the tubular portion 72.

As shown in FIG. 3, the umbrella-shaped portion 76 projects toward the inner peripheral side of the annular member 70. Specifically, the umbrella-shaped portion 76 projects inward from the cylindrical portion 72 so as to approach the central axis X (FIG. 3) side toward the upper side. The umbrella-shaped portion 76 is inclined inward from the lower end (the upper end of the tubular portion 72). The outer peripheral surface of the umbrella-shaped portion 76 has a tapered surface 76A whose diameter decreases toward the upper side (one side in the thickness direction of the piezoelectric body 14). The center of the tapered surface 76A is the position of the central axis X, and in the region where the tapered surface 76A is provided, the shape of the tapered surface 76A at the cut surface orthogonal to the central axis X at any position in the direction of the central axis X. Is the diameter of the circle, and the diameter of the tapered surface 76A becomes smaller toward the upper side. An opening 76B is formed at the upper end of the umbrella-shaped portion 76. The opening area of the opening 76B is smaller than the opening area of the opening 72B. The opening area of the opening 76B is smaller than the opening area of the opening 72B. The umbrella-shaped portion 76 is arranged so as to cover the upper side of the piezoelectric element 10 (more specifically, the upper side near the peripheral edge portion of the piezoelectric element 10). Since it is arranged in this way, the influence of external noise on the piezoelectric element 10 can be reduced.

As shown in FIG. 3, in the ultrasonic transducer T, the surrounding member 80 is fixed to the peripheral portion of the piezoelectric element 10 in the acoustic transmission layer 20 by the adhesive 120. Therefore, the annular member 70 is indirectly fixed to the peripheral portion of the piezoelectric element 10 in the acoustic transmission layer 20 via the surrounding member 80. In the annular member 70 configured in this way, the umbrella-shaped portion 76 is arranged above the first conductive layer 11 (one side in the thickness direction of the piezoelectric body 14) in a state of being insulated from the first conductive layer 11. NS.

As shown in FIG. 3, the inner electrode 30 has the first conductive layer 11 as a contact target, and conducts while being in contact with the first conductive layer 11 (contact target). The inner electrode 30 corresponds to an example of a spring electrode. The inner electrode 30 has a coil spring 32 that is wound around a central axis X extending in the thickness direction (vertical direction) and whose outer diameter decreases toward the other side (lower side) in the thickness direction. The coil spring 32 is configured as a conical spring and functions as a compression spring. The inner electrode 30 is held in a state of being pressed against the first conductive layer 11 (contact target) from one side (upper side) in the thickness direction.

In the inner electrode 30, a coil spring 32 forming a part of the inner electrode 30 is arranged in a compressed state between the first conductive layer 11 (contact target) and the support portion 50, and the first conductive layer 11 (contact target) has the above thickness. It is held in a pressed state on the other side (lower side) in the longitudinal direction. The lower end of the coil spring 32 is formed in a circular shape. The lower end of the inner electrode 30 (specifically, the lower end of the coil spring 32) comes into contact with the upper surface 11A of the first conductive layer 11, and the lower end of the inner electrode 30 is the first conductive layer based on its own elastic force. The 11 is continuously pushed downward, and the state of being electrically connected to the first conductive layer 11 is maintained. The inner electrode 30 has its own upper end (specifically, the upper end of the coil spring 32) in contact with the protruding end surface 58 of the protruding portion 56, and its own upper end is based on its own elastic force. Continue to push upwards. A terminal 38 is integrally connected to the upper end of the coil spring 32. The terminal 38 extends linearly upward from the upper end of the coil spring 32, and is fixed to the substrate 110 while being supported by the support portion 50. The terminal 38 is electrically connected to a wiring portion formed on the substrate 110.

The outer electrode 40 corresponds to an example of a spring electrode. The outer electrode 40 is in contact with the annular member 70 electrically connected to the second conductive layer 12. More specifically, the outer electrode 40 has an umbrella-shaped portion 76 (annular conductor portion) as a contact target, and conducts while being in contact with the umbrella-shaped portion 76 (contact target). The outer electrode 40 has a coil spring 42 that is wound around a central axis X extending in the thickness direction (vertical direction) and whose outer diameter decreases toward one side (upper side) in the thickness direction. The coil spring 42 is configured as a conical spring. The outer electrode 40 is held in a state of being pressed against the umbrella-shaped portion 76 (contact target) from one side (upper side) in the thickness direction. The outer electrode 40 is held in a state in which the annular member 70 is pushed downward on the other side (lower side) in the thickness direction (specifically, a state in which the umbrella-shaped portion 76 (contact target) is pushed downward). NS.

The inner peripheral surface side of the coil spring 42 of the outer electrode 40 is supported from below by the tapered surface 76A of the umbrella-shaped portion 76. On the other hand, the terminal 48 is integrally connected to the end (upper end) of the coil spring 42 on one side in the thickness direction. The terminal 48 extends linearly toward the support portion 50 so as to go upward from the upper end portion of the coil spring 42, and is fixed to the substrate 110 while being held by the support portion 50. The terminal 48 is electrically connected to a wiring portion formed on the substrate 110.

The support portion 50 is provided with a protruding portion 56 closer to the central axis X, and a covering portion 52 is provided around the protruding portion 56. The protruding portion 56 projects to the other side (lower side) in the thickness direction. Further, the protruding portion 56 is configured to be inserted into the opening 76B formed at the upper end portion of the umbrella-shaped portion 76. The base end position of the protrusion 56 is a position above the opening 76B, and the tip position of the protrusion 56 is a position below the opening 76B. The protruding portion 56 is arranged so as to face the first conductive layer 11 (contact target), and sandwiches the inner electrode 30 (spring electrode) with the first conductive layer 11 (contact target).

The end portion of the coil spring 32 of the inner electrode 30 on one side (upper side) in the thickness direction is supported inside the annular member 70 by the end surface 58 on the protruding side of the protruding portion 56. The upper end portion of the coil spring 32 is arranged inside the annular member 70, is located below the upper end portion of the annular member 70, and is located above the lower end portion of the annular member 70.

An annular wall portion 60 projecting to the other side (lower side) in the thickness direction is formed on the end surface 58 on the protruding side of the protruding portion 56. The annular wall portion 60 is formed continuously or intermittently over the entire circumferential direction centered on the central axis X at the outer edge portion of the end surface 58 of the protruding portion 56. The annular wall portion 60 is formed so as to project downward from the support surface (the surface that supports the upper end portion of the coil spring 32) on the end surface 58, and is arranged so as to surround the upper end portion of the coil spring 32. There is. The annular wall portion 60 regulates that the upper end portion of the coil spring 32 moves in the radial direction (direction orthogonal to the central axis X).

The covering portion 52 is arranged so as to cover the coil spring 42. The covering portion 52 is arranged so as to face the tapered surface 76A of the umbrella-shaped portion 76. As shown in FIG. 3, the coil spring 42 of the outer electrode 40 is arranged on the outside of the umbrella-shaped portion 76 along the tapered surface 76A which is the outer peripheral surface of the umbrella-shaped portion 76. The coil spring 42 has a structure in which the inner diameter decreases toward one side (upper side) in the thickness direction, and is held in a state of being pressed against the tapered surface 76A. On the other hand, the covering portion 52 covers the coil spring 42 from the side opposite to the tapered surface 76A. The facing surface of the covering portion 52 facing the tapered surface 76A has a second tapered surface 52A. The second tapered surface 52A is arranged along the coil spring 42 and has a configuration in which the diameter decreases toward one side (upper side) in the thickness direction. In this configuration, the lower end of the tapered surface 76A is located below the upper end of the coil spring 42. The upper end of the tapered surface 76A is located above the lower end of the coil spring 42. Further, the lower end of the second tapered surface 52A is located below the upper end of the coil spring 42. The upper end of the second tapered surface 52A is located above the lower end of the coil spring 42.

The following description relates to an example of the effect of the ultrasonic transducer T.
In the ultrasonic transducer T, one spring electrode (inner electrode 30) is wound around the central axis X extending in the thickness direction (vertical direction) of the piezoelectric body 14, and is outward as it goes to one side in the thickness direction. It has a coil spring 32 having a smaller diameter. Further, the other spring electrode (outer electrode 40) is wound around the central axis X extending in the thickness direction (vertical direction) of the piezoelectric body 14, and the outer diameter becomes smaller toward the other side in the thickness direction. It has a coil spring 42. Therefore, in the ultrasonic transducer T, even if the size of the coil springs 32 and 42 in the thickness direction is reduced, the elastic force in the thickness direction of the coil springs 32 and 42 can be easily secured. Therefore, in the spring electrodes (inner electrode 30, outer electrode 40), the ultrasonic transducer T can easily achieve both the size reduction in the thickness direction and the securing of the elastic force in the thickness direction, and can be miniaturized while being electrically miniaturized. Connection can be enhanced.

The ultrasonic transducer T can both reduce the size of the inner electrode 30 configured as the spring electrode in the thickness direction (vertical direction) and secure the elastic force in the thickness direction. In particular, in the ultrasonic transducer T, the distance between the support portion 50 and the piezoelectric body 14 can be easily reduced, and the force with which the inner electrode 30 pushes the contact object can be easily secured.

By the way, in the ultrasonic transducer T, the electrode needs to be electrically connected to the first conductive layer 11 arranged on the piezoelectric body 14. However, when the electrodes are connected to the first conductive layer 11 by soldering, there is a concern that the oscillation characteristics of the piezoelectric element 10 will change depending on the amount of solder used for soldering. On the other hand, as in the ultrasonic transducer T, if the inner electrode 30 configured as a spring electrode is held in a state where the first conductive layer 11 is pushed to the other side (lower side) in the thickness direction. , No need to solder. Therefore, the ultrasonic transducer T can solve the problem that the oscillation characteristics of the piezoelectric element 10 change due to the amount of solder.

In the ultrasonic transducer T, the coil spring 32 of the inner electrode 30 has a configuration in which the outer diameter becomes smaller toward the other side (lower side) in the thickness direction. Therefore, in the ultrasonic transducer T, the outer diameter of the coil spring 32 of the inner electrode 30 is gradually suppressed toward the other side (lower side) in the thickness direction. Therefore, this ultrasonic transducer T can further reduce the size of the inner electrode 30 on the piezoelectric element 10 side.

In the ultrasonic transducer T, the outer electrode 40 configured as the spring electrode can easily achieve both the size reduction in the thickness direction and the securing of the elastic force in the thickness direction. Moreover, the ultrasonic transducer T has a configuration in which the outer electrode 40 is pressed against the conductive annular member 70, so that an electrical connection can be stably secured.

The ultrasonic transducer T can stably hold the annular member 70 by utilizing the peripheral portion of the piezoelectric element 10 in the acoustic transmission layer 20. Further, the ultrasonic transducer T is stably held in this way, and is insulated from the first conductive layer 11 at a position on one side (upper side) of the first conductive layer 11 in the thickness direction in the annular member 70. An umbrella-shaped portion 76 (annular conductor portion) is provided. Then, the ultrasonic transducer T can receive the outer electrode 40 by the umbrella-shaped portion 76. Therefore, the ultrasonic transducer T includes "electrical connection between the outer electrode 40 and the umbrella-shaped portion 76 at a position on one side (upper side) of the thickness direction of the first conductive layer 11" and "the first conductive layer 11". It is possible to achieve both "reliable insulation of the outer electrode 40".

The ultrasonic transducer T can secure both the electrical connection to the first conductive layer 11 and the electrical connection to the second conductive layer 12 with the spring electrode interposed therebetween. Further, in the ultrasonic transducer T, the support portion 50 is on the other side in the thickness direction with respect to the opening 76B provided at the end of the umbrella-shaped portion 76 (annular conductor portion) on one side (upper side) in the thickness direction. The protruding portion 56 provided on the (lower side) is inserted. Then, the end portion of the coil spring 32 of the inner electrode 30 on one side (upper side) in the thickness direction is supported by the end surface 58 on the protruding side of the protruding portion 56. Therefore, in this ultrasonic transducer T, the inner electrode 30 and the umbrella-shaped portion 76 are less likely to come into contact with each other, and the insulating property between the inner electrode 30 and the umbrella-shaped portion 76 is further enhanced.

An annular wall portion 60 projecting to the other side (lower side) in the thickness direction is formed on the end surface 58 on the projecting side of the projecting portion 56. The annular wall portion 60 is arranged so as to surround the end portion of the coil spring 32 on one side (upper side) in the thickness direction. In this way, in the ultrasonic transducer T, the relative movement of the inner electrode 30 is more reliably regulated at the end face 58 on the protruding side, so that the insulation between the inner electrode 30 and the umbrella-shaped portion 76 (annular conductor portion) is further improved. Increase.

In the ultrasonic transducer T, both the tapered surface 76A of the umbrella-shaped portion 76 (annular conductor portion) and the coil spring of the outer electrode 40 are aligned so that the inner diameter becomes smaller toward one side (upper side) in the thickness direction. .. Then, in this shape, the coil spring 42 of the outer electrode 40 is pressed against the tapered surface 76A and held. As described above, in the ultrasonic transducer T, the inside of the coil spring 42 of the outer electrode 40 is likely to be stably supported by the tapered surface 76A, and the coil spring 42 of the outer electrode 40 is less likely to be misaligned. The electrical connection of the umbrella-shaped portion 76 is likely to be stably maintained.

The support portion 50 has a covering portion 52 that is arranged to face the tapered surface 76A and covers the coil spring of the outer electrode 40 from the side opposite to the tapered surface 76A. The facing surface of the covering portion 52 facing the tapered surface 76A has a second tapered surface 52A that is arranged along the coil spring 42 and whose diameter decreases toward one side (upper side) in the thickness direction. In this way, in the ultrasonic transducer T, the portion (covered portion 52) of the support portion 50 that covers the coil spring 42 of the outer electrode 40 can be brought closer to the coil spring 42 in accordance with the tapered coil spring 42. can. Therefore, in this ultrasonic transducer T, the thickness of the covering portion 52 can be secured to be larger, and the strength in the vicinity of the covering portion 52 can be further increased.

The outer electrode 40 has a terminal 48 that extends from the end on one side (upper side) of the coil spring 42 in the thickness direction toward the support portion 50 and is held by the support portion 50. As described above, since the ultrasonic transducer T has a configuration in which the terminal 48 extends from the end portion of the coil spring 42 whose diameter is reduced toward the central axis X toward the support portion 50, the terminal at the support portion 50 is closer to the central axis X. It is advantageous in arranging 48.

<Second Embodiment>
The following description relates to the ultrasonic transducer T of the second embodiment shown in FIG.
In the ultrasonic transducer T of the second embodiment, the shape of the coil spring 32 of the inner electrode 30 is different from that of the first embodiment, and the other configurations other than the coil spring 32 of the inner electrode 30 are the same as those of the first embodiment. It is the same as the ultrasonic transducer T. Therefore, in the following description, detailed description is omitted except for the inner electrode 30.

Even in the configuration of FIG. 6, the inner electrode 30 has the first conductive layer 11 as a contact target, and conducts while being in contact with the first conductive layer 11 (contact target). The inner electrode 30 corresponds to an example of a spring electrode. The inner electrode 30 is wound around the central axis X extending in the thickness direction (vertical direction), and the outer diameter increases toward the other side (lower side) in the thickness direction. The coil spring 32 is configured as a conical spring and functions as a compression spring. The inner electrode 30 is held in a state of being pressed against the first conductive layer 11 (contact target) from one side (upper side) in the thickness direction. In the inner electrode 30, a coil spring 32 forming a part of the inner electrode 30 is arranged in a compressed state between the first conductive layer 11 (contact target) and the support portion 50, and the first conductive layer 11 (contact target) has the above thickness. It is held in a pressed state on the other side (lower side) in the longitudinal direction. The lower end of the coil spring 32 is formed in a circular shape. The lower end of the inner electrode 30 (specifically, the lower end of the coil spring 32) comes into contact with the upper surface 11A of the first conductive layer 11, and the lower end of the inner electrode 30 is the first conductive layer based on its own elastic force. The 11 is continuously pushed downward, and the state of being electrically connected to the first conductive layer 11 is maintained. The inner electrode 30 has its own upper end (specifically, the upper end of the coil spring 32) in contact with the protruding end surface 58 of the protruding portion 56, and its own upper end is based on its own elastic force. Continue to push upwards. A terminal 38 is integrally connected to the upper end of the coil spring 32. The terminal 38 extends linearly upward from the upper end of the coil spring 32, and is fixed to the substrate 110 while being supported by the support portion 50. The terminal 38 is electrically connected to a wiring portion formed on the substrate 110.

In the ultrasonic transducer T shown in FIG. 6, the outer diameter of the coil spring 32 of the inner electrode 30 gradually increases toward the other side (lower side) in the thickness direction, so that the size of the support portion 50 side of the spring electrode 30 Can be relatively reduced. Further, in the ultrasonic transducer T of FIG. 6, the lower end portion of the coil spring 32 having a larger diameter can be brought into contact with the first conductive layer 11 so as to be pressed against the first conductive layer 11, so that the contact state is maintained more stably. Moreover, a larger contact area can be secured.

<Other Embodiments>
The present disclosure is not limited to the embodiments described by the above description and drawings. For example, the features of the embodiments described above or below can be combined in any combination within a consistent range. Further, any of the features of the above-mentioned or later-described embodiments may be omitted unless it is clearly stated as essential. Further, the above-described embodiment may be modified as follows.

The ultrasonic transducer T may be configured as shown in FIG. The configuration of FIG. 7 is different from that of the first embodiment in that the first conductor portion 190 is interposed between the inner electrode 30 and the first conductive layer 11, and is the same as that of the first embodiment in other points. The first conductor portion 190 is a conductor portion electrically connected to the first conductive layer 11. In the ultrasonic transducer T of FIG. 7, the inner electrode 30 has a first conductor portion 190 electrically connected to the first conductive layer 11 as a contact target, and a coil spring 32 forming a part thereof is the first conductor portion. It is arranged in a compressed state between 190 (contact target) and the support portion 50. Then, the inner electrode 30 is held in a state where the first conductor portion 190 (contact target) is pushed to the other side (lower side) in the thickness direction. Although the first conductor portion 190 configured in a plate shape is illustrated here, the shape of the first conductor portion is not particularly limited. Further, the position of the first conductor portion is not limited to the position shown in FIG. 7 as long as it is electrically connected to the first conductive layer 11 and is pressed by the inner electrode 30.

In the above embodiment, the second conductive layer 12 and the conductor portion 88 are electrically connected by the conductive sheet 102, but the present invention is not limited to this configuration. For example, instead of the conductive sheet 102, a conductive film is formed on the upper surface of the acoustic transmission layer 20 by sputtering or plating, and the conductive film causes the second conductive layer 12 of the piezoelectric element 10 and the external conductor to be electrically connected. It may be connected to.

In the above embodiment, the bottom wall 91 of the case 90 is an acoustic lens. Not limited to this, the bottom wall of the case does not have to be an acoustic lens.

In the above embodiment, both the inner electrode 30 and the outer electrode 40 are provided, but one of them may not be provided. For example, when the inner electrode 30 is not provided, the first conductive layer 11 and the substrate 110 may be electrically connected by some structure (for example, an electric wire portion, a conductor portion, etc.). When the outer electrode 40 is not provided, the second conductive layer 12 and the substrate 110 may be electrically connected by some structure (for example, an electric wire portion, a conductor portion, etc.).

In the above embodiment, both the sound transmission layer 20 and the case 90 correspond to an example of the sound transmission unit, but at least one of the sound transmission layer and the case may correspond to the sound transmission unit. For example, in a configuration in which the case does not function as an acoustic transmission unit or a case does not exist, an acoustic transmission layer similar to the above embodiment may function as an acoustic transmission unit. Alternatively, a case similar to the above embodiment may function as the sound transmission unit in a configuration in which the sound transmission layer does not exist.

It should be noted that the embodiments disclosed this time are examples in all respects and are not restrictive. The scope of the present invention is not limited to the embodiments disclosed here, but includes all modifications within the scope indicated by the claims or within the scope equivalent to the claims. Is intended.

T ... Ultrasonic transducer 10 ... Piezoelectric element 11 ... First conductive layer (contact target)
12 ... Second conductive layer 14 ... Piezoelectric material 20 ... Acoustic transmission layer (acoustic transmission unit)
30 ... Inner electrode (spring electrode)
32 ... Coil spring 40 ... Outer electrode (spring electrode)
42 ... Coil spring 48 ... Terminal 50 ... Support part 52 ... Covering part 52A ... Second tapered surface 56 ... Protruding part 58 ... Protruding side end surface 60 ... Ring wall part 70 ... Ring member (contact target)
76 ... Umbrella-shaped part (annular conductor part)
76A ... Tapered surface 76B ... Opening 90 ... Case (acoustic transmission)
190 ... First conductor (contact target)
X ... Central axis

Claims (11)

A piezoelectric body, a first conductive layer arranged on the first surface on one side in the thickness direction of the piezoelectric body, and a second conductive layer arranged on the second surface on the other side in the thickness direction of the piezoelectric body. , And a piezoelectric element that generates ultrasonic waves in response to a voltage applied between the first conductive layer and the second conductive layer.
An acoustic transmission unit that transmits ultrasonic waves generated by the piezoelectric element,
Have,
An ultrasonic transducer in which the surface of the piezoelectric element on the side of the second conductive layer is fixed to the acoustic transmission portion.
A spring electrode that conducts contact with the first conductive layer, or a conductor portion electrically connected to any of the first conductive layer and the second conductive layer, and conducts contact with the contact target.
A support portion that is arranged to face the contact object and sandwiches the spring electrode between the contact object and the support portion.
Have,
The spring electrode has a coil spring that is wound around a central axis extending in the thickness direction and whose outer diameter decreases toward one side in the thickness direction or the other side in the thickness direction.
An ultrasonic transducer in which the spring electrode is held in a state of being pressed against the contact object from one side in the thickness direction. The inner electrode is included as the spring electrode, and the inner electrode is included.
The inner electrode has the first conductive layer or the first conductor portion electrically connected to the first conductive layer as the contact target, and the coil spring forming a part of itself is the contact target and the support portion. The ultrasonic transducer according to claim 1, wherein the ultrasonic transducer is arranged between the two in a compressed state and is held in a state where the contact object is pushed to the other side in the thickness direction. The ultrasonic transducer according to claim 2, wherein the coil spring of the inner electrode has an outer diameter that becomes smaller toward the other side in the thickness direction. The ultrasonic transducer according to claim 2, wherein the coil spring of the inner electrode has an outer diameter that increases toward the other side in the thickness direction. The outer electrode is included as the spring electrode, and the outer electrode is included.
The contact object includes an annular member that is conductive, is electrically connected to the second conductive layer, and is formed in an annular shape.
The ultrasonic transducer according to any one of claims 1 to 4, wherein the outer electrode is held in a state where the annular member is pushed to the other side in the thickness direction. The annular member is directly or indirectly fixed to the peripheral portion of the piezoelectric element in the acoustic transmission portion via another member.
In the annular member, an annular conductor portion is provided on one side of the first conductive layer in the thickness direction in a state of being insulated from the first conductive layer.
The ultrasonic transducer according to claim 5, wherein the outer electrode is held in a state of being pressed against the annular conductor portion from one side in the thickness direction. The spring electrode includes the inner electrode and the outer electrode, and includes the inner electrode and the outer electrode.
The outer electrode has an annular member that is conductive and is formed in an annular shape as a contact target.
The annular member is directly or indirectly fixed to the peripheral portion of the piezoelectric element in the acoustic transmission portion via another member.
In the annular member, an annular conductor portion is provided on one side of the first conductive layer in the thickness direction in a state of being insulated from the first conductive layer.
The outer electrode is held in a state of being pressed against the annular conductor portion from one side in the thickness direction.
The annular conductor portion is provided with an opening at one end on one side in the thickness direction of the annular conductor portion.
The support portion has a protrusion portion that protrudes to the other side in the thickness direction and is inserted into the opening portion.
2. The ultrasonic transducer described. An annular wall portion projecting to the other side in the thickness direction is formed on the end surface on the protruding side.
The ultrasonic transducer according to claim 7, wherein the annular wall portion is arranged so as to surround an end portion of the coil spring on one side in the thickness direction. The outer peripheral surface of the annular conductor portion has a tapered surface whose diameter decreases toward one side in the thickness direction.
The coil spring of the outer electrode is arranged along the tapered surface on the outside of the annular conductor portion, has a configuration in which the inner diameter decreases toward one side in the thickness direction, and is pressed against the tapered surface. The ultrasonic transducer according to any one of claims 6 to 8, which is held by. The support portion has a covering portion that is arranged to face the tapered surface and covers the coil spring of the outer electrode from the side opposite to the tapered surface.
The super-transducer according to claim 9, wherein the facing surface facing the tapered surface in the covering portion has a second tapered surface which is arranged along the coil spring and whose diameter decreases toward one side in the thickness direction. Ultrasonic transducer. The ultrasonic transducer according to claim 9 or 10, wherein the outer electrode has a terminal extending from one end of the coil spring on one side in the thickness direction toward the support portion and being held by the support portion.

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