Ultrasonic transducer

Abstract

To provide a technique capable of suppressing noise caused by vibration of a coil spring in an ultrasonic transducer.SOLUTION: An ultrasonic transducer 1 includes a first wiring part 40 having a first contact part 41 in contact with a first surface 21 of a diaphragm 10, and a second wiring part 50 having a second contact part 51 in contact with a second surface 22 of a piezoelectric element 11 on an opposite side to the diaphragm 10. A portion, of the first wiring part 40, arranged in a first through hole 15 comprises a first compression coil spring 43 including the first contact part 41, and a first inelastic member 44 in contact with a first conductive path 22. A portion, of the second wiring part 50, arranged in a second through hole 16 comprises a second compression coil spring 53 including the second contact part 51, and a second inelastic member 54 in contact with a second conductive path 23.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to ultrasound transducers. [Background technology]

[0002] Patent Document 1 discloses an ultrasonic transducer. This ultrasonic transducer includes a diaphragm, a piezoelectric element bonded to the diaphragm, a first wiring portion, a second wiring portion, and a base portion. The first wiring portion has a first contact portion that is in contact with or bonded to a first surface of the diaphragm. The second wiring portion has a second contact portion that is in contact with or bonded to a second surface of the piezoelectric element opposite the diaphragm side. A first base through hole and a second base through hole are formed in the base portion. The first wiring portion has a first coil spring that is inserted into the first base through hole. The second wiring portion has a second coil spring that is inserted into the second base through hole. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-28693 Summary of the Invention [Problem to be solved by the invention]

[0004] In the configuration of Patent Document 1, when the diaphragm vibrates with the first coil spring in contact with the inner circumferential surface of the first base through-hole, the vibration is transmitted to the first coil spring, which may rub against the inner circumferential surface of the first base through-hole, generating noise. Similar problems are of concern for the second coil spring.

[0005] The present disclosure aims to provide a technique capable of suppressing noise caused by vibration of a coil spring in an ultrasonic transducer. [Means for solving the problem]

[0006] The ultrasonic transducer of the present disclosure comprises: a conductive diaphragm that vibrates to generate annular nodes; a piezoelectric element bonded to a part of a first surface on one side of the vibration plate in a thickness direction; a first wiring portion having a first contact portion that contacts the first surface of the diaphragm; a second wiring portion having a second contact portion that contacts a second surface of the piezoelectric element opposite to the vibration plate side; a circuit board having a first conductive path that contacts the first wiring portion on the side opposite to the first contact portion, and a second conductive path that contacts the second wiring portion on the side opposite to the second contact portion; a base portion having a first through hole penetrating in the thickness direction and a second through hole penetrating in the thickness direction, the base portion being disposed between the piezoelectric element and the circuit board; Equipped with At least a portion of the first wiring portion is disposed within the first through hole, At least a portion of the second wiring portion is disposed in the second through hole, the first contact portion contacts the first surface of the diaphragm at a position overlapping the node when viewed from the thickness direction; the second contact portion is an ultrasonic transducer that contacts the second surface of the piezoelectric element at a position that overlaps the node when viewed from the thickness direction, a portion of the first wiring portion disposed within the first through hole includes a first compression coil spring including the first contact portion and a first non-elastic member in contact with the first conductive path; The portion of the second wiring portion disposed within the second through hole is made up of a second compression coil spring including the second contact portion, and a second non-elastic member in contact with the second conductive path. [Effects of the Invention]

[0007] According to the present disclosure, noise caused by vibration of a coil spring in an ultrasonic transducer can be suppressed. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a cross-sectional view of an ultrasonic transducer according to a first embodiment. [Figure 2] FIG. 2 is a plan view of the base portion, the first wiring portion, and the second wiring portion. [Figure 3] FIG. 3 is a cross-sectional view taken along line AA in FIG. [Figure 4] FIG. 4 is a cross-sectional view of the ultrasonic transducer of the second embodiment. [Figure 5] FIG. 5 is a cross-sectional view taken along line BB in FIG. [Figure 6] FIG. 6 is a cross-sectional view of the ultrasonic transducer of the third embodiment. [Figure 7] FIG. 7 is a cross-sectional view of an ultrasonic transducer according to the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] [Description of the embodiments of the present disclosure] In the following, embodiments of the present disclosure are listed and illustrated.

[0010] [1] A conductive diaphragm that vibrates to generate an annular node; a piezoelectric element bonded to a part of a first surface on one side of the vibration plate in a thickness direction; a first wiring portion having a first contact portion that contacts the first surface of the diaphragm; a second wiring portion having a second contact portion that contacts a second surface of the piezoelectric element opposite to the vibration plate side; a circuit board having a first conductive path that contacts the first wiring portion on the side opposite to the first contact portion, and a second conductive path that contacts the second wiring portion on the side opposite to the second contact portion; a base portion having a first through hole penetrating in the thickness direction and a second through hole penetrating in the thickness direction, the base portion being disposed between the piezoelectric element and the circuit board; Equipped with At least a portion of the first wiring portion is disposed within the first through hole, At least a portion of the second wiring portion is disposed in the second through hole, the first contact portion contacts the first surface of the diaphragm at a position overlapping the node when viewed from the thickness direction; the second contact portion is an ultrasonic transducer that contacts the second surface of the piezoelectric element at a position that overlaps the node when viewed from the thickness direction, a portion of the first wiring portion disposed within the first through hole includes a first compression coil spring including the first contact portion and a first non-elastic member in contact with the first conductive path; The portion of the second wiring portion disposed in the second through hole includes a second compression coil spring including the second contact portion and a second non-elastic member in contact with the second conductive path. Ultrasonic transducer.

[0011] In the ultrasonic transducer, the portion of the first wiring portion disposed within the first through hole comprises a first compression coil spring including a first contact portion and a first inelastic member in contact with the first conductive path. In other words, the first compression coil spring is disposed only partially within the first through hole in the through-hole direction. Therefore, even if the first compression coil spring contacts the inner circumferential surface of the first through hole, the contact area is limited to only a portion of the first through hole in the through-hole direction. Therefore, the ultrasonic transducer can suppress noise caused by vibration of the first compression coil spring. Similarly, the ultrasonic transducer can suppress noise caused by vibration of the second compression coil spring. Furthermore, with this configuration, the length of the first compression coil spring is shorter than when the entire first wiring portion is made of a compression coil spring. This reduces the likelihood of the first compression coil spring collapsing or buckling. As a result, the first compression coil spring is less likely to come into contact with the inner circumferential surface of the first through hole due to the first compression coil spring collapsing or buckling. Similarly, the second compression coil spring is less likely to come into contact with the inner circumferential surface of the second through hole due to the second compression coil spring collapsing or buckling.

[0012] [2] At least at any position in the thickness direction, a diameter of a circumscribing circle circumscribing an outer peripheral edge of the first compression coil spring is 0.85 times or more the diameter of an inscribing circle inscribing an inner peripheral surface of the first through hole, At least at any position in the thickness direction, the diameter of a circumscribing circle circumscribing the outer periphery of the second compression coil spring is 0.85 times or more the diameter of an inscribing circle inscribing the inner periphery of the second through hole. The ultrasonic transducer described in [1].

[0013] This configuration reduces the distance between the first compression coil spring and the inner circumferential surface of the first through hole, making it easier to accurately position the first compression coil spring in the first through hole, and similarly, it makes it easier to accurately position the second compression coil spring in the second through hole.

[0014] [3] When viewed from the thickness direction, the first non-elastic member is disposed inside an inner circumferential surface of the first through hole, the first compression coil spring is disposed inside the outer circumferential edge of the first non-elastic member, the second non-elastic member is disposed inside an inner circumferential surface of the second through hole, The second compression coil spring is disposed inside the outer circumferential edge of the second inelastic member. The ultrasonic transducer according to [1] or [2].

[0015] With this configuration, even if the position of the first compression coil spring is slightly misaligned, it is less likely to come into contact with the inner surface of the first through hole, and even if the position of the second compression coil spring is slightly misaligned, it is less likely to come into contact with the inner surface of the second through hole.

[0016] [4] In the thickness direction, The length of the first non-elastic member is equal to or longer than the length of the first compression coil spring, The length of the second inelastic member is equal to or longer than the length of the second compression coil spring. An ultrasonic transducer according to any one of [1] to [3].

[0017] According to this configuration, the length of the first compression coil spring is less than half the length of the first wiring portion. This makes it even less likely that the first compression coil spring will collapse or buckle. As a result, it is even less likely that the first compression coil spring will collapse or buckle, causing the first compression coil spring to come into contact with the inner circumferential surface of the first through hole. Similarly, it is even less likely that the second compression coil spring will collapse or buckle, causing the second compression coil spring to come into contact with the inner circumferential surface of the second through hole.

[0018] [Details of the embodiments of the present disclosure] The ultrasonic transducer of the present disclosure is used in, for example, an ultrasonic distance sensor, an ultrasonic oscillation device, a parametric speaker, and the like.

[0019] 1. First embodiment The ultrasonic transducer 1 of the first embodiment shown in FIG. 1 generates ultrasonic waves when a drive signal is given, and converts the ultrasonic waves into electrical signals when the ultrasonic waves are received.

[0020] The ultrasonic transducer 1 includes a diaphragm 10, a piezoelectric element 11, a resonator 12, an interposing member 13, a base portion 14, a circuit board 30, a first wiring portion 40, a second wiring portion 50, and a case 60.

[0021] The diaphragm 10 is plate-shaped (more specifically, disk-shaped). The diaphragm 10 is electrically conductive. The diaphragm 10 is made of metal, such as 42 alloy (42Ni-Fe). The width (maximum width) of the diaphragm 10 is greater than the widths (maximum widths) of the resonator 12, the intervening member 13, and the piezoelectric element 11. The width (maximum width) of the diaphragm 10 refers to the length (maximum length) in a direction perpendicular to the thickness direction of the diaphragm 10. In this embodiment, the width (maximum width) of the diaphragm 10 is the diameter of the outer periphery of the diaphragm 10.

[0022] The diaphragm 10 has a piezoelectric element 11 bonded to a first surface 21 on one side in the thickness direction, and a resonator 12 bonded to the other surface. In this specification, the term "bonding" is used to refer not only to a direct bonding configuration, but also to a bonding configuration via another member.

[0023] The resonator 12 resonates with the vibration of the diaphragm 10 to generate ultrasonic waves. The resonator 12 has the function of increasing the efficiency of sound wave transmission from the diaphragm 10, which is excited in response to the periodic supply of power to the piezoelectric element 11. The resonator 12 is made of metal, such as an aluminum alloy. The resonator 12 is bonded to the diaphragm 10. The bonding method is not limited, and may be, for example, bonding with an adhesive such as an epoxy adhesive, or soldering. The resonator 12 is cone-shaped. The inner peripheral surface of the resonator 12 is tapered, widening as it approaches the opposite side from the diaphragm 10.

[0024] The piezoelectric element 11 has a plate shape. The piezoelectric element 11 is bonded to the diaphragm 10 so as to be stacked. The piezoelectric element 11 is bonded to a part of the first surface 21 of the diaphragm 10. In other words, the first surface 21 of the diaphragm 10 includes a part to which the piezoelectric element 11 is bonded and a part to which it is not bonded. The piezoelectric element 11 is bonded to the diaphragm 10 with a heat-curing epoxy adhesive or the like.

[0025] The piezoelectric element 11 has a plate-shaped piezoelectric body 11A and electrodes 11B and 11C provided on both sides of the piezoelectric body 11A in the thickness direction. The piezoelectric body 11A is made of a ceramic, such as lead zirconate titanate (PZT) or potassium sodium niobate (KNN). Of the electrodes 11B and 11C provided on both sides of the piezoelectric element 11, one electrode 11B is bonded to the diaphragm 10 and electrically connected to the first wiring portion 40 via the diaphragm 10. Of the electrodes 11B and 11C provided on both sides of the piezoelectric element 11, the other electrode 11C is electrically connected to the second wiring portion 50. A base portion 14 is bonded to a second surface 22 of the piezoelectric element 11 opposite the diaphragm 10 side via an intervening member 13.

[0026] Intervening member 13 is disposed between piezoelectric element 11 and base portion 14, and is bonded to both piezoelectric element 11 and base portion 14. Intervening member 13 is insulating and elastic. Intervening member 13 has a lower Young's modulus than base portion 14. Intervening member 13 is made of, for example, rubber such as silicone rubber, or resin such as a silicon-based adhesive. Intervening member 13 is annular (more specifically, circular). The axial direction of intervening member 13 is aligned with the thickness direction of diaphragm 10, more specifically, the same as the thickness direction of diaphragm 10.

[0027] Base portion 14 has insulating properties. Base portion 14 is made of synthetic resin and configured as a resin stand. Base portion 14 has first through-hole 15 penetrating diaphragm 10 in the thickness direction and second through-hole 16 penetrating diaphragm 10 in the thickness direction.

[0028] In this embodiment, the cross-sectional shape of the inner circumferential surface of the first through hole 15 and the second through hole 16 is circular, but it does not have to be circular. For example, the cross-sectional shape may be polygonal or elliptical, or may be a shape in which a portion of the inner circumferential surface in the circumferential direction protrudes inward, or a shape in which a portion of the inner circumferential surface in the circumferential direction is recessed outward. Furthermore, in this embodiment, the cross-sectional shape is constant in the penetration direction of the first through hole 15 and the second through hole 16, but it does not have to be constant. Note that the cross-sectional shape here refers to the cross-sectional shape when cut in a direction perpendicular to the penetration direction of the first through hole 15 and the second through hole 16.

[0029] The circuit board 30 is provided on the opposite side of the base portion 14 to the piezoelectric element 11 side. In other words, the base portion 14 is disposed between the piezoelectric element 11 and the circuit board 30. The circuit board 30 has a board main body 31, a first conductive path 32, and a second conductive path 33.

[0030] The substrate body 31 is insulating. The substrate body 31 is plate-shaped. The first conductive path 32 and the second conductive path 33 are formed by wiring patterns provided on the substrate body 31. At least a portion of the first conductive path 32 is exposed to the vibration plate 10 side. At least a portion of the first conductive path 32 faces the first surface 21 of the vibration plate 10 via the first through hole 15. At least a portion of the second conductive path 33 is exposed to the piezoelectric element 11 side. At least a portion of the second conductive path 33 faces the second surface 22 of the piezoelectric element 11 via the second through hole 16. A drive voltage for driving the ultrasonic transducer 1 is applied between the first conductive path 32 and the second conductive path 33.

[0031] The first wiring portion 40 is conductive. The first wiring portion 40 is made of, for example, metal. At least a portion of the first wiring portion 40 is disposed within the first through-hole 15. The first wiring portion 40 is provided between the diaphragm 10 and the first conductive path 32. The first wiring portion 40 has a first contact portion 41 that contacts the first surface 21 of the diaphragm 10 and a third contact portion 42 that contacts the first conductive path 32. The first contact portion 41 may or may not be fixed to the first surface 21. The third contact portion 42 may or may not be fixed to the first conductive path 32. The first wiring portion 40 electrically connects the first conductive path 32 to the diaphragm 10.

[0032] The first wiring portion 40 includes a first compression coil spring 43 and a first inelastic member 44. The first compression coil spring 43 includes a first contact portion 41 and contacts the first surface 21 of the diaphragm 10. The first compression coil spring 43 is arranged so that its direction of expansion and contraction is along the thickness direction of the diaphragm 10. The diameter of a circumscribed circle circumscribing the outer edge of the first compression coil spring 43 is constant. The first compression coil spring 43 is fixed to the first inelastic member 44. The first inelastic member 44 is arranged between the first compression coil spring 43 and the first conductive path 32. The first inelastic member 44 includes a third contact portion 42 and contacts the first conductive path 32.

[0033] With this configuration, the length of the first compression coil spring 43 is shorter than when the entire first wiring portion 40 is made of a compression coil spring. This makes it less likely for the first compression coil spring 43 to collapse or buckle. As a result, it is less likely for the first compression coil spring 43 to come into contact with the inner circumferential surface of the first through hole 15 due to the first compression coil spring 43 collapsing or buckling.

[0034] The portion of the first wiring part 40 that is disposed within the first through hole 15 is made up of a first compression coil spring 43 and a first inelastic member 44. That is, the first compression coil spring 43 is disposed only partially in the through-hole 15 in the through-hole direction. Therefore, even if the first compression coil spring 43 contacts the inner circumferential surface of the first through hole 15, the contact area is limited to only a portion of the first through hole 15 in the through-hole direction. Therefore, the ultrasonic transducer 1 can suppress noise caused by vibration of the first compression coil spring 43.

[0035] The length of the first non-elastic member 44 is longer than the length of the first compression coil spring 43 in the thickness direction of the diaphragm 10. With this configuration, the length of the first compression coil spring 43 is less than half the length of the first wiring portion 40. This makes it even more unlikely that the first compression coil spring 43 will collapse or buckle. As a result, it is even more unlikely that the first compression coil spring 43 will collapse or buckle, causing the first compression coil spring 43 to come into contact with the inner circumferential surface of the first through hole 15.

[0036] The second wiring portion 50 is conductive. The second wiring portion 50 is made of, for example, metal. At least a portion of the second wiring portion 50 is disposed within the second through-hole 16. The second wiring portion 50 is provided between the piezoelectric element 11 and the second conductive path 33. The second wiring portion 50 has a second contact portion 51 that contacts the second surface 22 of the piezoelectric element 11 and a fourth contact portion 52 that contacts the second conductive path 33. The second contact portion 51 may or may not be fixed to the second surface 22. The fourth contact portion 52 may or may not be fixed to the second conductive path 33. The second wiring portion 50 electrically connects the second conductive path 33 to the piezoelectric element 11.

[0037] The second wiring portion 50 includes a second compression coil spring 53 and a second inelastic member 54. The second compression coil spring 53 includes a second contact portion 51 and contacts the second surface 22 of the piezoelectric element 11. The second compression coil spring 53 is arranged so that its direction of expansion and contraction is along the thickness direction of the diaphragm 10. The diameter of a circumscribed circle circumscribing the outer periphery of the second compression coil spring 53 is constant. The second compression coil spring 53 is fixed to the second inelastic member 54. The second inelastic member 54 is arranged between the second compression coil spring 53 and the second conductive path 33. The second inelastic member 54 includes a fourth contact portion 52 and contacts the second conductive path 33.

[0038] With this configuration, the length of the second compression coil spring 53 is shorter than when the entire second wiring portion 50 is made of a compression coil spring. This makes it less likely for the second compression coil spring 53 to collapse or buckle. As a result, it is less likely for the second compression coil spring 53 to come into contact with the inner circumferential surface of the second through hole 16 due to the second compression coil spring 53 collapsing or buckling.

[0039] The portion of the second wiring part 50 that is disposed within the second through hole 16 is made up of a second compression coil spring 53 and a second inelastic member 54. That is, the second compression coil spring 53 is disposed only partially in the through-hole 16 in the through-hole direction. Therefore, even if the second compression coil spring 53 contacts the inner circumferential surface of the second through hole 16, the contact area is limited to only a portion of the second through hole 16 in the through-hole direction. Therefore, the ultrasonic transducer 1 can suppress noise caused by vibration of the second compression coil spring 53.

[0040] The length of the second inelastic member 54 is longer than the length of the second compression coil spring 53 in the thickness direction of the diaphragm 10. This configuration makes it even less likely that the second compression coil spring 53 will come into contact with the inner circumferential surface of the second through hole 16 due to collapse or buckling of the second compression coil spring 53.

[0041] The first inelastic member 44 and the second inelastic member 54 have a spring constant greater than 5 N / mm. The spring constant is measured, for example, using a spring testing machine. A displacement x [mm] is measured when a compression force F [N] is applied. The spring constant k is calculated by k = F / x. The first inelastic member 44 and the second inelastic member 54 may be, for example, a contact spring or a metal block. If the first inelastic member 44 is a contact spring, the contact spring may be seamlessly connected to the first compression coil spring 43. If the second inelastic member 54 is a contact spring, the contact spring may be seamlessly connected to the second compression coil spring 53.

[0042] The case 60 is a member that protects the resonator 12 to prevent foreign matter from coming into contact with the resonator 12. The case 60 is fixed to the base 14. The case 60 has a peripheral wall 60A that surrounds the periphery of the resonator 12. A plurality of openings are formed in the case 60 on the side opposite the base 14 side of the resonator 12, and ultrasonic waves are sent to the outside through these openings and enter the case 60 from the outside.

[0043] 2, when viewed in the thickness direction of the diaphragm 10, the first inelastic member 44 is arranged inside the inner circumferential surface of the first through hole 15. The first compression coil spring 43 is arranged inside the outer circumferential edge of the first inelastic member 44. The second inelastic member 54 is arranged inside the inner circumferential surface of the second through hole 16. The second compression coil spring 53 is arranged inside the outer circumferential edge of the second inelastic member 54.

[0044] With this configuration, even if the position of the first compression coil spring 43 is slightly misaligned, it is less likely to come into contact with the inner surface of the first through hole 15, and even if the position of the second compression coil spring 53 is slightly misaligned, it is less likely to come into contact with the inner surface of the second through hole 16.

[0045] As shown in FIG. 3, the diaphragm 10 vibrates to generate an annular (more specifically, circular) node 20. The diaphragm 10 generates only one annular node 20. The node 20 is the portion of the diaphragm 10 where the amount of displacement in the thickness direction is smallest or where no vibration occurs when the diaphragm 10 vibrates. The node 20 is uniquely determined by the shapes and materials of the diaphragm 10, the piezoelectric element 11, and the resonator 12. The piezoelectric element 11 is significantly smaller than the diaphragm 10 and the resonator 12. Therefore, the position of the node 20 is largely determined by the shapes and materials of the diaphragm 10 and the resonator 12, and the shape and material of the piezoelectric element 11 have little effect on determining the position of the node 20. The outer periphery of the diaphragm 10 is a free end. In other words, the ultrasonic transducer 1 is a so-called open type, which is more likely to vibrate than a closed type in which the outer periphery of the diaphragm 10 is fixed. The node 20 is generated inside the outer periphery and outside the center of the diaphragm 10 in a planar direction perpendicular to the thickness direction. The vibration of the diaphragm 10 increases from the node 20 toward the outer periphery and increases from the node 20 toward the center.

[0046] Piezoelectric element 11 has notch 11D cut inward from the outer periphery. When viewed in the thickness direction of diaphragm 10, piezoelectric element 11 has a rectangular shape with notch 11D provided on one side.

[0047] When viewed from the thickness direction, the piezoelectric element 11 is disposed in a position overlapping a portion of the node 20. In other words, when viewed from the thickness direction, the node 20 includes a portion that overlaps with the piezoelectric element 11 and a portion that does not overlap. When viewed from the thickness direction, the piezoelectric element 11 is disposed so as to straddle a portion of the node 20 from the inside to the outside. The cutout portion 11D of the piezoelectric element 11 is cut out so as to straddle a portion of the node 20 from the outside to the inside. In other words, when the diaphragm 10 is viewed from the base portion 14 side, a portion of the node 20 is covered by the piezoelectric element 11, and the other portion of the node 20 is not covered by the piezoelectric element 11.

[0048] Furthermore, an intervening member 13 is bonded to a second surface 22 of the piezoelectric element 11. The intervening member 13 is arranged so that a vibration node 20 of the vibration plate 10 is located between an inscribed circle 13A that inscribes the intervening member 13 and a circumscribed circle 13B that circumscribes the intervening member 13 in a planar direction perpendicular to the thickness direction of the vibration plate 10. The intervening member 13 has a shape that is partially interrupted in the circumferential direction. The intervening member 13 is interrupted in two places. The intervening member 13 is arranged so that, when the vibration plate 10 is viewed from the base portion 14 side, the interrupted portions of the intervening member 13 expose a portion of the node 20 that is not covered by the piezoelectric element 11 and a portion of the piezoelectric element 11 that covers a portion of the node 20.

[0049] The first contact portion 41 is arranged in contact with a portion of the node 20 that is not covered by the piezoelectric element 11. As a result, the first contact portion 41 contacts the first surface 21 of the diaphragm 10 at a position that overlaps the node 20 when viewed from the thickness direction. In addition, a portion of the first contact portion 41 is arranged inside the cutout portion 11D. The second contact portion 51 is arranged in contact with a portion of the piezoelectric element 11 that covers part of the node 20. As a result, the second contact portion 51 contacts the second surface 22 of the diaphragm 10 at a position that overlaps the node 20 when viewed from the thickness direction.

[0050] Furthermore, in a planar direction perpendicular to the thickness direction, the piezoelectric element 11 is disposed in a part of region Z between an inscribed circle 13A inscribed in the interposed member 13 and a circumscribed circle 13B circumscribed therein. That is, region Z includes a first region Z1 in which the piezoelectric element 11 is not disposed and a second region Z2 in which the piezoelectric element 11 is disposed. The first region Z1 is disposed inside the cutout portion 11D of the piezoelectric element 11. The first contact portion 41 contacts the first surface 21 of the diaphragm 10 in the first region Z1. The second contact portion 51 contacts the second surface 22 of the diaphragm 10 in the second region Z2.

[0051] In this way, in ultrasonic transducer 1, first contact portion 41 contacts first surface 21 of diaphragm 10, and second contact portion 51 contacts second surface 22 of piezoelectric element 11, at positions overlapping with nodes 20 when viewed from the thickness direction. This makes it difficult for vibrations of diaphragm 10 to be transmitted to first contact portion 41 and second contact portion 51. Furthermore, when first wiring portion 40 is joined to the surface of diaphragm 10 opposite first surface 21 using lead wires, there are concerns about the labor required for routing the lead wires, reduced connection reliability due to longer lead wires, and changes in vibration frequency due to the lead wires contacting the outer periphery of diaphragm 10, but these problems do not arise.

[0052] Furthermore, vibration of the diaphragm 10 is suppressed in the annular region to which the intervening member 13 is bonded. In the ultrasonic transducer 1 of the first embodiment, in the region where this vibration is suppressed, that is, in region Z between the inscribed circle 13A inscribed in the intervening member 13 and the circumscribed circle 13B circumscribed therearound, the first contact portion 41 contacts the first surface 21 of the diaphragm 10, and the second contact portion 51 contacts the second surface 22 of the piezoelectric element 11. This makes it difficult for vibration of the diaphragm 10 to be transmitted to the first contact portion 41 and the second contact portion 51. Furthermore, when the first wiring portion 40 is bonded to the surface of the diaphragm 10 opposite to the first surface 21 using a lead wire, there are concerns about the labor required for routing the lead wire, a decrease in connection reliability due to the lead wire being longer, and a change in vibration frequency due to the lead wire contacting the outer peripheral edge of the diaphragm 10, but these problems do not arise.

[0053] 2. Second embodiment 4, the ultrasonic transducer 201 of the second embodiment has a first compression coil spring 243 instead of the first compression coil spring 43 described in the first embodiment. Also, the ultrasonic transducer 201 has a second compression coil spring 253 instead of the second compression coil spring 53 described in the first embodiment. In other respects, the ultrasonic transducer 201 is common to the ultrasonic transducer 1 described in the first embodiment.

[0054] The ultrasonic transducer 201 includes a first wiring portion 240 and a second wiring portion 250. The first wiring portion 240 includes a first compression coil spring 243 and a first inelastic member 44. The second wiring portion 250 includes a second compression coil spring 253 and a second inelastic member 54.

[0055] 5, at any position in the thickness direction of the diaphragm 10, the diameter D1 of the circumscribing circle circumscribing the outer periphery of the first compression coil spring 243 is 0.85 times or more the diameter D2 of the inscribing circle inscribing the inner periphery of the first through hole 15. Furthermore, at any position in the thickness direction of the diaphragm 10, the diameter D3 of the circumscribing circle circumscribing the outer periphery of the second compression coil spring 253 is 0.85 times or more the diameter D4 of the inscribing circle inscribing the inner periphery of the second through hole 16.

[0056] According to the ultrasonic transducer 201 of the second embodiment, the distance between the first compression coil spring 243 and the inner circumferential surface of the first through hole 15 is narrow, and therefore the first compression coil spring 243 can be easily positioned accurately by the first through hole 15. Similarly, the second compression coil spring 253 can also be easily positioned accurately by the second through hole 16.

[0057] 3. Third embodiment 6, the ultrasonic transducer 301 of the third embodiment has a first compression coil spring 343 instead of the first compression coil spring 43 described in the first embodiment. Moreover, the ultrasonic transducer 301 has a second compression coil spring 353 instead of the second compression coil spring 53 described in the first embodiment. In other respects, the ultrasonic transducer 301 is common to the ultrasonic transducer 1 described in the first embodiment.

[0058] The ultrasonic transducer 301 includes a first wiring portion 340 and a second wiring portion 350. The first wiring portion 340 includes a first compression coil spring 343 and a first inelastic member 44. The second wiring portion 350 includes a second compression coil spring 353 and a second inelastic member 54.

[0059] The first compression coil spring 343 is a conical spring. The outer shape of the first compression coil spring 343 is formed so as to become smaller toward the other side in the thickness direction of the diaphragm 10. The first compression coil spring 343 is formed so that a circumscribed circle circumscribing the outer edge of the first compression coil spring 343 becomes smaller as it approaches the diaphragm 10. This configuration can reduce the contact area between the first contact portion 341 of the first compression coil spring 343 and the diaphragm 10 while suppressing collapse or buckling of the first compression coil spring 343. The smaller contact area makes it more difficult for vibrations of the diaphragm 10 to be transmitted to the first compression coil spring 343. The smaller contact area also makes it easier to avoid contact at positions away from the nodes 20, making it easier to prevent vibrations of the diaphragm 10 from being transmitted to the first compression coil spring 343.

[0060] The second compression coil spring 353 is a conical spring. The outer shape of the second compression coil spring 353 is formed so that it becomes smaller toward the other side in the thickness direction of the diaphragm 10. The second compression coil spring 353 is formed so that the circumscribed circle circumscribing the outer edge of the second compression coil spring 353 becomes smaller as it approaches the piezoelectric element 11. This configuration can reduce the contact area between the second contact portion 351 of the second compression coil spring 353 and the piezoelectric element 11 while suppressing collapse or buckling of the second compression coil spring 353. The reduced contact area reduces the transmission of vibrations from the diaphragm 10 to the second compression coil spring 353. The reduced contact area also makes it easier to avoid contact at positions away from the nodes 20, making it easier to prevent vibrations from the diaphragm 10 from being transmitted to the second compression coil spring 353.

[0061] 4. Fourth embodiment The ultrasonic transducer 401 of the fourth embodiment differs from the ultrasonic transducer 1 described in the first embodiment in the shapes of the first through hole and the second through hole. In other respects, the ultrasonic transducer 401 is common to the ultrasonic transducer 1 described in the first embodiment.

[0062] As shown in FIG. 7, the ultrasonic transducer 401 includes a base portion 414 having a first through-hole 415 and a second through-hole 416 .

[0063] The first through hole 415 is configured such that the inscribed circle inscribed in the inner peripheral surface of the first through hole 415 becomes larger toward the diaphragm 10. With this configuration, the distance between the outer peripheral edge of the first compression coil spring 43 and the inner peripheral surface of the first through hole 415 becomes wider, and the distance between the outer peripheral edge of the first non-elastic member 44 and the inner peripheral surface of the first through hole 415 becomes narrower. Therefore, the first wiring part 40 can be positioned by the first non-elastic member 44, while the first compression coil spring 43 is less likely to come into contact with the inner peripheral surface of the first through hole 415.

[0064] The second through hole 416 is configured such that the inscribed circle inscribed in the inner circumferential surface of the second through hole 416 becomes larger toward the piezoelectric element 11. With this configuration, the distance between the outer circumferential edge of the second compression coil spring 53 and the inner circumferential surface of the second through hole 416 becomes wider, and the distance between the outer circumferential edge of the second inelastic member 54 and the inner circumferential surface of the second through hole 416 becomes narrower. Therefore, the second wiring part 50 can be positioned by the second inelastic member 54, while the second compression coil spring 53 is less likely to come into contact with the inner circumferential surface of the second through hole 416.

[0065] <Other embodiments> The present invention is not limited to the embodiments described above and illustrated in the drawings, and the following embodiments are also included within the technical scope of the present invention. Furthermore, the various features of the above-mentioned embodiments and the embodiments to be described later may be combined in any manner as long as they are not contradictory.

[0066] In each of the above embodiments, the length of the first inelastic member is longer than the length of the first compression coil spring. However, the length of the first inelastic member may be the same as or shorter than the length of the first compression coil spring.

[0067] In each of the above embodiments, the length of the second inelastic member is longer than the length of the second compression coil spring. However, the length of the second inelastic member may be the same as or shorter than the length of the second compression coil spring.

[0068] It should be noted that the embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is not limited to the embodiments disclosed herein, but is intended to include all modifications within the scope indicated by the claims or the scope equivalent to the claims. [Explanation of symbols]

[0069] 1...Ultrasonic transducer 10…Diaphragm 11...Piezoelectric element 11A...Piezoelectric body 11B...Electrode 11C...Electrode 11D...Notch 12...Resonator 13…Intervening member 13A...Inscribed circle inscribed in the intervening member 13B...Circumscribed circle circumscribing the intervening member 14...Base 15...First through hole 16...Second through hole Section 20... 21...Side 1 22…Second side 30...Circuit board 31...Board body 32...First conductive path 33...Second conductive path 40...1st wiring section 41...First contact part 42...Third contact point 43...First compression coil spring 44...First inelastic member 50…Second wiring section 51...Second contact part 52...Fourth contact point 53...Second compression coil spring 54...Second inelastic member 60…cases 60A...peripheral wall part 201...Ultrasonic transducer 240...1st wiring section 243...First compression coil spring 250…Second wiring section 253...Second compression coil spring 301...Ultrasonic transducer 340...1st wiring section 341...First contact point 343...First compression coil spring 350…Second wiring section 351...Second contact part 353...Second compression coil spring 401...Ultrasonic transducer 414...Base 415...First through hole 416...Second through hole D1: Diameter of the circumscribed circle that circumscribes the outer edge of the first compression coil spring D2: Diameter of the inscribed circle inscribed on the inner circumferential surface of the first through hole D3: Diameter of the circumscribed circle that circumscribes the outer edge of the second compression coil spring D4: Diameter of the inscribed circle inscribed on the inner surface of the second through hole Z: The area between the inscribed circle inscribed in the intervening member and the circumscribed circle Z1…1st area Z2…Second area

Claims

1. a conductive diaphragm that vibrates to generate annular nodes; a piezoelectric element bonded to a part of a first surface on one side of the vibration plate in a thickness direction; a first wiring portion having a first contact portion that contacts the first surface of the vibration plate; a second wiring portion having a second contact portion that contacts a second surface of the piezoelectric element opposite to the vibration plate side; a circuit board having a first conductive path that contacts the first wiring portion on the side opposite to the first contact portion, and a second conductive path that contacts the second wiring portion on the side opposite to the second contact portion; a base portion having a first through hole penetrating in the thickness direction and a second through hole penetrating in the thickness direction, the base portion being disposed between the piezoelectric element and the circuit board; Equipped with At least a portion of the first wiring portion is disposed within the first through hole, At least a portion of the second wiring portion is disposed in the second through hole, the first contact portion contacts the first surface of the diaphragm at a position overlapping the node when viewed from the thickness direction; the second contact portion is an ultrasonic transducer that contacts the second surface of the piezoelectric element at a position that overlaps the node when viewed from the thickness direction, a portion of the first wiring portion disposed within the first through hole includes a first compression coil spring including the first contact portion and a first non-elastic member in contact with the first conductive path; The portion of the second wiring portion disposed in the second through hole includes a second compression coil spring including the second contact portion and a second non-elastic member in contact with the second conductive path. Ultrasonic transducer.

2. At least at any position in the thickness direction, a diameter of a circumscribing circle circumscribing an outer peripheral edge of the first compression coil spring is 0.85 times or more a diameter of an inscribing circle inscribing an inner peripheral surface of the first through hole, At least at any position in the thickness direction, the diameter of a circumscribing circle circumscribing the outer periphery of the second compression coil spring is 0.85 times or more the diameter of an inscribing circle inscribing the inner periphery of the second through hole.

2. The ultrasonic transducer of claim 1.

3. When viewed from the thickness direction, the first non-elastic member is disposed inside an inner circumferential surface of the first through hole, the first compression coil spring is disposed inside an outer circumferential edge of the first non-elastic member, the second non-elastic member is disposed inside an inner circumferential surface of the second through hole, The second compression coil spring is disposed inside the outer circumferential edge of the second inelastic member.

3. The ultrasonic transducer according to claim 1 or 2.

4. In the thickness direction, a length of the first non-elastic member is equal to or longer than a length of the first compression coil spring; The length of the second inelastic member is equal to or longer than the length of the second compression coil spring.

3. The ultrasonic transducer according to claim 1 or 2.

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