Ultrasonic transducer

Abstract

An ultrasonic transducer (1) includes a base portion (14), a piezoelectric element (11), a vibrating plate (10), and a resonator (12). The resonator (12) is bonded to a first surface (21) of the vibrating plate (10). A surface of the piezoelectric element (11) opposite to a surface bonded to the base portion (14) is bonded to a second surface (22) of the vibrating plate (10). A through hole (30) is formed in the piezoelectric element (11) so as to penetrate in a thickness direction of the vibrating plate (10). In a planar direction orthogonal to the thickness direction of the vibrating plate (10), a bonding portion (40) at which the vibrating plate (10) and the resonator (12) are bonded is disposed at a position inward of a node (20) of vibration of the vibrating plate (10), and the through hole (30) is disposed at a position inward of the node (20).

Description

Technical Field

[0001] This disclosure relates to an ultrasonic transducer. Background Technology

[0002] Patent Document 1 discloses an ultrasonic transducer. This ultrasonic transducer comprises a piezoelectric vibrator formed by bonding a piezoelectric element and a metal together using an adhesive, and a funnel-shaped resonator fixed to the piezoelectric vibrator. The piezoelectric vibrator is fixed to a base member via a buffer material.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2001-258098 Summary of the Invention

[0006] The problem the invention aims to solve

[0007] In this type of ultrasonic transducer, the resonator vibrates when the transducer is driven. Stress is easily applied to the piezoelectric element near the junction of the resonator and the metal (vibrating plate). Therefore, there is a potential risk that the piezoelectric element may crack or break due to repeated driving of the ultrasonic transducer.

[0008] The purpose of this disclosure is to provide a technique that can reduce the stress on a piezoelectric element caused by the vibration of a resonator.

[0009] Solution for solving the problem

[0010] The first ultrasonic transducer of the present invention includes: a base; a piezoelectric element joined to the base; a vibrating plate joined to the piezoelectric element, vibrating to generate annular nodes; and a resonator joined to the vibrating plate. The resonator is joined to a first surface on one side of the vibrating plate in the thickness direction. The side of the piezoelectric element opposite to the side joined to the base is joined to a second surface on the other side of the vibrating plate in the thickness direction. A through hole is formed in the piezoelectric element extending along the thickness direction. In a plane direction orthogonal to the thickness direction, the joint where the vibrating plate and the resonator are joined is located inside the nodes, and the through hole is also located inside the nodes.

[0011] In this ultrasonic transducer, the joint where the vibrating plate and the resonator meet is positioned inside the node of the vibrating plate. Therefore, stress is more easily applied to the piezoelectric element at this inner position. However, a through-hole for the piezoelectric element is provided in the region where stress from this joint is easily applied. Therefore, according to this ultrasonic transducer, the stress applied to the piezoelectric element due to the vibration of the resonator can be reduced.

[0012] The second ultrasonic transducer of the present invention includes: a base; a clamping member, which is annular and engages with the base; a piezoelectric element, which is engaged with the base via the clamping member; a vibrating plate, which is engaged with the piezoelectric element and vibrates to generate annular nodes; and a resonator, which is engaged with the vibrating plate. A first surface of the vibrating plate on one side in the thickness direction is engaged with the resonator. A second surface of the vibrating plate on the other side in the thickness direction is engaged with a surface of the piezoelectric element opposite to the side engaged with the base. A through hole is formed in the piezoelectric element extending along the thickness direction. In a plane direction orthogonal to the thickness direction, the engagement portion of the vibrating plate and the resonator is positioned inside the inscribed circle of the clamping member, and the through hole is positioned inside the inscribed circle.

[0013] In this ultrasonic transducer, the joint where the vibrating plate and the resonator meet is positioned further inside the inscribed circle of the clamping member. Therefore, the vibrating plate is more prone to vibration at this position, and stress is more easily applied to the piezoelectric element at this position. However, a through-hole for the piezoelectric element is positioned in the area where stress from this joint is easily applied. Therefore, according to this ultrasonic transducer, the stress applied to the piezoelectric element due to the vibration of the resonator can be reduced.

[0014] Alternatively, when viewed from the thickness direction, at least a portion of the joint may be positioned to overlap with the through hole.

[0015] According to this structure, since at least a portion of the joint is positioned to overlap with the through hole, the stress exerted on the piezoelectric element by the vibration of the resonator can be reduced more effectively.

[0016] Alternatively, when viewed from the thickness direction, the joint is positioned to overlap with the through hole.

[0017] According to this structure, since the joint is configured to overlap with the through hole, the stress on the piezoelectric element caused by the vibration of the resonator can be reduced more effectively.

[0018] Alternatively, the vibrating plate may have a hole, and when viewed from the thickness direction, at least a portion of the joint may be positioned to overlap with the hole.

[0019] This structure allows for easy vibration of the diaphragm and reduces the power consumption required to vibrate it.

[0020] The effects of the invention

[0021] According to the present invention, the stress exerted on the piezoelectric element due to the vibration of the resonator can be reduced. Attached Figure Description

[0022] Figure 1 This is a schematic cross-sectional view showing the ultrasonic transducer of the first embodiment.

[0023] Figure 2 This is a top view of the piezoelectric element according to the first embodiment.

[0024] Figure 3 This is a top view of the ultrasonic transducer according to the first embodiment.

[0025] Figure 4 This is a top view of the piezoelectric element according to the second embodiment.

[0026] Figure 5 This is a top view of the ultrasonic transducer according to the second embodiment.

[0027] Figure 6 This is a top view of the piezoelectric element according to the third embodiment.

[0028] Figure 7 This is a top view of the ultrasonic transducer according to the third embodiment.

[0029] Figure 8 This is a cross-sectional view of the vibrating plate, piezoelectric element, and resonator of the fourth embodiment.

[0030] Figure 9 This is a cross-sectional view of the vibrating plate, piezoelectric element, and resonator of the fifth embodiment.

[0031] Figure 10 This is a cross-sectional view of the vibrating plate, piezoelectric element, and resonator of the sixth embodiment. Detailed Implementation

[0032] <First Embodiment>

[0033] Figure 1 The ultrasonic transducer 1 shown is used, for example, in medical or industrial ultrasonic devices. The ultrasonic transducer 1 generates ultrasonic waves when given a drive signal and converts the ultrasonic waves into electrical signals when received.

[0034] The ultrasonic transducer 1 includes a vibrating plate 10, a piezoelectric element 11, a resonator 12, a clamping member 13, a base 14, a first wiring section 15, a second wiring section 16, and a housing 17.

[0035] The vibrating plate 10 is plate-shaped (more specifically, circular). The vibrating plate 10 is conductive. The vibrating plate 10 is made of metal, for example, a material such as Alloy 42 (42Ni-Fe). The width (maximum width) of the vibrating plate 10 is greater than the width (maximum width) of the resonator 12, the clamping member 13, and the piezoelectric element 11. The width (maximum width) of the vibrating plate 10 is its length (maximum length) in a direction orthogonal to the thickness direction of the vibrating plate 10. In this embodiment, the width (maximum width) of the vibrating plate 10 is the diameter of its outer perimeter.

[0036] The vibrating plate 10 vibrates to generate a ring-shaped (more specifically, a circular ring) node 20. The vibrating plate 10 generates only one ring-shaped node 20. The node 20 is the portion of the vibrating plate 10 with the smallest displacement in the thickness direction during vibration, or the portion without vibration. The node 20 is uniquely determined by the shape and material of the vibrating plate 10, the piezoelectric element 11, and the resonator 12. Furthermore, in Figure 1 In the diagram, the piezoelectric element 11 is exaggeratedly depicted as large, but it is actually much smaller than the vibrating plate 10 and the resonator 12. Therefore, the position of the node 20 is roughly determined by the shape and material of the vibrating plate 10 and the resonator 12, while the shape and material of the piezoelectric element 11 have a smaller influence on the position of the node 20. The outer periphery of the vibrating plate 10 is a free end. That is, the ultrasonic transducer 1 is a so-called open type, which is easier to vibrate compared to the closed type where the outer periphery of the vibrating plate 10 is fixed. The node 20 is generated in a plane direction orthogonal to the plate thickness direction, located inside the outer periphery of the vibrating plate 10 and outside the center. The vibration of the vibrating plate 10 increases from the node 20 toward the outer periphery and from the node 20 toward the center.

[0037] The vibrating plate 10 has a first surface 21 on one side and a second surface 22 on the other side in the thickness direction. A resonator 12 is joined to the first surface 21. A piezoelectric element 11 is joined to the second surface 22. In addition, in this specification, "joining" is a concept that includes not only structures joined directly but also structures joined by means of other components.

[0038] The vibrating plate 10 has a hole 23. The hole 23 is formed on the first surface 21 and is shaped to recess the first surface 21. The hole 23 is formed, for example, by cutting. The cutting surface obtained by cutting the hole 23 with a plane orthogonal to the thickness direction of the vibrating plate 10 is circular, and the cutting surface is fixed in the thickness direction of the vibrating plate 10.

[0039] The resonator 12 resonates with the vibration of the vibrating plate 10 to generate ultrasonic waves. The resonator 12 has the function of maximizing the transmission efficiency of sound waves from the vibrating plate 10, which is excited by the periodic power supply to the piezoelectric element 11. The resonator 12 is made of metal, for example, an aluminum alloy. The resonator 12 is joined to the vibrating plate 10. The joining method is not limited; for example, it can be bonding using an adhesive such as epoxy adhesive, or soldering, ultrasonic welding, laser welding, etc. The resonator 12 is conical. The resonator 12 has a flat portion 12A and a conical portion 12B. The flat portion 12A is flat and plate-shaped (more specifically, circular plate-shaped). The flat portion 12A is joined to the first surface 21 of the vibrating plate 10. The flat portion 12A is shaped to be housed within a hole 23 and is joined to the bottom surface 23A of the hole 23 formed on the first surface 21. The conical portion 12B extends in a cylindrical shape from the outer periphery of the flat portion 12A toward the side opposite to the vibrating plate 10. The inner peripheral surface of the conical portion 12B has a conical shape that expands toward the side opposite to the vibrating plate 10.

[0040] The piezoelectric element 11 is plate-shaped and is laminated to the vibrating plate 10. The piezoelectric element 11 is bonded to the vibrating plate 10 using a heat-curing epoxy adhesive or the like. Figure 2 As shown, the piezoelectric element 11 has a rectangular shape when viewed from the thickness direction of the vibrating plate 10. Furthermore, a through hole 30 is formed in the piezoelectric element 11, extending along the thickness direction of the vibrating plate 10. The cross-section obtained by cutting the through hole 30 with a plane perpendicular to the through direction is circular. Figure 1 As shown, the piezoelectric element 11 has a plate-shaped piezoelectric body 31 and electrodes 32 and 33 respectively disposed on both sides of the piezoelectric body 31 in the thickness direction. The piezoelectric body 31 is formed of ceramics such as lead zirconate titanate (PZT) or potassium sodium niobate (KNN). One of the electrodes 32 and 33 disposed on both sides of the piezoelectric element 11 is joined to a vibrating plate 10 and electrically connected to a first wiring portion 15 via the vibrating plate 10. The other electrode 33 disposed on both sides of the piezoelectric element 11 is electrically connected to a second wiring portion 16. A base 14 is joined to the side of the piezoelectric element 11 opposite to the vibrating plate 10 via a clamping member 13.

[0041] The clamping member 13 is disposed between the piezoelectric element 11 and the base 14, and is engaged with both the piezoelectric element 11 and the base 14. The clamping member 13 is insulating and elastic. The Young's modulus of the clamping member 13 is lower than that of the base 14. The clamping member 13 is formed, for example, from rubber such as silicone rubber, or resin such as a silicone adhesive. The clamping member 13 is annular (more specifically, circular). The axial direction of the clamping member 13 is along the thickness direction of the vibrating plate 10, and more specifically, it is the same as the thickness direction of the vibrating plate 10. The clamping member 13 is configured such that, in a plane direction orthogonal to the thickness direction of the vibrating plate 10, a node 20 of the vibration of the vibrating plate 10 is disposed between an inscribed circle 13A tangent to the clamping member 13 and an circumscribed circle 13B circumscribed to the clamping member 13 (see reference). Figure 3 ).

[0042] The base 14 is made of synthetic resin and serves as a resin platform. The base 14 is plate-shaped. The thickness direction of the base 14 is along the thickness direction of the vibrating plate 10, and more specifically, it is the same as the thickness direction of the vibrating plate 10.

[0043] The first wiring portion 15 has a first metal terminal 15A and a first helical spring 15B. A first base through hole 14A extending in the thickness direction is formed in the base 14. The first wiring portion 15 passes through the first base through hole 14A. The first terminal 15A is fixed to the base 14 at a position that blocks the opening of the first base through hole 14A on the side opposite to the vibrating plate 10. The extension and contraction direction of the first helical spring 15B is along the thickness direction of the vibrating plate 10, more specifically, the same as the thickness direction. The first helical spring 15B is configured to be sandwiched between the vibrating plate 10 and the first terminal 15A, and is configured to be compressed by being pushed by the vibrating plate 10 and the first terminal 15A. One end of the first helical spring 15B contacts the vibrating plate 10, and the other end contacts the first terminal 15A. The first wiring portion 15 is electrically connected to one of the positive side conductive circuit and the negative side conductive circuit (e.g., ground).

[0044] The second wiring portion 16 has a metal second terminal 16A and a second helical spring 16B. A second base through hole 14B extending in the thickness direction is formed in the base 14. The second wiring portion 16 passes through the second base through hole 14B. The second terminal 16A is fixed to the base 14 at a position that blocks the opening of the second base through hole 14B on the side opposite to the vibrating plate 10. The extension and contraction direction of the second helical spring 16B is along the thickness direction of the vibrating plate 10, more specifically, the same as the thickness direction. The second helical spring 16B is disposed between the piezoelectric element 11 and the second terminal 16A, and is disposed in a compressed state by being pushed by the piezoelectric element 11 and the second terminal 16A. One end of the second helical spring 16B contacts the surface of the piezoelectric element 11 on the side opposite to the vibrating plate 10 (that is, the electrode 33 of the piezoelectric element 11), and the other end contacts the second terminal 16A. The second wiring section 16 is electrically connected to another conductive path in the positive side conductive path and the negative side conductive path (e.g., ground).

[0045] The housing 17 is a component that protects the resonator 12 from contact with foreign objects. The housing 17 is fixed to the base 14. The housing 17 has a peripheral wall portion 17A surrounding the resonator 12. Multiple openings are formed in the housing 17 on the side opposite to the base 14 than the resonator 12, through which ultrasonic waves are transmitted to the outside, and also into the housing 17 from the outside.

[0046] like Figure 3 As shown, in a plane orthogonal to the thickness direction of the vibrating plate 10, the joint 40 where the vibrating plate 10 and the resonator 12 are joined is positioned inside the wavelet 20, and the through hole 30 of the piezoelectric element 11 is positioned inside the wavelet 20. Furthermore, in the aforementioned plane direction, the joint 40 where the vibrating plate 10 and the resonator 12 are joined is positioned inside the inscribed circle 13A of the clamping member 13, and the through hole 30 is positioned inside the inscribed circle 13A. Moreover, when viewed from the thickness direction of the vibrating plate 10, the joint 40 is positioned to overlap with the through hole 30. Furthermore, when viewed from the thickness direction of the vibrating plate 10, the joint 40 is positioned to overlap with the hole 23.

[0047] The following description relates to the effects of the first embodiment.

[0048] In the ultrasonic transducer 1 of the first embodiment, the joint 40 where the vibrating plate 10 and the resonator 12 are joined is located inside the node 20 of the vibration of the vibrating plate 10. Therefore, it is easier to apply stress to the piezoelectric element 11 at a position inside the node 20. However, a through hole 30 of the piezoelectric element 11 is provided in the area where stress from the joint 40 is easily applied. Therefore, according to this ultrasonic transducer 1, the stress applied to the piezoelectric element 11 due to the vibration of the resonator 12 can be reduced.

[0049] Furthermore, in the ultrasonic transducer 1 of the first embodiment, the joint 40 where the vibrating plate 10 and the resonator 12 are joined is positioned further inward than the inscribed circle 13A of the clamping member 13. Therefore, the vibrating plate 10 is more prone to vibration at a position further inward than the inscribed circle 13A of the clamping member 13, and stress is more easily applied to the piezoelectric element 11 at this position. However, a through hole 30 of the piezoelectric element 11 is provided in the area where stress from this joint 40 is easily applied. Therefore, according to this ultrasonic transducer 1, the stress applied to the piezoelectric element 11 due to the vibration of the resonator 12 can be reduced.

[0050] Furthermore, when viewed from the thickness direction of the vibrating plate 10, the joint 40 is entirely disposed at a position overlapping with the through hole 30. Therefore, since the joint 40 is entirely disposed at a position overlapping with the through hole 30, the stress exerted on the piezoelectric element 11 due to the vibration of the resonator 12 can be reduced more effectively.

[0051] Furthermore, when viewed from the thickness direction of the vibrating plate 10, the joint 40 is positioned to overlap with the hole 23. Therefore, it is easy to vibrate the vibrating plate 10 and the power consumption for vibrating the vibrating plate 10 can be reduced.

[0052] <Second Implementation>

[0053] In the first embodiment, when viewed from the thickness direction of the vibrating plate, the joint is entirely disposed at a position overlapping the through hole; however, it may not be configured such that the entire joint is disposed at a position overlapping the through hole. In the second embodiment, an example in which a portion of the joint is disposed at a position overlapping the through hole when viewed from the thickness direction of the vibrating plate will be described. Furthermore, the ultrasonic transducer of the second embodiment differs from the ultrasonic transducer of the first embodiment only in the shape of the piezoelectric element; all other aspects are the same. In the following description, the same reference numerals are used for structures identical to those in the first embodiment, and detailed descriptions are omitted.

[0054] like Figure 4As shown, the piezoelectric element 211 of the second embodiment has a rectangular shape when viewed from the thickness direction of the vibrating plate 10. A through hole 230 is formed in the piezoelectric element 211, extending through the thickness direction of the vibrating plate 10. The cross-sectional shape obtained by cutting the through hole 230 with a plane orthogonal to the through direction of the through hole 230 is rectangular.

[0055] like Figure 5 As shown, when viewed from the thickness direction of the vibrating plate 10, a portion of the joint 40 where the vibrating plate 10 and the resonator 12 are joined is positioned to overlap with the through hole 230. Furthermore, the through hole 230 has a portion that does not overlap with the joint 40 when viewed from the thickness direction of the vibrating plate 10.

[0056] As described above, in the second embodiment, a portion of the joint 40 of the ultrasonic transducer 201 is positioned to overlap with the through hole 230 when viewed from the thickness direction. Therefore, compared to a structure in which the joint 40 is positioned to completely avoid overlapping with the through hole 230, the ultrasonic transducer 201 can more effectively reduce the stress exerted on the piezoelectric element 211 by the vibration of the resonator 12.

[0057] <Third Implementation>

[0058] In the first embodiment, the number of through holes formed in the piezoelectric element is one, but it can also be multiple. In the third embodiment, an example in which multiple through holes are formed in the piezoelectric element will be described. Furthermore, the ultrasonic transducer of the third embodiment is the same as that of the ultrasonic transducer of the first embodiment, except that the shape of the piezoelectric element differs. In the following description, the same reference numerals are used for structures identical to those in the first embodiment, and detailed descriptions are omitted.

[0059] like Figure 6 As shown, the piezoelectric element 311 of the third embodiment is rectangular in shape when viewed from the thickness direction of the vibrating plate 10. A through hole 330 is formed in the piezoelectric element 311, extending along the thickness direction of the vibrating plate 10. The cross-section obtained by cutting the through hole 330 with a plane orthogonal to the through direction of the through hole 330 is circular. A plurality of (five in this embodiment) through holes 330 are formed in the piezoelectric element 311. More specifically, one through hole 330A is formed at the center of the piezoelectric element 311, and four through holes 330B are formed around this through hole 330A.

[0060] like Figure 7 As shown, when viewed from the thickness direction of the vibrating plate 10, a portion of the joint 40 where the vibrating plate 10 and the resonator 12 are joined is positioned at a location overlapping the through hole 330.

[0061] As described above, in the third embodiment, a portion of the joint 40 of the ultrasonic transducer 301 is positioned to overlap with the through hole 330 when viewed from the thickness direction. Therefore, compared to a structure in which the joint 40 is positioned to completely avoid overlapping with the through hole 330, the ultrasonic transducer 301 can more effectively reduce the stress exerted on the piezoelectric element 311 by the vibration of the resonator 12.

[0062] <Fourth Implementation>

[0063] In the first embodiment, the vibrating plate is configured to have holes, but it can also be configured so that the vibrating plate does not have holes. The ultrasonic transducer of the fourth embodiment differs from the ultrasonic transducer of the first embodiment in that the vibrating plate does not have holes, but is the same in all other respects. In the following description, the same reference numerals are used to refer to the same structures as in the first embodiment, and detailed descriptions are omitted.

[0064] like Figure 8 As shown, the ultrasonic transducer of the fourth embodiment includes a vibrating plate 410, a piezoelectric element 11, and a resonator 12. The vibrating plate 410 has the same structure as the vibrating plate 10 of the first embodiment, except that it does not have any holes. That is, both surfaces of the vibrating plate 410 in the thickness direction are flat. The thickness of the vibrating plate 410 is uniform throughout. According to the ultrasonic transducer of the fourth embodiment, since the vibrating plate 410 does not have any holes, its forming is easy.

[0065] <Fifth Implementation>

[0066] In the first embodiment, the holes in the vibrating plate are formed by machining, but they can also be formed by other methods. In the fifth embodiment, an example is described where the holes in the vibrating plate are formed by semi-stamping. The ultrasonic transducer of the fifth embodiment differs from the ultrasonic transducer of the first embodiment in that the holes in the vibrating plate are formed by semi-stamping, but they are the same in all other respects. In the following description, the same reference numerals are used to refer to the same structures as in the first embodiment, and detailed descriptions are omitted.

[0067] like Figure 9 As shown, the ultrasonic transducer of the fifth embodiment includes a vibrating plate 510, a piezoelectric element 11, and a resonator 12. The vibrating plate 510 has a first surface 521 on one side in the thickness direction and a second surface 522 on the other side. The resonator 12 is attached to the first surface 521. The piezoelectric element 11 is attached to the second surface 522.

[0068] The vibrating plate 510 has a hole 523 and a protrusion 524. The hole 523 is formed on the first surface 521 and is shaped to make the first surface 521 concave. The hole 523 is formed by semi-stamping. The cut surface of the hole 523 obtained by cutting with a surface orthogonal to the thickness direction of the vibrating plate 510 is circular, and the cut surface is fixed in the thickness direction of the vibrating plate 510. The flat portion 12A of the resonator 12 is embedded in the hole 523 and engages with the bottom surface 523A of the hole 523.

[0069] A protrusion 524 is formed on the second surface 522. At least a portion of the protrusion 524, when viewed from the thickness direction of the vibrating plate 510, is positioned to overlap with the hole 523. The protrusion 524 is formed when the hole 523 is formed by a semi-stamping process. The protrusion 524 is embedded within the through hole 30 of the piezoelectric element 11. The protrusion dimension of the protrusion 524 is smaller than the thickness of the piezoelectric element 11. Therefore, the protrusion 524 does not protrude outward from the through hole 30.

[0070] The ultrasonic transducer according to the fifth embodiment is less prone to generating debris compared to the case where the hole of the vibrating plate is formed by machining.

[0071] <Sixth Implementation>

[0072] In the first embodiment, the hole in the vibrating plate does not penetrate the vibrating plate, but it can also be configured such that the hole penetrates the vibrating plate. In the sixth embodiment, an example in which the hole in the vibrating plate penetrates the vibrating plate will be described. The ultrasonic transducer of the sixth embodiment differs from the ultrasonic transducer of the first embodiment in that the hole in the vibrating plate penetrates the vibrating plate, but is the same in all other respects. In the following description, the same reference numerals are used to refer to the same structures as in the first embodiment, and detailed descriptions are omitted.

[0073] like Figure 10 As shown, the ultrasonic transducer of the sixth embodiment includes a vibrating plate 610, a piezoelectric element 11, and a resonator 12. The vibrating plate 610 has a first surface 621 on one side in the thickness direction and a second surface 622 on the other side. The resonator 12 is attached to the first surface 621. The piezoelectric element 11 is attached to the second surface 622.

[0074] The vibrating plate 610 has a hole 623. The hole 623 extends through the vibrating plate 610 along its thickness direction. The hole 623 is positioned inside the outer periphery of the flat portion 12A of the resonator 12 in a plane orthogonal to the thickness direction of the vibrating plate 610. The hole 623 is also positioned inside the inner wall of the through hole 30 in a plane orthogonal to the thickness direction of the vibrating plate 610. The cutting surface obtained by cutting the hole 623 with a plane orthogonal to the thickness direction of the vibrating plate 610 is circular, and the cutting surface is constant in the thickness direction of the vibrating plate 610.

[0075] <Other Implementation Methods>

[0076] This invention is not limited to the embodiments described above and in the accompanying drawings. For example, the following embodiments are also included within the scope of protection of this invention. Furthermore, the various features of the above-described embodiments and the embodiments described below can be combined arbitrarily as long as they are not contradictory.

[0077] In the above embodiments, when viewed from the thickness direction of the vibrating plate, at least a portion of the joint is disposed at a position overlapping with the through hole, but it may also be disposed at a position that does not overlap with the through hole at all.

[0078] In the above embodiments, the first and second helical springs are not joined, but they can also be joined. The joining method is not limited; for example, it can be soldering, laser welding, ultrasonic welding, etc.

[0079] Furthermore, the embodiments disclosed herein should be considered illustrative in all respects and not restrictive. The scope of the invention is not limited to the embodiments disclosed herein, and is intended to include all modifications within the scope defined by or equivalent to the claims.

[0080] Explanation of reference numerals in the attached figures

[0081] 1. Ultrasonic transducer; 10. Vibrating plate; 11. Piezoelectric element; 12. Resonator; 12A. Flat portion; 12B. Conical portion; 13. Clamping member; 13A. Inscribed circle; 13B. Circumscribed circle; 14. Base; 14A. First base through hole; 14B. Second base through hole; 15. First wiring section; 15A. First terminal; 15B. First helical spring; 16. Second wiring section; 16A. Second terminal; 16B. Second helical spring; 17. Housing; 17A. Peripheral wall; 20. Node; 21. First surface; 22. Second Surface; 23, Hole; 23A, Bottom surface; 30, Through hole; 31, Piezoelectric element; 32, Electrode; 33, Electrode; 40, Joint; 201, Ultrasonic transducer; 211, Piezoelectric element; 230, Through hole; 301, Ultrasonic transducer; 311, Piezoelectric element; 330, Through hole; 330A, Through hole; 330B, Through hole; 410, Vibrating plate; 510, Vibrating plate; 521, First surface; 522, Second surface; 523, Hole; 610, Vibrating plate; 621, First surface; 622, Second surface; 623, Hole.

Claims

1. An ultrasonic transducer, wherein, The ultrasonic transducer includes: Base; A piezoelectric element, which is coupled to the base; A vibrating plate, which is coupled to the piezoelectric element, vibrates to generate ring-shaped nodes; and The resonator, which is coupled to the vibrating plate, The vibrating plate has a concave hole on one side of its thickness direction on its first surface. The resonator is connected to the vibrating plate in a position that at least partially engages with the hole on the first surface. Furthermore, the resonator has a plate-shaped flat portion and a conical portion extending cylindrically from the outer periphery of the flat portion toward a side opposite to the vibrating plate side. The flat portion is positioned separate from the inner peripheral surface of the aperture and engages with the bottom surface of the aperture. The piezoelectric element is joined to a second surface on the opposite side of the thickness direction of the vibrating plate, on the side opposite to the side joined to the base. A through hole is formed in the piezoelectric element, extending along the thickness direction. In a plane direction orthogonal to the thickness direction, the joint where the vibrating plate and the resonator are joined is located inside the node, and the through hole is located inside the node.

2. An ultrasonic transducer, wherein, The ultrasonic transducer includes: Base; A clamping member, which is ring-shaped, engages with the base bottom; A piezoelectric element, which is engaged with the base by means of the clamping member; A vibrating plate, which is coupled to the piezoelectric element, vibrates to generate ring-shaped nodes; and The resonator, which is coupled to the vibrating plate, The Young's modulus of the clamping member is lower than that of the base. The first surface of the vibrating plate on one side in the thickness direction is engaged with the resonator. The vibrating plate has a concave hole on the first surface, which is formed by a thinning of the hole. The resonator has a plate-shaped flat portion and a conical portion extending cylindrically from the outer periphery of the flat portion toward a side opposite to the vibrating plate side. The flat portion is positioned separate from the inner peripheral surface of the aperture and engages with the bottom surface of the aperture. The second surface of the vibrating plate on the other side of the thickness direction is joined to the surface of the piezoelectric element on the side opposite to the side joined to the base. A through hole is formed in the piezoelectric element, extending along the thickness direction. In a plane direction orthogonal to the thickness direction, the joint where the vibrating plate and the resonator engage is positioned inside the inscribed circle of the clamping member, and the through hole is positioned inside the inscribed circle.

3. The ultrasonic transducer according to claim 1 or 2, wherein, When viewed from the thickness direction, at least a portion of the joint is positioned to overlap with the through hole.

4. The ultrasonic transducer according to claim 3, wherein, When viewed from the thickness direction, the joint is positioned to overlap with the through hole.

5. The ultrasonic transducer according to claim 1 or 2, wherein, When viewed from the thickness direction, at least a portion of the joint is positioned to overlap with the hole.

Images