Ultrasonic transducer

Abstract

To provide an ultrasonic transducer that makes it possible to inhibit the displacement of an oscillator.SOLUTION: An ultrasonic transducer 1 is equipped with a resin base 10, an oscillator 11, and an intervening member 12. The oscillator 11 is installed on the resin base 10. The intervening member 12 is placed between the resin base 10 and the oscillator 11, and is joined to the resin base 10 and the oscillator 11. The resin base 10 is composed of a laser-permeable resin. The intervening member 12 has laser absorbency.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an ultrasonic transducer and a method for manufacturing the ultrasonic transducer.

Background Art

[0002] Patent Document 1 discloses a parametric speaker that irradiates ultrasonic waves. This parametric speaker is configured to bond a piezoelectric vibrator to a substrate with a conductive adhesive.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the technology of Patent Document 1, when bonding the piezoelectric vibrator to the substrate, it is necessary to apply pressure so that the piezoelectric vibrator and the substrate are in close contact with the conductive adhesive. Therefore, when pressure is applied, the piezoelectric vibrator may be displaced relative to the substrate.

[0005] An object of the present invention is to provide a technique capable of suppressing displacement of a vibrator.

Means for Solving the Problems

[0006] [1] The ultrasonic transducer of the present invention includes a resin base, a vibrator, and an intervening member. The vibrator is installed on the resin base. The intervening member is disposed between the resin base and the vibrator and is joined to the resin base and the vibrator. The resin base is made of a laser-transmissive resin. The intervening member has laser absorptivity.

[0007] According to this configuration, the intervening member can be melted by the laser that has passed through the resin base, and the vibrator can be welded to the resin base. That is, since the pressurization for joining the vibrator to the resin base can be omitted or suppressed, the displacement of the vibrator caused by strong pressurization can be suppressed.

[0008] [2] The above resin base may have a base portion and a joint portion joined to the vibrator via an intervening member. A plurality of joint portions may be provided on the base portion.

[0009] According to this configuration, while suppressing the displacement of the vibrator, a plurality of vibrators can be installed on the resin base.

[0010] [3] The above intervening member may be annular and may be partially missing so as to connect the space on the outer peripheral side and the space on the inner peripheral side.

[0011] According to this configuration, a part of the vibrator can be exposed from the missing part of the intervening member, and an electrical connection member can be connected to this exposed portion. That is, since the electrical connection member can be connected to a portion of the vibrator that is difficult to vibrate, it is possible to suppress the electrical connection member from coming off the vibrator due to the vibration of the vibrator.

[0012] [4] The method for manufacturing the ultrasonic transducer of the present invention includes a preparation step, an arrangement step, an irradiation step, and a welding step. In the preparation step, a resin base, a vibrator, and an intervening member are prepared. In the arrangement step, the intervening member is arranged between the resin base and the vibrator. In the irradiation step, a laser is irradiated onto the intervening member through the resin base. In the welding step, the intervening member is melted by the irradiation of the laser, and the vibrator is welded to the resin base.

[0013] According to this configuration, the intervening member can be melted by the laser that has passed through the resin base, and the vibrator can be welded to the resin base. That is, since the pressurization for joining the vibrator to the resin base can be omitted or suppressed, the displacement of the vibrator caused by strong pressurization can be suppressed.

[0014] [5] The upper resin base may have a base portion and a joint portion joined to the vibrator via an intervening member. A plurality of joint portions may be provided. In the preparation step, a plurality of vibrators and intervening members may be prepared respectively. In the arrangement step, each intervening member may be arranged between each joint portion and each vibrator. In the irradiation step, the laser may be irradiated through the resin base to each intervening member by changing the irradiation position. In the welding step, each intervening member may be melted by the irradiation of the laser, and each vibrator may be welded to each joint portion.

[0015] According to this configuration, after arranging the resin base, the vibrator, and the intervening member in a predetermined positional relationship, since joining is performed at a plurality of locations while changing the irradiation position of the laser, it is possible to efficiently join while suppressing displacement at each part.

Advantages of the Invention

[0016] According to the present invention, displacement of the vibrator can be suppressed.

Brief Description of the Drawings

[0017]

Figure 1

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MODE FOR CARRYING OUT THE INVENTION

[0018] 1. First Embodiment 1-1. Configuration of Ultrasonic Transducer 1 The ultrasonic transducer 1 of the first embodiment shown in FIG. 1 is used, for example, in a medical or industrial ultrasonic device. The ultrasonic transducer 1 transmits and receives ultrasonic waves.

[0019] The ultrasonic transducer 1 shown in FIG. 1 includes a resin base 10, an oscillator 11, an intervening member 12, a cone 13, conductive paths 14 and 15, and electrical connection members 16 and 17 (see FIG. 7).

[0020] The resin base 10 is made of a laser-transmissive resin. The laser transmittance of the resin base 10 is preferably 30% or more. The laser-transmissive resin is, for example, a polyamide resin such as nylon 6 or nylon 66, a polyolefin resin, a polyester resin, or the like. The resin base 10 has a plate-shaped base portion 20 and a joint portion 21 provided on the base portion 20. The base portion 20 has a first surface 20A that is the surface and a second surface 20B that is the surface opposite to the first surface 20A (back surface). The joint portion 21 is provided on the first surface 20A and protrudes from the first surface 20A. The joint portion 21 is annular in plan view and is partially missing so as to connect the space on the outer peripheral side and the space on the inner peripheral side. The joint portion 21 is C-shaped. The shape and size of the joint portion 21 are substantially the same as those of the intervening member 12 in plan view. The joint portion 21 is joined to the vibrator 11 via the intervening member 12. A plurality of joint portions 21 are provided at intervals from each other. The plurality of joint portions 21 are regularly arranged in a predetermined positional relationship.

[0021] The vibrator 11 has a diaphragm 30 and a piezoelectric element 31. The diaphragm 30 is made of, for example, metal and has a disc shape. The diaphragm 30 vibrates so as to generate an annular (more specifically, circular annular) node. The diaphragm 30 generates only one annular node. A node is a portion where the displacement amount in the thickness direction when the diaphragm 30 vibrates is the smallest or a portion where there is no vibration. The node is uniquely determined by the shapes and materials of the diaphragm 30, the piezoelectric element 31, and the cone 13. The outer shape of the diaphragm 30 is larger than the outer shape of any of the piezoelectric element 31, the intervening member 12, and the joint portion 21 in a plan view. The piezoelectric element 31 has a rectangular shape in a plan view. The piezoelectric element 31 has a plate-shaped piezoelectric body 31A and electrodes 31B and 31C provided on both surfaces of the piezoelectric body 31A. The piezoelectric body 31A is made of piezoelectric ceramics. The diaphragm 30 and the piezoelectric element 31 are adhered to each other. That is, one electrode 31B of the piezoelectric element 31 is adhered to the diaphragm 30. As shown in FIGS. 5 and 7, the other electrode 31C of the piezoelectric element 31 is electrically connected to the conductive path 14 via the electrical connection member 16, and the diaphragm 30 is electrically connected to the conductive path 15 via the electrical connection member 17. The piezoelectric element 31 is disposed closer to the resin base 10 than the diaphragm 30.

[0022] The intervening member 12 has laser absorbability and insulation properties. The intervening member 12 has elasticity. The Young's modulus of the intervening member 12 is preferably 30 MPa or less. The intervening member 12 is preferably made of rubber, resin, etc. in which carbon black, calcium carbonate, etc. are kneaded. As shown in FIG. 3, the intervening member 12 is annular in plan view and is partially missing so as to connect the space on the outer peripheral side and the space on the inner peripheral side. The intervening member 12 has a C shape. The thickness of the intervening member 12 is constant throughout the entire region of the intervening member 12. The intervening member 12 is disposed between the resin base 10 and the vibrator 11 and is joined to the resin base 10 and the vibrator 11. The intervening member 12 is joined to the portion where the node of the diaphragm 30 is formed so as not to inhibit the vibration of the vibrator 11. The intervening member 12 melts after being irradiated with laser and then solidifies to weld the resin base 10 and the vibrator 11. That is, in the state where the ultrasonic transducer 1 is completed, the intervening member 12 is melted by laser irradiation and then solidified. A plurality of intervening members 12 are provided. The ultrasonic transducer 1 has a connecting portion 32 that connects the intervening members 12 to each other. The plurality of intervening members 12 connected by the connecting portion 32 are arranged in a positional relationship corresponding to each of the joint portions 21 of the resin base 10. The connecting portion 32 is formed integrally with the intervening member 12.

[0023] The cone 13 has a tapered shape. The cone 13 is fixed to the diaphragm 30 of the vibrator 11.

[0024] The conductive paths 14, 15 are wiring patterns provided on the resin base 10. One of the conductive paths 14, 15 is a conductive path on the positive electrode side, and the other is a conductive path on the negative electrode side. The conductive paths 14, 15 are respectively arranged along the first surface 20A of the base portion 20 in the resin base 10. As shown in FIG. 5, the conductive paths 14, 15 each have a main conductive path 14A, 15A and a branch path 14B, 15B branched from the main conductive paths 14A, 15A corresponding to each of the joint portions 21.

[0025] As shown in FIGS. 5 to 7, the electrical connection members 16 and 17 are members that electrically connect the conductive paths 14 and 15 to the vibrator 11. In this embodiment, the electrical connection members 16 and 17 are lead wires and are joined to the vibrator 11 by soldering or the like.

[0026] 1-2. Manufacturing Method of Ultrasonic Transducer 1 As shown in FIG. 2, the manufacturing method of the ultrasonic transducer 1 includes a preparation step, an arrangement step, an irradiation step, a welding step, and a wiring step.

[0027] In the preparation step (step S10), the resin base 10, the vibrator 11, the intervening member 12, and the cone 13 are prepared. In the preparation step, a plurality of vibrators 11, intervening members 12, and cones 13 are prepared respectively. Conductive paths 14 and 15 are arranged in advance on the resin base 10. In the preparation step, the diaphragm 30 and the piezoelectric element 31 of the vibrator 11 are adhered to each other. In the preparation step, the cone 13 is fixed to the vibrator 11.

[0028] In the arrangement step (step S11), as shown in FIG. 3, a plurality of vibrators 11 are arranged side by side along the horizontal direction so as to have a predetermined positional relationship. The predetermined positional relationship is a positional relationship corresponding to each of the joint portions 21 of the resin base 10. The vibrator 11 is arranged in an upside-down state, that is, in a state where the piezoelectric element 31 is on the upper side rather than the diaphragm 30. An intervening member 12 is arranged above each piezoelectric element 31. The resin base 10 is arranged above each intervening member 12. The resin base 10 is arranged in an upside-down state, that is, in a state where the joint portion 21 is located on the lower side, so that each joint portion 21 is placed on the upper surface of each intervening member 12. Thereby, as shown in FIG. 4, the intervening member 12 is arranged between the joint portion 21 of the resin base 10 and the vibrator 11. That is, each intervening member 12 is arranged between each joint portion 21 and each vibrator 11.

[0029] In the irradiation step (step S12), as shown in FIG. 4, a laser is transmitted through the resin stage 10 and irradiated onto the intervening member 12. The type of laser is not particularly limited. Known techniques such as gas lasers, solid-state lasers, and semiconductor lasers can be used for the type of laser. The laser can be selected to have an optimal wavelength and output according to the materials and thicknesses of the resin stage 10, the vibrator 11, and the intervening member 12. That is, the laser can be selected to have a type, wavelength, and output suitable for transmitting through the resin stage 10, melting the intervening member 12, and welding the vibrator 11 to the resin stage 10 by the intervening member 12. In the irradiation step, the irradiation is performed in a C shape along the shape of the intervening member 12. In the irradiation step, the laser is irradiated onto a plurality of intervening members 12 by changing the irradiation position.

[0030] In the welding step (step S13), the intervening member 12 is melted by the irradiation of the laser, and the vibrator 11 is welded to the resin stage 10. More specifically, in the welding step, the intervening member 12 is melted by the irradiation of the laser, and after melting, it is solidified, so that the vibrator 11 and the resin stage 10 are welded by the intervening member 12. In the welding step, each intervening member 12 is sequentially melted by the irradiation of the laser, and after melting, it is solidified, so that each vibrator 11 is welded to each joint portion 21. As the laser welding technique, a known technique (for example, the technique of JP-A-2009-269401) can be used.

[0031] In the arrangement step (step S14), as shown in FIGS. 5 to 7, the conductive paths 14 and 15 are respectively connected to the vibrator 11 by the electrical connection members 16 and 17. Specifically, the electrical connection member 16 is electrically connected to the branch path 14B of the conductive path 14 and the other electrode 31C of the piezoelectric element 31. The electrical connection member 17 is electrically connected to the branch path 15B of the conductive path 15 and the diaphragm 30.

[0032] The vibrator 11 (specifically, each of the piezoelectric element 31 and the diaphragm 30) is exposed at the missing part (C-shaped opening part) of the annular intervening member 12. The branch paths 14B and 15B of the conductive paths 14 and 15 are respectively exposed at the missing part of the joint part 21. The exposed part of the piezoelectric element 31 faces the branch path 14B of the conductive path 14. The electrical connection member 16 is disposed between the exposed part of the piezoelectric element 31 facing each other and the branch path 14B, and is electrically connected to the exposed part of the piezoelectric element 31 and the branch path 14B. The exposed part of the diaphragm 30 faces the branch path 15B of the conductive path 15. The electrical connection member 17 is disposed between the exposed part of the diaphragm 30 facing each other and the branch path 15B, and is electrically connected to the exposed part of the diaphragm 30 and the branch path 15B.

[0033] 1-3. Effects of the First Embodiment In the ultrasonic transducer 1 of the first embodiment, the resin base 10 is made of a laser-transmissive resin, and the intervening member 12 has laser absorptivity. Therefore, the intervening member 12 can be melted by the laser transmitted through the resin base 10, and the vibrator 11 can be welded to the resin base 10. That is, since the pressurization for joining the vibrator 11 to the resin base 10 can be omitted or suppressed, the displacement of the vibrator 11 caused by strong pressurization can be suppressed.

[0034] Furthermore, the resin base 10 has a base portion 20 and a joint portion 21 joined to the vibrator 11 via the intervening member 12. A plurality of joint portions 21 are provided on the base portion 20. Therefore, a plurality of vibrators 11 can be installed on the resin base 10 while suppressing the displacement of the vibrator 11.

[0035] Furthermore, the intervening member 12 is annular and partially missing so as to connect the space on the outer peripheral side and the space on the inner peripheral side. Therefore, a part of the vibrator 11 can be exposed from the missing part of the intervening member 12, and the electrical connection members 16, 17 can be connected to this exposed part. In the annular part where the intervening member 12 is joined, it becomes difficult for the vibrator to vibrate. Since the electrical connection members 16, 17 can be connected to this difficult-to-vibrate part, it is possible to suppress the electrical connection between the electrical connection members 16, 17 and the vibrator 11 from being disconnected due to the vibration of the vibrator 11. In particular, in the present embodiment, the intervening member 12 is arranged along the node of the vibrator. For this reason, the electrical connection members 16, 17 are less likely to receive vibration, and it is possible to more reliably suppress the electrical connection with the vibrator 11 from being disconnected.

[0036] Also, according to the manufacturing method of the ultrasonic transducer 1 of the first embodiment, the intervening member 12 can be melted by the laser transmitted through the resin base 10, and the vibrator 11 can be welded to the resin base 10. That is, since the pressurization for joining the vibrator 11 to the resin base 10 can be omitted or suppressed, the displacement of the vibrator 11 due to strong pressurization can be suppressed.

[0037] Furthermore, according to the manufacturing method of this ultrasonic transducer 1, after arranging the resin base 10, the vibrator 11, and the intervening member 12 in a predetermined positional relationship, since they are joined at a plurality of locations while changing the irradiation position of the laser, it is possible to efficiently join while suppressing displacement at each part.

[0038] 2. Second Embodiment In the first embodiment, the electrical connection member was a lead wire, but it does not have to be a lead wire. In the second embodiment, an example in which the electrical connection member has a coil spring will be described. In the following description, the same reference numerals are given to the configurations common to the first embodiment, and detailed descriptions thereof are omitted.

[0039] As shown in Fig. 8, the ultrasonic transducer 201 of the second embodiment includes a resin base 210, a vibrator 211, an intervening member 212, a cone 13, and electrical connection members 216 and 217.

[0040] The resin base 210 is different from the resin base 10 of the first embodiment in that through holes 210A and 210B are formed, and is common in other respects.

[0041] The vibrator 211 has a diaphragm 30 and a piezoelectric element 231. The piezoelectric element 231 is different from the piezoelectric element 31 of the first embodiment in that the shape when viewed from the thickness direction is rectangular instead of square, and is common in other respects (see Fig. 9).

[0042] The intervening member 212 is different from the intervening member 12 of the first embodiment in that the opening part is large, and is common in other respects.

[0043] The electrical connection member 216 has a terminal 216A and a coil spring 216B. The terminal 216A and the coil spring 216B each have conductivity and are made of, for example, metal. A through hole 210A penetrating in the thickness direction is formed in the resin base 210. The electrical connection member 216 is inserted through the through hole 210A. The terminal 216A is fixed to the resin base 210 at a position closing the opening on the side opposite to the diaphragm 30 side in the through hole 210A. The fixing method is, for example, adhesion, press-fitting, etc. The expansion and contraction direction of the coil spring 216B is along the thickness direction of the diaphragm 30, and more specifically, is the same as the thickness direction. The coil spring 216B is disposed sandwiched between the piezoelectric element 231 and the terminal 216A, and is disposed in a compressed state being pressed by the piezoelectric element 231 and the terminal 216A. One end of the coil spring 216B contacts the piezoelectric element 231, and the other end contacts the terminal 216A (see Figs. 8 and 9).

[0044] The electrical connection member 217 has a terminal 217A and a coil spring 217B. The terminal 217A and the coil spring 217B each have conductivity and are made of, for example, metal. The resin base 210 is formed with a through hole 210B penetrating in the thickness direction. The electrical connection member 217 is inserted through the through hole 210B. The terminal 217A is fixed to the resin base 210 at a position closing the opening on the side opposite to the diaphragm 30 side in the through hole 210B. The fixing method is, for example, adhesion, press fitting, etc. The expansion and contraction direction of the coil spring 217B is along the thickness direction of the diaphragm 30, and more specifically, it is the same as the thickness direction. The coil spring 217B is disposed sandwiched between the diaphragm 30 and the terminal 217A, and is disposed in a compressed state being pressed by the diaphragm 30 and the terminal 217A. One end of the coil spring 217B contacts the diaphragm 30, and the other end contacts the terminal 217A (see FIGS. 8 and 9).

[0045] According to the ultrasonic transducer 201 of the second embodiment, operations such as soldering are unnecessary when installing the electrical connection members 216 and 217.

[0046] <Other embodiments> The present invention is not limited to the embodiments described by the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention. Also, various features of the above-described embodiments and the embodiments described later may be combined in any combination as long as they do not conflict with each other.

[0047] In the above embodiment, a part of the intervening member had a missing shape, but it may have another shape. For example, the intervening member may be annular without a missing part, or may not be annular. Similarly, the joint part of the resin base may have another shape. For example, the joint part may be annular without a missing part, or may not be annular.

[0048] In the above embodiment, the vibrator had a configuration having only a diaphragm and a piezoelectric element, but it may have another configuration. For example, the vibrator may have a configuration having members other than the diaphragm and the piezoelectric element.

[0049] In the above-described embodiment, both electrodes of the piezoelectric element are connected to the wiring patterns of the resin base, but another configuration may be used. For example, a configuration in which the respective diaphragms are electrically connected to make them at the same potential may be used.

[0050] It should be considered that the embodiments disclosed this time are illustrative in all respects and not restrictive. The scope of the present invention is not limited to the embodiments disclosed this time, and it is intended that all modifications within the scope indicated by the claims or within the scope equivalent to the claims are included.

Explanation of Reference Numerals

[0051] 1... Ultrasonic transducer 10... Resin base 11... Vibrator 12... Intervening member 20... Base 21... Joint 201... Ultrasonic transducer 210... Resin base 211... Vibrator 212... Intervening member

Claims

1. A resin base, a vibrator installed on the resin base, and an intervening member disposed between the resin base and the vibrator and joined to the resin base and the vibrator, wherein the resin base is made of a laser-transmissive resin, the intervening member has laser absorbability, and the intervening member is an ultrasonic transducer having an annular shape and partially missing so as to connect the space on the outer peripheral side and the space on the inner peripheral side.

2. The resin base has a base portion and a joint portion joined to the vibrator via the intervening member, wherein a plurality of the joint portions are provided on the base portion, the ultrasonic transducer according to Claim 1.

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