JPWO2019234854A1 - Ultrasonic transducer and method of manufacturing the same - Google Patents

Abstract

An ultrasonic transducer according to the present invention has a first surface and a second surface facing one side and the other side in the plate thickness direction, respectively, and an elastic plate vibrating in the plate thickness direction, and a first surface of the elastic plate. A plurality of piezoelectric elements fixed in parallel with each other, and a sealing member provided on the first surface of the elastic plate so as to form a plurality of accommodating spaces covering the plurality of piezoelectric elements, respectively, The elastic plate includes a plurality of vibrating regions to which the plurality of piezoelectric elements are mounted, a plurality of constraining regions surrounding the plurality of vibrating regions, one constraining region, and a radial direction outward of the one constraining region. A boundary region that partitions the outer region to be located, wherein the boundary region mechanically divides the one constraint region and the outer region into a slit portion and the one constraint region to the outer region. And a bridge portion connected to.

Description

The present invention relates to an ultrasonic transducer in which a plurality of piezoelectric elements are arranged in parallel and which can be suitably used as a phased array sensor, and a manufacturing method thereof.

An ultrasonic transducer in which a plurality of vibrating bodies including a piezoelectric element and a vibrating plate are arranged in parallel is suitably used as a phased array sensor for detecting the shape of an object or detecting the presence or absence of an object over a wide range. Although possible, in this case, the following items are required for the ultrasonic transducer.

That is, in order to suppress the occurrence of the grating globe phenomenon between the plurality of vibrators, the array pitch of the plurality of vibrators needs to be 1/2 or less of the wavelength λ of the ultrasonic waves emitted by the vibrators. There is.

On the other hand, in order to detect an object several meters away, it is necessary to set the frequency of ultrasonic waves emitted by the vibrating body used for the ultrasonic transducer to a low frequency of about 40 kHz.

Since the wavelength λ of the ultrasonic wave having a frequency of 40 kHz is 8.6 mm, in order to suppress the occurrence of the grating globe phenomenon while keeping the frequency of the ultrasonic wave radiated by the vibrating body at 40 kHz, the array pitch of the plurality of vibrating bodies is set. It is necessary to set 8.6 mm/2=4.3 mm or less.

However, at present, the diameter of the vibrating body capable of radiating ultrasonic waves of 40 kHz is about 10 mm, and therefore it is impossible to satisfy the above-mentioned demand by using the vibrating body at the present time.

In this regard, a configuration in which a waveguide (acoustic tube) is combined with an ordinary vibrating body that emits ultrasonic waves of 40 kHz (hereinafter referred to as a first conventional configuration) has been proposed.

In the first conventional configuration, one end side opening of the waveguide is connected to each of the plurality of vibrators arranged in parallel, and the vibrator radiates the array pitch of the other end side openings of the waveguide. It is configured so that it can be set to ½ or less of the wavelength of ultrasonic waves.

However, the first conventional configuration has a problem that the overall size of the sensor including the waveguide becomes large.
There is also a problem that the reflection of ultrasonic waves generated in the waveguide adversely affects the emission profile of ultrasonic waves.

As a configuration different from the first conventional configuration, an ultrasonic transducer (hereinafter, referred to as a second conventional configuration) including a plurality of vibrators manufactured by using a MEMS (Mico Electro Mechanical Systems) technique has been proposed ( For example, see Patent Documents 1 and 2 below.

In the second conventional configuration, the size of the vibrating plate vibrated by the piezoelectric element can be set to 400 to 800 μm, and a plurality of vibrating bodies can be arranged at an arrangement pitch of λ/2 or less.

However, in the second conventional configuration, the size of the diaphragm becomes too small, and it becomes difficult to generate an ultrasonic wave having a low frequency of about 40 kHz necessary for detecting an object several meters away.
In addition, there is a problem that the manufacturing cost rises as the manufacturing process becomes complicated.

JP, 2010-164331, A JP, 2013-046086, A

The present invention has been made in view of such a conventional technique, and is an ultrasonic transducer including a plurality of piezoelectric elements arranged in parallel, and an array of a plurality of vibrating bodies formed by the plurality of piezoelectric elements, respectively. An object of the present invention is to provide an ultrasonic transducer capable of preventing vibration propagation between the plurality of vibrating bodies as much as possible while narrowing the pitch.
Another object of the present invention is to provide a manufacturing method capable of efficiently manufacturing the ultrasonic transducer.

In order to achieve the above object, a first aspect of the present invention is an elastic plate having a first surface and a second surface facing one side and the other side in the plate thickness direction, respectively, and an elastic plate vibrating in the plate thickness direction, Sealing provided on the first surface of the elastic plate so as to form a plurality of piezoelectric elements fixed in parallel to the first surface of the elastic plate and a plurality of accommodating spaces that cover the plurality of piezoelectric elements, respectively. And a plurality of vibrating regions to which the plurality of piezoelectric elements are respectively mounted, a plurality of constraining regions surrounding the plurality of vibrating regions, one constraining region and the one constraining region. Including a boundary region that defines an outer region located more radially outward, the boundary region is a slit portion that divides the one constraint region and the outer region, and the one constraint region An ultrasonic transducer having a bridge portion mechanically connecting to an outer region is provided.

According to the ultrasonic transducer of the first aspect, it is possible to prevent the vibration propagation between the plurality of vibrating bodies as much as possible while narrowing the arrangement pitch of the plurality of vibrating regions.
Therefore, it is possible to effectively radiate low-frequency ultrasonic waves while effectively preventing or reducing mutual interference between the plurality of piezoelectric elements.

In the first aspect, preferably, a region along the outer peripheral edge of the vibrating region of the elastic plate is located at the vibrating region located radially inward of the region and radially outward of the region. The rigidity is lower than that of the constraint area.

According to such a configuration, the vibration region is flexibly supported by the low-rigidity region. Therefore, even if the area of the vibration region is reduced, a low resonance frequency can be realized, and the sound pressure of the vibration region can be reduced. Can be increased.

The low-rigidity region may be formed by a groove provided in a region of the first surface of the elastic plate along an outer peripheral edge of the vibration region.

According to such a configuration, the groove can be used as an alignment mark when the piezoelectric element is mounted on the vibrating region.

Instead of this, in the region along the outer peripheral edge of the vibrating region of the elastic plate, openings that divide the inside and the outside of the vibrating region and connecting portions that connect the inside and the outside of the vibrating region are alternately provided in the circumferential direction. It is also possible to form the low-rigidity region by the opening and the connecting portion.

According to this structure, the opening and the connecting portion can be used as alignment marks when the piezoelectric element is mounted in the vibration area.

In order to achieve the above-mentioned object, a second aspect of the present invention is a conductive metal plate that has a first surface and a second surface facing one side and the other side in the plate thickness direction, respectively, and is vibrating in the plate thickness direction. A formed elastic plate and a piezoelectric body and a pair of upper surface electrode layers and lower surface electrode layers arranged on both sides of the piezoelectric body in the thickness direction, respectively, and the lower surface electrode layer faces the first surface of the elastic plate. A plurality of piezoelectric elements fixed in parallel to the first surface of the elastic plate in a closed state, and a plurality of accommodating spaces that respectively cover the plurality of piezoelectric elements with a gap therebetween. A plurality of vibrating regions in which the plurality of piezoelectric elements are respectively mounted, and a plurality of low-rigidity regions surrounding the plurality of vibrating regions, respectively. A plurality of constraint areas surrounding the plurality of low-rigidity areas, and a boundary area partitioning the one constraint area and an outer area located radially outward of the one constraint area, Has a slit portion that divides the one restraint region and the outer region, and a bridge portion that mechanically connects the one restraint region to the outer region, and the low rigidity region, The first surface is a groove area closer to the second surface than the first surface of the vibration area and the restraint area, and the piezoelectric element is fixed to the first surface of the vibration area with an insulating adhesive. A central portion and an extending portion that extends radially outward from the central portion and ends in the low rigidity region in a plan view, and the lower surface electrode layer in the extending portion is formed by a conductive adhesive. An ultrasonic transducer electrically connected to a first surface of a low stiffness region.

With the ultrasonic transducer according to the second aspect, it is possible to prevent the vibration propagation between the plurality of vibrating bodies as much as possible while narrowing the arrangement pitch of the plurality of vibrating regions.
Therefore, it is possible to effectively radiate low-frequency ultrasonic waves while effectively preventing or reducing mutual interference between the plurality of piezoelectric elements.

Further, since the vibrating region is flexibly supported by the low-rigidity region, a low resonance frequency can be realized even if the area of the vibrating region is reduced, and the sound pressure of the sound wave radiated from the vibrating region can be increased. it can.
Further, the outer peripheral edge of the low rigidity region can be used as an alignment mark when the piezoelectric element is mounted in the vibration region.

In the second aspect, preferably, a ridge lower than the first surface of the vibrating region is bonded to the bottom surface of the groove region forming the low rigidity region in cooperation with the inner surface of the groove region. Providing a raised portion that forms an agent retention area, and providing the conductive adhesive that electrically connects the lower surface electrode layer in the extension portion and the first surface of the low-rigidity area in the adhesive retention area You can

According to such a configuration, an insulating adhesive that mechanically joins the central portion of the piezoelectric element and the vibration area, and the lower surface electrode layer of the extension portion of the piezoelectric element and the low rigidity area are electrically connected. It is possible to effectively prevent undesired mixing with the conductive adhesive, which can improve the reliability of electrical connection between the lower surface electrode layer of the piezoelectric element and the elastic plate.

In the various configurations of the first and second aspects, it is preferable that a gap exists between the upper surface of the piezoelectric element and a portion of the inner surface of the sealing member facing the upper surface of the piezoelectric element. The sound absorbing material can be fixed.
According to such a configuration, it is possible to effectively suppress sound wave leakage from the first surface side of the elastic plate.

Alternatively, the accommodation space may be filled with a sound absorbing material formed of a foaming resin.
Also with such a configuration, it is possible to effectively suppress the sound wave leakage from the first surface side of the elastic plate.

Further, the ultrasonic transducers according to the various configurations of the first and second aspects preferably further include a mass fixed to the first surface of the restraint region so as to surround the vibration region in a plan view. A member can be included.

According to such a configuration, it is possible to suppress the vibration of the constraint region, reduce the cross stroke between the plurality of vibration regions, and increase the vibration amplitude of the vibration region to increase the sound pressure of the generated sound wave. ..

Further, the ultrasonic transducers according to the various configurations of the first and second aspects are preferably a protection member joined to the second surface of the elastic plate, and the vibration region is outwardly extended. A protective member having an opening that opens to the inside can be provided.

According to such a configuration, it is possible to effectively prevent external contact with the elastic plate and effectively prevent damage to the elastic plate.

Preferably, a rigid protective plate having a through hole corresponding to the opening can be joined to the outer end surface of the protective member.

With such a configuration, it is possible to effectively prevent damage to the surface of the protective member and suppress vibration of the surface of the protective member.

In the ultrasonic transducers according to the various configurations of the first and second aspects, the sealing member is a tubular portion that covers the entire circumference of the vibration region, and the base end face is at a position including the boundary region. Between a cylindrical portion joined to the first surface of the elastic plate and having an end surface on the free end side separated from the first surface of the elastic plate more than the upper surface of the piezoelectric element, and the upper surface of the piezoelectric element. And a closing portion which forms an accommodation space by closing an opening on the free end side of the tubular portion while leaving a gap.
In this case, preferably, a rigid reinforcing plate is fixed to the outer surface of the closed portion.

More preferably, the ultrasonic transducer is a cylindrical partition wall member that surrounds the vibrating region in a plan view, wherein one end side in the axial direction is connected to the rigid reinforcing plate and the other end side in the axial direction is the elastic plate. A partition member may be further embedded in the tubular portion with a gap between the partition member and the first surface.

According to such a configuration, it is possible to effectively prevent or reduce the vibration propagation between the adjacent vibration regions without hindering the vibration operation of the vibration region.

In the ultrasonic transducers according to various configurations of the first and second aspects, for example, the elastic plate is a conductive metal plate, and the piezoelectric element includes a piezoelectric body and a piezoelectric body on both sides in a thickness direction of the piezoelectric body. It has a pair of upper surface electrode layer and lower surface electrode layer which are arranged.
In this case, preferably, the elastic plate is provided with a wiring body including an insulating layer provided on the first surface and a plurality of wiring conductors laminated on the insulating layer, and the lower surface electrode layer is made of a conductive material. Is bonded mechanically and electrically to the first surface of the elastic plate by a conductive adhesive, and the upper electrode layer is electrically connected to the corresponding wiring conductor by a conductive adhesive or solder.

According to such a configuration, it is possible to realize electrical connection between the piezoelectric element and an external voltage with a simple structure.

Preferably, an insulating adhesive is interposed between the conductive adhesive or solder that electrically connects the upper electrode layer and the corresponding wiring conductor, and the first surface of the elastic plate.

According to such a configuration, it is possible to effectively prevent the conductive adhesive or the solder from unintentionally contacting the first surface of the elastic plate and short-circuiting the upper surface electrode layer and the lower surface electrode layer. You can

In the ultrasonic transducers according to the various configurations of the first and second aspects, for example, the plurality of constraint regions are m (m is 1) arranged along a first plate surface direction of the elastic plate. The constraint region group formed by the constraint regions of (the above integers) is provided in n rows (n is an integer of 1 or more) in the second plate surface direction orthogonal to the first plate surface direction, and is expressed by m× It is assumed to have n constraint regions.

In this case, preferably, the slit portions are located on both sides in the second plate surface direction of the one piezoelectric element mounted in the vibration region in the one restraint region, and extend along the first plate surface direction. A first plate surface direction slit, and a pair of second plate surface direction slits located on both sides of the first piezoelectric element in the first plate surface direction and extending along the second plate surface direction, The pair of first plate surface direction slits are longer than the first plate surface direction length of the one piezoelectric element, and the pair of second plate surface direction slits are larger than the second plate surface direction length of the pair of piezoelectric elements. It is made long and is configured such that four locations defined by the ends of the first plate surface direction slit and the second plate surface direction slit adjacent to each other in the circumferential direction form the bridge portion.

More preferably, a single common slit is provided between the adjacent constraining regions, and the single common slit defines the outer peripheral edges of both of the adjoining constraining regions.

Further, according to the present invention, an elastic plate having a first surface and a second surface respectively facing one side and the other side in the plate thickness direction and vibrating in the plate thickness direction, and a piezoelectric body and a thickness direction of the piezoelectric body, respectively. A plurality of piezoelectric elements each having an upper surface electrode layer and a lower surface electrode layer disposed on both sides, wherein the lower surface electrode layer is fixed to the first surface of a plurality of vibrating regions provided on the elastic plate; A sealing member provided on the first surface of the elastic plate so as to form a plurality of accommodating spaces that cover the respective elements, and the elastic plate includes a plurality of constraining regions that respectively surround the plurality of vibrating regions. A boundary region that divides the one constraint region and an outer region located radially outward of the one constraint region, and the boundary region divides the one constraint region and the outer region. It has a slit portion and a bridge portion that mechanically connects the one restraint region to the outer region, the first surface of the elastic plate is laminated on the insulating layer and the insulating layer, A method of manufacturing an ultrasonic transducer, wherein a wiring body including a plurality of wiring conductors electrically connected to upper surface electrode layers of the plurality of piezoelectric elements is provided, wherein conductive elastic material forming the elastic plate is provided. A step of preparing a plate forming body, and an insulating layer forming member for forming the insulating layer and a wiring conductor forming member for forming the plurality of wiring conductors are provided on the first surface of the elastic plate forming body on one side in the plate thickness direction. A step of etching away the unnecessary portions of the insulating layer forming member and the wiring conductor forming member to form the insulating layer and the plurality of wiring conductors; and etching the elastic plate forming body to form the slit portion. The step of forming an elastic plate, the step of adhering the lower surface electrode layers of the plurality of piezoelectric elements to the first surface of the plurality of vibrating regions with a conductive adhesive, and the tips of the plurality of wiring conductors. An electrical connection step of electrically connecting to the upper surface electrode layer of the piezoelectric element with a conductive adhesive or solder, and a sealing member installation step of providing the sealing member on the first surface of the elastic plate. A method for manufacturing a sound wave transducer is provided.

According to such a manufacturing method, it is possible to manufacture the ultrasonic transducer having the above configuration at low cost and with good yield.

Preferably, in the elastic plate etching step, in addition to the formation of the slit portion, a groove is formed in a region along the outer peripheral edge of the vibrating region of the first surface of the elastic plate, or the vibrating region is formed. It is configured to form a plurality of openings along the outer peripheral edge, with a connecting portion left between the openings adjacent to each other in the circumferential direction.

Further, according to the present invention, an elastic plate having a first surface and a second surface respectively facing one side and the other side in the plate thickness direction and vibrating in the plate thickness direction, and a piezoelectric body and a thickness direction of the piezoelectric body, respectively. A plurality of piezoelectric elements each having an upper surface electrode layer and a lower surface electrode layer disposed on both sides, wherein the lower surface electrode layer is fixed to the first surface of a plurality of vibration regions provided on the elastic plate; A sealing member provided on the first surface of the elastic plate so as to form a plurality of accommodating spaces that cover the piezoelectric elements, respectively, and the elastic plate has a plurality of low-rigidities surrounding the plurality of vibration regions. A region, a plurality of constraint regions surrounding the plurality of low-rigidity regions, and a boundary region that partitions one constraint region and an outer region located radially outward of the one constraint region, The low-rigidity region is a groove region in which the first surface of the low-rigidity region is closer to the second surface than the first surface of the vibration region and the restraint region and is open to the first surface side. The bottom surface is provided with a raised portion that is lower than the first surface of the vibrating region and the constraining region and that forms an adhesive retention region in cooperation with the inner side surface of the groove region. The region has a slit part that divides the one constraint region and the outer region, and a bridge part that mechanically connects the one constraint region to the outer region, and the piezoelectric element, In the low-rigidity region, which extends in a radial direction outward from the central portion, which overlaps with the vibration region in plan view and is bonded to the first surface of the vibration region by an insulating adhesive, and in the plan view. And an extension portion joined to the first surface of the low-rigidity region by a conductive adhesive disposed in the adhesive retention region, the first surface of the elastic plate, A method of manufacturing an ultrasonic transducer, comprising: an insulating layer; and a wiring body that is laminated on the insulating layer and that includes a plurality of wiring conductors electrically connected to upper surface electrode layers of the plurality of piezoelectric elements. A step of preparing a conductive elastic plate forming body for forming the elastic plate; an insulating layer forming member for forming the insulating layer on the first surface of the elastic plate forming body on one side in the plate thickness direction; Providing a wiring conductor forming member for forming a wiring conductor, and etching away unnecessary portions of the insulating layer forming member and the wiring conductor forming member to form the insulating layer and the plurality of wiring conductors; and forming the elastic plate. The body is etched to form the slit portion, and the region corresponding to the low rigidity region is half-etched from the first surface side. An elastic plate etching process for forming the low rigidity region which is a groove region, and an insulating adhesive and a conductive adhesive applied to the first surface of the vibrating region and the first surface of the adhesive retention region, respectively. Piezoelectric element bonding step of bonding the plurality of piezoelectric elements with an agent, and electrical connection step of electrically connecting the tip end portions of the plurality of wiring conductors to the corresponding upper surface electrode layer of the piezoelectric element with a conductive adhesive or solder. And a sealing member installation step of providing the sealing member on the first surface of the elastic plate, and the half etching process for forming the low rigidity region that is the groove region corresponds to the vibration region. The low rigidity region is reduced by covering the region and the region corresponding to the constrained region with a mask and the region corresponding to the raised portion with a mask having a width narrower than twice the side etching amount. Provided is a method for manufacturing an ultrasonic transducer, which is configured to leave a raised portion lower than the vibrating region and the constraining region on the bottom surface of the groove region while forming the groove region that opens to the first surface side.

According to such a manufacturing method, it is possible to manufacture the ultrasonic transducer having the above configuration at low cost and with good yield.

The manufacturing method according to various configurations of the present invention preferably comprises a step of applying an insulating resin between the tip portions of the plurality of wiring conductors and the corresponding piezoelectric elements before the electrical connecting step. , The conductive adhesive or the solder in the electrical connection step, the insulating resin is interposed between the conductive adhesive or the solder and the first surface of the elastic plate, Of the wiring conductor is provided so as to be electrically connected to the corresponding upper surface electrode layer of the piezoelectric element.

In one aspect of the manufacturing method according to the present invention, the sealing member is a tubular portion that covers the entire circumference of the vibration region, and the first end of the elastic plate is at a position where a base end face includes the boundary region. A cylindrical portion that is joined to the surface and is formed such that the end surface on the free end side is separated from the first surface of the elastic plate with respect to the upper surface electrode layer of the piezoelectric element, and the free end side of the cylindrical portion. A closing part that closes the opening to form the accommodation space, and the sealing member installation step includes a step of preparing the sealing member and an outer surface of the closing part of the sealing member. Between the step of fixing the rigid reinforcing plate, and before or after the step of fixing the rigid reinforcing plate, between the upper electrode layer of the piezoelectric element in the state where the sealing member is fixed to the first surface of the elastic plate. A step of fixing a sound absorbing material to the inner surface of the closed part so that a gap exists, and a step of fixing the rigid reinforcing plate and the sealing member with the sound absorbing material fixed to the first surface of the elastic plate It is assumed to include and.

In another aspect, the sealing member installation step includes a step of joining the tubular portion to the first surface of the elastic plate, and a step of filling the tubular portion with foamable silicone that acts as a sound absorbing material, The method includes a step of forming the closed portion and a step of fixing a rigid reinforcing plate to an outer surface of the closed portion.

Preferably, in the manufacturing method according to the present invention, after the sealing member installation step, a resin protective member having an opening that opens the vibration region outward is joined to the second surface of the elastic plate. Can include steps.

More preferably, the manufacturing method according to the present invention further comprises a step of, after the step of joining the protective member, joining a rigid protective plate having a through hole corresponding to the opening to an outer end surface of the protective member. You can

FIG. 1 is a plan view of an ultrasonic transducer according to a first embodiment of the present invention, showing a state in which some constituent members are removed. FIG. 2 is an enlarged view of part II in FIG. FIG. 3 is a sectional view taken along line III-III in FIG. FIG. 4 is a partially enlarged plan view of the ultrasonic transducer according to the first modification of the first embodiment, showing a state in which some of the constituent members are removed. FIG. 5 is a partially enlarged plan view of the ultrasonic transducer according to the second modification of the first embodiment, showing a state in which some of the constituent members are removed. FIG. 6 is a partially enlarged plan view of the ultrasonic transducer according to the third modification of the first embodiment, showing a state in which some of the constituent members are removed. FIG. 7 is a plan view of the ultrasonic transducer according to the fourth modified example of the first embodiment, showing a state in which some of the constituent members are removed. FIG. 8 is a partial vertical cross-sectional view of the ultrasonic transducer according to the fifth modified example of the first embodiment. 9A to 9C are process diagrams of the method for manufacturing the ultrasonic transducer according to the first embodiment. 10A to 10C are process diagrams of the manufacturing method following FIG. 9C. 11A to 11C are process diagrams of the manufacturing method following FIG. 10C. 12(a) to 12(c) are process diagrams of the manufacturing method following FIG. 11(c). 13A to 13C are process diagrams of a method of manufacturing an assembly formed of the sealing member, the reinforcing plate, and the sound absorbing material in the ultrasonic transducer according to the first embodiment. 14A to 14C are process drawings of a method for manufacturing an ultrasonic transducer according to the fifth modification. 15A to 15C are process diagrams of the manufacturing method following FIG. 14C. FIG. 16 is a partial vertical cross-sectional view of the ultrasonic transducer according to the second embodiment of the present invention. FIG. 17 is a partial vertical cross-sectional view of the ultrasonic transducer according to the third embodiment of the present invention. FIG. 18 is a plan view of the ultrasonic transducer according to the fourth embodiment of the present invention, showing a state in which some of the constituent members are removed. 19 is a sectional view taken along line IX-IX in FIG. 20A to 20C are process diagrams of the method for manufacturing the ultrasonic transducer according to the fourth embodiment.

Embodiment 1
An embodiment of an ultrasonic transducer according to the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a plan view of an ultrasonic transducer 1A according to the present embodiment, in which a sealing member 40 and a reinforcing plate 60 described below are removed.
2 and 3 show an enlarged view of the II portion in FIG. 1 and a cross-sectional view taken along the line III-III in FIG. 2, respectively.

The ultrasonic transducer 1A according to the present embodiment is preferably used as a phased array sensor used for detecting the shape of an object, detecting a wide range of objects, and the like.

Specifically, as shown in FIGS. 1 to 3, the ultrasonic transducer 1A includes an elastic plate 10 having a first surface 10a and a second surface 10b facing one side and the other side in the plate thickness direction, respectively, A plurality of piezoelectric elements 30 fixed to the first surface 10a of the elastic plate 10 in parallel in the plate surface direction and a plurality of accommodation spaces 40a that cover the plurality of piezoelectric elements 30 with a gap therebetween are formed. Thus, the sealing member 40 provided on the first surface 10a of the elastic plate 10 is provided.

As long as the elastic plate 10 has elasticity capable of vibrating in the plate thickness direction, it is made of a metal plate such as stainless steel, Ni-Fe alloy, aluminum alloy, or titanium alloy, and various materials such as carbon fiber reinforced plastic and ceramics. obtain.
The elastic plate 10 has a thickness of, for example, 0.05 mm to 0.1 mm.
In the present embodiment, the elastic plate 10 is formed of a conductive metal plate.

The piezoelectric element 30 has a piezoelectric body made of PZT (lead titanate dilyconate) and a pair of upper surface electrode layers and lower surface electrode layers arranged on both sides in the thickness direction of the piezoelectric body.
The piezoelectric body has a thickness of, for example, 0.05 mm to 0.3 mm, and the upper surface electrode layer and the lower surface electrode layer are formed of, for example, Ag or Au having a thickness of 0.05 μm to several μm.

The plurality of piezoelectric elements 30 are fixed to the first surface 10a of the elastic plate 10 in parallel with the lower surface electrode layer facing the first surface 10a of the elastic plate 10.

Specifically, as shown in FIGS. 1 to 3, the elastic plate 10 has a plurality of vibrating regions 12 in which the plurality of piezoelectric elements 30 are mounted, and a plurality of restraints surrounding the plurality of vibrating regions 12, respectively. A region 14 and a boundary region 16 that divides the one restraint region 14 and the outer region located radially outward of the one restraint region 14 are provided.

In the present embodiment, as shown in FIG. 1, the plurality of constraint regions 14 surrounding the plurality of vibration regions 12 in a plan view are arranged along the first plate surface direction D1 of the elastic plate 10. The constrained region group 14A formed by the m (five in the illustrated embodiment) constrained regions 14 has n rows (in the illustrated embodiment) in the second plate surface direction D2 orthogonal to the first plate surface direction D1. Has 3 rows), and m×n (5×3=15 in the illustrated embodiment) constraint regions 14 that appear by being provided.

The plurality of vibrating regions 12 each surrounded by the plurality of constraining regions 14 also include m×n vibrating regions 12.
The m×n piezoelectric elements 30 are attached to the m×n vibration regions 12, respectively.

In addition, in the present embodiment, as shown in FIG. 1, the plurality of vibration regions 12 (the plurality of constraint regions 14) are arranged in a grid pattern, but of course, the plurality of vibration regions 12 ( The plurality of constrained regions 14) are not limited to such an arrangement, and may be arranged in a staggered pattern or a radial pattern.

In the present embodiment, as described above, the elastic plate 10 is a conductive metal plate, and the piezoelectric element 30 has the lower surface electrode layer formed of the elastic plate by the conductive adhesive 38 (see FIG. 3). The elastic plate 10 is mechanically fixed to the first surface 10a of the elastic plate 10 while being electrically connected to the first surface 10a of the elastic plate 10.

As shown in FIG. 2, the boundary region 16 is a slit that divides the one constraint region 14 that defines the outer peripheral edge of the boundary region and the outer region that is adjacent radially outward of the one constraint region 14. It has a part 17 and a bridge part 18 that maintains the mechanical connection of the one restraint region 14 to the outer region.

As shown in FIG. 3, the sealing member 40 is a plurality of tubular portions 42 that cover each of the plurality of vibration regions 12 in a plan view, and the elasticity is provided at a position where a base end surface includes the boundary region 16. A plurality of cylindrical portions 42 joined to the first surface 10a of the plate 10 and having an end surface on the free end side separated from the first surface 10a of the elastic plate 10 by a distance from the upper surface electrode layer of the piezoelectric element 30; Closure for forming a plurality of accommodation spaces 40a for accommodating the plurality of piezoelectric elements 30 by closing the openings on the free end side of the plurality of cylindrical portions 42 with a gap between the element 30 and the upper surface electrode layer. And a portion 44.

By providing a gap between the inner surface of the closing portion 44 and the piezoelectric element 30, the sealing member 40 does not restrict the vibration of the piezoelectric element 30 and the vibration region 12.

The sealing member 40 is made of, for example, a polymer material such as silicone and is bonded to the elastic plate 10 with an adhesive.

As described above, in the ultrasonic transducer 1A according to the present embodiment, by mounting a plurality of piezoelectric elements 30 on one elastic plate 10, a plurality of vibrations vibrated by the plurality of piezoelectric elements 30 are provided. By virtue of the slit portion 17, it is possible to realize that the vibration of one vibration region 12 propagates to the outer region located radially outward of the one vibration region 12 while realizing the closest possible arrangement between the regions 12. It can be effectively prevented or reduced.

Therefore, it is possible to emit a low frequency ultrasonic wave (for example, 30 kHz to 40 kHz) from the piezoelectric element 30 and the vibration region 12, and it is effective that a grating globe phenomenon occurs between the plurality of piezoelectric elements 30. Can be prevented or reduced.

In the present embodiment, as shown in FIG. 2, the slit portions 17 are located on both sides of the one piezoelectric element 30 mounted in the vibration region 12 in the one constraint region 14 in the second plate surface direction D2. A pair of first plate surface direction slits 17a extending along the first plate surface direction D1 and both sides of the one piezoelectric element 30 in the first plate surface direction D1 and in the second plate surface direction D2. It includes a pair of second plate surface direction slits 17b extending along.

The pair of first plate surface direction slits 17a are longer than the first plate surface direction length 30a of the one piezoelectric element 30, and the pair of second plate surface direction slits 17b are the second of the one piezoelectric element 30. It is made longer than the plate surface direction length 30b, and at four locations defined by the ends of the first plate surface direction slit 17a and the second plate surface direction slit 17b which are circumferentially adjacent to each other. The bridge portion 18 is provided.

According to such a configuration, it is possible to effectively prevent the vibration from propagating between the plurality of piezoelectric elements 30 arranged in a rectangular shape, and stably hold the plurality of constraint regions 14.

In addition, in the present embodiment, as shown in FIGS. 1 and 2, a single common slit 17 is provided between the adjacent constraint regions 14, and the single common slit 17 is adjacent. It is configured to define both outer peripheral edges of the restraint region 14.

According to such a configuration, it is possible to effectively prevent the vibration propagation between the plurality of piezoelectric elements 30 and reduce the installation area of the plurality of constraint regions 14 as much as possible.

The slit portion 17 and the bridge portion 18 can have various configurations.
FIG. 4 shows a partially enlarged plan view of an ultrasonic transducer 1B according to a modified example including the slit portion 21 and the bridge portion 22 having different configurations.

In the modification 1B shown in FIG. 4, the slit portion 21 has an arc shape.
The four restraint portions 21 are configured to surround one restraint region 14, and the bridge portion 22 is provided between the two neighboring slit portions 21 in the circumferential direction.

Further, FIG. 5 shows a partially enlarged plan view of an ultrasonic transducer 1C according to another modified example including the slit portion 23 and the bridge portion 24 having a different configuration.

In the modification 1C shown in FIG. 5, the slit portion 23 is substantially L-shaped in a plan view.
Further, the one restraint region 14 is configured such that the four slit portions 23 surround the one restraint region 14.

Specifically, the two L-shaped slits 23 that are adjacent to each other in the circumferential direction overlap in the circumferential direction in a state in which a part 23 a of one slit 23 is located radially inward of a part 23 b of the other slit 23. And the radial gap between the part 23a of the one slit 23 and the part 23b of the other slit 23 forms the bridge portion 24.

In the slit portions 17 (21, 23) and the bridge portions 18 (22, 24) having various configurations, preferably, when the circumferential length of the boundary region 16 is L, the plurality of slit portions 17 (21 , 23), the total length La in the circumferential direction may satisfy La≧0.9×L.

As shown in FIGS. 1 to 3, in the ultrasonic transducer 1A according to the present embodiment, the region of the elastic plate 10 along the outer peripheral edge of the vibrating region 12 is located within the radial direction of the region. It is configured so as to be a low-rigidity region 26 having a lower rigidity than the vibration region 12 located on one side and the constraint region 14 located on the outside in the radial direction of the region.

By providing such a configuration, the vibration characteristics of the vibration region 12 can be enhanced.
Therefore, it is possible to generate a low frequency sound wave while reducing the size of the vibrating region 12 to reduce the array pitch of the plurality of vibrating regions 12.

In the present embodiment, as shown in FIGS. 2 and 3, the outer shape of the vibrating region 12 and the outer shape of the piezoelectric element 30 are the same, and the first surface 10a of the elastic plate 10 has the same shape. A groove 27 is provided in a region along the outer peripheral edge of the vibration region 12, and the groove 27 forms the low-rigidity region 26.

According to such a configuration, the groove 27 can be used as an alignment mark when the piezoelectric element 30 is mounted on the vibrating region 12 while forming the low-rigidity region 26 by the groove 27.

FIG. 6 shows a partially enlarged plan view of an ultrasonic transducer 1D according to a modified example in which the low rigidity region 26 is formed by a different structure.

In Modification 1D shown in FIG. 6, an opening 28a that divides the inside and outside of the vibration region 12 and the inside and outside of the vibration region 12 are connected to a region along the outer peripheral edge of the vibration region 12 of the elastic plate 10. Connecting portions 28b are provided alternately in the circumferential direction, and the low-rigidity region 26 is formed by the openings 28a and the connecting portions 28b.
Like the groove 27, the opening 28a and the connecting portion 28b can also be used as alignment marks when the piezoelectric element 30 is mounted on the vibrating region 12.

In the present embodiment, the vibrating region 12 has a circular shape in plan view and the piezoelectric element 30 has a circular shape in plan view having the same shape as that of the piezoelectric element 30. It is not limited to such a form.
FIG. 7 shows a plan view of an ultrasonic transducer 1E according to a modified example including the vibration region 12 having a rectangular shape in plan view and the piezoelectric element 30.

As shown in FIG. 3, in the ultrasonic transducer 1A according to the present embodiment, the piezoelectric element 30 is further provided on a portion of the inner surface of the sealing member 40 facing the upper surface electrode layer of the piezoelectric element 30. The sound absorbing material 50 is fixed to the upper electrode layer with a gap.
The sound absorbing material 50 is formed of, for example, foamable silicone.

By providing the sound absorbing material 50, it is possible to prevent or reduce leakage of ultrasonic waves from the vibrating region 12 to the rear (the first surface 10a side in the plate thickness direction of the elastic plate 1), and at the same time, burst ultrasonic waves can be prevented. After being emitted, the reverberation of the ultrasonic wave can be effectively suppressed.

FIG. 8 shows a partial vertical cross-sectional view of an ultrasonic transducer 1F according to a modified example in which a sound absorbing material 55 is provided instead of the sound absorbing material 50.
In Modification 1F shown in FIG. 8, the sound absorbing material 55 formed of, for example, foaming silicone is filled in the accommodation space 40a.

As shown in FIG. 3, the ultrasonic transducer 1A according to the present embodiment further includes a reinforcing plate 60 fixed to the outer surface of the closing portion 44 of the sealing member 40.
The reinforcing plate 60 is formed of a rigid plate such as stainless steel.

By providing the reinforcing plate 60, the strength of the ultrasonic transducer 1A can be increased without impairing vibration characteristics.

The ultrasonic transducer 1A according to the present embodiment is further a protection member 70 joined to the second surface 10b of the elastic plate 10, and has an opening 72 that opens the vibrating region 12 to the outside. The member 70 is provided.
The protection member 70 is made of, for example, silicone.

By providing the protection member 70, the elastic plate 10 can be protected without impairing vibration characteristics.

The ultrasonic transducer 1A further includes a rigid protective plate 75 joined to the outer end surface of the protective member 70.
The protective plate 75 is provided with a through hole 77 corresponding to the opening 72 of the protective member 70.
The protection plate 75 is formed of, for example, a metal plate such as stainless steel, Ni—Fe alloy, aluminum alloy, or titanium alloy.

By providing the protection plate 75, it is possible to effectively prevent or reduce damage to the protection member 70, and effectively suppress unintentional vibration of the protection member 70.

Further, the ultrasonic transducer 1A according to the present embodiment integrally includes a wiring body 80 for applying a voltage to the upper surface electrode layer of the piezoelectric element 30, as shown in FIGS. ing.

The wiring body 80 has an insulating layer 82 fixed on the first surface 10 a of the elastic plate 10 and a conductor layer 84 laminated on the insulating layer 82.
The insulating layer 82 is formed of polyimide, for example.
The conductor layer 84 is formed of Cu/Au, for example.

The conductor layer 84 has a plurality of wiring conductors 85 electrically connected to the upper surface electrode layers of the plurality of piezoelectric elements 30, respectively.

As shown in FIG. 3, the plurality of wiring conductors 85 are electrically connected to the upper surface electrode layer of the piezoelectric element 30 corresponding to the tip end portion through a conductive adhesive or solder 87, and the base end portion. Form a pad 86 (see FIG. 1) for connection with the outside.

In the present embodiment, as shown in FIG. 3, the conductive adhesive or the solder 87 and the elastic plate 10 that electrically connect the tip portion of the wiring conductor 85 and the upper surface electrode layer of the piezoelectric element 30. The insulating resin 88 is interposed between the first surface 10a and the first surface 10a, thereby effectively preventing the wiring conductor 85 and the upper electrode layer from being short-circuited to the elastic plate 10.

As described above, the lower surface electrode layers of the plurality of piezoelectric elements 30 are electrically connected to the conductive elastic plate 10 via the conductive adhesive 38.
The elastic plate 10 is provided with a lower surface electrode layer pad 89 in a state of being electrically connected to the elastic plate 10.

The wiring body 80 may be provided with an insulating cover layer (not shown) surrounding the conductor layer 84 in order to effectively prevent the conductor layer 84 from contacting the outside.

Next, a method for manufacturing the ultrasonic transducer 1A will be described.
In the manufacturing method, a step of preparing a conductive elastic plate forming body 110 for forming the elastic plate 10 and forming the insulating layer 82 on the first surface of the elastic plate forming body 110 on one side in the plate thickness direction. A step of providing a wiring body forming member 180 including an insulating layer forming member 182 and a wiring conductor forming member 185 forming the plurality of wiring conductors 85 (FIG. 9A), and an unnecessary portion of the wiring body forming body 180 is etched. And removing the insulating layer 82 and the wiring body 80 including the plurality of wiring conductors 85 (FIGS. 9B and 9C).

In the present embodiment, in the step of forming the wiring body 80, first, unnecessary portions of the wiring conductor forming member 185 are removed by etching to form the plurality of wiring conductors 85 (FIG. 9B). After that, an unnecessary portion of the insulating layer forming member 182 is removed by etching to form the insulating layer 82 (FIG. 9C).

The manufacturing method further includes an elastic plate etching step (FIGS. 10A and 10B) of forming the slit portion 17 by etching the elastic plate forming body 110.

In the present embodiment, in the elastic plate etching step, in addition to the formation of the slit portion 17, a groove 27 is formed in a region of the first surface 10 a of the elastic plate 10 along the outer peripheral edge of the vibrating region 12. Is formed (see FIG. 10(a)).

In the present embodiment, first, the groove 27 is formed by half etching and then the slit portion 17 is formed, but the order of forming the groove 27 and the slit portion 17 does not matter.

When the low-rigidity region 26 is exposed by the plurality of openings 28a as in the modification 1D, the elastic plate etching step replaces the formation of the groove 27 with the vibration region 12. A plurality of openings 28a along the outer peripheral edge of which are formed so that the connecting portions 28b are left between the openings 28a adjacent in the circumferential direction.

The manufacturing method further includes a piezoelectric element mounting step of bonding the lower surface electrode layers of the plurality of piezoelectric elements 30 to the first surfaces 10a of the plurality of vibration regions 12 with the conductive adhesive 38, respectively.

Specifically, the piezoelectric element mounting step includes a step of applying a conductive adhesive 38 to the first surfaces 10a of the plurality of vibration regions 12 (FIG. 10(c)), and a step of applying the conductive adhesive 38 onto the first surface 10a. The step (11(a)) of mounting the piezoelectric element 30 on the substrate and curing the conductive adhesive 38.

10(a) to 10(c), reference numeral 39 is gold plating provided on the first surface 10a of the vibrating region 12 before the application of the conductive adhesive 38. This is for improving the reliability of electrical connection with the first surface 10a of the vibrating region 12.

The manufacturing method further includes an electrical connection step of electrically connecting the tip ends of the plurality of wiring conductors 85 to the corresponding upper surface electrode layers of the piezoelectric elements 30 with a conductive adhesive or solder 87 (FIG. 11(c)). )have.

Here, in the present embodiment, in order to effectively prevent the conductive adhesive 87 from coming into contact with the elastic plate 10 and short-circuiting the upper surface electrode layer and the lower surface electrode layer, the manufacturing method Has a step (FIG. 11(b)) of applying an insulating adhesive 88 between the tips of the plurality of wiring conductors 85 and the corresponding piezoelectric elements 30 before the electrical connection step. ..

In this case, the electrically conductive adhesive or the solder 87 in the electrical connection step has the insulating adhesive 88 interposed between the electrically conductive adhesive or the solder 87 and the first surface 10a of the elastic plate 10. In the inserted state, it is applied so that the tip ends of the plurality of wiring conductors 85 are electrically connected to the corresponding upper surface electrode layers of the piezoelectric element 30.

The manufacturing method further includes a sealing member installation step (FIG. 12A) in which the sealing member 40 is provided on the first surface 10a of the elastic plate 10.

Here, as shown in FIG. 3, the ultrasonic transducer 1A according to the present embodiment has the sound absorbing material 50 and the rigid reinforcing plate 60 fixed to the sealing member 40.

In this case, the sealing member installation step includes a step of preparing a sealing member 40 integrally including the tubular portion 42 and the closing portion 44 (FIG. 13(a)), and the sealing member 40 The sealing member 40 is attached to the elastic plate 10 before or after the step of fixing the rigid reinforcing plate 60 to the outer surface of the closing portion 44 (FIG. 13B) and the step of fixing the rigid reinforcing plate 60. A step of fixing the sound absorbing material 50 to the inner surface of the closing portion 44 so that there is a gap between the piezoelectric element 30 and the upper surface electrode layer in the state of being fixed to the first surface 10a (FIG. 13(c)); The step of fixing the sealing member 40 with the rigid reinforcing plate 60 and the sound absorbing material 50 fixed to the first surface of the elastic plate (FIG. 12(a)).

In the case of manufacturing the modified example 1F shown in FIG. 8 in which the accommodation space 40a is filled with the sound absorbing material 55, the sealing member installation step is performed on the first surface 10a of the elastic plate 10 in the above-described manner. A step of joining the tubular portion 42 (FIG. 14(a)), a step of filling the tubular portion 42 with a foaming silicone acting as a sound absorbing material 55 (FIG. 14(b)), and the closing portion 44. 14(c) and a step of fixing the rigid reinforcing plate 60 to the outer surface of the closed portion 44 (FIG. 15(a)).

In the manufacturing method, further, after the sealing member installation step, a resin protective member 70 having an opening 72 that opens the vibrating region 12 to the outside is joined to the second surface 10b of the elastic plate 10. The step (FIGS. 12(b) and 15(b)) and the step of joining a rigid protective plate 75 having a through hole 77 corresponding to the opening 72 to the outer end surface of the protective member 70 (FIG. 12(c)). And FIG. 15(c)).

Embodiment 2
Hereinafter, another embodiment of the ultrasonic transducer according to the present invention will be described with reference to the accompanying drawings.
FIG. 16 is a vertical cross-sectional view of the ultrasonic transducer 2 according to the present embodiment, which corresponds to FIG. 3 in the first embodiment.
In the drawings, the same members as those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be appropriately omitted.

As shown in FIG. 16, the ultrasonic transducer 2 according to the present embodiment further surrounds the vibrating region 12 in a plan view as compared with the ultrasonic transducer 1A according to the first embodiment. As described above, the mass member 210 fixed to the first surface 10a of the restraint region 14 is provided.
The mass member 210 has a cylindrical shape that surrounds the vibrating region 12 in a plan view, and is made of a metal member such as stainless steel.

By including the mass member 210, it is possible to effectively and effectively reduce the vibration of the vibrating region 12 propagating to the constraining region 14 and vibrating the constraining region 14.

The mass member 210 is joined to the first surface 10a of the restraint region 14 by spot welding with an adhesive or a laser in a state where the base end surface of the mass member 210 is in contact with the first surface 10a.
The joining of the mass member 210 to the restraint region 14 is performed before the sealing member installation step.

When the mass member 210 is bonded to the constraining region 14 with an adhesive, the resonance frequency of the vibrating region 12 may be affected due to variations in the distribution of the adhesive.

On the other hand, when the mass member 210 is joined to the constrained region 14 by spot welding, the installation posture of the mass member 210 can be stabilized, and the resonance frequency of the vibration region 12 can be reduced. Variation can be effectively suppressed.

A recess that covers the wiring body 80 may be formed in a portion of the base end surface of the mass member 210 located on the wiring body 80.
By providing such a configuration, it is possible to effectively prevent contact between the mass member 210 and the wiring body 80 while providing the mass member 210 over the entire circumference of the vibration region 12.

In the present embodiment, as shown in FIG. 16, the outer peripheral surface and the upper end surface of the mass member 210 are in contact with the inner surface of the sealing member 40.
By providing such a configuration, the vibration preventing effect of the mass member 210 on the restraint region 14 can be further improved.

Note that, as shown in FIG. 16, in the present embodiment, the mass member 210 is configured such that the outer peripheral edge of the mass member 210 and the inner peripheral edge of the boundary region 16 coincide with each other.

Embodiment 3
Hereinafter, still another embodiment of the ultrasonic transducer according to the present invention will be described with reference to the accompanying drawings.
FIG. 17 is a vertical cross-sectional view of the ultrasonic transducer 3 according to the present embodiment, which corresponds to FIG. 3 in the first embodiment and FIG. 16 in the second embodiment.
In the drawings, the same members as those in Embodiments 1 and 2 are designated by the same reference numerals, and detailed description thereof will be appropriately omitted.

As shown in FIG. 17, the ultrasonic transducer 3 according to the present embodiment further includes a partition member 230 as compared with the ultrasonic transducer 1A according to the first embodiment.

As shown in FIG. 17, the partition member 230 has a cylindrical shape surrounding the vibrating region 12 in a plan view, one end side in the axial direction is connected to the rigid reinforcing plate 60, and the other end side in the axial direction is the elastic member. It is embedded in the tubular portion 42 of the sealing member 40 in a state in which there is a gap between the plate 10 and the first surface 10a.

The partition member 230 may be formed integrally with the rigid reinforcing plate 60, or may be formed separately from the rigid reinforcing plate 60 and bonded to the rigid reinforcing plate 60 by adhesion or welding. Is.
The partition wall member 230 may be formed by casting using aluminum, or cutting or etching an iron-based member such as stainless steel.

By providing the partition member 230, it is possible to improve the occlusivity of the sealing member 40 by the tubular portion 42, and at the same time, prevent or reduce the vibration propagation from the vibration region 12, while suppressing the vibration of the vibration region 12. The movement can be suppressed, and the vibration characteristics of the vibration region 12 can be improved.

Of course, it is possible to equip the ultrasonic transducer 2 according to the second embodiment with the partition member 230.

Embodiment 4
Hereinafter, still another embodiment of the ultrasonic transducer according to the present invention will be described with reference to the accompanying drawings.
FIG. 18 is a plan view of the ultrasonic transducer 4 according to the present embodiment, in which the sealing member 40 and the reinforcing plate 60 are removed.
Further, FIG. 19 shows a cross-sectional view taken along line IXX-IXX in FIG.
In the figure, the same members as those in the first to third embodiments are designated by the same reference numerals, and detailed description thereof will be appropriately omitted.

The ultrasonic transducer 4 according to the present embodiment mainly has an elastic plate 310 and a plurality of piezoelectric elements 330 instead of the elastic plate 10 and the plurality of piezoelectric elements 30. The ultrasonic transducer 1A according to the first embodiment is different.

The elastic plate 310 has a first surface 310a and a second surface 310b that face one side and the other side in the plate thickness direction, respectively, and is formed of a conductive metal plate that can vibrate in the plate thickness direction.

As shown in FIGS. 18 and 19, the elastic plate 310 is provided in parallel in the plate surface direction, and a plurality of vibration regions 312 to which the plurality of piezoelectric elements 330 are respectively mounted and a plurality of vibration regions 312. A plurality of low-rigidity regions 326 that respectively surround in a plan view, a restraint region 314 that surrounds the low-rigidity region 326 in a plan view, one restraint region 314, and an outside located radially outward of the one restraint region 314. And a boundary area 316 that divides the other area.

The boundary area 316 has the slit portion 17 and the bridge portion 18 as in the boundary area 16.

The low-rigidity region 326 is a groove region having a groove that opens on the first surface 310a side, and is made thinner than the corresponding vibration region 312 and the corresponding restraint region 314, whereby the vibration region 312 is formed. The rigidity is lower than that of the restraint region 314.

That is, the second surface 310b of the elastic plate 310 is flush with the vibration region 312, the low-rigidity region 326, and the restraint region 314, while the first surface 310a is the low-rigidity region 326. Is recessed in.
That is, the low-rigidity area 326 is a groove area that opens toward the first surface, where the first surface of the low-rigidity area 326 is closer to the second surface than the first surfaces of the vibration area 312 and the restraint area 314. It is said that.

The piezoelectric element 330 has an outer diameter that is larger than the vibration region 312 and smaller than the low rigidity region 326.
That is, the piezoelectric element 330 has a central portion 331 fixed to the first surface of the vibrating region 312 by an insulating adhesive 340, and extends radially outward from the central portion 331. And an extending portion 333 that ends in 326.

Note that, in the present embodiment, as shown in FIG. 18, the vibration region 312 is circular in plan view, the piezoelectric element 330 is rectangular in plan view, and the low-rigidity region 326 is plan view. Although it is rectangular, the present invention is not limited to such a shape.

That is, as long as the outer diameter of the piezoelectric element 330 is larger than the outer diameter of the vibrating area 312 and smaller than the outer diameter of the low rigidity area 326, the vibrating area 312, the piezoelectric element 330, and the low area. Various shapes are possible, such as making all the rigid regions 326 circular in a plan view.

Preferably, the low rigidity region 326 has the same outer shape as the piezoelectric element 330 and has an outer diameter slightly larger than the outer diameter of the piezoelectric element 330.
With such a configuration, the outer peripheral edge of the low-rigidity region 326 can be used as an alignment mark when the piezoelectric element 330 is mounted on the vibration region 312.

Furthermore, as shown in FIG. 19, the lower surface electrode layer of the extending portion 333 is electrically connected to the first surface 310 a of the low rigidity region 326 by a conductive adhesive 345.

Note that the upper surface electrode layer of the piezoelectric element 330 and the corresponding wiring conductor 85 are formed by a conductive adhesive or solder 87, as in the first embodiment, and the conductive adhesive or solder is used. An insulating adhesive 88 is interposed between the 87 and the first surface 310 a of the elastic plate 310 and the conductive adhesive 345.

As described above, in the present embodiment, by mechanically joining the vibration region 312 and the central portion 331 of the piezoelectric element 330 with the insulating adhesive 340, it is possible to stabilize and support the piezoelectric element 330. The low rigidity region 326 and the lower surface electrode layer of the extending portion 333 of the piezoelectric element 330 are connected by a conductive adhesive 345 to electrically connect the lower surface electrode layer of the piezoelectric element 330 and the elastic plate 310. Is getting

Further, in the ultrasonic transducer 4, as shown in FIG. 19, a raised portion 328 lower than the first surface 310 a of the vibration region 312 is formed on the bottom surface of the groove region forming the low rigidity region 326. A ridge 328 that cooperates with the inner surface of the groove area to form an adhesive retention area.

The conductive adhesive 345 that electrically connects the lower surface electrode layer of the extending portion 333 and the first surface 310a of the low-rigidity area 326 is provided in the adhesive retention area.

According to such a configuration, the insulating adhesive 340 that mechanically joins the central portion 331 of the piezoelectric element 330 and the vibration region 312, the lower surface electrode layer of the extending portion 333 of the piezoelectric element 330, and the low rigidity. It is possible to effectively prevent the conductive adhesive 345 that electrically connects the region 326 from being unintentionally mixed and impairing the reliability of the electrical connection between the lower electrode layer of the piezoelectric element 330 and the elastic plate 310. can do.

Note that, in the present embodiment, as shown in FIG. 18, the raised portions 328 are provided at two locations, but of course, the present invention is not limited to this form, and the raised portions are not limited to this. It is also possible to provide 328 only at one location or at three or more locations.

The ultrasonic transducer 4 according to the present embodiment can be suitably manufactured, for example, by a manufacturing method that includes the following modifications as compared with the method for manufacturing the ultrasonic transducer 1A according to the first embodiment.

That is, in the manufacturing method of the present embodiment, in the elastic plate etching step of forming the slit portion 17, in addition to etching and removing the slit portion 17, the low rigidity region 326 is half-etched. It is configured (FIG. 20(a)).

At this time, the region corresponding to the raised portion 328 is covered with a resist mask having a width slightly narrower than twice the side etching amount. Accordingly, the raised portion 328 can be left so that its top position is lower than the first surface 310a of the vibrating region 312 and the constraining region 314, and contact with the lower surface of the piezoelectric element 330 can be prevented. it can.

Next, a conductive adhesive 328 is applied in the adhesive retention area and an insulating adhesive 340 is applied in the vibration area 312 (FIG. 20(b)), and after mounting the piezoelectric element 330 (FIG. 20( c)), the conductive adhesive 328 and the insulating adhesive 340 are cured.

In addition, in order to improve the reliability of the electrical connection between the conductive adhesive 345 and the elastic plate 310, reference numeral 346 in FIG. 19 indicates that before the conductive adhesive 345 is applied to the adhesive retention area, It is Au plating provided on the first surface of the adhesive retention region.

1A-1F, 2-4 Ultrasonic transducer 10, 310 Elastic plate 10a, 310a 1st surface 10b, 310b 2nd surface 12, 312 Vibration area 14, 314 Restraint area 16, 316 Border area 17 Slit part 17a, 17b No. 1st and 2nd board surface direction slit 18 Bridge part 26,326 Low-rigidity area|region 27 Groove 28a Opening part 28b Connecting part 30,330 Piezoelectric element 40 Sealing member 42 Cylindrical part 44 Closing part 50, 55 Sound absorbing material 60 Rigid reinforcement plate 70 Protective member 72 Opening 75 Protective plate 77 Through hole 80 Wiring body 82 Insulating layer 85 Wiring conductor 87 Conductive adhesive or solder 88 Insulating adhesive 110 Elastic plate forming body 182 Insulating layer forming member 185 Wiring conductor forming member 210 Mass member 230 partition wall member 328 raised portion 331 central portion 333 extended portion 340 insulating adhesive 345 conductive adhesive

That is, in order to suppress the gray Tin glow over blanking phenomenon occurs between a plurality of vibrators, the arrangement pitch of the plurality of vibrators is the vibrating body below half of the wavelength λ of the ultrasonic wave emitting Need to

Since frequency is 40kHz ultrasonic wavelength λ is 8.6 mm, while the 40kHz frequency of the ultrasonic wave vibrator radiates, in order to suppress the occurrence of gray tin glow over blanking phenomenon, the plurality of vibrators The array pitch needs to be 8.6 mm/2=4.3 mm or less.

Accordingly, the piezoelectric element 30 and the low frequency from said vibration region 12 (e.g., 30KHz～40kHz) can emit ultrasound, and gray tin glow over blanking phenomenon occurs between the plurality of piezoelectric elements 30 This can be effectively prevented or reduced.

Claims (25)

An elastic plate having a first surface and a second surface respectively facing one side and the other side in the plate thickness direction and capable of vibrating in the plate thickness direction;
A plurality of piezoelectric elements fixed in parallel to the first surface of the elastic plate;
A sealing member provided on the first surface of the elastic plate so as to form a plurality of accommodating spaces that respectively cover the plurality of piezoelectric elements,
The elastic plate includes a plurality of vibrating regions to which the plurality of piezoelectric elements are respectively mounted, a plurality of constraining regions surrounding the plurality of vibrating regions, one constraining region, and a radial direction outward of the one constraining region. Including a boundary region that defines an outer region located at
The boundary region has a slit part that divides the one constraint region and the outer region, and a bridge part that mechanically connects the one constraint region to the outer region. Ultrasonic transducer. The region of the elastic plate along the outer peripheral edge of the vibrating region has rigidity higher than that of the vibrating region located radially inward of the region and the constraining region radially outward of the region. The ultrasonic transducer according to claim 1, wherein the ultrasonic transducer has a low and low rigidity region. The groove is provided in a region along the outer peripheral edge of the vibrating region on the first surface of the elastic plate, and the groove forms the low-rigidity region. Ultrasonic transducer. In the region along the outer peripheral edge of the vibrating region of the elastic plate, an opening that divides the inside and the outside of the vibrating region and a connecting portion that connects the inside and the outside of the vibrating region are alternately provided in the circumferential direction, The ultrasonic transducer according to claim 2, wherein the opening and the connecting portion form the low rigidity region. An elastic plate having a first surface and a second surface respectively facing one side and the other side in the plate thickness direction and formed of a conductive metal plate capable of vibrating in the plate thickness direction;
Each of the elastic plates has a piezoelectric body and a pair of upper surface electrode layers and lower surface electrode layers arranged on both sides in the thickness direction of the piezoelectric body, and the lower surface electrode layer faces the first surface of the elastic plate. A plurality of piezoelectric elements fixed in parallel to the first surface of
A sealing member provided on the first surface of the elastic plate so as to form a plurality of accommodating spaces that respectively cover the plurality of piezoelectric elements with a gap therebetween,
The elastic plate has a plurality of vibration regions in which the plurality of piezoelectric elements are respectively mounted, a plurality of low-rigidity regions surrounding the plurality of vibration regions, and a plurality of restraint regions surrounding the plurality of low-rigidity regions, respectively. , Including a boundary region that defines one constraint region and an outer region located radially outward of the one constraint region,
The boundary region has a slit part that divides the one constraint region and the outer region, and a bridge part that mechanically connects the one constraint region to the outer region,
The low-rigidity region is a groove region in which the first surface is closer to the second surface than the first surface of the vibration area and the restraint area,
The piezoelectric element has a central portion fixed to the first surface of the vibrating region with an insulating adhesive, and an extending portion extending radially outward from the central portion and ending in the low rigidity region in plan view. Including and
An ultrasonic transducer, wherein the lower surface electrode layer in the extending portion is electrically connected to the first surface of the low rigidity region by a conductive adhesive. On the bottom surface of the groove area forming the low-rigidity area, there is a ridge portion lower than the first surface of the vibration area, and a ridge portion that cooperates with the inner surface of the groove area to form an adhesive retention area. Is provided,
The conductive adhesive that electrically connects the lower surface electrode layer in the extending portion and the first surface of the low-rigidity region is provided in the adhesive retention region. The ultrasonic transducer described. The sound absorbing material is fixed to a portion of the inner surface of the sealing member facing the upper surface of the piezoelectric element, with a gap being provided between the sound absorbing material and the upper surface of the piezoelectric element. 7. The ultrasonic transducer according to any one of 6 to 6. The ultrasonic transducer according to claim 1, wherein the accommodation space is filled with a sound absorbing material formed of a foaming resin. 9. The ultrasonic transducer according to claim 1, further comprising a mass member fixed to the first surface of the constraining region so as to surround the vibrating region in a plan view. The ultrasonic transducer according to any one of claims 1 to 9, wherein a protective member having an opening that opens the vibrating region to the outside is joined to the second surface of the elastic plate. 11. The ultrasonic transducer according to claim 10, wherein a rigid protective plate having a through hole corresponding to the opening is joined to an outer end surface of the protective member. The sealing member is a cylindrical portion that covers the entire circumference of the vibrating region, and has a base end surface joined to the first surface of the elastic plate at a position including the boundary region and an end surface on the free end side of the piezoelectric member. The opening on the free end side of the tubular portion is closed by leaving a gap between the tubular portion that is farther from the first surface of the elastic plate than the upper surface of the element and the upper surface of the piezoelectric element. And a closing portion that forms a storage space,
The ultrasonic transducer according to any one of claims 1 to 11, wherein a rigid reinforcing plate is fixed to the outer surface of the closed portion. A cylindrical partition wall member surrounding the vibrating region in a plan view, in which one axial side is connected to the rigid reinforcing plate and the other axial side has a gap with the first surface of the elastic plate. 13. The ultrasonic transducer according to claim 12, further comprising a partition member embedded in the cylindrical portion. The elastic plate is a conductive metal plate,
The piezoelectric element has a piezoelectric body and a pair of upper surface electrode layers and lower surface electrode layers arranged on both sides in the thickness direction of the piezoelectric body,
The elastic plate is provided with a wiring body including an insulating layer provided on the first surface and a plurality of wiring conductors laminated on the insulating layer,
The lower electrode layer is mechanically and electrically bonded to the first surface of the elastic plate by a conductive adhesive, and the upper electrode layer is electrically connected to the corresponding wiring conductor by a conductive adhesive or solder. The ultrasonic transducer according to any one of claims 1 to 13, wherein: An insulating adhesive is interposed between the conductive adhesive or solder for electrically connecting the upper electrode layer and the corresponding wiring conductor and the first surface of the elastic plate. The ultrasonic transducer according to claim 14, which is characterized in that. In the plurality of constraint regions, a constraint region group formed by m (m is an integer of 1 or more) constraint regions arranged along the first plate surface direction of the elastic plate is orthogonal to the first plate surface direction. N rows (n is an integer greater than or equal to 1) in the second plate surface direction, and m×n constrained regions that appear by being provided,
The slit portions are located on both sides in the second plate surface direction of the one piezoelectric element mounted in the vibration area in the one restraint area, and extend in the first plate surface direction in a pair of first plate surface directions. A slit and a pair of second plate surface direction slits located on both sides of the one piezoelectric element in the first plate surface direction and extending along the second plate surface direction;
The pair of first plate surface direction slits are longer than the first plate surface direction length of the one piezoelectric element, and the pair of second plate surface direction slits are larger than the second plate surface direction length of the pair of piezoelectric elements. Considered to be long,
4. The bridge portion is formed at four locations defined by the ends of the first plate surface direction slit and the second plate surface direction slit that are adjacent to each other in the circumferential direction. 16. The ultrasonic transducer according to any one of 15. The single common slit is provided between the adjacent constraining regions, and the single common slit defines both outer peripheral edges of the adjacent constraining regions. Ultrasonic transducer. Elastic plates that have a first surface and a second surface that respectively face one side and the other side in the plate thickness direction, and that can vibrate in the plate thickness direction, and a piezoelectric body and an upper surface that is arranged on both sides of the piezoelectric body in the thickness direction. A plurality of piezoelectric elements each having an electrode layer and a lower surface electrode layer, the plurality of piezoelectric elements having the lower surface electrode layer fixed to the first surface of the plurality of vibrating regions provided on the elastic plate, and a plurality of piezoelectric elements covering each of the plurality of piezoelectric elements. A sealing member provided on the first surface of the elastic plate so as to form a housing space of the elastic plate, the elastic plate including a plurality of constraining regions surrounding the plurality of vibrating regions, and one constraining region. Including a boundary region that defines an outer region located radially outward of the one constraint region, the boundary region including a slit portion that divides the one constraint region and the outer region; And a bridge portion that mechanically connects the constrained region to the outer region, the first surface of the elastic plate is laminated on the insulating layer and the insulating layer, A method of manufacturing an ultrasonic transducer, wherein a wiring body including a plurality of wiring conductors electrically connected to an upper surface electrode layer is provided,
A step of preparing a conductive elastic plate forming body for forming the elastic plate,
An insulating layer forming member for forming the insulating layer and a wiring conductor forming member for forming the plurality of wiring conductors are provided on the first surface of the elastic plate forming body on one side in the plate thickness direction, and the insulating layer forming member and the wiring are provided. A step of forming an insulating layer and the plurality of wiring conductors by etching away unnecessary portions of a conductor forming member;
An elastic plate etching step of forming the slit portion by performing etching on the elastic plate forming body,
Bonding the lower surface electrode layers of the plurality of piezoelectric elements to the first surfaces of the plurality of vibration regions with a conductive adhesive, respectively.
An electrical connection step of electrically connecting the tip end portions of the plurality of wiring conductors to the corresponding upper surface electrode layer of the piezoelectric element with a conductive adhesive or solder.
A method of manufacturing an ultrasonic transducer, comprising a step of installing a sealing member on the first surface of the elastic plate. In the elastic plate etching step, in addition to the formation of the slit portion, a groove is formed in a region along the outer peripheral edge of the vibrating region of the first surface of the elastic plate, or an outer peripheral edge of the vibrating region is formed. 19. The ultrasonic transducer according to claim 18, further comprising: forming a plurality of openings along the circumferential direction, wherein a plurality of openings are left between the openings adjacent to each other in the circumferential direction. Production method. Elastic plates that have a first surface and a second surface that respectively face one side and the other side in the plate thickness direction, and that can vibrate in the plate thickness direction, and a piezoelectric body and an upper surface that is arranged on both sides of the piezoelectric body in the thickness direction. A plurality of piezoelectric elements each having an electrode layer and a lower surface electrode layer, the lower surface electrode layer being fixed to the first surface of the plurality of vibration regions provided on the elastic plate, and the plurality of piezoelectric elements, respectively. A sealing member provided on the first surface of the elastic plate so as to form a plurality of accommodating spaces, and the elastic plate includes a plurality of low-rigidity regions respectively surrounding the plurality of vibration regions, and a plurality of the plurality of low-rigidity regions. The low-rigidity region includes a plurality of constraint regions that respectively surround the low-rigidity regions, a boundary region that partitions one constraint region and an outer region located radially outward of the one constraint region, The first surface of the low-rigidity area is a groove area that is closer to the second surface than the first surface of the vibration area and the restraint area and that opens toward the first surface, and the bottom surface of the groove area has the vibration A ridge lower than the first surface of the region and the restraint region, the ridge forming an adhesive retention region in cooperation with the inner side surface of the groove region is provided; The piezoelectric element has a slit portion that divides the restraint region and the outer region, and a bridge portion that mechanically connects the one restraint region to the outer region, and the piezoelectric element has the vibrating region in plan view. And a central portion that is bonded to the first surface of the vibrating region by an insulating adhesive and that extends radially outward from the central portion and ends in the low-rigidity region in plan view. An extending portion joined to the first surface of the low-rigidity area by a conductive adhesive disposed in the retention area, and an insulating layer and an insulating layer on the first surface of the elastic plate. A method of manufacturing an ultrasonic transducer, comprising: a wiring body that is laminated on the wiring body and that includes a plurality of wiring conductors that are electrically connected to an upper surface electrode layer of the plurality of piezoelectric elements;
A step of preparing a conductive elastic plate forming body for forming the elastic plate,
An insulating layer forming member for forming the insulating layer and a wiring conductor forming member for forming the plurality of wiring conductors are provided on the first surface of the elastic plate forming body on one side in the plate thickness direction, and the insulating layer forming member and the wiring are provided. A step of forming an insulating layer and the plurality of wiring conductors by etching away unnecessary portions of a conductor forming member;
The elastic plate forming body is etched to form the slit portion, and the region corresponding to the low rigidity region is half-etched from the first surface side to form the groove region, which is the low rigidity region. An elastic plate etching step for forming
A piezoelectric element bonding step of bonding the plurality of piezoelectric elements with an insulating adhesive and a conductive adhesive applied to the first surface of the vibration area and the first surface of the adhesive retention area, respectively.
An electrical connection step of electrically connecting the tip end portions of the plurality of wiring conductors to the corresponding upper surface electrode layer of the piezoelectric element with a conductive adhesive or solder.
A sealing member installation step of providing the sealing member on the first surface of the elastic plate,
The half-etching process for forming the low-rigidity region, which is a groove region, covers the region corresponding to the vibrating region and the region corresponding to the restraint region with a mask, and the amount of side etching on the region corresponding to the raised portion. By covering with a mask having a width narrower than twice, the low rigidity region is a groove region that opens to the first surface side, and the bottom surface of the groove region is smaller than the vibration region and the constraint region. A method for manufacturing an ultrasonic transducer, characterized in that it is configured to leave the low raised portion. Prior to the electrical connection step, a step of applying an insulating resin between the tip portions of the plurality of wiring conductors and the corresponding piezoelectric elements,
The conductive adhesive or the solder in the electrical connection step, in the state in which the insulating resin is interposed between the conductive adhesive or the solder and the first surface of the elastic plate, the plurality of 21. The method of manufacturing an ultrasonic transducer according to claim 18, wherein the tip end of the wiring conductor is electrically connected to the corresponding upper surface electrode layer of the piezoelectric element. The sealing member is a tubular portion that covers the entire circumference of the vibrating region, and the base end face is joined to the first face of the elastic plate at a position including the boundary region, and the end face on the free end side is the A tubular portion formed so as to be more distant from the first surface of the elastic plate than the upper surface electrode layer of the piezoelectric element, and an opening for closing the free end side opening of the tubular portion to form the accommodation space. Part and
The sealing member installation step, a step of preparing the sealing member, a step of fixing a rigid reinforcing plate to the outer surface of the closed portion of the sealing member, before or after the step of fixing the rigid reinforcing plate, Fixing a sound absorbing material to the inner surface of the closing portion so that a gap exists between the sealing member and the upper surface electrode layer of the piezoelectric element in a state where the sealing member is fixed to the first surface of the elastic plate; 22. The step of fixing the sealing member, to which the rigid reinforcing plate and the sound absorbing material are fixed, to the first surface of the elastic plate, the ultrasonic wave according to any one of claims 18 to 21. Transducer manufacturing method. The sealing member is a tubular portion that covers the entire circumference of the vibrating region, and the base end face is joined to the first face of the elastic plate at a position including the boundary region, and the end face on the free end side is the A tubular portion formed so as to be more distant from the first surface of the elastic plate than the upper surface electrode layer of the piezoelectric element, and an opening for closing the free end side opening of the tubular portion to form the accommodation space. Part and
In the step of installing the sealing member, a step of joining the tubular portion to the first surface of the elastic plate, a step of filling the tubular portion with foaming silicone that acts as a sound absorbing material, and the formation of the closed portion 22. The method for manufacturing an ultrasonic transducer according to claim 18, further comprising: a step of fixing the rigid reinforcing plate to the outer surface of the closed portion. 19. The method according to claim 18, further comprising, after the step of installing the sealing member, joining a resin-made protective member having an opening that opens the vibration region to the second surface of the elastic plate. 23. The method for manufacturing an ultrasonic transducer according to any one of 23. The method of manufacturing an ultrasonic transducer according to claim 24, further comprising a step of joining a rigid protective plate having a through hole corresponding to the opening to an outer end surface of the protective member.