Patent ID: 12262176

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to the drawings, transducers according to preferred embodiments of the present invention will be described below. In the following description of preferred embodiments, the same or corresponding elements and portions in the drawings are denoted by the same reference numeral, and the description will not be repeated. In the following description, a center of a base110is a position including a center C and the vicinity of center C of base110described later.

FIG.1is a plan view illustrating the transducer according to a preferred embodiment of the present invention.FIG.2is a sectional view illustrating the transducer inFIG.1as viewed from an arrow direction of a line II-II.FIG.3is an enlarged partial plan view illustrating a portion III inFIG.1.

As illustrated inFIGS.1to3, a transducer100of a preferred embodiment of the present invention includes annular base110, a first beam120a, a second beam120b, and a first connection portion130a. Transducer100further includes a third beam120c, a fourth beam120d, a second connection portion130b, a third connection portion130c, and a fourth connection portion130d. Transducer100of the present preferred embodiment can be used as an ultrasonic transducer in which each of a plurality of beams can perform bending vibration.

Base110has an annular shape when viewed from a multilayer direction of a plurality of layers described later, and specifically, has, for example, a rectangular or substantially rectangular annular shape. The shape of base110when viewed from the multilayer direction is not particularly limited as long as the shape of base110is annular. When viewed from the multilayer direction, an outer peripheral side surface of base110may have, for example, a polygonal shape or a circular shape, and an inner peripheral side surface of base110may have a polygonal shape or a circular shape.

As illustrated inFIG.1, first beam120aincludes a first fixed end121aconnected to base110and a first tip122alocated closer to the center of base110on the side opposite to first fixed end121a, and first beam120aextends from first fixed end121atowards first tip122a.

Second beam120bincludes a second fixed end121badjacent to first beam120ain a circumferential direction of base110and connected to base110and a second tip122blocated closer the center of base110on the side opposite to second fixed end121b, and second beam120bextends from second fixed end121btowards second tip122b.

Third beam120cincludes a third fixed end121cadjacent to second beam120bin the circumferential direction of base110and connected to base110, and a third tip122clocated closer to the center of base110on the opposite side of third fixed end121c, and third beam120cextends from third fixed end121ctowards the third tip122c.

Fourth beam120dincludes a fourth fixed end121dadjacent to each of third beam120cand first beam120ain the circumferential direction of base110and connected to base110and a fourth tip122dlocated closer the center of base110on the side opposite to fourth fixed end121d, and fourth beam120dextends from fourth fixed end121dtowards fourth tip122d.

Each of first beam120a, second beam120b, third beam120c, and fourth beam120dis located along the same or substantially the same plane. At least one of first beam120a, second beam120b, third beam120c, and fourth beam120dmay be warped so as to intersect with the plane. Each of first beam120a, second beam120b, third beam120c, and fourth beam120dextends from annular base110towards the center of annular base110and is adjacent to each other in the circumferential direction of base110. In the present preferred embodiment, first beam120a, second beam120b, third beam120c, and fourth beam120dare configured to be rotationally symmetric with respect to the center of base110.

First connection portion130aconnects first tip122aand second tip122bto each other. Second connection portion130bconnects second tip122band third tip122cto each other. Third connection portion130cconnects third tip122cand fourth tip122dto each other. Fourth connection portion130dconnects fourth tip122dand first tip122ato each other.

As illustrated inFIG.2, each of first beam120a, second beam120b, third beam120c, and fourth beam120dis a piezoelectric vibration portion including a plurality of layers10. InFIG.1, each of the plurality of layers10is not illustrated. Details of the configuration of the plurality of layers10will be described later.

First fixed end121a, second fixed end121b, third fixed end121c, and fourth fixed end121dare located in the same or substantially the same virtual plane. First fixed end121a, second fixed end121b, third fixed end121c, and fourth fixed end121dare connected to the inner peripheral surface of annular base110when viewed from the multilayer direction. First fixed end121a, second fixed end121b, third fixed end121c, and fourth fixed end121dare adjacent to each other on the inner peripheral surface when viewed from the multilayer direction. In the present preferred embodiment, first fixed end121a, second fixed end121b, third fixed end121c, and fourth fixed end121dare respectively connected to a plurality of sides of the rectangular or substantially rectangular annular inner peripheral surface of base110, thus being positioned so as to correspond to the plurality of sides of the rectangular or substantially rectangular annular inner peripheral surface of base110in a one-to-one manner when viewed from the multilayer direction.

In the present preferred embodiment, each of first beam120a, second beam120b, third beam120c, and fourth beam120dextends along the same or substantially the same virtual plane in a state where transducer100is not driven.

As illustrated inFIG.1, each of first beam120a, second beam120b, third beam120c, and fourth beam120dhas a tapered outer shape when viewed from the multilayer direction. Specifically, each of first beam120a, second beam120b, third beam120c, and fourth beam120dhas a trapezoidal or substantially trapezoidal outer shape when viewed from the multilayer direction.

In the present preferred embodiment, a length of each of first beam120a, second beam120b, third beam120c, and fourth beam120din the extending direction is preferably, for example, at least about 5 times a thickness dimension of each of first beam120a, second beam120b, third beam120c, and fourth beam120din the multilayer direction from the viewpoint of facilitating the bending vibration. InFIG.2, the thicknesses of first beam120a, second beam120b, third beam120c, and fourth beam120dare schematically illustrated.

As illustrated inFIGS.1and3, a first slit141aextending towards the center of base110is provided between first beam120aand second beam120b. A second slit141bextending towards the center of base110is provided between second beam120band third beam120c. A third slit141cextending towards the center of base110is provided between third beam120cand fourth beam120d. A fourth slit141dextending towards the center of base110is provided between fourth beam120dand first beam120a.

First slit141ais positioned along two sides extending from first fixed end121atowards first tip122ain the trapezoidal or substantially trapezoidal outer shape of first beam120a. Second slit141bis positioned along two sides extending from second fixed end121btowards the second tip122bin the trapezoidal or substantially trapezoidal outer shape of second beam120b. Third slit141cis positioned along two sides extending from the third fixed end121ctowards the third tip122cin the trapezoidal or substantially trapezoidal outer shape of third beam120c. Fourth slit141dis positioned along two sides extending from fourth fixed end121dtowards fourth tip122din the trapezoidal or substantially trapezoidal outer shape of fourth beam120d. In the present preferred embodiment, first slit141a, second slit141b, third slit141c, and fourth slit141dextend from each of the plurality of corners of the rectangular or substantially rectangular annular shape of base110towards the center of base110when viewed from the multilayer direction, thus being positioned so as to correspond to each of the corners of the rectangular or substantially rectangular annular shape of base110in a one-to-one correspondence.

The widths of first slit141a, second slit141b, third slit141c, and fourth slit141dwhen viewed from the multilayer direction are, for example, preferably less than or equal to about 10 μm and more preferably less than or equal to about 1 μm. The width of each of first slit141a, second slit141b, third slit141c, and fourth slit141dwhen viewed from the multilayer direction is, for example, preferably less than or equal to about 300%, and more preferably less than or equal to about 30% with respect to the thickness of each of first beam120a, second beam120b, third beam120c, and fourth beam120d.

First connection portion130a, second connection portion130b, third connection portion130c, and fourth connection portion130dare partitioned from each other by a split slit142. Split slit142includes a first split slit142a, a second split slit142b, a third split slit142c, and a fourth split slit142d.

First split slit142aextends along a first direction (X-axis direction) from first fixed end121atowards first tip122ato connect a center122acof first tip122aand the center of base110. Second split slit142bextends along a second direction (Y-axis direction) from second fixed end121btowards second tip122bto connect a center122bcof second tip122band the center of base110. Third split slit142cextends along the first direction (X-axis direction) from third fixed end121ctowards third tip122cand connects a center122ccof third tip122cand the center of base110. Fourth split slit142dextends along the second direction (Y-axis direction) from fourth fixed end121dtowards fourth tip122dto connect a center122dcof fourth tip122dand the center of base110.

As illustrated inFIGS.1and3, first connection portion130ais surrounded by first split slit142aand second split slit142bthat connect center122acof first tip122a, the center of base110, and center122bcof second tip122b, first tip122a, and second tip122b. First connection portion130ais connected to center122acof first tip122aand center122bcof second tip122b.

Second connection portion130bis surrounded by second split slit142band third split slit142cthat connect center122bcof second tip122b, the center of base110, and center122ccof third tip122c, second tip122b, and third tip122c. Second connection portion130bis connected to center122bcof second tip122band center122ccof third tip122c.

Third connection portion130cis surrounded by third split slit142cand fourth split slit142dthat connect center122ccof third tip122c, the center of base110, and center122dcof fourth tip122d, third tip122c, and fourth tip122d. Third connection portion130cis connected to center122ccof third tip122cand center122dcof fourth tip122d.

Fourth connection portion130dis surrounded by fourth split slit142dand first split slit142athat connect center122dcof fourth tip122d, the center of base110, and center122acof first tip122a, fourth tip122d, and first tip122a. Fourth connection portion130dis connected to center122dcof fourth tip122dand center122acof first tip122a.

Each of first connection portion130a, second connection portion130b, third connection portion130c, and fourth connection portion130dhas a meandering shape.FIG.4is an enlarged partial plan view illustrating a first connection portion of the transducer according to the present preferred embodiment of the present invention. As illustrated inFIGS.3and4, first connection portion130a, second connection portion130b, third connection portion130c, and fourth connection portion130dare arranged side by side around center C of base110.

As illustrated inFIG.4, first connection portion130aincludes a plurality of longitudinal portions131and at least one short portion. In the present preferred embodiment, the at least one short portion includes a plurality of short portions. Specifically, first connection portion130aincludes a first short portion132A and a second short portion132B as the plurality of short portions.

Each of the plurality of longitudinal portions131extends along the first direction (X-axis direction) from first fixed end121atowards first tip122a. The lengths of the plurality of longitudinal portions131are the same or substantially the same.

The at least one short portion extends along the second direction (Y-axis direction) from second fixed end121btowards second tip122b, and connects one ends in the first direction (X-axis direction) of the plurality of longitudinal portions131adjacent to each other in the plurality of longitudinal portions131. The width of the at least one short portion in the first direction (X-axis direction) is wider than the width in the second direction (Y-axis direction) of each of the plurality of longitudinal portions131. However, the width in the first direction (X-axis direction) of the at least one short portion may be less than or equal to the width in the second direction (Y-axis direction) of each of the plurality of longitudinal portions131.

Longitudinal portions131arranged in the second direction (Y-axis direction) in the plurality of longitudinal portions131are alternately connected at the first end and the second end in the first direction (X-axis direction) by the corresponding short portion of the plurality of short portions. Specifically, the plurality of longitudinal portions131are arranged in parallel or substantially in parallel to longitudinal portion131connected to the center of first tip122atowards second tip122b, and the second ends on the side of second split slit142bare connected to each other by second short portion132B in longitudinal portion131connected to the center of first tip122aand longitudinal portion131adjacent to longitudinal portion131. In longitudinal portion131that is adjacent to longitudinal portion131connected to the center of first tip122aand connected to the second end, and longitudinal portion131adjacent to second tip122bof longitudinal portion131, the first ends on the side of first tip122aare connected to each other by first short portion132A. Thus, first short portion132A and second short portion132B alternately connect the first end and the second end of the plurality of longitudinal portions131towards second tip122b. Among the plurality of longitudinal portions131, the second end of longitudinal portion131opposite to second tip122bis connected to the center of second tip122b.

A plurality of first intermediate slits143aand at least one second intermediate slit143bare provided in first connection portion130a. Each of the plurality of first intermediate slits143aextends from second split slit142btowards tip122aof first beam120a. At least one second intermediate slit143bis disposed between first intermediate slits143aadjacent to each other in the plurality of first intermediate slits143a, and extends from the side of tip122aof first beam120atowards second split slit142b. Specifically, the plurality of first intermediate slits143aand the plurality of second intermediate slits143bare provided so as to partition the plurality of longitudinal portions131from each other. The plurality of first intermediate slits143aextend from second split slit142bto the central portion in the second direction (Y-axis direction) of first short portion132A.

In the present preferred embodiment, the plurality of second intermediate slits143bare provided in first connection portion130a. However, at least one second intermediate slit143bmay be provided in first connection portion130a. Each of the plurality of second intermediate slits143bis connected to a first connection slit140abextending from the tip of first slit141atowards one side in the Y-axis direction. Specifically, the plurality of second intermediate slits143bextend from first connection slit140abto the central portion in the second direction (Y-axis direction) of second short portion132B.

The plurality of first intermediate slits143aand the plurality of second intermediate slits143bare alternately arranged one by one in the second direction (Y-axis direction). Each of the plurality of first intermediate slits143aand the at least one second intermediate slit143bis located in parallel or substantially in parallel with first split slit142a. A length La of each of the plurality of first intermediate slits143aand a length Lb of at least one second intermediate slit143bare the same or substantially the same.

A first defining slit140baextending in the X-axis direction between the tip of first slit141aand second split slit142bis provided in first connection portion130a. In the present preferred embodiment, first defining slit140bais connected to the tip of first slit141a.

A boundary of first connection portion130ais defined by first split slit142a, second split slit142b, first connection slit140ab, and first defining slit140ba. Specifically, first connection slit140abis located at the boundary between first beam120aand first connection portion130a. First defining slit140bais located at a boundary between second beam120band first connection portion130a.

As illustrated inFIG.4, the width of each slit is Ws. The width in the second direction (Y-axis direction) of longitudinal portion131is Wm. The width in the first direction (X-axis direction) of each of first short portion132A and second short portion132B is a. The length of each in the first direction (X-axis direction) and the second direction (Y-axis direction) of first connection portion130ais L. For example, Wm=about 10 μm, Ws=about 1 μm, and a=about 15 μm. Ws≤about 1 μm is preferably satisfied, for example.

Width Wm in the second direction (Y-axis direction) of each of the plurality of longitudinal portions131is wider than the width Ws in the second direction (Y-axis direction) of the intermediate slit between adjacent longitudinal portions131of the plurality of longitudinal portions131. That is, the dimension of shortest distance Wm between first intermediate slit143aand second intermediate slit143badjacent to each other is larger than the dimension of width Ws in the second direction (Y-axis direction) of each of the plurality of first intermediate slits143aand the dimension in the (Y-axis direction) of width Ws of at least one second intermediate slit143b.

The dimension of a shortest distance a between at least one second intermediate slit143band second split slit142bis larger than the dimension of shortest distance Wm between first intermediate slit143aand second intermediate slit143badjacent to each other. However, the dimension of shortest distance a between at least one second intermediate slit143band second split slit142bmay be less than or equal to the dimension of shortest distance Wm between first intermediate slit143aand second intermediate slit143badjacent to each other.

When the number of turns of the meandering shape of first connection portion130ais n, for example, a relationship of L=(Wm+Ws)×n or L=(Wm+Ws)×(n+1) is satisfied. The number n of turns of the meandering shape of first connection portion130ainFIG.4is 6, and a relationship of L=(Wm+Ws)×7 is satisfied, for example. However, the relationship of L=(Wm+Ws)×n or L=(Wm+Ws)×(n+1) may not be necessarily satisfied.

In the region surrounded by first split slit142a, second split slit142b, first tip122a, and second tip122b, first connection portion130ahas an area greater than or equal to about 70% and less than about 100%, for example. First connection portion130amay be, for example, less than about 70% in the region surrounded by first split slit142a, second split slit142b, first tip122a, and second tip122b.

Each of second connection portion130b, third connection portion130c, and fourth connection portion130dhas the same or substantially the same configuration as that of first connection portion130a.

In second connection portion130b, each of the plurality of first intermediate slits143aextends from second split slit142btowards tip122cof third beam120c. Each of the plurality of second intermediate slits143bis connected to a second connection slit140cbextending from the tip of second slit141btowards one side in the Y-axis direction.

A second defining slit140bcextending in the X-axis direction between the tip of second slit141band second split slit142bis provided in second connection portion130b. In the present preferred embodiment, second defining slit140bcis connected to the tip of second slit141b.

The boundary of second connection portion130bis defined by second split slit142b, third split slit142c, second connection slit140cb, and second defining slit140bc. Specifically, second defining slit140bcis located at the boundary between second beam120band second connection portion130b. Second connection slit140cbis located at the boundary between third beam120cand second connection portion130b.

In the region surrounded by second split slit142b, third split slit142c, second tip122b, and third tip122c, second connection portion130bhas, for example, an area greater than or equal to about 90% and less than about 100%.

In third connection portion130c, each of the plurality of first intermediate slits143aextends from fourth split slit142dtowards third tip122cof third beam120c. Each of the plurality of second intermediate slits143bis connected to third connection slit140cdextending from the tip of third slit141ctowards the other side in the Y-axis direction.

Third defining slit140dcextending in the X-axis direction between the tip of third slit141cand fourth split slit142dis provided in third connection portion130c. In the preferred embodiment, third defining slit140dcis connected to the tip of third slit141c.

The boundary of third connection portion130cis defined by third split slit142c, fourth split slit142d, third connection slit140cd, and third defining slit140dc. Specifically, third connection slit140cdis located at the boundary between third beam120cand third connection portion130c. Third defining slit140dcis located at the boundary between fourth beam120dand third connection portion130c.

In the region surrounded by third split slit142c, fourth split slit142d, third tip122c, and fourth tip122d, third connection portion130chas, for example, an area greater than or equal to about 90% and less than about 100%.

In fourth connection portion130d, each of the plurality of first intermediate slits143aextends from fourth split slit142dtowards tip122aof first beam120a. Each of the plurality of second intermediate slits143bis connected to a fourth connection slit140adextending from the tip of fourth slit141dtowards the other side in the Y-axis direction.

Fourth defining slit140daextending in the X-axis direction between the tip of fourth slit141dand fourth split slit142dis provided in fourth connection portion130d. In the present preferred embodiment, fourth defining slit140dais connected to the tip of fourth slit141d.

The boundary of fourth connection portion130dis defined by third split slit142c, fourth split slit142d, fourth connection slit140ad, and fourth defining slit140da. Specifically, fourth defining slit140dais located at the boundary between fourth beam120dand fourth connection portion130d. Fourth connection slit140adis located at the boundary between first beam120aand fourth connection portion130d.

In the region surrounded by fourth split slit142d, first split slit142a, fourth tip122d, and the first tip122a, fourth connection portion130dhas, for example, an area greater than or equal to about 90% and less than about 100%.

Here, a transducer according to a first modification of a present preferred embodiment of the present invention having a different slit shape will be described.

FIG.5is a partial plan view illustrating the transducer according to the first modification.FIG.5illustrates a portion the same as or similar to transducer100of the preferred embodiment of the present invention shown inFIG.4.

As illustrated inFIG.5, in a transducer100aaccording to the first modification, a connection spot of each slit is curved. The end of each slit is rounded. Thus, internal stress in first connection portion130acan be reduced.

The plurality of layers10will be described below. As illustrated inFIG.2, in the present preferred embodiment, the plurality of layers10includes a piezoelectric layer11, a first electrode layer12, and a second electrode layer13.

Piezoelectric layer11is made of, for example, a single crystal piezoelectric body. A cutting orientation of piezoelectric layer11is appropriately selected so as to exhibit desired device characteristics. In the present preferred embodiment, piezoelectric layer11is obtained by thinning a single crystal substrate, and the single crystal substrate is specifically a rotating Y-cut substrate. The cutting orientation of the rotating Y-cut substrate is specifically 30°, for example. For example, the thickness of piezoelectric layer11is greater than or equal to about 0.3 μm and less than or equal to about 5.0 μm. The single-crystal piezoelectric body has a polarization axis. Details of the axial direction of the polarization axis will be described later.

A material of piezoelectric layer11is appropriately selected such that transducer100exhibits the desired device characteristics. In the present preferred embodiment, piezoelectric layer11is made of, for example, an inorganic material. Specifically, piezoelectric layer11is made of, for example, an alkali niobate compound or an alkali tantalate compound. In the present preferred embodiment, the alkali metal included in the alkali niobate compound or the alkali tantalate compound includes, for example, at least one of lithium, sodium, and potassium. In the present preferred embodiment, piezoelectric layer11is made of, for example, lithium niobate (LiNbO3) or lithium tantalate (LiTaO3).

As illustrated inFIG.2, first electrode layer12is disposed on one side of piezoelectric layer11in the multilayer direction of the plurality of layers10. Second electrode layer13is disposed on the other side of piezoelectric layer11so as to be opposed to at least a portion of first electrode layer12with piezoelectric layer11interposed therebetween.

In the present preferred embodiment, adhesion layers (not illustrated) are disposed between first electrode layer12and piezoelectric layer11, between second electrode layer13and piezoelectric layer11, and between second electrode layer13and piezoelectric layer11.

In the present preferred embodiment, each of first electrode layer12and second electrode layer13is made of, for example, Pt. Each of first electrode layer12and second electrode layer13may be made of another material such as, for example, Al. The adhesion layer is made of, for example, Ti. The adhesion layer may be made of another material such as, for example, a NiCr alloy. Each of first electrode layer12, second electrode layer13, and the adhesion layer may be an epitaxial growth film. When piezoelectric layer11is made of, for example, lithium niobate (LiNbO3), the adhesion layer is preferably made of, for example, NiCr from the viewpoint of preventing diffusion of the material constituting the adhesion layer into first electrode layer12or second electrode layer13. This improves reliability of transducer100.

In the present preferred embodiment, for example, the thickness of each of first electrode layer12and second electrode layer13is greater than or equal to about 0.05 μm and less than or equal to about 0.2 μm. For example, the thickness of the adhesion layer is greater than or equal to about 0.005 μm and less than or equal to about 0.05 μm.

The plurality of layers10further include a support layer14. Support layer14is disposed on the side opposite to first electrode layer12of piezoelectric layer11and on the side opposite to piezoelectric layer11of second electrode layer13. Support layer14includes a first support14aand a second support14blaminated on the side opposite to piezoelectric layer11of first support14a. In the present preferred embodiment, first support14ais made of, for example, SiO2, and second support14bis made of, for example, single crystal Si. In the present preferred embodiment, the thickness of support layer14is preferably thicker than that of piezoelectric layer11from the viewpoint of the bending vibration of first to fourth beams120ato120d. The mechanism of the bending vibration of first to fourth beams120ato120dwill be described later.

As illustrated inFIG.2, in the present preferred embodiment, first to fourth connection portions130ato130dare configured by continuing the plurality of layers10respectively defining first to fourth beams120ato120din the direction orthogonal or substantially orthogonal to the multilayer direction. However, in the present preferred embodiment, the plurality of layers10in first to fourth connection portions130ato130ddo not include first electrode layer12and second electrode layer13. When second support14bis made of low-resistance Si, second support14bcan define and function as the lower electrode layer without providing second electrode layer13. In this case, the plurality of layers10in first to fourth connection portions130ato130dinclude the lower electrode layer.

Furthermore, members defining base110will be described. As illustrated inFIG.2, in the present preferred embodiment, base110includes the plurality of layers10similar to first to fourth beams120ato120d. The plurality of layers10of base110are structured by continuing the plurality of layers10of first to fourth beams120ato120d. Specifically, piezoelectric layer11, first electrode layer12, second electrode layer13, and support layer14of base110are continuous to piezoelectric layer11, first electrode layer12, second electrode layer13, and support layer14of first to fourth beams120ato120d, respectively. Base110further includes a substrate layer15, a first connection electrode layer20, and a second connection electrode layer30.

Substrate layer15is connected to support layer14on the side opposite to piezoelectric layer11in the axial direction of the central axis of annular base110. Substrate layer15includes a first substrate layer15aand a second substrate layer15blaminated on the side opposite to support layer14of first substrate layer15ain the axial direction of the central axis. In the present preferred embodiment, first substrate layer15ais made of, for example, SiO2, and second substrate layer15bis made of, for example, single crystal Si.

As illustrated inFIG.2, first connection electrode layer20is exposed to the outside while being electrically connected to first electrode layer12with an adhesion layer (not illustrated) interposed therebetween. Specifically, first connection electrode layer20is disposed on the side opposite to support layer14of second electrode layer13in base110.

For example, the thickness of each of first connection electrode layer20and second connection electrode layer30is greater than or equal to about 0.1 μm and less than or equal to about 1.0 μm. For example, the thickness of each of the adhesion layer connected to first connection electrode layer20and the adhesion layer connected to second connection electrode layer30is greater than or equal to about 0.005 μm and less than or equal to about 0.1 μm.

In the present preferred embodiment, each of first connection electrode layer20and second connection electrode layer30is made of, for example, Au. First connection electrode layer20and second connection electrode layer30may be made of another conductive material such as, for example, Al. For example, each of the adhesion layer connected to first connection electrode layer20and the adhesion layer connected to second connection electrode layer30is made of Ti. These adhesion layers may be made of, for example, NiCr.

As illustrated inFIG.2, an opening101that opens to the side opposite to piezoelectric layer11in the multilayer direction is provided in transducer100of the present preferred embodiment.

Here, the axial direction of the polarization axis of the single-crystal piezoelectric body defining piezoelectric layer11will be described. Preferably, the axial direction of the virtual axis when the polarization axis of the single-crystal piezoelectric body is projected from the multilayer direction onto the virtual plane orthogonal or substantially orthogonal to the multilayer direction extends in the same or substantially the same direction in any of first to fourth beams120ato120d, and preferably the angle formed with the extending direction of each of first to fourth slits141ato141dis not about 45 degrees or about 135 degrees when viewed from the multilayer direction.

More specifically, in the present preferred embodiment, the axial direction of the virtual axis preferably has, for example, an angle formed by the extending direction of each of first to fourth slits141ato141dof greater than or equal to about 0 degrees and less than or equal to about 5 degrees, greater than or equal to about 85 degrees and less than or equal to about 95 degrees, or greater than or equal to about 175 degrees and less than or equal to about 180 degrees when viewed from the multilayer direction.

In addition, the angle formed by the extending direction of each of the first to fourth beams120ato120dwhen viewed from the multilayer direction and the axial direction of the virtual axis when viewed from the multilayer direction is more preferably, for example, greater than or equal to about 40 degrees and less than or equal to about 50 degrees, or greater than or equal to about 130 degrees and less than or equal to about 140 degrees. The reason why a suitable range exists for each angle with respect to the virtual axis will be described later.

In the present preferred embodiment, the axial direction of the virtual axis is oriented in a specific direction, but the axial direction of the virtual axis is not particularly limited.

In the present preferred embodiment, because the single-crystal piezoelectric body has a polarization axis, thermal stress is generated in first to fourth beams120ato120d, so that each of first to fourth beams120ato120dis sometimes warped when viewed from the direction orthogonal or substantially orthogonal to the multilayer direction. A modification in which each of first to fourth beams120ato120dis warped will be described below. In the following description, second beam120band third beam120care illustrated by way of example.

FIG.6is a plan view illustrating a transducer according to a second modification of a preferred embodiment of the present invention.FIG.7is a partial sectional view illustrating the transducer inFIG.6as viewed from the arrow direction of a line VII-VII.

As illustrated inFIG.6, in a transducer100bof the second modification, the angle between the axial direction of the virtual axis and each of first to fourth slits141ato141dis, for example, approximately 45 degrees when viewed from the multilayer direction.

In the present modification, when the thermal stress is applied to first to fourth beams120ato120d, adjacent beams warp in different manners in a vicinity of first to fourth connection portions130ato130d.

In transducer100baccording to the second modification, the above-described thermal stress is applied to first to fourth beams120ato120d. As a result, as illustrated inFIG.7, in the state where transducer100bis not driven, the ends of the adjacent beams in the vicinity of the centers of first to fourth connection portions130ato130dare located at different positions in the multilayer direction.

FIG.8is a plan view illustrating a transducer according to a third modification of a preferred embodiment of the present invention.FIG.9is a partial sectional view illustrating the transducer inFIG.8as viewed from the arrow direction of a line IX-IX.

As illustrated inFIG.8, in a transducer100caccording to the third modification, the angle between the axial direction of the virtual axis of the single-crystal piezoelectric body and each of first to fourth slits141ato141dis approximately 0 degrees or approximately 90 degrees when viewed from the multilayer direction.

In transducer100cof the third modification, each of first to fourth beams120ato120dis warped by applying the thermal stress to first to fourth beams120ato120d. As a result, as illustrated inFIG.9, in the state where transducer100cis not driven, ends on the center side of first to fourth connection portions130ato130dof the beams adjacent to each other in the vicinity of the center of first to fourth connection portions130ato130dare located at the same or substantially the same position in the multilayer direction. As described above, in the third modification, even when each of first to fourth beams120ato120dis warped by the thermal stress, breakage of first to fourth connection portions130ato130d, particularly, first short portion132A and second short portion132B can be prevented.

As described above, by comparing transducer100baccording to the second modification and transducer100caccording to the third modification, it can be seen that the difference in displacement due to thermal stress between adjacent beams can be prevented from increasing as the angle between the axial direction of the virtual axis and the extending direction of each of first to fourth slits141ato141dapproaches 0 degrees or 90 degrees from the state where the angle is about 45 degrees or about 135 degrees when viewed from the multilayer direction.

As illustrated inFIG.9, in transducer100caccording to the third modification, when each of the beams adjacent to each other is viewed from the sides of first to fourth slits141ato141d, each of the beams adjacent to each other is inclined in any one direction of the multilayer direction.

In transducer100of the present preferred embodiment, each of first to fourth beams120ato120dis configured to be capable of performing the bending vibration. Here, the mechanism of the bending vibration of first to fourth beams120ato120dwill be described.

FIG.10is a sectional view schematically illustrating a portion of the beam of the transducer according to the present preferred embodiment.FIG.11is a sectional view schematically illustrating a portion of the beam during driving of the transducer according to the present preferred embodiment. InFIGS.10and11, the first electrode layer and the second electrode layer are not illustrated.

As illustrated inFIGS.10and11, in the present preferred embodiment, in first to fourth beams120ato120d, piezoelectric layer11defines and functions as a stretchable layer stretchable in an in-plane direction orthogonal or substantially orthogonal to the multilayer direction, and layers other than piezoelectric layer11define and function as a constraining layer. In the present preferred embodiment, support layer14mainly defines and functions as the constraining layer. As described above, the constraining layer is laminated on the stretchable layer in the direction orthogonal or substantially orthogonal to the extending direction of the stretchable layer. Instead of the constraining layer, first to fourth beams120ato120dmay include a reverse-direction stretchable layer that can contract in the in-plane direction when the stretchable layer extends in the in-plane direction and extend in the in-plane direction when the stretchable layer contracts in the in-plane direction.

When piezoelectric layer11that is the stretchable layer attempts to expand and contract in the in-plane direction, support layer14that is a main portion of the constraining layer constrains the expansion and contraction of piezoelectric layer11at a joining surface with piezoelectric layer11. Furthermore, in the present preferred embodiment, in each of first to fourth beams120ato120d, piezoelectric layer11that is the stretchable layer is located only on one side of a stress neutral plane N of each of first to fourth beams120ato120d. The position of the center of gravity of support layer14mainly defining the constraining layer is located on the other side of stress neutral plane N. Thus, as illustrated inFIGS.10and11, when piezoelectric layer11that is the stretchable layer expands and contracts in the in-plane direction, each of first to fourth beams120ato120dis bent in the direction orthogonal or substantially orthogonal to the in-plane direction. A displacement amount of each of first to fourth beams120ato120dwhen each of first to fourth beams120ato120dis bent increases as the separation distance between stress neutral plane N and piezoelectric layer11increases. In addition, the displacement amount increases as the stress with which piezoelectric layer11tries to expand and contract increases. In this manner, each of first to fourth beams120ato120dperforms the bending vibration with first to fourth fixed ends121ato121das starting points in the direction orthogonal or substantially orthogonal to the in-plane direction.

Furthermore, in transducer100of the present preferred embodiment, since first to fourth connection portions130ato130dare provided, the vibration in a fundamental vibration mode is likely to be generated, and the generation of the vibration in a coupled vibration mode is reduced or prevented. The fundamental vibration mode is a mode in which the phases when first to fourth beams120ato120dperform the bending vibration are aligned, and entire or substantially the entire first to fourth beams120ato120dare displaced upward or downward. On the other hand, the coupled vibration mode is a mode in which a phase of at least one of first to fourth beams120ato120dis not aligned with a phase of another beam120when each of first to fourth beams120ato120dperforms the bending vibration.

FIG.12is a perspective view illustrating the transducer of the present preferred embodiment vibrating in the fundamental vibration mode by simulation. Specifically,FIG.12illustrates transducer100in the state in which each of first to fourth beams120ato120dis displaced towards first electrode layer12. InFIG.12, the color becomes lighter as the displacement amount by which each of first to fourth beams120ato120dis displaced towards the side of first electrode layer12becomes larger. InFIG.12, each layer of the plurality of layers10is not illustrated.

As illustrated inFIG.12, for each of first to fourth beams120ato120d, the beams adjacent to each other are connected to each other by first to fourth connection portions130ato130d, so that the generation of the coupled vibration mode is prevented. In this manner, because first to fourth beams120ato120dare connected to each other at the tips, the coupled vibration mode can be less likely to be generated.

Furthermore, because each of first to fourth connection portions130ato130dof transducer100of the present preferred embodiment has a meandering shape, first to fourth connection portions130ato130ddefine and function as leaf springs when first to fourth beams120ato120dvibrate, and first to fourth connection portions130ato130dconnect the beams adjacent to each other, and the lengths of first to fourth connection portions130ato130das the leaf springs are increased, so that connection force can be prevented from becoming too strong.

In transducer100of the present preferred embodiment, the vibration in the fundamental vibration mode is likely to be generated, and the generation of the coupled vibration mode is reduced or prevented, so that the device characteristic is improved particularly when the transducer is used as an ultrasonic transducer. A functional action of transducer100of the present preferred embodiment when the transducer100is used as the ultrasonic transducer will be described below.

First, when the ultrasonic wave is generated by transducer100, voltage is applied between first connection electrode layer20and second connection electrode layer30inFIG.2. Then, the voltage is applied between first electrode layer12connected to first connection electrode layer20and second electrode layer13connected to second connection electrode layer30. Further, also in each of first to fourth beams120ato120d, the voltage is applied between first electrode layer12and second electrode layer13that are opposite to each other with piezoelectric layer11interposed therebetween. Then, because piezoelectric layer11expands and contracts along the in-plane direction orthogonal or substantially orthogonal to the multilayer direction, each of first to fourth beams120ato120dperforms the bending vibration along the multilayer direction by the above-described mechanism. Thus, the force is applied to the medium around first to fourth beams120ato120dof transducer100, and the medium further vibrates to generate the ultrasonic wave.

Further, in transducer100of the present preferred embodiment, each of first to fourth beams120ato120dhas a unique mechanical resonance frequency. Therefore, when the applied voltage is a sinusoidal voltage and the frequency of the sinusoidal voltage is close to the value of the resonance frequency, the displacement amount when each of first to fourth beams120ato120dis bent increases.

When the ultrasonic wave is detected by transducer100, the medium around each of first to fourth beams120ato120dvibrates by the ultrasonic wave, the force is applied to each of first to fourth beams120ato120dfrom the surrounding medium, and each of first to fourth beams120ato120dperforms the bending vibration. When each of first to fourth beams120ato120dperforms the bending vibration, the stress is applied to piezoelectric layer11. When the stress is applied to piezoelectric layer11, an electric charge is induced in piezoelectric layer11. The electric charge induced in piezoelectric layer11generates a potential difference between first electrode layer12and second electrode layer13that are opposite to each other with piezoelectric layer11interposed therebetween. This potential difference is detected by first connection electrode layer20connected to first electrode layer12and second connection electrode layer30connected to second electrode layer13. This enables transducer100to detect the ultrasonic wave.

In addition, when the ultrasonic wave that is the detection target includes many specific frequency components and when these frequency components are close to the value of the resonance frequency, the displacement amount when each of first to fourth beams120ato120dperforms the bending vibration increases. The potential difference increases as the displacement amount increases.

As described above, when transducer100of the present preferred embodiment is used as an ultrasonic transducer, the design of the resonance frequencies of first to fourth beams120ato120dis significant. The resonance frequency varies depending on the length in the extending direction of each of first to fourth beams120ato120d, the thickness in the axial direction of the central axis, the length of first to fourth fixed ends121ato121dwhen viewed from the axial direction, and the density and elastic modulus of the material of first to fourth beams120ato120d.

For example, in transducer100of the present preferred embodiment inFIGS.1to4, when the resonance frequency of each of first to fourth beams120ato120dis designed to be in the vicinity of 40 kHz, for each of first to fourth beams120ato120d, the material of piezoelectric layer11may be lithium niobate, the thickness of piezoelectric layer11may be about 1 μm, the thickness of each of first electrode layer12and second electrode layer13may be about 0.1 μm, the thickness of first support14amay be about 0.8 μm, the thickness of second support14bmay be about 1.4 μm, and the shortest distance from first to fourth fixed ends121ato121dto first to fourth tips122ato122dof each of first to fourth beams120ato120dmay be about 316 μm, length L of each of the first direction (X-axis direction) and the second direction (Y-axis direction) of first to fourth connection portions130ato130dmay be about 77 μm, and the length of each of first to fourth fixed ends121ato121dwhen viewed from the multilayer direction may be about 786 μm.

Because transducer100of the present preferred embodiment includes first to fourth connection portions130ato130dhaving the above-described structure, the vibration in the fundamental vibration mode is likely to be generated, and the generation of the coupled vibration mode is reduced or prevented. For this reason, in the case where transducer100is used as the ultrasonic transducer, even when the ultrasonic wave having the same or substantially the same frequency component as the resonance frequency is detected, the phases of vibrations of first to fourth beams120ato120dare prevented from being different from each other. As a result, the phases of vibrations of first to fourth beams120ato120dare different from each other, so that the electric charge generated in piezoelectric layer11of each of first to fourth beams120ato120dis prevented from canceling each other in first electrode layer12or second electrode layer13.

As described above, in transducer100, the device characteristics as the ultrasonic transducer are improved.

A non-limiting example of a method for manufacturing transducer100according to a preferred embodiment of the present invention will be described below.FIG.13is a sectional view illustrating the state in which the second electrode layer is provided on the piezoelectric single crystal substrate in the non-limiting example of a method for manufacturing the transducer.FIG.13andFIGS.14to19are illustrated in the same sectional view asFIG.2.

As illustrated inFIG.13, first, after the adhesion layer (not illustrated) is provided on the lower surface of piezoelectric single crystal substrate11a, second electrode layer13is provided on the side opposite to piezoelectric single crystal substrate11aof the adhesion layer. Second electrode layer13is formed to have a desired pattern by, for example, a vapor deposition lift-off method. Second electrode layer13is laminated over the entire or substantially the entire lower surface of piezoelectric single crystal substrate11aby, for example, sputtering, and then a desired pattern may be formed by, for example, an etching method. Second electrode layer13and the adhesion layer may be epitaxially grown.

FIG.14is a sectional view illustrating the state in which the first support is provided in the non-limiting example of a method for manufacturing the transducer. As illustrated inFIG.14, first support14ais provided on the lower surface of each of piezoelectric single crystal substrate11aand second electrode layer13by, for example, a chemical vapor deposition (CVD) method, a physical vapor deposition (PVD) method, or the like. Immediately after first support14ais provided, a portion of the lower surface of first support14alocated on the side opposite to second electrode layer13of first support14aswells. For this reason, the lower surface of first support14ais scraped and planarized by, for example, chemical mechanical polishing (CMP) or the like.

FIG.15is a sectional view illustrating the state in which the multilayer body is joined to the first support in the non-limiting example of a method for manufacturing the transducer. As illustrated inFIG.15, multilayer body16including second support14band substrate layer15is joined to the lower surface of first support14aby, for example, surface activation joining or atomic diffusion joining. In the present preferred embodiment, multilayer body16is, for example, a silicon on insulator (SOI) substrate. A yield of transducer100is improved by planarizing previously the upper surface of second support14bby, for example, the CMP or the like. When second support14bis made of low-resistance Si, second support14bcan define and function as the lower electrode layer, and in this case, the formation of second electrode layer13and CMP of the lower surface of first support14acan be made unnecessary.

FIG.16is a sectional view illustrating the state in which the piezoelectric single crystal substrate is shaved to form the piezoelectric layer in the non-limiting example of a method for manufacturing the transducer. As illustrated inFIGS.15and16, the upper surface of piezoelectric single crystal substrate11ais ground with a grinder to be thinned. The upper surface of thinned piezoelectric single crystal substrate11ais further polished by, for example, the CMP or the like to mold piezoelectric single crystal substrate11ainto piezoelectric layer11.

The ion may be previously implanted on the upper surface side of piezoelectric single crystal substrate11ato form a peeling layer, and the peeling layer may be peeled off to form piezoelectric single crystal substrate11ainto piezoelectric layer11. In addition, the upper surface of piezoelectric single crystal substrate11aafter the peeling layer is peeled off may be further polished by, for example, the CMP or the like to form piezoelectric single crystal substrate11ainto piezoelectric layer11.

FIG.17is a sectional view illustrating the state in which the first electrode layer is provided on the piezoelectric layer in the non-limiting example of a method for manufacturing the transducer. As illustrated inFIG.17, after the adhesion layer (not illustrated) is provided on the upper surface of piezoelectric layer11, first electrode layer12is provided on the side opposite to piezoelectric layer11of the adhesion layer. First electrode layer12is formed to have the desired pattern by, for example, the vapor deposition lift-off method. First electrode layer12is laminated over the entire or substantially the entire upper surface of piezoelectric layer11by, for example, sputtering, and then a desired pattern may be formed by, for example, an etching method. First electrode layer12and the adhesion layer may be epitaxially grown.

FIG.18is a sectional view illustrating the state in which a groove and a recess are provided in the non-limiting example of a method for manufacturing the transducer. As illustrated inFIG.18, in the region corresponding to the region inside base110of transducer100as viewed in the multilayer direction, dry etching is performed by, for example, reactive ion etching (RIE) or the like to form slits in piezoelectric layer11and first support14a. The slit may be formed by, for example, wet etching using nitrohydrofluoric acid or the like. Furthermore, second support14bexposed to the slit is etched by, for example, deep reactive ion etching (DRIE) such that the slit reaches the upper surface of substrate layer15. Thus, a groove17inFIG.18corresponding to split slit142in transducer100inFIGS.1and2is formed.

Furthermore, as illustrated inFIG.18, in a portion corresponding to base110of transducer100, piezoelectric layer11is etched such that a portion of second electrode layer13is exposed by the dry etching or the wet etching. Consequently, a recess18is formed.

FIG.19is a partial sectional view illustrating the state in which the first connection electrode layer and the second electrode connection layer are provided in the non-limiting example of a method for manufacturing the transducer. As illustrated inFIG.19, in a portion corresponding to base110, after the adhesion layer (not illustrated) is provided on each of first electrode layer12and second electrode layer13, first connection electrode layer20and second connection electrode layer30are provided on the upper surface of each adhesion layer by the vapor deposition lift-off method. First connection electrode layer20and second connection electrode layer30are laminated over the entire or substantially the entire surfaces of piezoelectric layer11, first electrode layer12, and exposed second electrode layer13by non-limiting example of a sputtering, and then a desired pattern may be formed by the etching method.

Finally, a portion of second substrate layer15bin substrate layer15is removed by the DRIE, and then a portion of first substrate layer15ais removed by the RIE. Thus, as illustrated inFIG.2, first to fourth beams120ato120dand first to fourth connection portions130ato130dare formed while opening101is provided.

Through the above processes, transducer100of the present preferred embodiment of the present invention inFIGS.1to4is manufactured.

As described above, in transducer100of the present preferred embodiment, first connection portion130aconnects first tip122aand second tip122bto each other. First connection portion130ais surrounded by split slit142connecting center122acof first tip122a, the center of base110, and center122bcof second tip122b, first tip122a, and second tip122b. Thus, the entire or substantially the entire first beam120aincluding first tip122aof first beam120aand entire second beam120bincluding second tip122bof second beam120bcan be resonantly vibrated in synchronization with each other. In addition, not all of first to fourth beams120ato120dare connected to each other, but only the adjacent beams are connected to each other, so that the beams (for example, first beam120aand third beam120c) in which the tips are opposite to each other can be displaced so as to be separated from each other. Therefore, obstruction of mutual vibration between the opposing beams can be reduced or prevented. As a result, the entire or substantially the entire beams can be synchronized and resonantly vibrated without obstructing mutual vibration between the beams.

In the present preferred embodiment, first connection portion130ahas the meandering shape. Thus, the internal stress in first connection portion130acan be reduced or prevented. In addition, because first connection portion130ahas the meandering shape, the connection between first beam120aand second beam120bcan be prevented from becoming too strong, and the vibration between first beam120aand second beam120bcan be prevented from being obstructed.

In the present preferred embodiment, the longitudinal portions131arranged in the second direction (Y-axis direction) in the plurality of longitudinal portions131are alternately connected at the first end and the second end in the first direction (X-axis direction) by the corresponding short portion of the plurality of short portions132A,132B. Thus, the number of turns of the meandering shape of first connection portion130acan be made plural, and the internal stress in first connection portion130acan be effectively reduced or prevented. In addition, as the number of turns of the meandering shape of first connection portion130aincreases, the connection between first beam120aand second beam120bcan be effectively prevented from becoming too strong, and the vibration of first beam120aand second beam120bcan be prevented from being further obstructed.

In the present preferred embodiment, width Wm in the second direction (Y-axis direction) of each of the plurality of longitudinal portions131is larger than width Ws in the second direction (Y-axis direction) of first and second intermediate slits143a,143bbetween longitudinal portions131adjacent to each other in the plurality of longitudinal portions131. Thus, in transmission and reception of the sound wave in first connection portion130a, the amount of air (medium) transmitted and received by longitudinal portion131is larger than the amount of air (medium) passing through first intermediate slit143aand second intermediate slit143b, so that transmission and reception efficiency can be maintained high.

In the present preferred embodiment, the width in the first direction (X-axis direction) of at least one of short portions132A,132B is wider than the width in the second direction (Y-axis direction) of each of the plurality of longitudinal portions131. Thus, short portions132A,132B that are stress concentration spots in first connection portion130acan be thickened and strengthened, and the damage to first connection portion130acan be reduced or prevented.

In the present preferred embodiment, the lengths of the plurality of longitudinal portions131are the same or substantially the same. Thus, the bias of the stress distribution generated in first connection portion130acan be reduced to prevent the damage of first connection portion130a.

In the present preferred embodiment, each of the plurality of first intermediate slits143aand at least one second intermediate slit143bis located in parallel or substantially in parallel with first split slit142a. Thus, longitudinal portions131adjacent to each other in the first direction (X-axis direction) can be prevented from coming into contact with each other when transducer100is driven.

In the present preferred embodiment, in the region surrounded by split slit142, first tip122a, and second tip122b, first connection portion130ahas an area greater than or equal to about 90% and less than about 100%, for example. High sound wave transmission and reception efficiency in first connection portion130acan be maintained.

In the present preferred embodiment, first to fourth beams120ato120dand first to fourth connection portions130ato130dare provided. Thus, the volume of the medium that can act when transducer100is driven increases, and the sound pressure that can be transmitted and received can be increased.

In the present preferred embodiment, the plurality of layers10include piezoelectric layer11, first electrode layer12, and second electrode layer13. Piezoelectric layer11is made of the single crystal piezoelectric body. First electrode layer12is disposed on one side of piezoelectric layer11in the multilayer direction of the plurality of layers10. Second electrode layer13is disposed on the other side of piezoelectric layer11so as to be opposed to at least a portion of first electrode layer12with piezoelectric layer11interposed therebetween. Thus, transducer100can be driven by the piezoelectric effect. Transducer100may be a capacitively-driven transducer.

In the present preferred embodiment, the axial direction of the virtual axis when the polarization axis of the single crystal piezoelectric body is projected from the multilayer direction onto the virtual plane orthogonal or substantially orthogonal to the multilayer direction extends in the same direction in both first beam120aand second beam120b, and intersects with the extending direction of each of first beam120aand second beam120bwhen viewed from the multilayer direction. As a result, even when the thermal stress is generated in each of first beam120aand second beam120bin transducer100in which piezoelectric layer11is made of the single-crystal piezoelectric body having a polarization axis, the bias of the stress distribution generated in first connection portion130acan be reduced to reduce or prevent damage of first connection portion130a.

In the present preferred embodiment, when viewed from the multilayer direction, the angle formed by the extending direction of each of first beam120aand second beam120band the axial direction of the virtual axis is greater than or equal to about 40 degrees and less than or equal to about 50 degrees, or greater than or equal to about 130 degrees and less than or equal to about 140 degrees, for example. As a result, even when the thermal stress is generated in first beam120aand second beam120b, because each of first beam120aand second beam120bhas the same or substantially the same stress distribution in the extending direction, the warpage of each of first beam120aand second beam120bis the same or substantially the same. As a result, degradation of the device characteristics of transducer100can be reduced or prevented.

In the present preferred embodiment, piezoelectric layer11is made, for example, of lithium niobate (LiNbO3) or lithium tantalate (LiTaO3). Thus, the piezoelectric characteristic of piezoelectric layer11can be improved, so that the device characteristics of transducer100can be improved.

Modifications different from transducer100of the present preferred embodiment only in the configuration of the connection portion will be described below. The description of the same or substantially the same configuration as that of transducer100according to the present preferred embodiment will not be repeated.

FIG.20is a partial plan view illustrating a transducer according to a fourth modification of a preferred embodiment of the present invention. InFIG.20, the same portion as that inFIG.3is illustrated in an enlarged manner.

As illustrated inFIG.20, in a transducer100daccording to the fourth modification, the number n of turns of the meandering shape of each of first to fourth connection portions130ato130dis, for example, 5.

First defining slit140bais connected to the tip of second split slit142b. Second defining slit140bcis connected to the tip of second split slit142b. Third defining slit140dcis connected to the tip of fourth split slit142d. Fourth defining slit140dais connected to the tip of fourth split slit142d.

First connection portion130ais connected to center122acof first tip122aand an end122baof second tip122bcloser to first beam120a. Second connection portion130bis connected to an end122bcof second tip122bcloser to third beam120cand a center122ccof third tip122c. Third connection portion130cis connected to center122ccof third tip122cand an end122dcof fourth tip122dcloser to third beam120c. Fourth connection portion130dis connected to an end122daof fourth tip122dcloser to first beam120aand center122acof first tip122a.

FIG.21is a partial plan view illustrating a transducer according to a fifth modification of a preferred embodiment of the present invention. InFIG.21, the same portion as that inFIG.3is illustrated in an enlarged manner.

As illustrated inFIG.21, in a transducer100eaccording to the fifth modification, first connection portion130aincludes a first additional connection portion133aextending in the Y-axis direction at a connection position with first tip122aof first beam120a.

A first bent slit144abextending from first split slit142ato the other side in the Y-axis direction on the side of first beam120awith respect to first connection slit140abis provided in first connection portion130a. A first extension slit144baextending from second split slit142bto the other side in the X-axis direction on the side of second beam120bwith respect to first defining slit140bais provided.

First additional connection portion133aextends to the other side in the Y-axis direction between first connection slit140aband first bent slit144ab. First connection portion130aextends to the other side in the X-axis direction between first defining slit140baand first extension slit144ba. Thus, first connection portion130ais connected to an end122abof first tip122acloser to second beam120band an end122baof second tip122bcloser to first beam120a.

Second connection portion130bincludes a second additional connection portion133bextending in the Y-axis direction at a connecting position with third tip122cof third beam120c.

A second bent slit144cbextending from third split slit142cto the other side in the Y-axis direction on the side of third beam120cwith respect to second connection slit140cbis provided in second connection portion130b. A second extension slit144bcextending from second split slit142bto one side in the X-axis direction is provided on the side of second beam120bwith respect to second defining slit140bc.

Second additional connection portion133bextends to the other side in the Y-axis direction between second connection slit140cband second bent slit144cb. Second connection portion130bextends to one side in the X-axis direction between second defining slit140bcand second extension slit144bc. Thus, second connection portion130bis connected to an end122bcof second tip122bcloser to third beam120cand an end122cbof third tip122ccloser to second beam120b.

Third connection portion130cincludes a third additional connection portion133cextending in the Y-axis direction at a connecting position with third tip122cof third beam120c.

A third bent slit144cdextending from third split slit142cto one side in the Y-axis direction on the side of third beam120cwith respect to third connection slit140cdis provided in third connection portion130c. In addition, a third extension slit144dcextending from fourth split slit142dto one side in the X-axis direction is provided on the side of fourth beam120cwith respect to third defining slit140dc.

Third additional connection portion133cextends to one side in the Y-axis direction between third connection slit140cdand third bent slit144cd. Third connection portion130cextends to one side in the X-axis direction between third defining slit140dcand third extension slit144dc. Thus, third connection portion130cis connected to an end122cdof third tip122ccloser to fourth beam120dand an end122dcof fourth tip122dcloser to third beam120c.

Fourth connection portion130dincludes a fourth additional connection portion133dextending in the Y-axis direction at a connecting position with first tip122aof first beam120a.

A fourth bent slit144adextending from first split slit142ato one side in the Y-axis direction on the side of first beam120awith respect to fourth connection slit140adis provided in fourth connection portion130d. A fourth extension slit144daextending from fourth split slit142dtowards the other side in the X-axis direction is provided on the side of fourth beam120cwith respect to fourth defining slit140da.

Fourth additional connection portion133dextends to one side in the Y-axis direction between fourth connection slit140adand fourth bent slit144ad. Fourth connection portion130dextends to the other side in the X-axis direction between fourth defining slit140daand fourth extension slit144da. Accordingly, fourth connection portion130dis connected to end122daof fourth tip122dcloser to first beam120aand an end122adof first tip122acloser to fourth beam120d.

In the fifth modification, the ends of the tips of first to fourth beams120ato120dare connected to first to fourth connection portions130ato130d, respectively, such that the balance of vibrations of first to fourth beams120ato120dis improved, and first to fourth additional connection portions133ato133dare provided, such that the stress distribution in first to fourth connection portions130ato130dcan be made uniform or substantially uniform.

FIG.22is a partial plan view illustrating a transducer according to a sixth modification of a preferred embodiment of the present invention. InFIG.22, the same portion as that in FIG.3is illustrated in an enlarged manner. In the description of the sixth modification, the description of the same or substantially the same configuration as transducer100eaccording to the fifth modification of the preferred embodiment of the present invention will not be repeated.

As illustrated inFIG.22, in a transducer100faccording to the sixth modification, first connection portion130aincludes first additional connection portion133afolded back while extending in the Y-axis direction at the connection position with first tip122aof first beam120a.

A first additional bent slit145abextending from first slit141ato one side in the Y-axis direction on the side of first beam120awith respect to first bent slit144abis provided in first connection portion130a. First additional extension slit145baextending from first slit141ato one side in the X-axis direction is provided on the side of second beam120bwith respect to first extension slit144ba.

First additional connection portion133aextends to one side in the Y-axis direction between first bent slit144aband first additional bent slit145ab. First connection portion130aextends to one side in the X-axis direction between first extension slit144baand first additional extension slit145ba. Thus, first connection portion130ais connected to center122acof first tip122aand center122bcof second tip122b.

Second connection portion130bincludes second additional connection portion133bthat is folded back while extending in the Y-axis direction at the connection position with third tip122cof the third beam120c.

A second additional bent slit145cbextending from second slit141bto one side in the Y-axis direction on the side of third beam120cwith respect to second bent slit144cbis provided in second connection portion130b. A second additional extension slit145bcextending from second slit141bto the other side in the X-axis direction is provided on the side of second beam120bwith respect to second extension slit144bc.

Second additional connection portion133bextends to one side in the Y-axis direction between second bent slit144cband second additional bent slit145cb. Second connection portion130bextends to the other side in the X-axis direction between second extension slit144bcand second additional extension slit145bc. Thus, second connection portion130bis connected to center122bcof second tip122band center122ccof third tip122c.

Third connection portion130cincludes third additional connection portion133cthat is folded back while extending in the Y-axis direction at the connection position with third tip122cof the third beam120c.

A third additional bent slit145cdextending from third slit141cto the other side in the Y-axis direction on the side of third beam120cwith respect to third bent slit144cdis provided in third connection portion130c. In addition, a third additional extension slit145dcextending from third slit141cto the other side in the X-axis direction is provided on the side of fourth beam120dwith respect to third extension slit144dc.

Third additional connection portion133cextends to the other side in the Y-axis direction between third bent slit144cdand third additional bent slit145cd. Third connection portion130cextends to the other side in the X-axis direction between third extension slit144dcand third additional extension slit145dc. Thus, third connection portion130cis connected to center122ccof third tip122cand center122dcof fourth tip122d.

Fourth connection portion130dincludes fourth additional connection portion133dthat is folded back while extending in the Y-axis direction at the connection position with first tip122aof first beam120a.

A fourth additional bent slit145adextending from first slit141ato the other side in the Y-axis direction on the side of first beam120awith respect to fourth bent slit144adis provided in fourth connection portion130d. A fourth additional extension slit145daextending from first slit141ato one side in the X-axis direction is provided on the side of fourth beam120dwith respect to fourth extension slit144da.

Fourth additional connection portion133dextends to the other side in the Y-axis direction between fourth bent slit144adand fourth additional bent slit145ad. Fourth connection portion130dextends to one side in the X-axis direction between fourth extension slit144daand fourth additional extension slit145da. Thus, fourth connection portion130dis connected to center122dcof fourth tip122dand center122acof first tip122a.

In the sixth modification, first to fourth connection portions130ato130dare connected to the centers of the tips of first to fourth beams120ato120d, respectively, so that the balance of vibrations of first to fourth beams120ato120dis improved, and first to fourth additional connection portions133ato133dare folded back, so that the stress distribution in first to fourth connection portions130ato130dcan be effectively made uniform or substantially uniform.

FIG.23is a partial plan view illustrating a transducer according to a seventh modification of a preferred embodiment of the present invention. InFIG.23, the same portion as that inFIG.3is illustrated in an enlarged manner. In the description of the seventh modification, the description of the same or substantially the same configuration as transducer100eaccording to the fifth modification of the preferred embodiment of the present invention will not be repeated.

As illustrated inFIG.23, in a transducer100gaccording to the seventh modification, first connection portion130ais connected to a position shifted by a certain distance from center122acof first tip122ato the other side in the Y-axis direction and a position shifted by the certain distance from center122bcof second tip122bto the other side in the X-axis direction.

Second connection portion130bis connected to a position shifted by the certain distance from center122bcof second tip122bto one side in the X-axis direction and a position shifted by the certain distance from center122ccof third tip122cto the other side in the Y-axis direction.

Third connection portion130cis connected to a position shifted by the certain distance from center122ccof third tip122cto one side in the Y-axis direction and a position shifted by the certain distance from center122dcof fourth tip122dto one side in the X-axis direction.

Fourth connection portion130dis connected to a position shifted by the certain distance from center122dcof fourth tip122dto the other side in the X-axis direction and a position shifted by the certain distance from center122acof first tip122ato the one side in the Y-axis direction.

In the seventh modification, the connection positions and connection angles of first to fourth beams120ato120dand first to fourth connection portions130ato130dare uniform or substantially uniform, and the stress distribution in first to fourth connection portions130ato130dcan be effectively uniformized while the balance of vibrations of first to fourth beams120ato120dis improved.

FIG.24is a partial plan view illustrating a transducer according to an eighth modification of a preferred embodiment of the present invention. InFIG.24, the same portion as that inFIG.3is illustrated in an enlarged manner.

As illustrated inFIG.24, in a transducer100haccording to the eighth modification, first to fourth connection portions130ato130dare arranged point-symmetrically with respect to center C of base110. In each of second connection portion130band fourth connection portion130d, each of the plurality of first intermediate slits143dand the plurality of second intermediate slits143eextends in the Y-axis direction.

FIG.25is a partial plan view illustrating a transducer according to a ninth modification of a preferred embodiment of the present invention. InFIG.25, the same portion as that inFIG.3is illustrated in an enlarged manner.

As illustrated inFIG.25, in a transducer100iaccording to the ninth modification, first to fourth connection portions130ato130dare arranged point-symmetrically with respect to center C of base110. In each of first connection portion130aand third connection portion130c, each of a plurality of first intermediate slits143fand a plurality of second intermediate slits143gextends in the direction of about 45° with respect to the X-axis direction. In each of second connection portion130band fourth connection portion130d, each of a plurality of first intermediate slits143hand a plurality of second intermediate slits143iextends in the direction of about 135° with respect to the X-axis direction.

In the description of the above preferred embodiments and modifications, configurations that can be combined may be combined with each other.

While preferred embodiments of the present invention have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the present invention. The scope of the present invention, therefore, is to be determined solely by the following claims.