Transducer

Abstract

The present invention is provided with an annular base section (110), a plurality of beam sections (120), and a connecting section (130). Each of the plurality of beam sections (120) has a fixed end section (121) connected to the base section (110), and a tip section (122) positioned closer to the center of the base section (110) on the opposite side of the fixed end section (121), and extends from the fixed end section (121) toward the tip section (122). The connecting part (130) connects a pair of beam parts (120) adjacent to each other in the circumferential direction of the base part (110) among the plurality of beam parts (120). The connecting portion (130) includes at least one tortuous portion. At least one dividing slit (143) is formed in the connecting part (130) and divides the connecting part (130) in a manner that the connecting part (130) partially branches and then merges again.

Description

Technical Field

[0001] This invention relates to transducers, and more particularly to acoustic transducers capable of being used as transmitters for transmitting sound waves and receivers (pickups) for receiving sound waves. In particular, it relates to an ultrasonic transceiver capable of transmitting and receiving ultrasonic waves. Background Technology

[0002] International Publication No. 2022 / 049944 (Patent Document 1) discloses the structure of a transducer. The transducer described in Patent Document 1 comprises an annular base, multiple beams, and a connecting portion. Each beam has a fixed end connected to the base and a front end located opposite the fixed end, extending from the fixed end toward the front end. The connecting portion connects a pair of beams that are circumferentially adjacent to each other in the base. Each beam is a piezoelectric vibrating part comprising multiple layers. A slit and an opening are provided between the pair of beams. The slit is formed by a portion of a pair of adjacent end edges of the pair of beams. The opening is located spaced apart from the slit and adjacent to the front ends of each pair of beams, and is formed by another portion of the pair of end edges. The connecting portion is provided in a folded-back manner between the pair of beams. The connecting portion includes a first connecting portion, a second connecting portion, and a bridging portion. The first connecting portion extends along the slit and connects to one of the pair of beams. The second connecting portion extends along the slit and connects to the other side of the pair of beams. The bridging portion is located between the slit and the opening and connects to the first connecting portion and the second connecting portion respectively. The multiple beams are each located at a position sandwiched by slits extending in intersecting directions, and are interconnected in the aforementioned circumferential direction via connecting portions.

[0003] Prior art literature

[0004] Patent documents

[0005] Patent Document 1: International Publication No. 2022 / 049944 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] In the transducer disclosed in Patent Document 1, there is a goal to release the in-plane stress of the connecting portion without excessively hindering the vibration of each beam portion, and to suppress vibration deviations in multiple beam portions. To achieve the above, it is necessary to appropriately adjust the in-plane stiffness and the thickness stiffness of the connecting portion. However, the range of adjustment of the in-plane and thickness stiffness of the connecting portion is limited by adjusting the size of the connecting portion alone. Therefore, there is room for appropriately adjusting the in-plane and thickness stiffness of the connecting portion.

[0008] The present invention was made in view of the above-mentioned problems, and its object is to provide a transducer that can appropriately adjust the rigidity of the connection in the in-plane direction and the thickness direction, release the stress in the in-plane direction of the connection through the connection without excessively hindering the vibration of each beam, and can efficiently suppress vibration deviation in multiple beams.

[0009] Methods for solving problems

[0010] The transducer based on the present invention comprises an annular base, a plurality of beam portions, and a connecting portion. Each of the plurality of beam portions has a fixed end portion connected to the base, and a front end portion located near the center of the base on the opposite side of the fixed end portion, extending from the fixed end portion toward the front end portion. The connecting portion connects a pair of beam portions that are circumferentially adjacent to each other in the base. The connecting portion includes at least one bend. At least one dividing slit is formed on the connecting portion, which divides the connecting portion in a manner that the beam portions partially branch and then re-merge.

[0011] The effects of the invention

[0012] According to the present invention, the rigidity of the connection in the in-plane direction and the thickness direction can be appropriately adjusted, the stress in the in-plane direction of the connection can be released through the connection without excessively hindering the vibration of each beam, and the vibration deviation in multiple beams can be effectively suppressed. Attached Figure Description

[0013] Figure 1 This is a top view of the transducer according to Embodiment 1 of the present invention.

[0014] Figure 2 Observe from the direction of the arrow on line II-II Figure 1 A cross-sectional view of the transducer.

[0015] Figure 3 It is Figure 1 Part III is a magnified partial top view.

[0016] Figure 4 This is a cross-sectional view schematically showing a portion of the beam of the transducer according to Embodiment 1 of the present invention.

[0017] Figure 5 This is a schematic cross-sectional view of a portion of the beam portion of the transducer according to Embodiment 1 of the present invention during operation.

[0018] Figure 6 This is a perspective view illustrating the state of vibration of the transducer according to Embodiment 1 of the present invention in a basic vibration mode.

[0019] Figure 7This is a top view showing the extension length of each of the multiple beams of the transducer according to Embodiment 1 of the present invention, the shortest distance between the front end and the central axis, and the length of the fixed end.

[0020] Figure 8 This is a cross-sectional view showing the state in which a second electrode layer is provided on a piezoelectric single crystal substrate in the transducer manufacturing method according to Embodiment 1 of the present invention.

[0021] Figure 9 This is a cross-sectional view showing the state in which the first support portion is provided in the transducer manufacturing method according to Embodiment 1 of the present invention.

[0022] Figure 10 This is a cross-sectional view showing the state in which the laminate is joined to the first support portion in the transducer manufacturing method according to Embodiment 1 of the present invention.

[0023] Figure 11 This is a cross-sectional view showing the state in which a piezoelectric layer is formed by cutting a piezoelectric single crystal substrate in the manufacturing method of the transducer according to Embodiment 1 of the present invention.

[0024] Figure 12 This is a cross-sectional view showing the state in which a first electrode layer is provided on the piezoelectric layer in the transducer manufacturing method according to Embodiment 1 of the present invention.

[0025] Figure 13 This is a cross-sectional view showing the state in which the groove and recess are provided in the manufacturing method of the transducer according to Embodiment 1 of the present invention.

[0026] Figure 14 This is a partial cross-sectional view showing the state in which the first connecting electrode layer and the second electrode connecting layer are provided in the manufacturing method of the transducer according to Embodiment 1 of the present invention.

[0027] Figure 15 It is a diagram used to illustrate the state of deformation caused by applying an in-plane load to one end of the folded portion of the connecting part involved in the comparative example.

[0028] Figure 16 This diagram illustrates the state in which an in-plane load is applied to one end of the folded portion of the connecting portion involved in the embodiment, causing it to deform.

[0029] Figure 17 It is a diagram showing the distribution of internal stress generated when an in-plane load is applied to one end of the folded part of the connection involved in the comparative example, causing it to deform.

[0030] Figure 18This is a diagram showing the distribution of internal stress generated when an in-plane load is applied to one end of the folded portion of the connecting portion involved in the embodiment, causing it to deform.

[0031] Figure 19 It is a diagram used to illustrate the state of deformation caused by applying a load in the thickness direction to one end of the folded part of the connecting part involved in the comparative example.

[0032] Figure 20 This diagram illustrates the state in which a load in the thickness direction is applied to one end of the folded portion of the connecting portion involved in the embodiment, causing it to deform.

[0033] Figure 21 It is a diagram showing the distribution of internal stress generated when a load in the thickness direction is applied to one end of the folded part of the connection involved in the comparative example, causing it to deform.

[0034] Figure 22 This is a diagram showing the distribution of internal stress generated when a load in the thickness direction is applied to one end of the folded portion of the connection portion involved in the embodiment, causing it to deform.

[0035] Figure 23 This is a diagram illustrating the distribution of internal stress generated at the folded-back portion of the connection involved in the comparative examples and embodiments.

[0036] Figure 24 It is a graph showing the shift of the maximum principal stress based on the distance from the root of section R on line A, i.e., point S.

[0037] Figure 25 This is an enlarged top view showing part of the connection section composed of a second elastomer layer and a piezoelectric layer that function as the lower electrode layer.

[0038] Figure 26 Observed from the XXVI-XXVI direction Figure 25 Cross-sectional view of the connection part.

[0039] Figure 27 This is a top view showing an enlarged portion of the connection consisting only of the second elastomer layer.

[0040] Figure 28 Observed from the XXVIII-XXVIII direction Figure 27 Cross-sectional view of the connection part.

[0041] Figure 29 This is a top view of the transducer according to the first variation of Embodiment 1 of the present invention.

[0042] Figure 30 This is a top view of the transducer according to the second variation of Embodiment 1 of the present invention.

[0043] Figure 31 This is a top view of the transducer according to the third variation of Embodiment 1 of the present invention.

[0044] Figure 32 This is a top view of the transducer according to the fourth variation of Embodiment 1 of the present invention.

[0045] Figure 33 This is a top view of the transducer according to the fifth variation of Embodiment 1 of the present invention.

[0046] Figure 34 This is a top view of the transducer according to the sixth variation of Embodiment 1 of the present invention.

[0047] Figure 35 This is a top view of the transducer according to Embodiment 2 of the present invention.

[0048] Figure 36 This is a top view of the transducer involved in a variation of Embodiment 2 of the present invention.

[0049] Figure 37 This is a cross-sectional view of the transducer according to Embodiment 3 of the present invention.

[0050] Figure 38 This is a cross-sectional view showing the state in which the laminate is joined to the first support portion in the transducer manufacturing method according to Embodiment 2 of the present invention.

[0051] Figure 39 This is a cross-sectional view of the transducer involved in a variation of Embodiment 3 of the present invention. Detailed Implementation

[0052] Hereinafter, the transducers according to various embodiments of the present invention will be described with reference to the accompanying drawings. In the following description of the embodiments, the same or equivalent parts in the drawings will be labeled with the same reference numerals, and their descriptions will not be repeated. Furthermore, in the following description, the center of the base 110 includes the central axis C of the base 110 and the location near the central axis C, which will be described later.

[0053] (Implementation Method 1)

[0054] Figure 1 This is a top view of the transducer according to Embodiment 1 of the present invention. Figure 2 Observe from the direction of the arrow on line II-II Figure 1 A cross-sectional view of the transducer. Figure 3 It is Figure 1 Part III is a magnified partial top view. Figure 1 and Figure 3 For convenience, the electrode layers are not shown in the diagram.

[0055] like Figures 1 to 3 As shown, the transducer 100 according to Embodiment 1 of the present invention includes an annular base 110, a plurality of beam portions 120, and a connecting portion 130. In this embodiment, the transducer 100 includes four beam portions 120. However, the number of beam portions 120 is not limited to four, and any number is acceptable. The plurality of beam portions 120 of the transducer 100 according to this embodiment are each capable of bending and vibrating, and can be used as an ultrasonic transducer.

[0056] In this embodiment, from Figure 2 Viewed axially from the central axis C, the base 110 has a square annular shape extending along both the X and Y axes. Furthermore, the shape of the base 110 is not particularly limited as long as it is annular when viewed from the central axis direction (Z-axis direction). Viewed from the central axis direction (Z-axis direction), the outer peripheral surface of the base 110 can be polygonal or circular, and the inner peripheral surface of the base 110 can also be polygonal or circular. For example, the length of one side of the inner peripheral surface of the base 110 is 0.6 mm or more and 1.5 mm or less, and the thickness of the base 110 is 0.2 mm or more and 0.5 mm or less.

[0057] like Figure 2 As shown, the base 110 includes a support layer 15. An opening 101 is formed in the support layer 15. A vibration layer 10 is disposed on the upper side of the support layer 15. The base 110 has a portion of the vibration layer 10 located on the upper side of the support layer 15, and a first connecting electrode layer 20 and a second connecting electrode layer 30 disposed on this portion.

[0058] The support layer 15 has an intermediate layer 15a and a substrate layer 15b. The intermediate layer 15a is formed on the substrate layer 15b. In this embodiment, the intermediate layer 15a is made of SiO2, and the substrate layer 15b is made of single-crystal Si. Furthermore, the materials constituting the intermediate layer 15a and the substrate layer 15b are not limited to Si, and may also be other semiconductor materials.

[0059] The vibrating layer 10 has a piezoelectric layer 11, a first electrode layer 12, a second electrode layer 13, and an elastomer layer 14. The thickness of the vibrating layer 10 is, for example, 0.5 μm or more and 6.0 μm or less.

[0060] The piezoelectric layer 11 is composed of a single-crystal piezoelectric material. The cutting orientation of the piezoelectric layer 11 is appropriately selected in a manner that reveals the desired device characteristics. In this embodiment, the piezoelectric layer 11 is formed by thinning a single-crystal substrate, specifically a rotary Y-cut substrate. The cutting orientation of the rotary Y-cut substrate is specifically 30°. The thickness of the piezoelectric layer 11 is, for example, 0.3 μm or more and 5.0 μm or less.

[0061] The material constituting the piezoelectric layer 11 is appropriately selected in a manner that allows the transducer 100 to exhibit the desired device characteristics. In this embodiment, the piezoelectric layer 11 is composed of an inorganic material. Specifically, the piezoelectric layer 11 is composed of a basic niobate-based compound or a basic tantalate-based compound. In this embodiment, the alkali metal contained in the basic niobate-based compound or the basic tantalate-based compound is at least one of lithium, sodium, and potassium. In this embodiment, the piezoelectric layer 11 is composed of lithium niobate (LiNbO3) or lithium tantalate (LiTaO3).

[0062] like Figure 2 As shown, the first electrode layer 12 is disposed on the upper side of the piezoelectric layer 11. The second electrode layer 13 is disposed on the lower side of the piezoelectric layer 11, facing the first electrode layer 12 with a gap between it and the piezoelectric layer 11. In this embodiment, sealing layers (not shown) are disposed between the first electrode layer 12 and the piezoelectric layer 11, and between the second electrode layer 13 and the piezoelectric layer 11, respectively.

[0063] In this embodiment, the first electrode layer 12 and the second electrode layer 13 are each made of Pt. The first electrode layer 12 and the second electrode layer 13 may also be made of other materials such as Al. The sealing layer is made of Ti. The sealing layer may also be made of other materials such as NiCr alloy. The first electrode layer 12, the second electrode layer 13, and the sealing layer can each be an epitaxially grown film. When the piezoelectric layer 11 is made of lithium niobate (LiNbO3), from the perspective of suppressing the diffusion of the material constituting the sealing layer into the first electrode layer 12 or the second electrode layer 13, it is preferable that the sealing layer is made of NiCr alloy. This improves the reliability of the transducer 100.

[0064] In this embodiment, the dimensions of the first electrode layer 12 and the second electrode layer 13 are, for example, 0.05 μm or more and 0.2 μm or less. The thickness of the sealing layer is, for example, 0.005 μm or more and 0.05 μm or less.

[0065] The elastomeric layer 14 is disposed on the opposite side of the first electrode layer 12 of the piezoelectric layer 11 and on the opposite side of the piezoelectric layer 11 of the second electrode layer 13. The elastomeric layer 14 has a first elastomeric layer 14a and a second elastomeric layer 14b stacked on the opposite side of the piezoelectric layer 11 of the first elastomeric layer 14a. In this embodiment, the first elastomeric layer 14a is made of SiO2, and the second elastomeric layer 14b is made of single-crystal Si. In this embodiment, from the perspective of the bending vibration of the plurality of beam portions 120, it is preferable that the thickness of the elastomeric layer 14 is thicker than that of the piezoelectric layer 11. Furthermore, the mechanism of the bending vibration of the plurality of beam portions 120 will be described later.

[0066] like Figure 2As shown, a first connecting electrode layer 20 is formed on a first electrode layer 12 via an adhesive layer (not shown). A second connecting electrode layer 30 is formed on a second electrode layer 13 via an adhesive layer (not shown).

[0067] The thickness of each of the first connecting electrode layer 20 and the second connecting electrode layer 30 is, for example, 0.1 μm or more and 1.0 μm or less. The thickness of each of the sealing layer connected to the first connecting electrode layer 20 and the sealing layer connected to the second connecting electrode layer 30 is, for example, 0.005 μm or more and 0.1 μm or less.

[0068] In this embodiment, both the first connecting electrode layer 20 and the second connecting electrode layer 30 are made of Au. Alternatively, they can be made of other conductive materials such as Al. The sealing layer connected to the first connecting electrode layer 20 and the sealing layer connected to the second connecting electrode layer 30 are each made of, for example, Ti. These sealing layers can also be made of a NiCr alloy.

[0069] like Figures 1-3 As shown, viewed from the central axis direction (Z-axis direction), a first slit 141 and a second slit 142, connected to each other, are formed in the portion of the vibrating layer 10 located inside the base 110. Viewed from the central axis direction (Z-axis direction), the first slit 141 extends from the corner of the inner peripheral side surface of the base 110 toward the center of the base 110. In this embodiment, the second slit 142 is formed in a comb-like shape.

[0070] Viewed from the central axis direction (Z-axis direction), from the perspective of suppressing sound leakage caused by each slit, it is preferable that the width of each of the first slit 141 and the second slit 142 is 10 μm or less. In addition, from the perspective of reducing the Q value in the resonant frequency of the transducer 100, it is sometimes preferable to set the width of each of the first slit 141 and the second slit 142 to be 3 μm or more.

[0071] By forming a first slit 141 and a second slit 142 penetrating the vibrating layer 10 at a portion located inside the base 110, a plurality of beam portions 120 and at least one connecting portion 130 are formed.

[0072] like Figure 1 As shown, each of the plurality of beam portions 120 has a fixed end portion 121 connected to the base portion 110, and a front end portion 122 located on the opposite side of the fixed end portion 121 near the center of the base portion 110, extending from the fixed end portion 121 toward the front end portion 122. Figure 2 As shown, multiple beams 120 are located at positions covering the opening 101. Each of the multiple beams 120 extends along the same imaginary plane in a state where the transducer 100 is not driven.

[0073] like Figure 1 As shown, a plurality of beam portions 120 each extend from an annular base 110 toward the center of the base 110 and are adjacent to each other in the circumferential direction of the base 110. In this embodiment, viewed from the central axis direction (Z-axis direction), the plurality of beam portions 120 are configured to be rotationally symmetrical about the central axis C of the base 110.

[0074] Viewed from the central axis direction (Z-axis direction), each of the multiple beam portions 120 has a tapering shape at its front end. Specifically, viewed from the central axis direction (Z-axis direction), each of the multiple beam portions 120 has a generally isosceles trapezoidal shape. The fixed end portion 121 of each of the multiple beam portions 120 is connected to multiple edges of the inner circumferential surface of the base 110, and therefore, viewed from the central axis direction (Z-axis direction), it is located at a position corresponding to each edge of the inner circumferential surface of the base 110. For example, viewed from the central axis direction (Z-axis direction), the length of the fixed end portion 121 is 0.5 mm or more and 1.5 mm or less.

[0075] like Figure 2 As shown, each of the multiple beam portions 120 is a vibrating portion containing a piezoelectric layer 11. Specifically, viewed from the central axis direction (Z-axis direction), each of the multiple beam portions 120 is a portion of the vibrating layer 10 located inside the base portion 110 that does not become a connecting portion 130.

[0076] Each of the multiple beam sections 120 is configured to vibrate when a voltage is applied through the piezoelectric layer 11. Furthermore, it is configured to detect vibration by converting the vibration acting on each of the multiple beam sections 120 into a voltage using the piezoelectric layer 11. Moreover, the multiple beam sections 120 are not limited to a configuration where vibration generation and detection are performed using a piezoelectric method as described above; they can also be configured to generate and detect vibration using an electrostatic method.

[0077] From the perspective of facilitating bending vibration, it is preferable that the length of each of the plurality of beams 120 in its extending direction is at least five times the thickness of each of the plurality of beams 120 in the direction of its central axis (Z-axis). Furthermore, in Figure 2 In the diagram, the extension lengths and thicknesses of the multiple beam sections 120 are shown only schematically and are not actual proportions.

[0078] like Figure 1 As shown, a pair of beam portions 120 that are circumferentially adjacent to each other at the base 110 are connected to each other by a connecting portion 130. In this embodiment, the front ends 122 of a pair of beam portions 120 are connected to each other by the connecting portion 130. Each of the multiple beam portions 120 is connected to a connecting portion 130 at a location.

[0079] The connecting portion 130 includes at least one bend. A bend refers to the portion of the connecting portion 130 where the extending direction changes at approximately 90°. In this embodiment, the connecting portion 130 has multiple folds, exhibiting a meandering shape. Each fold is composed of two bends. Furthermore, the bend can also be curved. In this case, the fold is formed in a C-shape.

[0080] like Figure 1 and Figure 3 As shown, at least one dividing slit 143 is formed in the connecting portion 130, which divides the connecting portion 130 in a manner that the connecting portion 130 partially branches and then rejoins. The dividing slit 143 penetrates the connecting portion 130 in the thickness direction (Z-axis direction), causing the connecting portion 130 to partially branch in the in-plane direction. The dividing slit 143 divides the connecting portion 130 approximately equally at the portion where the connecting portion 130 partially branches.

[0081] In this embodiment, in the connecting portion 130, a dividing slit 143 is formed in the straight extension adjacent to the bend, and the straight extension is branched into two. The straight extension is divided in such a way that its width is bisected by the dividing slit 143. From the perspective of suppressing sound leakage caused by the dividing slit 143, it is preferable that the width of the dividing slit 143 is 10 μm or less.

[0082] like Figure 2 As shown, in this embodiment, the connecting portion 130 is formed by continuous vibration layers 10 of each of the multiple beam portions 120 in a direction orthogonal to the stacking direction. In this embodiment, the vibration layer 10 in the connecting portion 130 does not include the first electrode layer 12 and the second electrode layer 13. However, the vibration layer 10 in the connecting portion 130 may also include the first electrode layer 12 and the second electrode layer 13. Furthermore, when the second elastomer layer 14b is made of low-resistance Si, the second elastomer layer 14b can function as a lower electrode layer without providing the second electrode layer 13. In this case, the first elastomer layer 14a is not provided, and the vibration layer 10 in the connecting portion 130 includes a lower electrode layer made of the second elastomer layer 14b.

[0083] Here, the mechanism of bending vibration of multiple beam sections 120 is explained.

[0084] Figure 4 This is a cross-sectional view schematically showing a portion of the beam of the transducer according to Embodiment 1 of the present invention. Figure 5 This is a schematic cross-sectional view of a portion of the beam portion of the transducer according to Embodiment 1 of the present invention during operation. Furthermore, in Figure 4 and Figure 5 The first electrode layer and the second electrode layer are not shown in the figure.

[0085] like Figure 4 and Figure 5 As shown, in this embodiment, among the plurality of beam portions 120, the piezoelectric layer 11 functions as a stretching layer capable of stretching and contracting in an in-plane direction (XY direction) orthogonal to the thickness direction (Z-axis direction) of the connecting portion 130, while the layers other than the piezoelectric layer 11 function as constraint layers. In this embodiment, the elastomer layer 14 primarily functions as the constraint layer. Thus, the constraint layer is stacked relative to the stretching layer in a direction orthogonal to the stretching direction of the stretching layer. Furthermore, the plurality of beam portions 120 may also include a reverse stretching layer instead of a constraint layer, which, as a reverse stretching layer, contracts in the in-plane direction when the stretching layer stretches in the in-plane direction, and stretches in the in-plane direction when the stretching layer contracts in the in-plane direction.

[0086] Furthermore, if the piezoelectric layer 11, which serves as a stretching layer, is to stretch or contract along the aforementioned in-plane direction, the elastomeric layer 14, which is the main part of the constraint layer, constrains the stretching or contraction of the piezoelectric layer 11 at the interface with it. In addition, in this embodiment, in each of the plurality of beam portions 120, the piezoelectric layer 11, which serves as a stretching layer, is located only on one side of the stress neutral plane N of each of the plurality of beam portions 120. The center of gravity of the elastomeric layer 14, which mainly constitutes the constraint layer, is located on the other side of the stress neutral plane N. Thus, as... Figure 4 and Figure 5 As shown, when the piezoelectric layer 11, which serves as a stretching layer, stretches and contracts in the aforementioned in-plane direction, each of the plurality of beam portions 120 bends in a direction orthogonal to the aforementioned in-plane direction (Z-axis direction). Furthermore, the displacement of each of the plurality of beam portions 120 during bending increases with the increasing separation distance between the stress neutral plane N and the piezoelectric layer 11. Additionally, the greater the stress required for the piezoelectric layer 11 to stretch and contract, the greater the displacement. In this way, each of the plurality of beam portions 120 undergoes bending vibration originating from a fixed end 121 in a direction orthogonal to the aforementioned in-plane direction.

[0087] Furthermore, in the transducer 100 according to this embodiment, since the connecting portion 130 is provided, vibration in the basic vibration mode is easily generated, while the generation of vibration in the coupled vibration mode is suppressed. The basic vibration mode refers to a mode in which the phases of the multiple beam portions 120 are consistent when they each undergo bending vibration, and the multiple beam portions 120 as a whole are displaced in one direction (up or down). On the other hand, the coupled vibration mode refers to a mode in which the phase of at least one beam portion of the multiple beam portions 120 is inconsistent with the phases of the other beam portions 120 when they each undergo bending vibration.

[0088] Figure 6This is a perspective view simulating the state of vibration of the transducer according to Embodiment 1 of the present invention in a basic vibration mode. Specifically, in Figure 6 The image shows a transducer 100 in which multiple beam sections 120 are each displaced toward the first electrode layer 12. Additionally, in... Figure 6 In the middle, the greater the displacement of each of the multiple beams 120 towards the first electrode layer 12, the lighter the color.

[0089] like Figure 6 As shown, for each of the plurality of beam sections 120, since adjacent beam sections are connected to each other through the connecting section 130, the occurrence of coupled vibration modes is suppressed. In this way, by connecting the plurality of beam sections 120 to each other at their respective front ends, it is possible to make coupled vibration modes difficult to occur.

[0090] Furthermore, since the connecting portions 130 of the transducer 100 involved in this embodiment each have a meandering shape, the connecting portions 130 function like leaf springs when the multiple beam portions 120 vibrate. The connecting portions 130 connect adjacent beam portions to each other, and the length of the connecting portions 130 as leaf springs becomes longer, thereby suppressing the situation where the connection force becomes too strong.

[0091] The transducer 100 according to this embodiment easily generates vibration in the basic vibration mode and suppresses the generation of coupled vibration modes, thus improving the device characteristics, especially when used as an ultrasonic transducer. Hereinafter, the function of the transducer 100 when used as an ultrasonic transducer according to this embodiment will be explained.

[0092] First, when ultrasonic waves are generated by transducer 100, in Figure 2 A voltage is applied between the first connecting electrode layer 20 and the second connecting electrode layer 30. Furthermore, a voltage is applied between the first electrode layer 12 connected to the first connecting electrode layer 20 and the second electrode layer 13 connected to the second connecting electrode layer 30. Additionally, in each of the plurality of beam portions 120, a voltage is also applied between the first electrode layer 12 and the second electrode layer 13, which are opposite each other and separated by the piezoelectric layer 11. In this way, the piezoelectric layer 11 expands and contracts in an in-plane direction orthogonal to the thickness direction (Z-axis direction) of the connecting portion 130, and thus, through the above mechanism, each of the plurality of beam portions 120 bends and vibrates along the thickness direction (Z-axis direction) of the connecting portion 130. As a result, the medium surrounding the plurality of beam portions 120 of the transducer 100 is subjected to force, causing the medium to vibrate and thereby generating ultrasonic waves.

[0093] Furthermore, in the transducer 100 according to this embodiment, each of the plurality of beam portions 120 has an inherent mechanical resonant frequency. Therefore, when the applied voltage is a sinusoidal voltage and the frequency of the sinusoidal voltage is close to the aforementioned resonant frequency, the displacement of each of the plurality of beam portions 120 when bending increases.

[0094] When ultrasonic waves are detected by transducer 100, the medium surrounding each of the plurality of beams 120 vibrates due to the ultrasonic waves, and a force is applied to each of the plurality of beams 120 from the surrounding medium, causing each of the plurality of beams 120 to bend and vibrate. If the plurality of beams 120 bend and vibrate, stress is applied to the piezoelectric layer 11. By applying stress to the piezoelectric layer 11, an electric charge is induced in the piezoelectric layer 11. The electric charge induced in the piezoelectric layer 11 generates a potential difference between the first electrode layer 12 and the second electrode layer 13, which are opposite each other across the piezoelectric layer 11. This potential difference is detected by the first connecting electrode layer 20 connected to the first electrode layer 12 and the second connecting electrode layer 30 connected to the second electrode layer 13. Thus, ultrasonic waves can be detected in transducer 100.

[0095] Furthermore, when the ultrasonic wave being tested contains a large number of specific frequency components, and these frequency components are close to the aforementioned resonant frequency, the displacement of each of the multiple beams 120 during bending vibration increases. This increase in displacement leads to an increase in the aforementioned potential difference.

[0096] Thus, when the transducer 100 according to this embodiment is used as an ultrasonic transducer, the resonant frequency of the plurality of beams 120 is 20 kHz or higher and 60 kHz or lower. When the transducer 100 is used as an acoustic device such as a loudspeaker or a pickup, the resonant frequency of the plurality of beams 120 is set to be less than 20 kHz, which is within the audible range.

[0097] Figure 7 This is a top view showing the extension length of each of the multiple beams of the transducer according to Embodiment 1 of the present invention, the shortest distance between the front end and the central axis, and the length of the fixed end. Figure 7 For simplicity, the electrode layers are not illustrated in the diagram. Figure 7 As shown, in this embodiment, if the extension length of each of the multiple beam portions 120 is set as L1, the shortest distance between the front end portion 122 and the central axis C is set as L2, and the length of the fixed end portion 121 is set as L3, then the relationship L3 ≒ 2 (L1 + L2) is satisfied.

[0098] The resonant frequencies of the basic vibration modes of the multiple beams 120 vary depending on the extension length L1 of each of the multiple beams 120, the shortest distance L2 between the front end 122 and the central axis C, the length L3 of the fixed end 121, the axial thickness of the central axis C, and the density and elastic modulus of the materials constituting the multiple beams 120.

[0099] For example, in Figures 1 to 3 In the transducer 100 according to Embodiment 1 of the present invention, when the resonant frequency of each of the plurality of beams 120 is designed to be around 40kHz, for each of the plurality of beams 120, the piezoelectric layer 11 can be made of lithium niobate, the thickness of the piezoelectric layer 11 can be 1μm, the thickness of the first electrode layer 12 and the second electrode layer 13 can be 0.1μm, the thickness of the first elastomer layer 14a can be 0.2μm, the thickness of the second elastomer layer 14b can be 2.0μm, the extension length L1 of each of the plurality of beams 120 can be 316μm, the shortest distance L2 between the front end 122 and the central axis C can be 77μm, and the length L3 of each of the fixed ends 121 when viewed from the above-mentioned stacking direction can be 786μm. When the thickness of each layer constituting the vibration layer 10 is different from that described above, by appropriately adjusting the extension length L1 of each of the multiple beams 120, the resonant frequency of the basic vibration mode of the multiple beams 120 can be made to the desired frequency.

[0100] The manufacturing method of the transducer 100 according to Embodiment 1 of the present invention will be described below. Figure 8 This is a cross-sectional view showing the state in which a second electrode layer is provided on a piezoelectric single-crystal substrate in the manufacturing method of the transducer according to Embodiment 1 of the present invention. Figure 8 and the following shown Figures 9 to 14 In, with Figure 2 The same cross-sectional view is illustrated.

[0101] like Figure 8 As shown, firstly, after forming an adhesive layer (not shown) on the lower surface of the piezoelectric single-crystal substrate 11a, a second electrode layer 13 is formed on the opposite side of the adhesive layer from the piezoelectric single-crystal substrate 11a side. The second electrode layer 13 is formed with a desired pattern by a vapor deposition lift-off method. Alternatively, the second electrode layer 13 can be formed by sputtering the entire surface of the lower surface of the piezoelectric single-crystal substrate 11a and then etching to form the desired pattern. The second electrode layer 13 and the adhesive layer can also be epitaxially grown.

[0102] Figure 9 This is a cross-sectional view showing the state in which the first support portion is provided in the manufacturing method of the transducer according to Embodiment 1 of the present invention. Figure 9As shown, a first elastomer layer 14a is formed on the lower surface of the piezoelectric single crystal substrate 11a and the second electrode layer 13 using methods such as CVD (Chemical Vapor Deposition) or PVD (Physical Vapor Deposition). Immediately after the first elastomer layer 14a is formed, a portion of the lower surface of the first elastomer layer 14a opposite to the side of the second electrode layer 13 protrudes. Therefore, the lower surface of the first elastomer layer 14a is planarized by cutting it using methods such as Chemical Mechanical Polishing (CMP).

[0103] Figure 10 This is a cross-sectional view showing the state in which the laminate is joined to the first support portion in the transducer manufacturing method according to Embodiment 1 of the present invention. Figure 10 As shown, a laminate 16 consisting of a second elastomer layer 14b and a support layer 15 is bonded to the lower surface of the first elastomer layer 14a via surface activation bonding or atomic diffusion bonding. In this embodiment, the laminate 16 is an SOI (Silicon on Insulator) substrate. Furthermore, by pre-planarizing the upper surface of the second elastomer layer 14b using CMP or the like, the yield of the transducer 100 is improved. Additionally, when the second elastomer layer 14b is made of low-resistance Si, it can function as a lower electrode layer, in which case the second electrode layer 13 and the first elastomer layer 14a do not need to be formed.

[0104] Figure 11 This is a cross-sectional view showing the state in which a piezoelectric layer is formed by cutting a piezoelectric single-crystal substrate in the manufacturing method of the transducer according to Embodiment 1 of the present invention. Figure 11 As shown, the upper surface of the piezoelectric single crystal substrate 11a is thinned by grinding with a grinding machine. The upper surface of the thinned piezoelectric single crystal substrate 11a is further ground by CMP or the like, thereby forming the piezoelectric single crystal substrate 11a into a piezoelectric layer 11.

[0105] Alternatively, the piezoelectric single crystal substrate 11a can be formed into a piezoelectric layer 11 by pre-implanting ions into the upper surface side of the piezoelectric single crystal substrate 11a, forming a release layer, and then peeling off the release layer. Alternatively, the upper surface of the piezoelectric single crystal substrate 11a after the release layer has been peeled off can be further polished using CMP or the like, thereby forming the piezoelectric single crystal substrate 11a into a piezoelectric layer 11.

[0106] Figure 12This is a cross-sectional view showing the state in which a first electrode layer is provided on the piezoelectric layer in the manufacturing method of the transducer according to Embodiment 1 of the present invention. Figure 12 As shown, after a sealing layer (not shown) is formed on the upper surface of the piezoelectric layer 11, a first electrode layer 12 is formed on the opposite side of the piezoelectric layer 11 side of the sealing layer. The first electrode layer 12 is formed with a desired pattern by vapor deposition and lift-off. The first electrode layer 12 can also be formed by etching after sputtering the entire surface of the upper surface of the piezoelectric layer 11. The first electrode layer 12 and the sealing layer can also be epitaxially grown.

[0107] Figure 13 This is a cross-sectional view showing the state in which the groove and recess are provided in the manufacturing method of the transducer according to Embodiment 1 of the present invention. Figure 13 As shown, in a region corresponding to the area further inward than the base 110 of the transducer 100 when viewed from the aforementioned stacking direction, a slit is formed in the piezoelectric layer 11 and the first elastomer layer 14a by dry etching using RIE (Reactive Ion Etching) or the like. The slit can also be formed by wet etching using fluorinated nitric acid or the like. Furthermore, the second elastomer layer 14b exposed above the slit is etched by DRIE (Deep Reactive Ion Etching) until the slit reaches the upper surface of the support layer 15. Thus, a region corresponding to... Figure 1 and Figure 2 The first slit 141, the second slit 142, and the dividing slit 143 shown are... Figure 13 The groove 17 shown.

[0108] And, as Figure 13 As shown, at the portion corresponding to the base 110 of the transducer 100, the piezoelectric layer 11 is etched in such a way that a portion of the second electrode layer 13 is exposed by either the dry etching method or the wet etching method described above. This forms a recess 18.

[0109] Figure 14 This is a partial cross-sectional view showing the state in which the first connecting electrode layer and the second electrode connecting layer are provided in the manufacturing method of the transducer according to Embodiment 1 of the present invention. Furthermore, as... Figure 14As shown, in the portion corresponding to the base 110, after forming adhesive layers (not shown) on the first electrode layer 12 and the second electrode layer 13, a first connecting electrode layer 20 and a second connecting electrode layer 30 are formed on the upper surface of each adhesive layer by a vapor deposition stripping method. The first connecting electrode layer 20 and the second connecting electrode layer 30 can also be formed by etching after sputtering the entire surface of the piezoelectric layer 11, the first electrode layer 12 and the exposed second electrode layer 13.

[0110] Finally, after removing a portion of the substrate layer 15b in the support layer 15 using DRIE, a portion of the intermediate layer 15a is removed using RIE. Thus, as... Figure 2 As shown, an opening 101 is provided, and multiple beam portions 120 and connecting portions 130 are formed. Through the above processes, a product is manufactured. Figures 1 to 3 The transducer 100 shown is based on Embodiment 1 of the present invention.

[0111] Here, we will explain the results of simulation analysis of the internal stress generated when deformation occurs in the folded-back section of the connecting part in the embodiment with a dividing slit and in the folded-back section of the connecting part in the comparative example without a dividing slit.

[0112] Figure 15 It is a diagram used to illustrate the state of deformation caused by applying an in-plane load to one end of the folded portion of the connecting part involved in the comparative example. Figure 16 This diagram illustrates the state in which an in-plane load is applied to one end of the folded portion of the connecting portion involved in the embodiment, causing it to deform.

[0113] like Figure 15 and Figure 16 As shown, the foldback portion 931 of the connecting portion 930 in the comparative example and the foldback portion 131 of the connecting portion 130 in the embodiment are respectively configured with the following shapes: width W = 7 μm, length La = 35 μm, width Ws of the second slit 142 = 1 μm, diameter R of the end of the second slit 142 = 4 μm, thickness = 1.6 μm, length of the dividing slit 143 = 28 μm, and width of the dividing slit 143 = 0.1 μm. The material constituting the connecting portion 930 and the connecting portion 130 is single-crystal Si.

[0114] In the fold-back portion 931 of the connecting portion 930 involved in the comparative example and the fold-back portion 131 of the connecting portion 130 involved in the embodiment, with the first end on the right side of the figure fixed, the second end is displaced by 5μm by applying a load M1 in the in-plane direction to the second end on the left side of the figure.

[0115] Figure 17It is a diagram showing the distribution of internal stress generated when an in-plane load is applied to one end of the folded part of the connection involved in the comparative example, causing it to deform. Figure 18 This is a diagram showing the distribution of internal stress generated when an in-plane load is applied to one end of the folded portion of the connection portion involved in the embodiment, causing it to deform. Figure 17 and Figure 18 In the middle, as the internal stress increases, the color becomes lighter.

[0116] like Figure 17 and Figure 18 As shown, compared to the folded portion 931 of the connecting portion 930 in the comparative example, the internal stress generated during deformation of the folded portion 131 of the connecting portion 130 in the embodiment is smaller. That is, the folded portion 131 of the connecting portion 130 in the embodiment has a dividing slit 143, thereby reducing the rigidity of the connecting portion 130 in the in-plane direction and making it easier to deform in the in-plane direction.

[0117] When a pair of beams 120 connected by a connecting portion 130 are displaced by the same amount in the thickness direction (Z-axis direction) of the connecting portion 130, a load is applied to the connecting portion 130 in an in-plane manner. In the embodiment where the connecting portion 130 is prone to deformation in the in-plane direction, since it is prone to deformation due to the application of this in-plane load, the stress in the in-plane direction of the connecting portion 130 can be released, and the displacement of the pair of beams 120 in the Z-axis direction is not excessively impeded.

[0118] Figure 19 It is a diagram used to illustrate the state of deformation caused by applying a load in the thickness direction to one end of the folded part of the connecting part involved in the comparative example. Figure 20 This diagram illustrates the state in which a load in the thickness direction is applied to one end of the folded portion of the connecting portion involved in the embodiment, causing it to deform.

[0119] In the fold-back portion 931 of the connecting portion 930 involved in the comparative example and the fold-back portion 131 of the connecting portion 130 involved in the embodiment, with the first end on the right side of the figure fixed, the second end is displaced by 5μm by applying a load M2 along the thickness direction (Z-axis direction) to the second end on the left side of the figure.

[0120] Figure 21 It is a diagram showing the distribution of internal stress generated when a load in the thickness direction is applied to one end of the folded part of the connection involved in the comparative example, causing it to deform. Figure 22 This is a diagram showing the distribution of internal stress generated when a load in the thickness direction is applied to one end of the folded portion of the connection part involved in the embodiment, causing it to deform. Figure 21 and Figure 22In the middle, as the internal stress increases, the color becomes lighter.

[0121] like Figure 21 and Figure 22 As shown, the internal stress generated during deformation of the folded-back portion 931 of the connecting portion 930 in the comparative example and the folded-back portion 131 of the connecting portion 130 in the embodiment is approximately equal. That is, even though the folded-back portion 131 of the connecting portion 130 in the embodiment has a dividing slit 143, it maintains the same rigidity in the thickness direction of the connecting portion 130 as the folded-back portion 931 of the connecting portion 930 in the comparative example.

[0122] When a pair of beams 120 connected by the connecting portion 130 displaces with different amounts in the same direction (Z-axis direction) of the thickness direction of the connecting portion 130, or when the pair of beams 120 displaces in opposite directions in the thickness direction (Z-axis direction) of the connecting portion 130, a load is applied to the connecting portion 130 in a manner that expands in the thickness direction. Since the connecting portion 130 involved in the embodiment maintains rigidity in the thickness direction and has high deformation resistance, the difference in displacement in the Z-axis direction of the pair of beams 120 is reduced, thereby effectively suppressing the vibration deviation of the pair of beams 120.

[0123] Figure 23 This is a diagram illustrating the distribution of internal stress generated at the folded-back portion of the connection involved in the comparative examples and embodiments. For example... Figure 23 As shown, in the connecting parts 930 and 130 involved in the comparative examples and embodiments, the distribution of the maximum principal stress generated on line A, located on the extension line of the second slit 142, was simulated and analyzed.

[0124] Figure 24 This is a graph showing the shift of the maximum principal stress based on the distance from the root of section R on line A, i.e., point S. Figure 24 In the diagram, the vertical axis represents the maximum principal stress (GPa), and the horizontal axis represents the distance (μm) from point S on line A. Solid lines represent data under the condition that the connection portion 130 in the embodiment is subjected to a load M1 in the in-plane direction; single-dash lines represent data under the condition that the connection portion 930 in the comparative example is subjected to a load M1 in the in-plane direction; dashed lines represent data under the condition that the connection portion 130 in the embodiment is subjected to a load M2 in the thickness direction; and double-dash lines represent data under the condition that the connection portion 930 in the comparative example is subjected to a load M2 in the thickness direction.

[0125] like Figure 24As shown, the connecting portion 130 of the embodiment has a dividing slit 143, thereby significantly reducing the maximum principal stress generated during deformation in the in-plane direction compared to the connecting portion 930 of the comparative example. On the other hand, the maximum principal stress generated during deformation in the thickness direction is approximately equal in the connecting portion 930 of the comparative example and the connecting portion 130 of the embodiment.

[0126] Based on the above results, the transducer 100 according to Embodiment 1 of the present invention can appropriately adjust the rigidity of the connecting portion 130 in the in-plane direction (XY direction) and the thickness direction (Z-axis direction), release the stress in the in-plane direction of the connecting portion 130 through the connecting portion 130 without excessively hindering the vibration of each beam portion 120, and can efficiently suppress vibration deviations in multiple beam portions 120. In this way, by forming the dividing slit 143, the design freedom of the transducer 100 can be increased, and the design redundancy of the transducer 100 can be improved.

[0127] The transducer 100 according to this embodiment, having a connection portion 130 with the above-described configuration, facilitates vibration in the basic vibration mode and suppresses the occurrence of coupled vibration modes. Therefore, when the transducer 100 is used as an ultrasonic transducer, it is possible to suppress the situation where the phases of the vibrations of the multiple beam portions 120 are different when detecting ultrasonic waves with the same frequency component as the resonant frequency. Furthermore, by having different phases of vibration of the multiple beam portions 120, it is possible to suppress the situation where the charges generated in the piezoelectric layer 11 of each of the multiple beam portions 120 cancel each other out at the first electrode layer 12 or the second electrode layer 13. Thus, the device characteristics of the transducer 100 as an ultrasonic transducer are improved.

[0128] Furthermore, the dividing slit 143 divides the connecting portion 130 approximately equally at the part where it partially branches. As a result, the internal stress generated when the connecting portion 130 deforms can be evenly distributed, thus enabling the connecting portion 130 to form a robust structure.

[0129] Alternatively, two parallel dividing slits 143 can be formed, spaced apart from each other, with a portion of the connecting part 130 branched into three parts by the two dividing slits 143. This further increases the design freedom of the transducer 100.

[0130] Furthermore, the second slit 142 does not necessarily need to penetrate the connecting portion 130. In this case, sound leakage caused by the second slit 142 can be effectively suppressed.

[0131] Figure 25 This is an enlarged top view showing part of the connection section composed of a second elastomer layer and a piezoelectric layer that function as the lower electrode layer. Figure 26Observed from the XXVI-XXVI direction Figure 25 A cross-sectional view of the connection part. (See figure.) Figure 25 and Figure 26 As shown, the connecting portion 130 can also be constructed using a second elastomer layer 14b made of low-resistance Si and functioning as a lower electrode layer, and a piezoelectric layer 11 stacked on the second elastomer layer 14b. In this case, after forming a slit P of the desired width on the piezoelectric layer 11 located on the second elastomer layer 14b, a slit is formed on the second elastomer layer 14b, thereby forming a dividing slit 143. If layers other than the piezoelectric layer 11 are also stacked on the second elastomer layer 14b, the dividing slit 143 can also be formed using the same method.

[0132] Figure 27 This is a top view showing an enlarged portion of the connection consisting only of the second elastomer layer. Figure 28 Observed from the XXVIII-XXVIII direction Figure 27 A cross-sectional view of the connection part. (See figure.) Figure 27 and Figure 28 As shown, the connecting portion 130 may also be composed solely of the second elastomer layer 14b. In this case, the connecting portion 130 can be formed simply.

[0133] Figure 29 This is a top view of the transducer according to the first modification of Embodiment 1 of the present invention. Figure 29 As shown, in the transducer 100a according to the first variation of Embodiment 1 of the present invention, the second slit 142a is formed in a U-shape, thereby the connecting portion 130a has a folded-back portion. A plurality of beam portions 120a are each connected to a connecting portion 130a at a location.

[0134] Figure 30 This is a top view of the transducer according to the second variation of Embodiment 1 of the present invention. Figure 30 As shown, in the transducer 100b according to the second variation of Embodiment 1 of the present invention, viewed from the central axis direction (Z-axis direction), a square opening 141b is formed at the center of the base 110 in the vibrating layer 10. A pair of second slits 142b are formed such that they extend from the corners of the openings 141b in a direction parallel to the first slit 141 and sandwich a portion of the first slit 141 between each other, thereby giving the connecting portion 130b a folded-back portion. Each of the plurality of beam portions 120b is connected to a connecting portion 130b at a location.

[0135] Figure 31 This is a top view of the transducer according to the third variation of Embodiment 1 of the present invention. Figure 31As shown, in the transducer 100c according to the third variation of Embodiment 1 of the present invention, the second slit 142c is formed as a pair of U-shaped parts combined with each other, thereby the connecting portion 130c has two folded-back portions. A plurality of beam portions 120c are each connected to a connecting portion 130c at a location.

[0136] Figure 32 This is a top view of the transducer according to the fourth variation of Embodiment 1 of the present invention. Figure 32 As shown, in the transducer 100d according to the fourth variation of Embodiment 1 of the present invention, viewed from the central axis direction (Z-axis direction), a pair of second slits 142d are formed such that they extend in a direction parallel to the first slit 141 and sandwich a portion of the first slit 141 between each other, thereby giving the connecting portion 130d an H-shaped form. A plurality of beam portions 120d are each connected to a connecting portion 130d at two locations.

[0137] Figure 33 This is a top view of the transducer according to the fifth modification of Embodiment 1 of the present invention. Figure 33 As shown, in the transducer 100e according to the fifth variation of Embodiment 1 of the present invention, viewed from the central axis direction (Z-axis direction), it has two rectangular beam portions 120e. Viewed from the central axis direction (Z-axis direction), the first slit 141e extends from the middle position of both sides of the inner peripheral side surface of the base 110 toward the center of the base 110. The second slit 142e is formed in a U-shape, thereby the connecting portion 130e has a folded-back portion. Each of the plurality of beam portions 120e is connected to a connecting portion 130e at a position.

[0138] Figure 34 This is a top view of the transducer according to the sixth modification of Embodiment 1 of the present invention. Figure 34 As shown, in the transducer 100f according to the sixth variation of Embodiment 1 of the present invention, viewed from the central axis direction (Z-axis direction), it has two rectangular beam portions 120f. Viewed from the central axis direction (Z-axis direction), a pair of second slits 142f are formed such that they extend in a direction parallel to the first slit 141e and sandwich a portion of the first slit 141e between each other, thereby the connecting portion 130f has an H-shaped shape. Each of the plurality of beam portions 120f is connected to a connecting portion 130f at two locations.

[0139] In the transducers 100a~f described in the first to sixth modified examples above, the rigidity of the connecting portions 130a~f in the in-plane direction (XY direction) and the thickness direction (Z-axis direction) can be appropriately adjusted. The stress in the in-plane direction of the connecting portions 130a~f can be released through the connecting portions 130a~f without excessively hindering the vibration of each beam portion 120a~f, and the vibration deviation in the multiple beam portions 120a~f can be effectively suppressed.

[0140] (Implementation Method 2)

[0141] Hereinafter, the transducer according to Embodiment 2 of the present invention will be described with reference to the accompanying drawings. The transducer according to Embodiment 2 of the present invention differs from the transducer according to Embodiment 1 of the present invention in that a common connecting portion is formed in the center of the base. Therefore, the same configuration as that of the transducer according to Embodiment 1 of the present invention will not be described again.

[0142] Figure 35 This is a top view of the transducer according to Embodiment 2 of the present invention. Figure 35 As shown, the transducer 200 according to Embodiment 2 of the present invention includes an annular base 110, a plurality of beam portions 220, connecting portions 230, and a common connecting portion 250. In this embodiment, the transducer 200 includes four beam portions 220. These beam portions are formed into a square shape with U-shaped portions on each side via a second slit 242, thereby constituting four connecting portions 230 with a folded portion and a generally square common connecting portion 250 connected to the four connecting portions 230. Each of the plurality of beam portions 220 is connected to one connecting portion 230 at a location. Each of the four connecting portions 230 is connected to the common connecting portion 250 at a location.

[0143] A pair of beams 220 that are adjacent to each other in the circumferential direction of the base 110 are connected to each other by two connecting parts 230 and a common connecting part 250.

[0144] In the transducer 200 according to Embodiment 2 of the present invention, the rigidity of the connecting portion 230 in the in-plane direction (XY direction) and the thickness direction (Z axis direction) can be appropriately adjusted, the stress in the in-plane direction of the connecting portion 230 can be released through the connecting portion 230 without excessively hindering the vibration of each beam portion 220, and the vibration deviation in the multiple beam portions 220 can be effectively suppressed.

[0145] Figure 36 This is a top view of the transducer according to a variation of Embodiment 2 of the present invention. Figure 36As shown, in the transducer 200a according to a variation of Embodiment 2 of the present invention, the second slit 242a is formed into a square shape with an L-shaped portion on each side, thereby constituting four connecting portions 230a extending in a straight line and a generally square common connecting portion 250a connected to the four connecting portions 230a. Each of the plurality of beam portions 220a is connected to one connecting portion 230a at a location. Each of the four connecting portions 230a is connected to the common connecting portion 250a at a location.

[0146] A pair of beams 220a that are adjacent to each other in the circumferential direction of the base 110 are connected to each other by two connecting parts 230a whose extension directions differ by 90° and a common connecting part 250a. That is, a bend is formed by the two connecting parts 230a and the common connecting part 250a.

[0147] In the transducer 200a according to the modified example of Embodiment 2 of the present invention, the rigidity of the connecting portion 230a in the in-plane direction (XY direction) and the thickness direction (Z axis direction) can also be appropriately adjusted. The stress in the in-plane direction of the connecting portion 230a can be released through the connecting portion 230a without excessively hindering the vibration of each beam portion 220a, and the vibration deviation in multiple beam portions 220a can be effectively suppressed.

[0148] (Implementation Method 3)

[0149] Hereinafter, the transducer according to Embodiment 3 of the present invention will be described with reference to the accompanying drawings. The transducer according to Embodiment 3 of the present invention differs from the transducer according to Embodiment 1 of the present invention in that the connecting portion is partially branched in the thickness direction by dividing the slit; therefore, the same configuration as that of the transducer according to Embodiment 1 of the present invention will not be described again.

[0150] Figure 37 This is a cross-sectional view of the transducer according to Embodiment 3 of the present invention. Figure 37 In the middle, it is shown that... Figure 2 Same cross-sectional view. For example... Figure 37 As shown, in the transducer 300 of Embodiment 3 of the present invention, the dividing slit 342 penetrates the connecting portion 330 in an in-plane direction (XY direction) orthogonal to the thickness direction (Z-axis direction) of the connecting portion 330, so that the connecting portion 330 is partially branched in the thickness direction (Z-axis direction).

[0151] Hereinafter, the manufacturing method of the transducer 300 according to Embodiment 3 of the present invention will be described only in terms of the differences from the manufacturing method of the transducer 100 according to Embodiment 1.

[0152] Figure 38This is a cross-sectional view showing the state in which the laminate is joined to the first support portion in the transducer manufacturing method according to Embodiment 2 of the present invention. Figure 38 As shown, after cutting and planarizing the lower surface of the first elastomer layer 14a, the first elastomer layer 14a at position E corresponding to the formation position of the dividing slit 342 is removed. Then, a laminate 16 composed of the second elastomer layer 14b and the support layer 15 is bonded to the lower surface of the first elastomer layer 14a by surface activation bonding or atomic diffusion bonding. Subsequent steps are the same as the manufacturing method of the transducer 100 according to Embodiment 1. Furthermore, by embedding a sacrificial layer composed of ZnO or the like at the aforementioned position E and finally removing the sacrificial layer, the same structure can also be obtained.

[0153] Through the above-mentioned procedures, such as Figure 37 As shown, in the connection portion 330, a dividing slit 342 is formed between the piezoelectric layer 11 and the second elastomer layer 14b.

[0154] In the transducer 300 according to Embodiment 3 of the present invention, the connecting portion 330 is partially branched in the thickness direction (Z-axis direction) by means of the dividing slit 342. Therefore, the rigidity of the connecting portion 330 in the thickness direction (Z-axis direction) is reduced, making it easier to deform in the thickness direction (Z-axis direction). On the other hand, the rigidity of the connecting portion 330 in the in-plane direction is maintained. As a result, the stress in the thickness direction (Z-axis direction) of the connecting portion 330 can be released without excessively hindering the displacement of the pair of beam portions 120 in the Z-axis direction, and the displacement deviation of the pair of beam portions 120 in the in-plane direction is effectively suppressed.

[0155] Figure 39 This is a cross-sectional view of the transducer involved in a variation of Embodiment 3 of the present invention. For example... Figure 39 As shown, in the modified example of Embodiment 3 of the present invention, the transducer 300a has a dividing slit 342a formed in the second elastomer layer 14b in the connecting portion 330a.

[0156] In this modified example, the second elastomer layer 14b is formed, for example, by performing film formation in two stages. At this time, a sacrificial layer composed of ZnO or the like is embedded at position E corresponding to the formation position of the dividing slit 342a, and finally the sacrificial layer is removed, thereby enabling the forming of the dividing slit 342a.

[0157] In this modified example, at the portion where the connecting portion 330a is partially branched in the thickness direction (Z-axis direction), the two branched portions are made of the same material. This increases the design freedom of the transducer 300.

[0158] The dividing slit 342a divides the connecting portion 330a into approximately equal parts at the portion where it partially branches. This allows for a uniform distribution of internal stress generated during deformation of the connecting portion 330a, thus enabling the connecting portion 330a to form a robust structure.

[0159] (Postscript)

[0160] Those skilled in the art will understand that the above exemplary embodiments are specific examples of the following methods.

[0161] <1>

[0162] A transducer comprising:

[0163] A ring-shaped base;

[0164] A plurality of beam portions, each having a fixed end connected to the base and a front end located on the opposite side of the fixed end near the center of the base, extending from the fixed end toward the front end; and

[0165] A connecting portion that connects a pair of beams that are adjacent to each other in the circumferential direction at the base of the plurality of beams.

[0166] The connecting portion includes at least one bend.

[0167] At least one dividing slit is formed on the connecting portion, the dividing slit dividing the connecting portion in such a way that the connecting portion partially branches and then re-merges.

[0168] <2>

[0169] according to <1> The transducer wherein each of the plurality of beams is a vibrating part containing a piezoelectric layer.

[0170] <3>

[0171] according to <1> or <2> The transducer wherein at least one dividing slit penetrates the connecting portion in the thickness direction, causing the connecting portion to partially branch in the in-plane direction.

[0172] <4>

[0173] according to <1> or <2> The transducer wherein the at least one dividing slit penetrates the connecting portion in an in-plane direction orthogonal to the thickness direction of the connecting portion, causing the connecting portion to partially branch in the thickness direction.

[0174] <5>

[0175] according to <3> or <4> The transducer, wherein the at least one dividing slit divides the portion approximately equally at the portion where the connection portion partially branches.

[0176] <6>

[0177] according to <4> The transducer wherein, at the portion where the connecting portion partially branches in the thickness direction, the two branches are made of the same material.

[0178] <7>

[0179] according to <1> to <6> The transducer according to any one of the following methods, wherein each of the plurality of beams is connected to the connecting portion at two locations.

[0180] <8>

[0181] according to <1> to <7> In any one of the transducers, two parallel dividing slits are formed as the at least one dividing slit, spaced apart from each other.

[0182] A portion of the connecting part is divided into three parts by the two dividing slits.

[0183] In the description of the above embodiments, the components that can be combined can also be combined with each other.

[0184] The embodiments disclosed herein should be considered illustrative rather than restrictive in all respects. The scope of the invention is not indicated by the foregoing description, but rather by the claims, which are intended to include all modifications in the same sense and scope as the claims.

[0185] Explanation of the label

[0186] 10 Vibration layer; 11 Piezoelectric layer; 11a Single crystal substrate; 12 First electrode layer; 13 Second electrode layer; 14 Elastomer layer; 14a First elastomer layer; 14b Second elastomer layer; 15 Support layer; 15a Intermediate layer; 15b Substrate layer; 16 Laminate; 17 Groove; 18 Recess; 20 First connecting electrode layer; 30 Second connecting electrode layer; 100, 100a, 100b, 100c, 100d, 100e, 100f, 200, 200a, 300, 300a, f Transducer; 101 Opening; 110 Base; 120, 120a, 120b, 120c, 120d, 120e, 120f, 220, 220a, f Beam; 121 Fixed end; 122 Front end; 130, 130a, 130b, 130c, 130d, 130e, 130f, 230, 230a, 330, 330a, 930, f Connecting part; 131, 931 Reversing part; 141, 141e First slit; 141b Opening; 142, 142a, 142b, 142c, 142d, 142e, 142f, 242, 242a Second slit; 143, 342, 342a Dividing slit; 250, 250a Common connecting part; C Central axis.

Claims

1. A transducer comprising: A ring-shaped base; A plurality of beam portions, each having a fixed end connected to the base and a front end located on the opposite side of the fixed end near the center of the base, extending from the fixed end toward the front end; and A connecting portion that connects a pair of beams that are adjacent to each other in the circumferential direction at the base of the plurality of beams. The connecting portion includes at least one bend. At least one dividing slit is formed on the connecting portion, the dividing slit dividing the connecting portion in such a way that the connecting portion partially branches and then re-merges.

2. The transducer according to claim 1, wherein, Each of the multiple beams is a vibrating part containing a piezoelectric layer.

3. The transducer according to claim 1 or 2, wherein, The at least one dividing slit penetrates the connecting portion in the thickness direction, causing the connecting portion to partially branch in the in-plane direction.

4. The transducer according to claim 1 or 2, wherein, The at least one dividing slit penetrates the connecting portion in an in-plane direction orthogonal to the thickness direction of the connecting portion, causing the connecting portion to partially branch in the thickness direction.

5. The transducer according to claim 3 or 4, wherein, The at least one dividing slit divides the portion approximately equally at the part where the connection portion partially branches.

6. The transducer according to claim 4, wherein, At the portion where the connecting part partially branches in the thickness direction, the two branches are made of the same material.

7. The transducer according to any one of claims 1 to 6, wherein, Each of the plurality of beams is connected to the connecting portion at two locations.

8. The transducer according to any one of claims 1 to 7, wherein, As the at least one dividing slit, two dividing slits extending parallel to each other at a distance are formed. A portion of the connecting part is divided into three parts by the two dividing slits.

Images