WO2020136983A1 - Piezoelectric transducer - Google Patents

Piezoelectric transducer Download PDF

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Publication number
WO2020136983A1
WO2020136983A1 PCT/JP2019/032102 JP2019032102W WO2020136983A1 WO 2020136983 A1 WO2020136983 A1 WO 2020136983A1 JP 2019032102 W JP2019032102 W JP 2019032102W WO 2020136983 A1 WO2020136983 A1 WO 2020136983A1
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WIPO (PCT)
Prior art keywords
piezoelectric transducer
beam portions
plate
shaped portion
layer
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PCT/JP2019/032102
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French (fr)
Japanese (ja)
Inventor
伸介 池内
洋一 持田
文弥 黒川
青司 梅澤
永純 安達
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株式会社村田製作所
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Publication of WO2020136983A1 publication Critical patent/WO2020136983A1/en

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R17/00—Piezoelectric transducers; Electrostrictive transducers
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/01—Manufacture or treatment
    • H10N30/08—Shaping or machining of piezoelectric or electrostrictive bodies
    • H10N30/082—Shaping or machining of piezoelectric or electrostrictive bodies by etching, e.g. lithography
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/40—Piezoelectric or electrostrictive devices with electrical input and electrical output, e.g. functioning as transformers
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/80—Constructional details
    • H10N30/88—Mounts; Supports; Enclosures; Casings

Definitions

  • the present invention relates to a piezoelectric transducer.
  • Patent Document 1 Japanese Patent Publication No. 2018-520612
  • Patent Document 2 Japanese Patent Laid-Open No. 2017-22576
  • the piezoelectric transducer described in Patent Document 1 includes at least one central movable element, a plurality of peripheral bending benders, and at least one mechanical stopper.
  • Each of the plurality of peripheral bending benders is connected to the central movable element.
  • Each of the plurality of peripheral bending benders has at least a pair of electrodes and at least a piezoelectric material layer.
  • the mechanical stop is configured to limit the movement of the central movable element.
  • the piezoelectric transducer is configured to move the central movable element in response to an electrical stimulus applied to the electrodes along an axis orthogonal to the surface of the central movable element to produce sound.
  • the piezoelectric transducer described in Patent Document 2 includes a base material, a piezoelectric thin film, an upper electrode, and a lower electrode.
  • the base material has a cavity.
  • the piezoelectric thin film is supported by the base material and has a movable film portion facing the cavity. A slit is formed in the movable film portion.
  • the upper electrode is arranged on one surface of the piezoelectric thin film.
  • the lower electrode is arranged on the other surface of the piezoelectric thin film.
  • the present invention has been made in view of the above problems, and it is an object of the present invention to provide a piezoelectric transducer that has improved input/output characteristics in the piezoelectric transducer that inputs and outputs via air vibration.
  • the piezoelectric transducer includes a base portion, a plate-shaped portion, and a plurality of beam portions.
  • the base portion has an annular outer shape when viewed from above and below.
  • the plate-shaped portion is located inside the base portion while being separated from the base portion.
  • Each of the plurality of beam portions connects the base portion and the plate-shaped portion to each other and is arranged at intervals in the circumferential direction of the base portion.
  • Each of the plurality of beam portions has a piezoelectric layer, an upper electrode layer, and a lower electrode layer.
  • the upper electrode layer is arranged above the piezoelectric layer.
  • the lower electrode layer is arranged so as to face at least a part of the upper electrode layer with the piezoelectric layer interposed therebetween.
  • the flexural rigidity of each of the plurality of beam portions is higher than the flexural rigidity of the plate-shaped portion.
  • FIG. 2 is a cross-sectional view of the piezoelectric transducer shown in FIG. 1 as seen from the direction of arrows II-II.
  • FIG. 6 is a cross-sectional view showing a state in which a laminate having a handle layer, a box layer, and an active layer is prepared in the method for manufacturing a piezoelectric transducer according to the first embodiment of the present invention.
  • FIG. 5 is a cross-sectional view showing a state in which a lower electrode layer is provided on the upper surface of the active layer in the method for manufacturing the piezoelectric transducer according to the first embodiment of the present invention.
  • FIG. 6 is a cross-sectional view showing a state in which a piezoelectric layer is provided on the upper surface of each of the active layer and the lower electrode layer in the method for manufacturing the piezoelectric transducer according to the first embodiment of the present invention.
  • FIG. 6 is a cross-sectional view showing a state in which an upper electrode layer is provided on the upper surface of the piezoelectric layer in the method of manufacturing the piezoelectric transducer according to the first embodiment of the present invention.
  • FIG. 3 is a cross-sectional view showing a state in which laminated piezoelectric layers are patterned in the method for manufacturing a piezoelectric transducer according to the first embodiment of the present invention.
  • FIG. 5 is a cross-sectional view showing a state in which a plurality of slits are formed in the active layer in the method of manufacturing the piezoelectric transducer according to the first embodiment of the present invention.
  • FIG. 6 is a diagram showing a state in which a recess is formed in the handle layer in the method of manufacturing the piezoelectric transducer according to the first embodiment of the present invention. It is a perspective view from the front upper part showing the composition of the piezoelectric transducer concerning a comparative example.
  • FIG. 7 is a perspective view from the front upper side showing a state in which each of the plurality of beam portions is displaced to the uppermost side during driving of the piezoelectric transducer according to the comparative example.
  • FIG. 3 is a perspective view from the front upper side showing the piezoelectric transducer according to the first embodiment of the present invention in a state where each of the plurality of beam portions is displaced to the uppermost side during driving.
  • FIG. 13 is a cross-sectional view of the piezoelectric transducer shown in FIG. 12 as viewed in the direction of arrows XIII-XIII. It is sectional drawing which shows the structure of the piezoelectric transducer which concerns on Embodiment 2 of this invention. It is sectional drawing which shows the structure of the piezoelectric transducer which concerns on Embodiment 3 of this invention. It is a perspective view from the front upper part showing the composition of the piezoelectric transducer concerning Embodiment 4 of the present invention.
  • FIG. 1 is a perspective view from the front upper side showing the configuration of the piezoelectric transducer according to the first embodiment of the present invention.
  • FIG. 2 is a cross-sectional view of the piezoelectric transducer shown in FIG. 1 as seen in the direction of arrows II-II. It should be noted that in FIG. 1, the boundaries between the layers forming the piezoelectric transducer are not shown.
  • the piezoelectric transducer 100 includes a base portion 110, a plate-shaped portion 120, and a plurality of beam portions 130.
  • the base portion 110 is located outside each of the plurality of beam portions 130 when viewed in the horizontal direction.
  • the base 110 has an annular outer shape when viewed from above and below.
  • the recess 103 is provided on the inner peripheral side of the base 110.
  • the base 110 has a circular inner peripheral side surface when viewed from above and below.
  • the base 110 includes a handle layer 111, a box layer 112, and an active layer 114.
  • the box layer 112 is laminated on the handle layer 111.
  • the active layer 114 is stacked on the box layer 112.
  • the handle layer 111 is made of Si.
  • the box layer 112 is made of SiO 2 .
  • the active layer 114 is made of Si.
  • the base portion 110 may be one that fixes an outer end portion, which will be described later, in each of the plurality of beam portions 130.
  • Each of the laminated structure and constituent materials of the base 110 is not particularly limited.
  • the plate-shaped portion 120 is located inside the base 110 while being separated from the base 110. As shown in FIG. 2, the plate-shaped portion 120 is arranged such that the distance between the plate-shaped portion 120 and the base portions 110 located on both sides in the horizontal direction is substantially constant.
  • the plate-shaped portion 120 has a circular outer shape when viewed from above and below. Further, as shown in FIG. 2, the plate-shaped portion 120 has a substantially constant thickness. Further, in the present embodiment, the plate-shaped portion 120 is composed of a single layer member, but may be composed of a laminated body. In this embodiment, the plate-shaped portion 120 is composed of the active layer 114.
  • each of the four beam portions 130 connects the base portion 110 and the plate-shaped portion 120 to each other, and is arranged at intervals in the circumferential direction of the base portion 110.
  • the four beam portions 130 are located on the outer peripheral side of the plate-shaped portion 120 and are arranged at intervals on the circumference of a concentric circle with the plate-shaped portion 120.
  • each of the plurality of beam portions 130 is arranged so that the intervals are equal to each other.
  • the piezoelectric transducer according to the present embodiment includes four beam portions 130, but the number of beam portions 130 is not limited to four and may be any number.
  • each of the plurality of beam portions 130 has an extending portion 130A, an outer end portion 130B, and an inner end portion 130C when viewed from above and below.
  • the extending portion 130A extends along the circumferential direction of the base 110 while leaving a gap 101 with the base 110.
  • the extending portion 130 ⁇ /b>A extends along the outer peripheral edge of the plate-shaped portion 120 while leaving a gap 102 with the plate-shaped portion 120.
  • the width of each of the gap 101 and the gap 102 is substantially constant.
  • the outer end portion 130B connects one end of the extending portion 130A in the extending direction and the base portion 110 to each other.
  • the outer end portion 130B is located outside the extending portion 130A when viewed from above and below.
  • the inner end portion 130C connects the other end of the extending portion 130A in the extending direction and the plate-like portion 120 to each other.
  • the inner end portion 130C is located inside the extending portion 130A when viewed from above and below.
  • each of the plurality of beam portions 130 has a piezoelectric layer 131, an upper electrode layer 132, a lower electrode layer 133, and an active layer 114.
  • the piezoelectric layer 131 is arranged over the entire extension 130A, the outer end 130B, and the inner end 130C when viewed from above and below.
  • the piezoelectric layer 131 may be made of a polycrystalline material or a single crystal material.
  • the piezoelectric layer 131 is made of lead zirconate titanate (PZT)-based ceramics, aluminum nitride (AlN), lithium niobate (LiNbO 3 ), lithium tantalate (LiTaO 3 ), or the like.
  • the upper electrode layer 132 is arranged above the piezoelectric layer 131.
  • the upper electrode layer 132 is arranged over the entire extension 130A, the outer end 130B, and the inner end 130C when viewed from above and below.
  • the upper electrode layer 132 is made of a conductive material such as Pt.
  • An adhesion layer made of Ti or the like may be arranged between the upper electrode layer 132 and the piezoelectric layer 131.
  • the lower electrode layer 133 is arranged so as to face at least a part of the upper electrode layer 132 with the piezoelectric layer 131 interposed therebetween.
  • the lower electrode layer 133 is arranged over the entire extension 130A, the outer end 130B, and the inner end 130C when viewed from above and below.
  • the lower electrode layer 133 is made of a conductive material such as Pt.
  • An adhesion layer made of Ti or the like may be disposed between the lower electrode layer 133 and the piezoelectric layer 131.
  • the active layer 114 is arranged below the lower electrode layer 133. In the present embodiment, the active layer 114 is arranged on the lowermost side of each of the plurality of beam portions 130. In the present embodiment, the active layer 114 is arranged over the entire extension 130A, the outer end 130B, and the inner end 130C.
  • the active layer 114 forming each of the plurality of beam portions 130 is continuous with the active layer 114 forming the base 110 in the horizontal direction. Further, the active layers 114 forming each of the plurality of beam portions 130 are continuous with the active layer 114 forming the plate-shaped portion 120 in the horizontal direction.
  • the thickness of the active layer 114 is substantially constant as a whole.
  • the active layer 114 is composed of single crystal silicon.
  • the maximum vertical thickness of each of the plurality of beam portions 130 is the vertical direction of the plate-shaped portion 120. It is thicker than the maximum thickness.
  • the composite elastic modulus of the material forming each of the plurality of beam portions 130 is preferably higher than the composite elastic modulus of the material forming the plate-shaped portion 120.
  • the resonance frequency of the lowest-order bending vibration mode in each of the plurality of beam portions 130 is higher than the resonance frequency of the lowest-order bending vibration mode in the single body of the plate-shaped portion 120.
  • the bending rigidity of each of the plurality of beam portions 130 is higher than the bending rigidity of the plate-shaped portion 120.
  • the bending rigidity of each of the plurality of beam portions 130 may be higher than the bending rigidity of the plate-shaped portion 120 due to at least one factor of the maximum thickness, the composite elastic modulus, and the resonance frequency described above.
  • the neutral surface 120N of the plate-shaped portion 120 is located inside the plate-shaped portion 120.
  • the neutral surface 120N of the plate-shaped portion 120 is located substantially at the center of the plate-shaped portion 120 in the vertical direction. That is, the neutral surface 120N of the plate-shaped portion 120 is located in the active layer 114. Specifically, the neutral surface 120N of the plate-shaped portion 120 exists inside the single crystal silicon.
  • the neutral surface 130N of each of the plurality of beam portions 130 is located in the active layer 114. Specifically, the neutral surface 130N of each of the plurality of beam portions 130 exists inside the single crystal silicon.
  • FIG. 3 is a cross-sectional view showing a state in which a laminate having a handle layer, a box layer and an active layer is prepared in the method for manufacturing a piezoelectric transducer according to the first embodiment of the present invention.
  • a so-called SOI (Silicon on Insulator) substrate having a handle layer 111, a box layer 112 and an active layer 114 is prepared.
  • FIG. 4 is a cross-sectional view showing a state in which a lower electrode layer is provided on the upper surface of the active layer in the method for manufacturing the piezoelectric transducer according to the first embodiment of the present invention.
  • the lower electrode layer 133 is provided on the upper surface of the active layer 114 by a lift-off method, a plating method, an etching method, or the like.
  • FIG. 5 is a cross-sectional view showing a state in which a piezoelectric layer is provided on the upper surface of each of the active layer and the lower electrode layer in the method of manufacturing the piezoelectric transducer according to the first embodiment of the present invention.
  • the piezoelectric layer 131 is provided on the upper surfaces of the active layer 114 and the lower electrode layer 133 by a CVD (Chemical Vapor Deposition) method, a PVD (Physical Vapor Deposition) method, or the like.
  • FIG. 6 is a cross-sectional view showing a state in which an upper electrode layer is provided on the upper surface of the piezoelectric layer in the method of manufacturing the piezoelectric transducer according to the first embodiment of the present invention.
  • the upper electrode layer 132 is provided on the upper surface of the piezoelectric layer 131 by a lift-off method, a plating method, an etching method, or the like.
  • FIG. 7 is a cross-sectional view showing a state in which laminated piezoelectric layers are patterned in the method for manufacturing a piezoelectric transducer according to the first embodiment of the present invention.
  • the piezoelectric layer 131 is patterned by a lift-off method or an etching method. As a result, the outer shape of the piezoelectric layer 131 is defined.
  • FIG. 8 is a cross-sectional view showing a state in which a plurality of slits are formed in the active layer in the method of manufacturing the piezoelectric transducer according to the first embodiment of the present invention.
  • the active layer 114 by forming a plurality of slits in the active layer 114 by a lift-off method or etching, the active layer 114 forming the plate-like portion 120 and the active layer 114 forming the plate-shaped portion 120 and a plurality of slits are formed in the active layer 114.
  • the active layers 114 forming each of the beam portions 130 are separated.
  • the plurality of slits configure the gap 101 between the base portion 110 and each extending portion 130A of each of the plurality of beam portions 130, and the plate-shaped portion 120 and each extending portion 130A of each of the plurality of beam portions 130 are formed.
  • the gap 102 is formed.
  • FIG. 9 is a diagram showing a state in which a recess is formed in the handle layer in the method of manufacturing the piezoelectric transducer according to the first embodiment of the present invention.
  • the recess 103 is formed in the handle layer 111 by performing deep reactive ion etching (Deep RIE) from the lower surface of the handle layer 111 to the handle layer 111. ..
  • Deep RIE deep reactive ion etching
  • the recess 103 is formed in the box layer 112 by performing reactive ion etching on the box layer 112 from the lower side surface of the box layer 112. Through these steps, the outer shapes of the plate-shaped portion 120 and the plurality of beam portions 130 are defined, and the piezoelectric transducer 100 according to the first embodiment of the present invention as shown in FIG. 2 is manufactured.
  • the operation of the piezoelectric transducer 100 according to the present embodiment during driving will be described.
  • a voltage is applied between the upper electrode layer 132 and the lower electrode layer 133 in each of the plurality of beam portions 130.
  • This causes strain in the piezoelectric layer 131 constrained by the upper electrode layer 132, the lower electrode layer 133, and the active layer 114, so that each of the plurality of beam portions 130 has a connection position between the outer end portion 130B and the base portion 110. Bends and vibrates vertically with the fixed end as.
  • the plate-shaped portion 120 since each of the plurality of beam portions 130 is configured as described above, the plate-shaped portion 120 also vibrates in the up-down direction in accordance with the bending vibration of the plurality of beam portions 130.
  • the vibration mechanism of the plate-shaped portion 120 will be described in comparison with the piezoelectric transducer according to the comparative example below.
  • FIG. 10 is a perspective view from the front upper side showing the configuration of the piezoelectric transducer according to the comparative example.
  • the bending rigidity of the plurality of beam portions 930 is set to be equal to or less than the bending rigidity of the plate-shaped portion 920.
  • FIG. 11 is a perspective view from the front upper side showing a state in which each of the plurality of beam portions is displaced to the uppermost side when the piezoelectric transducer according to the comparative example is driven.
  • the portion having a larger displacement amount and located higher is shown in a lighter color.
  • each of the plurality of beam portions 930 warps during driving and is largely displaced upward. There is.
  • the rigidity of each of the plurality of beam portions 930 is low, almost no bending stress acts on the connection position of the plate portion 920 with the inner end of the beam portion 930, and the plate portion 920 maintains its shape during driving. However, it is displaced uniformly upward as a whole. As a result, the gap 902 between each of the plate-shaped portion 920 and the plurality of beam portions 930 is large.
  • FIG. 12 is a perspective view from the front upper side showing the piezoelectric transducer according to the first embodiment of the present invention in a state in which each of the plurality of beam portions is displaced to the uppermost side during driving.
  • FIG. 13 is a cross-sectional view of the piezoelectric transducer shown in FIG. 12 as seen in the direction of arrows XIII-XIII. In FIG. 12, the portion having a larger displacement amount and located higher is shown in a lighter color.
  • the piezoelectric transducer 100 since the bending rigidity of each of the plurality of beam portions 130 is high, the displacement amount of each of the plurality of beam portions 130 during driving is small. .. Further, since each of the plurality of beam portions 130 has high rigidity, bending stress concentrates and acts on the connection position of the plate-shaped portion 120 with the inner end portion 130C. As a result, the plate-shaped portion 120 deforms like a cone with the connection position as a virtual fixed end. Therefore, as shown in FIGS. 12 and 13, in the piezoelectric transducer 100, the conical vibration mode of the plate-shaped portion 120 can be excited.
  • the piezoelectric transducer 100 is configured such that, when the piezoelectric transducer 100 is driven, each of the plurality of beam portions 130 bends in the vertical direction so that the plate-shaped portion 120 deforms into a cone shape. ..
  • the central portion of the plate-shaped portion 120 deformed on the cone is the center of each of the plurality of beam portions 130. It is located above the upper surface.
  • the piezoelectric transducer 100 is configured such that the maximum vertical displacement of the plate-shaped portion 120 is larger than the maximum vertical displacement of each of the plurality of beam portions 130 when the piezoelectric transducer 100 is driven. Has been done.
  • the bending rigidity of each of the plurality of beam portions 130 is higher than the bending rigidity of the plate-shaped portion 120.
  • the plate-shaped portion 120 can be deformed into a cone shape and excited by using the connection position of the plate-shaped portion 120 with the inner end 130C as a virtual fixed end. As a result, the gap 102 between the plate-shaped portion 120 and each of the plurality of beam portions 130, and the gap 101 between each of the base portion 110 and each of the plurality of beam portions 130 are suppressed from becoming large and excited. You can
  • the piezoelectric transducer 100 inputs and outputs via air vibration, it is possible to suppress the leakage of air from each of the gap 101 and the gap 102 and improve the input/output characteristics of the piezoelectric transducer 100.
  • the maximum vertical thickness of each of the plurality of beam portions 130 is thicker than the maximum vertical thickness of the plate-shaped portion 120.
  • each of the plurality of beam portions 130 can be made higher than the bending rigidity of the plate-shaped portion 120 with a simple configuration.
  • the input/output characteristics of the piezoelectric transducer 100 can be easily improved.
  • the composite elastic modulus of the material forming each of the plurality of beam portions 130 is preferably higher than the composite elastic modulus of the material forming the plate-shaped portion 120.
  • the resonance frequency of the lowest bending vibration mode of each single beam portion 130 is higher than the resonance frequency of the lowest bending vibration mode of the single plate-shaped portion 120. ..
  • the plate-shaped portion 120 is made of single crystal silicon.
  • the neutral surface of the plate-shaped portion 120 is located inside the plate-shaped portion 120.
  • the residual stress in the plate-shaped portion 120 can be reduced. Consequently, in the piezoelectric transducer 100, it is possible to reduce the influence of residual stress and stabilize the input/output characteristics.
  • each of the plurality of beam portions 130 further includes the active layer 114 arranged below the lower electrode layer 133.
  • the active layer 114 is composed of single crystal silicon.
  • the neutral surface 130N of each of the plurality of beam portions 130 is located in the active layer 114.
  • the influence of the residual stress in the piezoelectric layer 131 can be reduced and the input/output characteristics can be stabilized.
  • the deformation of the piezoelectric layer 131 can be restricted by the single crystal silicon to reduce the displacement amount of each of the plurality of beam portions 130 during driving.
  • the input/output characteristics can be improved.
  • the piezoelectric transducer 100 is configured such that when the piezoelectric transducer 100 is driven, each of the plurality of beam portions 130 bends in the vertical direction so that the plate-shaped portion 120 deforms into a cone shape. ..
  • the piezoelectric transducer 100 is configured such that the maximum vertical displacement of the plate-shaped portion 120 is larger than the maximum vertical displacement of each of the plurality of beam portions 130 when the piezoelectric transducer 100 is driven. Has been done.
  • the piezoelectric transducer according to the second embodiment of the present invention will be described below.
  • the piezoelectric transducer according to the second embodiment of the present invention is different from the piezoelectric transducer 100 according to the first embodiment in the structure of the laminated body in each of the plurality of beam portions. Therefore, the description of the same configuration as the piezoelectric transducer 100 according to the first embodiment of the present invention will not be repeated.
  • FIG. 14 is a cross-sectional view showing the configuration of the piezoelectric transducer according to the second embodiment of the present invention.
  • the sectional view of the piezoelectric transducer 200 shown in FIG. 14 is shown in the same sectional view as the sectional view of the piezoelectric transducer 100 shown in FIG.
  • each of the plurality of beam portions 230 further includes an insulating layer 235 disposed between the lower electrode layer 133 and the active layer 114.
  • the insulating layer 235 is made of a material having an electrically insulating property such as SiO 2 .
  • a piezoelectric single crystal substrate prepared separately from the SOI substrate is formed on the piezoelectric single crystal substrate by a lift-off method, a plating method, an etching method, or the like.
  • the electrode layer 133 is laminated.
  • An insulating layer 235 is laminated on the lower surfaces of the piezoelectric single crystal substrate and the lower electrode layer 133 by the CVD method or the PVD method.
  • the lower surface of the insulating layer 235 is flattened by chemical mechanical polishing (CMP) or the like, and then bonded to the upper surface of the active layer 114.
  • CMP chemical mechanical polishing
  • the upper surface of the piezoelectric single crystal substrate is ground by CMP or the like, and the piezoelectric single crystal substrate is adjusted to a desired thickness, whereby the piezoelectric layer 131 is formed.
  • the insulating layer 235 is patterned after the piezoelectric layer 131 is patterned as in the method of manufacturing the piezoelectric transducer 100 according to the first embodiment of the present invention. This defines the outer shape of the insulating layer 235.
  • each of the plurality of beam portions 230 further includes the insulating layer 235 disposed between the lower electrode layer 133 and the active layer 114. ing.
  • the rigidity of each of the plurality of beam portions 230 can be further increased, and thus the amount of displacement when each of the plurality of beam portions 230 is bent can be reduced when the piezoelectric transducer 200 is driven.
  • the piezoelectric characteristics of the piezoelectric layer 131 can be improved, and the input/output characteristics of the piezoelectric transducer 200 can be improved.
  • the piezoelectric transducer according to the third embodiment of the present invention is different from the piezoelectric transducer 100 according to the first embodiment in the configuration of the laminated body in each of the plurality of beam portions. Therefore, the description of the same configuration as the piezoelectric transducer 100 according to the first embodiment of the present invention will not be repeated.
  • FIG. 15 is a cross-sectional view showing the configuration of the piezoelectric transducer according to the third embodiment of the present invention.
  • the sectional view of the piezoelectric transducer 300 shown in FIG. 15 is illustrated in the same sectional view as the sectional view of the piezoelectric transducer 100 shown in FIG.
  • each of the plurality of beam portions 330 further includes a protective layer 336 arranged above the upper electrode layer 132.
  • the protective layer 336 is made of a material having moisture resistance such as SiO 2 .
  • the protective layer 336 is provided on the upper surface of the upper electrode layer 132 by a CVD method, a PVD method, or the like.
  • each of the plurality of beam portions 330 can be further increased, it is possible to reduce the displacement amount when each of the plurality of beam portions 330 is bent when the piezoelectric transducer 300 is driven. Further, since the upper side of the piezoelectric layer 131 can be covered with the protective layer 336 having moisture resistance, the reliability of the piezoelectric transducer 300 can be improved.
  • the piezoelectric transducer according to the fourth embodiment of the present invention will be described below.
  • the piezoelectric transducer according to the fourth exemplary embodiment of the present invention is different from the piezoelectric transducer 100 according to the first exemplary embodiment of the present invention in the shape of the plurality of beam portions when viewed in the vertical direction. Therefore, the description of the same configuration as the piezoelectric transducer 100 according to the first embodiment of the present invention will not be repeated.
  • FIG. 16 is a perspective view from the front upper side showing the configuration of the piezoelectric transducer according to the fourth embodiment of the present invention.
  • each of the plurality of beam portions 430 is connected to the base portion 110 when viewed from above and below.
  • the other end of each of the plurality of beam portions 430 is connected to the plate-shaped portion 120.
  • the maximum vertical thickness of each of the plurality of beam portions 430 is thicker than the maximum vertical thickness of the plate-shaped portion 120.
  • the composite elastic modulus of the material forming each of the plurality of beam portions 430 is preferably higher than the composite elastic modulus of the material forming the plate-shaped portion 120.
  • the resonance frequency of the lowest bending vibration mode of each of the plurality of beam portions 430 is higher than the resonance frequency of the lowest bending vibration mode of the plate portion 120 alone.
  • the bending rigidity of each of the plurality of beam portions 430 is higher than the bending rigidity of the plate-shaped portion 120.
  • the bending rigidity of each of the plurality of beam portions 430 may be higher than the bending rigidity of the plate-shaped portion 120 due to at least one factor of the maximum thickness, the composite elastic modulus, and the resonance frequency described above.
  • each of the plurality of beam portions 430 is point-symmetrical with respect to the center O of the plate-shaped portion 120 when viewed from above and below. It has the same outer shape and at least a part of the outer shape is curved.
  • a gap 404 that extends while maintaining a constant interval is provided between the beam portions 430 that are adjacent to each other in the circumferential direction of the plurality of beam portions 430.
  • the piezoelectric transducer 400 when the piezoelectric transducer 400 is driven, the displacement amounts of the beam portions 430 adjacent to each other in the circumferential direction among the plurality of beam portions 430 become equal to each other. That is, when viewed from the circumferential direction of the outer peripheral side surface of the plate-shaped portion 120, the gap between the adjacent beam portions 430 does not widen. Therefore, when the piezoelectric transducer 400 is driven, it is possible to prevent air from leaking from between the beam portions 430 adjacent to each other, and it is possible to improve the input/output characteristics of the piezoelectric transducer 400.
  • the gap 404 extends from the outer peripheral side surface of the plate-shaped portion 120 to the inner peripheral side surface of the base portion 110.
  • the gap 404 is curved with a constant curvature over the entire length from the outer peripheral side surface of the plate-shaped portion 120 to the inner peripheral side surface of the base portion 110.
  • the gap 404 between the beam portions 430 adjacent to each other extends while maintaining a constant gap.
  • the piezoelectric transducer 400 that inputs and outputs via air vibration, the input/output characteristic of the piezoelectric transducer 400 can be improved.
  • each of the plurality of beam portions 430 when viewed from above and below, has a plate-like shape on the plate-shaped portion 120 side than on the base 110-side portion.
  • the outer peripheral side surface of the portion 120 faces in the radial direction.
  • Piezoelectric transducer 101, 102, 404, 902 Gap, 103 recess, 110 base, 111 handle layer, 112 box layer, 114 active layer, 120,920 plate, 120N, 130N Elevation, 130, 230, 330, 430, 930 beam, 130A extension, 130B outer end, 130C inner end, 131 piezoelectric layer, 132 upper electrode layer, 133 lower electrode layer, 235 insulating layer, 336 Protective layer.

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  • Transducers For Ultrasonic Waves (AREA)

Abstract

A piezoelectric transducer (100) is provided with a base part (110), a plate-shaped part (120), and a plurality of beam parts (130). The base part (110) has an annular outline as seen from the up/down direction. The plate-shaped part (120) is located on the inside of the base part (110), while being spaced apart from the base part (110). The plurality of beam parts (130) each connect the base part (110) and the plate-shaped part (120) to one another, and are arranged at an interval from one another in the circumferential direction of the base part (110). Each of the plurality of beam parts (130) has a piezoelectric layer (131), an upper electrode layer (132), and a lower electrode layer (133). The upper electrode layer (132) is arranged on the upper side of the piezoelectric layer (131). The lower electrode layer (133) is arranged so as to face at least a part of the upper electrode layer (132) with the piezoelectric layer (131) therebetween. The bending rigidity of the plurality of beam parts (130) is greater than that of the plate-shaped part (120).

Description

圧電トランスデューサPiezoelectric transducer
　本発明は、圧電トランスデューサに関する。 The present invention relates to a piezoelectric transducer.
　圧電トランスデューサの構成を開示した先行文献として、特表２０１８－５２０６１２号公報(特許文献１)および特開２０１７－２２５７６号公報(特許文献２)がある。 As prior documents disclosing the configuration of the piezoelectric transducer, there are Japanese Patent Publication No. 2018-520612 (Patent Document 1) and Japanese Patent Laid-Open No. 2017-22576 (Patent Document 2).
　特許文献１に記載された圧電トランスデューサは、少なくとも一の中央可動素子と、複数の周辺湾曲ベンダと、少なくとも一の機械的ストッパとを備えている。複数の周辺湾曲ベンダの各々は、中央可動素子に接続されている。複数の周辺湾曲ベンダの各々は、少なくとも一対の電極と、少なくとも圧電材料層とを有している。機械的ストッパは、中央可動素子の動きを制限するように構成されている。圧電トランスデューサは、中央可動素子の表面に直交する軸に沿って電極に与えられた電気的刺激に応じて中央可動素子を動かして音を生成するように構成されている。 The piezoelectric transducer described in Patent Document 1 includes at least one central movable element, a plurality of peripheral bending benders, and at least one mechanical stopper. Each of the plurality of peripheral bending benders is connected to the central movable element. Each of the plurality of peripheral bending benders has at least a pair of electrodes and at least a piezoelectric material layer. The mechanical stop is configured to limit the movement of the central movable element. The piezoelectric transducer is configured to move the central movable element in response to an electrical stimulus applied to the electrodes along an axis orthogonal to the surface of the central movable element to produce sound.
　特許文献２に記載された圧電トランスデューサは、基材と、圧電薄膜と、上部電極と、下部電極とを備えている。基材は、空洞を有している。圧電薄膜は、基材に支持され、空洞に対向する可動膜部を有している。可動膜部には、スリットが形成されている。上部電極は、圧電薄膜の一方表面に配置されている。下部電極は、圧電薄膜の他方表面に配置されている。 The piezoelectric transducer described in Patent Document 2 includes a base material, a piezoelectric thin film, an upper electrode, and a lower electrode. The base material has a cavity. The piezoelectric thin film is supported by the base material and has a movable film portion facing the cavity. A slit is formed in the movable film portion. The upper electrode is arranged on one surface of the piezoelectric thin film. The lower electrode is arranged on the other surface of the piezoelectric thin film.
特表２０１８－５２０６１２号公報Japanese Patent Publication No. 2018-520612 特開２０１７－２２５７６号公報JP, 2017-22576, A
　特許文献１および特許文献２の各々に記載された圧電トランスデューサにおいては、駆動時に可動部と基部との間の隙間が大きくなる。圧電トランスデューサが空気振動を介して入出力する場合、可動部と基部との間の隙間を通じて空気が漏れるため、当該隙間が大きくなることにより、圧電トランスデューサの入出力特性が低下する。 In the piezoelectric transducers described in each of Patent Document 1 and Patent Document 2, the gap between the movable portion and the base portion becomes large during driving. When the piezoelectric transducer inputs and outputs via air vibration, air leaks through the gap between the movable portion and the base portion, so that the gap becomes large and the input/output characteristics of the piezoelectric transducer deteriorate.
　本発明は上記の問題点に鑑みてなされたものであり、空気振動を介して入出力する圧電トランスデューサにおいて、入出力特性が向上された圧電トランスデューサを提供することを目的とする。 The present invention has been made in view of the above problems, and it is an object of the present invention to provide a piezoelectric transducer that has improved input/output characteristics in the piezoelectric transducer that inputs and outputs via air vibration.
　本発明に基づく圧電トランスデューサは、基部と、板状部と、複数の梁部とを備えている。基部は、上下方向から見て環状の外形を有している。板状部は、基部と離間しつつ基部の内側に位置している。複数の梁部の各々は、基部と板状部とを互いに接続し、基部の周方向に互いに間隔をあけて配置されている。複数の梁部の各々は、圧電体層と、上部電極層と、下部電極層とを有している。上部電極層は、圧電体層の上側に配置されている。下部電極層は、圧電体層を挟んで上部電極層の少なくとも一部に対向するように配置されている。複数の梁部の各々の曲げ剛性が、板状部の曲げ剛性より高い。 The piezoelectric transducer according to the present invention includes a base portion, a plate-shaped portion, and a plurality of beam portions. The base portion has an annular outer shape when viewed from above and below. The plate-shaped portion is located inside the base portion while being separated from the base portion. Each of the plurality of beam portions connects the base portion and the plate-shaped portion to each other and is arranged at intervals in the circumferential direction of the base portion. Each of the plurality of beam portions has a piezoelectric layer, an upper electrode layer, and a lower electrode layer. The upper electrode layer is arranged above the piezoelectric layer. The lower electrode layer is arranged so as to face at least a part of the upper electrode layer with the piezoelectric layer interposed therebetween. The flexural rigidity of each of the plurality of beam portions is higher than the flexural rigidity of the plate-shaped portion.
　空気振動を介して入出力する圧電トランスデューサにおいて、入出力特性を向上させることができる。 -It is possible to improve the input/output characteristics of a piezoelectric transducer that inputs and outputs via air vibration.
本発明の実施形態１に係る圧電トランスデューサの構成を示す、前方上方からの斜視図である。It is a perspective view from the front upper part showing the composition of the piezoelectric transducer concerning Embodiment 1 of the present invention. 図１に示した圧電トランスデューサについてＩＩ－ＩＩ線矢印方向から見た断面図である。FIG. 2 is a cross-sectional view of the piezoelectric transducer shown in FIG. 1 as seen from the direction of arrows II-II. 本発明の実施形態１に係る圧電トランスデューサの製造方法において、ハンドル層、ボックス層および活性層を有する積層体を準備した状態を示す断面図である。FIG. 6 is a cross-sectional view showing a state in which a laminate having a handle layer, a box layer, and an active layer is prepared in the method for manufacturing a piezoelectric transducer according to the first embodiment of the present invention. 本発明の実施形態１に係る圧電トランスデューサの製造方法において、活性層の上面に下部電極層を設けた状態を示す断面図である。FIG. 5 is a cross-sectional view showing a state in which a lower electrode layer is provided on the upper surface of the active layer in the method for manufacturing the piezoelectric transducer according to the first embodiment of the present invention. 本発明の実施形態１に係る圧電トランスデューサの製造方法において、活性層および下部電極層の各々の上面に圧電体層を設けた状態を示す断面図である。FIG. 6 is a cross-sectional view showing a state in which a piezoelectric layer is provided on the upper surface of each of the active layer and the lower electrode layer in the method for manufacturing the piezoelectric transducer according to the first embodiment of the present invention. 本発明の実施形態１に係る圧電トランスデューサの製造方法において、圧電体層の上面に上部電極層を設けた状態を示す断面図である。FIG. 6 is a cross-sectional view showing a state in which an upper electrode layer is provided on the upper surface of the piezoelectric layer in the method of manufacturing the piezoelectric transducer according to the first embodiment of the present invention. 本発明の実施形態１に係る圧電トランスデューサの製造方法において、積層された圧電体層をパターニングした状態を示す断面図である。FIG. 3 is a cross-sectional view showing a state in which laminated piezoelectric layers are patterned in the method for manufacturing a piezoelectric transducer according to the first embodiment of the present invention. 本発明の実施形態１に係る圧電トランスデューサの製造方法において、活性層に複数のスリットを形成した状態を示す断面図である。FIG. 5 is a cross-sectional view showing a state in which a plurality of slits are formed in the active layer in the method of manufacturing the piezoelectric transducer according to the first embodiment of the present invention. 本発明の実施形態１に係る圧電トランスデューサの製造方法において、ハンドル層に凹部が形成された状態を示す図である。FIG. 6 is a diagram showing a state in which a recess is formed in the handle layer in the method of manufacturing the piezoelectric transducer according to the first embodiment of the present invention. 比較例に係る圧電トランスデューサの構成を示す、前方上方からの斜視図である。It is a perspective view from the front upper part showing the composition of the piezoelectric transducer concerning a comparative example. 比較例に係る圧電トランスデューサが、駆動時において複数の梁部の各々が上側に最も変位したときの状態を示す、前方上方からの斜視図である。FIG. 7 is a perspective view from the front upper side showing a state in which each of the plurality of beam portions is displaced to the uppermost side during driving of the piezoelectric transducer according to the comparative example. 本発明の実施形態１に係る圧電トランスデューサが、駆動時において複数の梁部の各々が上側に最も変位した状態を示す、前方上方からの斜視図である。FIG. 3 is a perspective view from the front upper side showing the piezoelectric transducer according to the first embodiment of the present invention in a state where each of the plurality of beam portions is displaced to the uppermost side during driving. 図１２に示した圧電トランスデューサをＸＩＩＩ－ＸＩＩＩ線矢印方向から見た断面図である。FIG. 13 is a cross-sectional view of the piezoelectric transducer shown in FIG. 12 as viewed in the direction of arrows XIII-XIII. 本発明の実施形態２に係る圧電トランスデューサの構成を示す断面図である。It is sectional drawing which shows the structure of the piezoelectric transducer which concerns on Embodiment 2 of this invention. 本発明の実施形態３に係る圧電トランスデューサの構成を示す断面図である。It is sectional drawing which shows the structure of the piezoelectric transducer which concerns on Embodiment 3 of this invention. 本発明の実施形態４に係る圧電トランスデューサの構成を示す、前方上方からの斜視図である。It is a perspective view from the front upper part showing the composition of the piezoelectric transducer concerning Embodiment 4 of the present invention.
　以下、本発明の各実施形態に係る圧電トランスデューサについて図面を参照して説明する。以下の実施形態の説明においては、図中の同一または相当部分には同一符号を付して、その説明は繰り返さない。 A piezoelectric transducer according to each embodiment of the present invention will be described below with reference to the drawings. In the following description of the embodiments, the same or corresponding parts in the drawings will be denoted by the same reference numerals and the description thereof will not be repeated.
　(実施形態１)
　図１は、本発明の実施形態１に係る圧電トランスデューサの構成を示す、前方上方からの斜視図である。図２は、図１に示した圧電トランスデューサについてＩＩ－ＩＩ線矢印方向から見た断面図である。なお、図１においては、圧電トランスデューサを構成する各層の境界は図示していない。 (Embodiment 1)
FIG. 1 is a perspective view from the front upper side showing the configuration of the piezoelectric transducer according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view of the piezoelectric transducer shown in FIG. 1 as seen in the direction of arrows II-II. It should be noted that in FIG. 1, the boundaries between the layers forming the piezoelectric transducer are not shown.
　図１および図２に示すように、本発明の実施形態１に係る圧電トランスデューサ１００は、基部１１０と、板状部１２０と、複数の梁部１３０とを備えている。 As shown in FIGS. 1 and 2, the piezoelectric transducer 100 according to the first embodiment of the present invention includes a base portion 110, a plate-shaped portion 120, and a plurality of beam portions 130.
　図２に示すように、基部１１０は、水平方向から見て複数の梁部１３０の各々より外側に位置している。基部１１０は、上下方向から見て環状の外形を有している。本実施形態において、基部１１０の内周側に、凹部１０３が設けられている。これにより、基部１１０は、上下方向から見て円形状の内周側面を有している。 As shown in FIG. 2, the base portion 110 is located outside each of the plurality of beam portions 130 when viewed in the horizontal direction. The base 110 has an annular outer shape when viewed from above and below. In the present embodiment, the recess 103 is provided on the inner peripheral side of the base 110. As a result, the base 110 has a circular inner peripheral side surface when viewed from above and below.
　図２に示すように、本実施形態において、基部１１０は、ハンドル層１１１と、ボックス層１１２と、活性層１１４とを含んでいる。ボックス層１１２は、ハンドル層１１１上に積層されている。活性層１１４は、ボックス層１１２上に積層されている。 As shown in FIG. 2, in the present embodiment, the base 110 includes a handle layer 111, a box layer 112, and an active layer 114. The box layer 112 is laminated on the handle layer 111. The active layer 114 is stacked on the box layer 112.
　ハンドル層１１１は、Ｓｉで構成されている。ボックス層１１２は、ＳｉＯ2で構成されている。活性層１１４は、Ｓｉで構成されている。 The handle layer 111 is made of Si. The box layer 112 is made of SiO 2 . The active layer 114 is made of Si.
　なお、基部１１０は、複数の梁部１３０の各々において、後述する外側端部を固定するものであればよい。基部１１０の積層構造および構成材料の各々については、特に限定されない。 It should be noted that the base portion 110 may be one that fixes an outer end portion, which will be described later, in each of the plurality of beam portions 130. Each of the laminated structure and constituent materials of the base 110 is not particularly limited.
　図１および図２に示すように、板状部１２０は、基部１１０と離間しつつ基部１１０の内側に位置している。図２に示すように、板状部１２０は、水平方向において、両側に位置する基部１１０との距離が略一定となるように配置されている。 As shown in FIGS. 1 and 2, the plate-shaped portion 120 is located inside the base 110 while being separated from the base 110. As shown in FIG. 2, the plate-shaped portion 120 is arranged such that the distance between the plate-shaped portion 120 and the base portions 110 located on both sides in the horizontal direction is substantially constant.
　図１に示すように、本実施形態において、板状部１２０は、上下方向から見たときに円形状の外形を有している。また、図２に示すように、板状部１２０は略一定の厚みを有している。また、本実施形態において、板状部１２０は一層の部材から構成されているが、積層体で構成されていてもよい。本実施形態において、板状部１２０は、活性層１１４からなる。 As shown in FIG. 1, in the present embodiment, the plate-shaped portion 120 has a circular outer shape when viewed from above and below. Further, as shown in FIG. 2, the plate-shaped portion 120 has a substantially constant thickness. Further, in the present embodiment, the plate-shaped portion 120 is composed of a single layer member, but may be composed of a laminated body. In this embodiment, the plate-shaped portion 120 is composed of the active layer 114.
　本実施形態において、４つの梁部１３０の各々は、基部１１０と板状部１２０とを互いに接続し、基部１１０の周方向に互いに間隔をあけて配置されている。具体的には、４つの梁部１３０は、板状部１２０の外周側に位置し、板状部１２０と同心円の円周上において互いに間隔をあけて配置されている。 In the present embodiment, each of the four beam portions 130 connects the base portion 110 and the plate-shaped portion 120 to each other, and is arranged at intervals in the circumferential direction of the base portion 110. Specifically, the four beam portions 130 are located on the outer peripheral side of the plate-shaped portion 120 and are arranged at intervals on the circumference of a concentric circle with the plate-shaped portion 120.
　図１に示すように、本実施形態においては、上記間隔が互いに等しくなるように複数の梁部１３０の各々が配置されている。また、本実施形態に係る圧電トランスデューサは、４つの梁部１３０を備えているが、梁部１３０の数は４つに限定されず、複数であればよい。 As shown in FIG. 1, in the present embodiment, each of the plurality of beam portions 130 is arranged so that the intervals are equal to each other. Further, the piezoelectric transducer according to the present embodiment includes four beam portions 130, but the number of beam portions 130 is not limited to four and may be any number.
　図１に示すように、複数の梁部１３０の各々は、上下方向から見たときに、延在部１３０Ａと、外側端部１３０Ｂと、内側端部１３０Ｃとを有している。 As shown in FIG. 1, each of the plurality of beam portions 130 has an extending portion 130A, an outer end portion 130B, and an inner end portion 130C when viewed from above and below.
　図１および図２に示すように、延在部１３０Ａは、基部１１０と隙間１０１を空けつつ基部１１０の周方向に沿って延在している。延在部１３０Ａは、板状部１２０と隙間１０２を空けつつ板状部１２０の外周縁に沿って延在している。本実施形態において、隙間１０１および隙間１０２の各々の幅は、略一定である。 As shown in FIGS. 1 and 2, the extending portion 130A extends along the circumferential direction of the base 110 while leaving a gap 101 with the base 110. The extending portion 130</b>A extends along the outer peripheral edge of the plate-shaped portion 120 while leaving a gap 102 with the plate-shaped portion 120. In this embodiment, the width of each of the gap 101 and the gap 102 is substantially constant.
　図１に示すように、外側端部１３０Ｂは、延在部１３０Ａの延在方向における一方端と、基部１１０とを互いに接続する。外側端部１３０Ｂは、上下方向から見たときに、延在部１３０Ａより外側に位置している。 As shown in FIG. 1, the outer end portion 130B connects one end of the extending portion 130A in the extending direction and the base portion 110 to each other. The outer end portion 130B is located outside the extending portion 130A when viewed from above and below.
　内側端部１３０Ｃは、延在部１３０Ａの延在方向における他方端と、板状部１２０とを互いに接続する。内側端部１３０Ｃは、上下方向から見たときに、延在部１３０Ａより内側に位置している。 The inner end portion 130C connects the other end of the extending portion 130A in the extending direction and the plate-like portion 120 to each other. The inner end portion 130C is located inside the extending portion 130A when viewed from above and below.
　図２に示すように、複数の梁部１３０の各々は、圧電体層１３１と、上部電極層１３２と、下部電極層１３３と、活性層１１４とを有している。 As shown in FIG. 2, each of the plurality of beam portions 130 has a piezoelectric layer 131, an upper electrode layer 132, a lower electrode layer 133, and an active layer 114.
　本実施形態において、圧電体層１３１は、上下方向から見たときに、延在部１３０Ａ、外側端部１３０Ｂおよび内側端部１３０Ｃの各々の全体に亘って配置されている。 In the present embodiment, the piezoelectric layer 131 is arranged over the entire extension 130A, the outer end 130B, and the inner end 130C when viewed from above and below.
　圧電体層１３１は、多結晶材料で構成されていてもよいし、単結晶材料で構成されていてもよい。圧電体層１３１は、チタン酸ジルコン酸鉛(ＰＺＴ)系のセラミックス、窒化アルミニウム(ＡｌＮ)、ニオブ酸リチウム(ＬｉＮｂＯ3)またはタンタル酸リチウム(ＬｉＴａＯ3)などで構成されている。 The piezoelectric layer 131 may be made of a polycrystalline material or a single crystal material. The piezoelectric layer 131 is made of lead zirconate titanate (PZT)-based ceramics, aluminum nitride (AlN), lithium niobate (LiNbO 3 ), lithium tantalate (LiTaO 3 ), or the like.
　上部電極層１３２は、圧電体層１３１の上側に配置されている。本実施形態において、上部電極層１３２は、上下方向から見たときに、延在部１３０Ａ、外側端部１３０Ｂおよび内側端部１３０Ｃの各々の全体に亘って配置されている。 The upper electrode layer 132 is arranged above the piezoelectric layer 131. In the present embodiment, the upper electrode layer 132 is arranged over the entire extension 130A, the outer end 130B, and the inner end 130C when viewed from above and below.
　上部電極層１３２は、Ｐｔなどの導電性を有する材料で構成されている。上部電極層１３２と圧電体層１３１との間に、Ｔｉなどで構成された密着層が配置されていてもよい。 The upper electrode layer 132 is made of a conductive material such as Pt. An adhesion layer made of Ti or the like may be arranged between the upper electrode layer 132 and the piezoelectric layer 131.
　下部電極層１３３は、圧電体層１３１を挟んで上部電極層１３２の少なくとも一部に対向するように配置されている。本実施形態において、下部電極層１３３は、上下方向から見たときに、延在部１３０Ａ、外側端部１３０Ｂおよび内側端部１３０Ｃの各々の全体に亘って配置されている。 The lower electrode layer 133 is arranged so as to face at least a part of the upper electrode layer 132 with the piezoelectric layer 131 interposed therebetween. In the present embodiment, the lower electrode layer 133 is arranged over the entire extension 130A, the outer end 130B, and the inner end 130C when viewed from above and below.
　下部電極層１３３は、Ｐｔなどの導電性を有する材料で構成されている。下部電極層１３３と圧電体層１３１との間に、Ｔｉなどで構成された密着層が配置されていてもよい。 The lower electrode layer 133 is made of a conductive material such as Pt. An adhesion layer made of Ti or the like may be disposed between the lower electrode layer 133 and the piezoelectric layer 131.
　活性層１１４は、下部電極層１３３より下側に配置されている。本実施形態において、活性層１１４が複数の梁部１３０の各々の最も下側に配置されている。本実施形態において、活性層１１４は、延在部１３０Ａ、外側端部１３０Ｂおよび内側端部１３０Ｃの各々の全体に亘って配置されている。 The active layer 114 is arranged below the lower electrode layer 133. In the present embodiment, the active layer 114 is arranged on the lowermost side of each of the plurality of beam portions 130. In the present embodiment, the active layer 114 is arranged over the entire extension 130A, the outer end 130B, and the inner end 130C.
　本実施形態において、複数の梁部１３０の各々を構成する活性層１１４は、水平方向において、基部１１０を構成する活性層１１４と互いに連続している。また、複数の梁部１３０の各々を構成する活性層１１４は、水平方向において、板状部１２０を構成する活性層１１４と互いに連続している。 In the present embodiment, the active layer 114 forming each of the plurality of beam portions 130 is continuous with the active layer 114 forming the base 110 in the horizontal direction. Further, the active layers 114 forming each of the plurality of beam portions 130 are continuous with the active layer 114 forming the plate-shaped portion 120 in the horizontal direction.
　図２に示すように、活性層１１４の厚さは、全体的に略一定である。活性層１１４は、単結晶シリコンから構成されている。 As shown in FIG. 2, the thickness of the active layer 114 is substantially constant as a whole. The active layer 114 is composed of single crystal silicon.
　図２に示すように、複数の梁部１３０の各々は、上述のように構成されていることにより、複数の梁部１３０の各々の上下方向の最大厚さは、板状部１２０の上下方向の最大厚さより厚くなっている。なお、複数の梁部１３０の各々を構成する材料の複合弾性率は、板状部１２０を構成する材料の複合弾性率より高くなっていることが好ましい。さらに、複数の梁部１３０の各々の単体における最低次の屈曲振動モードの共振周波数は、板状部１２０の単体における最低次の屈曲振動モードの共振周波数より高くなっている。その結果、複数の梁部１３０の各々の曲げ剛性が、板状部１２０の曲げ剛性より高くなっている。なお、上記の最大厚さ、複合弾性率および共振周波数のうちの少なくとも１つの要因によって、複数の梁部１３０の各々の曲げ剛性が、板状部１２０の曲げ剛性より高くなっていればよい。 As shown in FIG. 2, since each of the plurality of beam portions 130 is configured as described above, the maximum vertical thickness of each of the plurality of beam portions 130 is the vertical direction of the plate-shaped portion 120. It is thicker than the maximum thickness. The composite elastic modulus of the material forming each of the plurality of beam portions 130 is preferably higher than the composite elastic modulus of the material forming the plate-shaped portion 120. Further, the resonance frequency of the lowest-order bending vibration mode in each of the plurality of beam portions 130 is higher than the resonance frequency of the lowest-order bending vibration mode in the single body of the plate-shaped portion 120. As a result, the bending rigidity of each of the plurality of beam portions 130 is higher than the bending rigidity of the plate-shaped portion 120. Note that the bending rigidity of each of the plurality of beam portions 130 may be higher than the bending rigidity of the plate-shaped portion 120 due to at least one factor of the maximum thickness, the composite elastic modulus, and the resonance frequency described above.
　板状部１２０の中立面１２０Ｎは、板状部１２０内に位置している。本実施形態において、板状部１２０の中立面１２０Ｎは、板状部１２０の上下方向における略中央に位置している。すなわち、板状部１２０の中立面１２０Ｎは、活性層１１４内に位置している。具体的には、板状部１２０の中立面１２０Ｎは、単結晶シリコンの内部に存在している。 The neutral surface 120N of the plate-shaped portion 120 is located inside the plate-shaped portion 120. In the present embodiment, the neutral surface 120N of the plate-shaped portion 120 is located substantially at the center of the plate-shaped portion 120 in the vertical direction. That is, the neutral surface 120N of the plate-shaped portion 120 is located in the active layer 114. Specifically, the neutral surface 120N of the plate-shaped portion 120 exists inside the single crystal silicon.
　複数の梁部１３０の各々の中立面１３０Ｎは、活性層１１４内に位置している。具体的には、複数の梁部１３０の各々の中立面１３０Ｎは、単結晶シリコンの内部に存在している。 The neutral surface 130N of each of the plurality of beam portions 130 is located in the active layer 114. Specifically, the neutral surface 130N of each of the plurality of beam portions 130 exists inside the single crystal silicon.
　以下、本発明の実施形態１に係る圧電トランスデューサ１００の製造方法について説明する。 Hereinafter, a method for manufacturing the piezoelectric transducer 100 according to the first embodiment of the present invention will be described.
　図３は、本発明の実施形態１に係る圧電トランスデューサの製造方法において、ハンドル層、ボックス層および活性層を有する積層体を準備した状態を示す断面図である。図３に示すように、ハンドル層１１１、ボックス層１１２および活性層１１４を有する積層体、いわゆるＳＯＩ(Silicon　on　Insulator)基板を準備する。 FIG. 3 is a cross-sectional view showing a state in which a laminate having a handle layer, a box layer and an active layer is prepared in the method for manufacturing a piezoelectric transducer according to the first embodiment of the present invention. As shown in FIG. 3, a so-called SOI (Silicon on Insulator) substrate having a handle layer 111, a box layer 112 and an active layer 114 is prepared.
　図４は、本発明の実施形態１に係る圧電トランスデューサの製造方法において、活性層の上面に下部電極層を設けた状態を示す断面図である。図４に示すように、リフトオフ法、めっき法、または、エッチング法などにより、活性層１１４の上面に下部電極層１３３を設ける。 FIG. 4 is a cross-sectional view showing a state in which a lower electrode layer is provided on the upper surface of the active layer in the method for manufacturing the piezoelectric transducer according to the first embodiment of the present invention. As shown in FIG. 4, the lower electrode layer 133 is provided on the upper surface of the active layer 114 by a lift-off method, a plating method, an etching method, or the like.
　図５は、本発明の実施形態１に係る圧電トランスデューサの製造方法において、活性層および下部電極層の各々の上面に圧電体層を設けた状態を示す断面図である。図５に示すように、ＣＶＤ(Chemical　Vapor　Deposition)法またはＰＶＤ(Physical　Vapor　Deposition)法などにより、活性層１１４および下部電極層１３３の上面に、圧電体層１３１を設ける。 FIG. 5 is a cross-sectional view showing a state in which a piezoelectric layer is provided on the upper surface of each of the active layer and the lower electrode layer in the method of manufacturing the piezoelectric transducer according to the first embodiment of the present invention. As shown in FIG. 5, the piezoelectric layer 131 is provided on the upper surfaces of the active layer 114 and the lower electrode layer 133 by a CVD (Chemical Vapor Deposition) method, a PVD (Physical Vapor Deposition) method, or the like.
　図６は、本発明の実施形態１に係る圧電トランスデューサの製造方法において、圧電体層の上面に上部電極層を設けた状態を示す断面図である。図６に示すように、リフトオフ法、めっき法、または、エッチング法などにより、圧電体層１３１の上面に、上部電極層１３２を設ける。 FIG. 6 is a cross-sectional view showing a state in which an upper electrode layer is provided on the upper surface of the piezoelectric layer in the method of manufacturing the piezoelectric transducer according to the first embodiment of the present invention. As shown in FIG. 6, the upper electrode layer 132 is provided on the upper surface of the piezoelectric layer 131 by a lift-off method, a plating method, an etching method, or the like.
　図７は、本発明の実施形態１に係る圧電トランスデューサの製造方法において、積層された圧電体層をパターニングした状態を示す断面図である。図７に示すように、リフトオフ法またはエッチング法などにより、圧電体層１３１をパターニングする。これにより、圧電体層１３１の外形が画定される。 FIG. 7 is a cross-sectional view showing a state in which laminated piezoelectric layers are patterned in the method for manufacturing a piezoelectric transducer according to the first embodiment of the present invention. As shown in FIG. 7, the piezoelectric layer 131 is patterned by a lift-off method or an etching method. As a result, the outer shape of the piezoelectric layer 131 is defined.
　図８は、本発明の実施形態１に係る圧電トランスデューサの製造方法において、活性層に複数のスリットを形成した状態を示す断面図である。図８に示すように、リフトオフ法またはエッチングなどによって活性層１１４に複数のスリットを形成することにより、基部１１０を構成する活性層１１４から、板状部１２０を構成する活性層１１４、および、複数の梁部１３０の各々を構成する活性層１１４を分離させる。すなわち、これらの複数のスリットが、基部１１０と複数の梁部１３０の各々の延在部１３０Ａとの隙間１０１を構成し、板状部１２０と複数の梁部１３０の各々の延在部１３０Ａとの隙間１０２を構成する。 FIG. 8 is a cross-sectional view showing a state in which a plurality of slits are formed in the active layer in the method of manufacturing the piezoelectric transducer according to the first embodiment of the present invention. As shown in FIG. 8, by forming a plurality of slits in the active layer 114 by a lift-off method or etching, the active layer 114 forming the plate-like portion 120 and the active layer 114 forming the plate-shaped portion 120 and a plurality of slits are formed in the active layer 114. The active layers 114 forming each of the beam portions 130 are separated. That is, the plurality of slits configure the gap 101 between the base portion 110 and each extending portion 130A of each of the plurality of beam portions 130, and the plate-shaped portion 120 and each extending portion 130A of each of the plurality of beam portions 130 are formed. The gap 102 is formed.
　図９は、本発明の実施形態１に係る圧電トランスデューサの製造方法において、ハンドル層に凹部が形成された状態を示す図である。図９に示すように、ハンドル層１１１の下側面からハンドル層１１１に対して深掘反応性イオンエッチング（Ｄｅｅｐ　ＲＩＥ：Deep　Reactive　Ion　Etching）をすることにより、ハンドル層１１１において凹部１０３が形成される。 FIG. 9 is a diagram showing a state in which a recess is formed in the handle layer in the method of manufacturing the piezoelectric transducer according to the first embodiment of the present invention. As shown in FIG. 9, the recess 103 is formed in the handle layer 111 by performing deep reactive ion etching (Deep RIE) from the lower surface of the handle layer 111 to the handle layer 111. ..
　さらに、ボックス層１１２の下側面からボックス層１１２に対して反応性イオンエッチングをすることにより、ボックス層１１２において凹部１０３が形成される。これらの工程により、板状部１２０および複数の梁部１３０の各々の外形が画定され、図２に示すような本発明の実施形態１に係る圧電トランスデューサ１００が製造される。 Further, the recess 103 is formed in the box layer 112 by performing reactive ion etching on the box layer 112 from the lower side surface of the box layer 112. Through these steps, the outer shapes of the plate-shaped portion 120 and the plurality of beam portions 130 are defined, and the piezoelectric transducer 100 according to the first embodiment of the present invention as shown in FIG. 2 is manufactured.
　ここで、本実施形態に係る圧電トランスデューサ１００の駆動時の動作について説明する。本実施形態に係る圧電トランスデューサ１００が音波または超音波を発生する際は、複数の梁部１３０の各々において、上部電極層１３２と下部電極層１３３との間に電圧が印加される。これにより、上部電極層１３２、下部電極層１３３および活性層１１４に拘束された圧電体層１３１に歪みが生ずるため、複数の梁部１３０の各々が、外側端部１３０Ｂと基部１１０との接続位置を固定端として上下方向に屈曲振動する。 Here, the operation of the piezoelectric transducer 100 according to the present embodiment during driving will be described. When the piezoelectric transducer 100 according to this embodiment generates a sound wave or an ultrasonic wave, a voltage is applied between the upper electrode layer 132 and the lower electrode layer 133 in each of the plurality of beam portions 130. This causes strain in the piezoelectric layer 131 constrained by the upper electrode layer 132, the lower electrode layer 133, and the active layer 114, so that each of the plurality of beam portions 130 has a connection position between the outer end portion 130B and the base portion 110. Bends and vibrates vertically with the fixed end as.
　本実施形態においては、複数の梁部１３０の各々が上述のように構成されているため、複数の梁部１３０の屈曲振動に伴い、板状部１２０も上下方向に振動する。板状部１２０の振動メカニズムについて、以下の比較例に係る圧電トランスデューサと対比しつつ説明する。 In the present embodiment, since each of the plurality of beam portions 130 is configured as described above, the plate-shaped portion 120 also vibrates in the up-down direction in accordance with the bending vibration of the plurality of beam portions 130. The vibration mechanism of the plate-shaped portion 120 will be described in comparison with the piezoelectric transducer according to the comparative example below.
　図１０は、比較例に係る圧電トランスデューサの構成を示す、前方上方からの斜視図である。比較例に係る圧電トランスデューサ９００において、複数の梁部９３０の曲げ剛性は、板状部９２０の曲げ剛性以下となるように構成されている。 FIG. 10 is a perspective view from the front upper side showing the configuration of the piezoelectric transducer according to the comparative example. In the piezoelectric transducer 900 according to the comparative example, the bending rigidity of the plurality of beam portions 930 is set to be equal to or less than the bending rigidity of the plate-shaped portion 920.
　図１１は、比較例に係る圧電トランスデューサが、駆動時において複数の梁部の各々が上側に最も変位したときの状態を示す、前方上方からの斜視図である。図１１においては、変位量が大きく上方に位置している部分ほど、薄い色で図示している。 FIG. 11 is a perspective view from the front upper side showing a state in which each of the plurality of beam portions is displaced to the uppermost side when the piezoelectric transducer according to the comparative example is driven. In FIG. 11, the portion having a larger displacement amount and located higher is shown in a lighter color.
　図１１に示すように、比較例に係る圧電トランスデューサ９００においては、複数の梁部９３０の各々の剛性が低いため、駆動時に複数の梁部９３０の各々が反り上がって、上方に大きく変位している。また、複数の梁部９３０の各々の剛性が低いため、板状部９２０における梁部９３０の内側端部との接続位置に曲げ応力がほとんど作用せず、駆動時に板状部９２０は形状を維持しつつ全体的に一様に上方に変位している。その結果、板状部９２０と複数の梁部９３０の各々の隙間９０２が大きくなっている。圧電トランスデューサ９００が空気振動を介して入出力する場合、当該隙間９０２を通じて空気が漏れるため、圧電トランスデューサ９００の入出力特性が低下する。 As shown in FIG. 11, in the piezoelectric transducer 900 according to the comparative example, since the rigidity of each of the plurality of beam portions 930 is low, each of the plurality of beam portions 930 warps during driving and is largely displaced upward. There is. In addition, since the rigidity of each of the plurality of beam portions 930 is low, almost no bending stress acts on the connection position of the plate portion 920 with the inner end of the beam portion 930, and the plate portion 920 maintains its shape during driving. However, it is displaced uniformly upward as a whole. As a result, the gap 902 between each of the plate-shaped portion 920 and the plurality of beam portions 930 is large. When the piezoelectric transducer 900 inputs/outputs through air vibration, air leaks through the gap 902, so that the input/output characteristics of the piezoelectric transducer 900 deteriorate.
　図１２は、本発明の実施形態１に係る圧電トランスデューサが、駆動時において複数の梁部の各々が上側に最も変位した状態を示す、前方上方からの斜視図である。図１３は、図１２に示した圧電トランスデューサをＸＩＩＩ－ＸＩＩＩ線矢印方向から見た断面図である。図１２においては、変位量が大きく上方に位置している部分ほど、薄い色で図示している。 FIG. 12 is a perspective view from the front upper side showing the piezoelectric transducer according to the first embodiment of the present invention in a state in which each of the plurality of beam portions is displaced to the uppermost side during driving. FIG. 13 is a cross-sectional view of the piezoelectric transducer shown in FIG. 12 as seen in the direction of arrows XIII-XIII. In FIG. 12, the portion having a larger displacement amount and located higher is shown in a lighter color.
　図１２および図１３に示すように、本実施形態に係る圧電トランスデューサ１００においては、複数の梁部１３０の各々の曲げ剛性が高いため、駆動時の複数の梁部１３０の各々の変位量が小さい。また、複数の梁部１３０の各々の剛性が高いため、板状部１２０における内側端部１３０Ｃとの接続位置に曲げ応力が集中して作用する。その結果、板状部１２０は、当該接続位置を仮想的な固定端として錐体状に変形する。よって、図１２および図１３に示すように、圧電トランスデューサ１００においては、板状部１２０による錐体状の振動モードを励振することができる。 As shown in FIGS. 12 and 13, in the piezoelectric transducer 100 according to the present embodiment, since the bending rigidity of each of the plurality of beam portions 130 is high, the displacement amount of each of the plurality of beam portions 130 during driving is small. .. Further, since each of the plurality of beam portions 130 has high rigidity, bending stress concentrates and acts on the connection position of the plate-shaped portion 120 with the inner end portion 130C. As a result, the plate-shaped portion 120 deforms like a cone with the connection position as a virtual fixed end. Therefore, as shown in FIGS. 12 and 13, in the piezoelectric transducer 100, the conical vibration mode of the plate-shaped portion 120 can be excited.
　このように、圧電トランスデューサ１００は、圧電トランスデューサ１００の駆動時において、複数の梁部１３０の各々が上下方向に屈曲することによって板状部１２０が錐体状に変形するように、構成されている。 As described above, the piezoelectric transducer 100 is configured such that, when the piezoelectric transducer 100 is driven, each of the plurality of beam portions 130 bends in the vertical direction so that the plate-shaped portion 120 deforms into a cone shape. ..
　また、図１２および図１３に示すように、複数の梁部１３０の各々が上方に最も変位したとき、錐体上に変形した板状部１２０の中心部は、複数の梁部１３０の各々の上面より上方に位置している。このように、圧電トランスデューサ１００は、圧電トランスデューサ１００の駆動時において、板状部１２０の上下方向の最大変位量が複数の梁部１３０の各々の上下方向の最大変位量より大きくなるように、構成されている。 Further, as shown in FIGS. 12 and 13, when each of the plurality of beam portions 130 is most displaced upward, the central portion of the plate-shaped portion 120 deformed on the cone is the center of each of the plurality of beam portions 130. It is located above the upper surface. As described above, the piezoelectric transducer 100 is configured such that the maximum vertical displacement of the plate-shaped portion 120 is larger than the maximum vertical displacement of each of the plurality of beam portions 130 when the piezoelectric transducer 100 is driven. Has been done.
　上記のように、本発明の実施形態１に係る圧電トランスデューサ１００においては、複数の梁部１３０の各々の曲げ剛性が、板状部１２０の曲げ剛性より高い。 As described above, in the piezoelectric transducer 100 according to the first embodiment of the present invention, the bending rigidity of each of the plurality of beam portions 130 is higher than the bending rigidity of the plate-shaped portion 120.
　これにより、圧電トランスデューサ１００の駆動時において、複数の梁部１３０の各々が屈曲した際の変位量を小さくすることができる。また、板状部１２０の内側端部１３０Ｃとの接続位置を仮想的な固定端として板状部１２０を錐体状に変形させて励振させることができる。その結果、板状部１２０と複数の梁部１３０の各々との隙間１０２、および、基部１１０と複数の梁部１３０の各々との隙間１０１、の各々が大きくなることを抑制しつつ励振することができる。 This makes it possible to reduce the amount of displacement when each of the plurality of beam portions 130 is bent when the piezoelectric transducer 100 is driven. Further, the plate-shaped portion 120 can be deformed into a cone shape and excited by using the connection position of the plate-shaped portion 120 with the inner end 130C as a virtual fixed end. As a result, the gap 102 between the plate-shaped portion 120 and each of the plurality of beam portions 130, and the gap 101 between each of the base portion 110 and each of the plurality of beam portions 130 are suppressed from becoming large and excited. You can
　よって、圧電トランスデューサ１００が空気振動を介して入出力する場合には、隙間１０１および隙間１０２の各々から空気が漏れることを抑制して、圧電トランスデューサ１００の入出力特性を向上させることができる。 Therefore, when the piezoelectric transducer 100 inputs and outputs via air vibration, it is possible to suppress the leakage of air from each of the gap 101 and the gap 102 and improve the input/output characteristics of the piezoelectric transducer 100.
　本実施形態に係る圧電トランスデューサ１００においては、複数の梁部１３０の各々の上下方向の最大厚さは、板状部１２０の上下方向の最大厚さより厚い。 In the piezoelectric transducer 100 according to the present embodiment, the maximum vertical thickness of each of the plurality of beam portions 130 is thicker than the maximum vertical thickness of the plate-shaped portion 120.
　これにより、簡易な構成で、複数の梁部１３０の各々の曲げ剛性を、板状部１２０の曲げ剛性より高くすることができる。ひいては、圧電トランスデューサ１００において、入出力特性を容易に向上させることができる。 With this, the bending rigidity of each of the plurality of beam portions 130 can be made higher than the bending rigidity of the plate-shaped portion 120 with a simple configuration. As a result, the input/output characteristics of the piezoelectric transducer 100 can be easily improved.
　本実施形態に係る圧電トランスデューサ１００においては、複数の梁部１３０の各々を構成する材料の複合弾性率は、板状部１２０を構成する材料の複合弾性率より高くなっていることが好ましい。 In the piezoelectric transducer 100 according to this embodiment, the composite elastic modulus of the material forming each of the plurality of beam portions 130 is preferably higher than the composite elastic modulus of the material forming the plate-shaped portion 120.
　これにより、複数の梁部１３０の各々における圧電体層１３１、上部電極層１３２および下部電極層１３３の形成後の残留応力による影響を低減することができる。ひいては、圧電トランスデューサ１００において、残留応力による影響を低減して入出力特性を安定させることができる。 With this, it is possible to reduce the influence of the residual stress after forming the piezoelectric layer 131, the upper electrode layer 132, and the lower electrode layer 133 in each of the plurality of beam portions 130. Consequently, in the piezoelectric transducer 100, it is possible to reduce the influence of residual stress and stabilize the input/output characteristics.
　本実施形態に係る圧電トランスデューサ１００においては、複数の梁部１３０の各々の単体における最低次の屈曲振動モードの共振周波数は、板状部１２０の単体における最低次の屈曲振動モードの共振周波数より高い。 In the piezoelectric transducer 100 according to the present embodiment, the resonance frequency of the lowest bending vibration mode of each single beam portion 130 is higher than the resonance frequency of the lowest bending vibration mode of the single plate-shaped portion 120. ..
　これにより、複数の梁部１３０の各々の屈曲振動の基本モードと、板状部１２０の円形基本モードとを、互いに近い周波数にして、圧電トランスデューサ１００の入出力特性を向上させることができる。 With this, it is possible to improve the input/output characteristics of the piezoelectric transducer 100 by making the fundamental mode of bending vibration of each of the plurality of beam portions 130 and the circular fundamental mode of the plate-shaped portion 120 close to each other.
　本実施形態に係る圧電トランスデューサ１００においては、板状部１２０は、単結晶シリコンから構成されている。板状部１２０の中立面は、板状部１２０内に位置している。 In the piezoelectric transducer 100 according to this embodiment, the plate-shaped portion 120 is made of single crystal silicon. The neutral surface of the plate-shaped portion 120 is located inside the plate-shaped portion 120.
　これにより、板状部１２０内の残留応力を低減することができる。ひいては、圧電トランスデューサ１００において、残留応力による影響を低減して入出力特性を安定させることができる。 Due to this, the residual stress in the plate-shaped portion 120 can be reduced. Consequently, in the piezoelectric transducer 100, it is possible to reduce the influence of residual stress and stabilize the input/output characteristics.
　本実施形態に係る圧電トランスデューサ１００においては、複数の梁部１３０の各々は、下部電極層１３３より下側に配置された活性層１１４をさらに有している。活性層１１４は、単結晶シリコンから構成されている。複数の梁部１３０の各々の中立面１３０Ｎが、活性層１１４内に位置している。 In the piezoelectric transducer 100 according to this embodiment, each of the plurality of beam portions 130 further includes the active layer 114 arranged below the lower electrode layer 133. The active layer 114 is composed of single crystal silicon. The neutral surface 130N of each of the plurality of beam portions 130 is located in the active layer 114.
　これにより、圧電トランスデューサ１００において、圧電体層１３１内の残留応力による影響を低減して、入出力特性を安定させることができる。また、圧電体層１３１の変形を単結晶シリコンによって拘束して複数の梁部１３０の各々の駆動時の変位量を小さくすることができる。ひいては、板状部１２０と複数の梁部１３０の各々との隙間１０２、および、基部１１０と複数の梁部１３０の各々との隙間１０１、の各々が大きくなることを抑制し、圧電トランスデューサ１００において、入出力特性を向上させることができる。 With this, in the piezoelectric transducer 100, the influence of the residual stress in the piezoelectric layer 131 can be reduced and the input/output characteristics can be stabilized. Further, the deformation of the piezoelectric layer 131 can be restricted by the single crystal silicon to reduce the displacement amount of each of the plurality of beam portions 130 during driving. As a result, it is possible to prevent the gap 102 between the plate-shaped portion 120 and each of the plurality of beam portions 130 and the gap 101 between the base portion 110 and each of the plurality of beam portions 130 from increasing, and thus in the piezoelectric transducer 100. The input/output characteristics can be improved.
　本実施形態に係る圧電トランスデューサ１００は、圧電トランスデューサ１００の駆動時において複数の梁部１３０の各々が上下方向に屈曲することによって板状部１２０が錐体状に変形するように、構成されている。 The piezoelectric transducer 100 according to the present embodiment is configured such that when the piezoelectric transducer 100 is driven, each of the plurality of beam portions 130 bends in the vertical direction so that the plate-shaped portion 120 deforms into a cone shape. ..
　これにより、複数の梁部１３０の各々の変位量を小さくしつつ板状部１２０を振動させることができる。その結果、複数の梁部１３０の各々の両側に位置する隙間１０１，１０２が拡がって空気が漏れることを抑制することができる。ひいては、圧電トランスデューサ１００において、入出力特性を向上させることができる。 With this, it is possible to vibrate the plate-shaped portion 120 while reducing the displacement amount of each of the plurality of beam portions 130. As a result, it is possible to prevent the gaps 101 and 102 located on both sides of each of the plurality of beam portions 130 from expanding and air leakage. As a result, the input/output characteristics of the piezoelectric transducer 100 can be improved.
　本実施形態に係る圧電トランスデューサ１００は、圧電トランスデューサ１００の駆動時において板状部１２０の上下方向の最大変位量が複数の梁部１３０の各々の上下方向の最大変位量より大きくなるように、構成されている。 The piezoelectric transducer 100 according to this embodiment is configured such that the maximum vertical displacement of the plate-shaped portion 120 is larger than the maximum vertical displacement of each of the plurality of beam portions 130 when the piezoelectric transducer 100 is driven. Has been done.
　これにより、圧電トランスデューサ１００の駆動時において、複数の梁部１３０の各々が上下方向において板状部１２０とは逆方向に変位する場合でも、板状部１２０の変位量によって圧電トランスデューサ１００の入出力特性が決まるため、圧電トランスデューサ１００の入出力特性を安定させることができる。 Accordingly, even when each of the plurality of beam portions 130 is displaced in the direction opposite to the plate-shaped portion 120 in the up-down direction when the piezoelectric transducer 100 is driven, the input/output of the piezoelectric transducer 100 depending on the displacement amount of the plate-shaped portion 120. Since the characteristics are determined, the input/output characteristics of the piezoelectric transducer 100 can be stabilized.
　(実施形態２)
　以下、本発明の実施形態２に係る圧電トランスデューサについて説明する。本発明の実施形態２に係る圧電トランスデューサは、複数の梁部の各々における積層体の構成が、実施形態１に係る圧電トランスデューサ１００と異なる。よって、本発明の実施形態１に係る圧電トランスデューサ１００と同様である構成については説明を繰り返さない。 (Embodiment 2)
The piezoelectric transducer according to the second embodiment of the present invention will be described below. The piezoelectric transducer according to the second embodiment of the present invention is different from the piezoelectric transducer 100 according to the first embodiment in the structure of the laminated body in each of the plurality of beam portions. Therefore, the description of the same configuration as the piezoelectric transducer 100 according to the first embodiment of the present invention will not be repeated.
　図１４は、本発明の実施形態２に係る圧電トランスデューサの構成を示す断面図である。図１４に示す圧電トランスデューサ２００の断面図は、図２に示す圧電トランスデューサ１００の断面図と同一の断面視にて図示している。 FIG. 14 is a cross-sectional view showing the configuration of the piezoelectric transducer according to the second embodiment of the present invention. The sectional view of the piezoelectric transducer 200 shown in FIG. 14 is shown in the same sectional view as the sectional view of the piezoelectric transducer 100 shown in FIG.
　図１４に示すように、本発明の実施形態２に係る圧電トランスデューサ２００においては、複数の梁部２３０の各々は、下部電極層１３３と活性層１１４との間に配置された絶縁層２３５をさらに有している。絶縁層２３５は、たとえばＳｉＯ2などの電気絶縁性を有する材料で構成されている。 As shown in FIG. 14, in the piezoelectric transducer 200 according to the second exemplary embodiment of the present invention, each of the plurality of beam portions 230 further includes an insulating layer 235 disposed between the lower electrode layer 133 and the active layer 114. Have The insulating layer 235 is made of a material having an electrically insulating property such as SiO 2 .
　本発明の実施形態２に係る圧電トランスデューサ２００の製造方法においては、ＳＯＩ基板とは別途準備された圧電単結晶基板に、リフトオフ法、めっき法、または、エッチング法などにより、圧電単結晶基板に下部電極層１３３が積層される。圧電単結晶基板および下部電極層１３３の下面には、ＣＶＤ法またはＰＶＤ法などにより、絶縁層２３５が積層される。絶縁層２３５は、下面が化学機械研磨(ＣＭＰ：Chemical　Mechanical　Polishing)などによって平坦にされた後、活性層１１４の上面と接合される。そして、圧電単結晶基板の上面をＣＭＰなどにより削り、圧電単結晶基板を所望の厚さに調整することにより、圧電体層１３１が形成される。 In the method of manufacturing the piezoelectric transducer 200 according to the second embodiment of the present invention, a piezoelectric single crystal substrate prepared separately from the SOI substrate is formed on the piezoelectric single crystal substrate by a lift-off method, a plating method, an etching method, or the like. The electrode layer 133 is laminated. An insulating layer 235 is laminated on the lower surfaces of the piezoelectric single crystal substrate and the lower electrode layer 133 by the CVD method or the PVD method. The lower surface of the insulating layer 235 is flattened by chemical mechanical polishing (CMP) or the like, and then bonded to the upper surface of the active layer 114. Then, the upper surface of the piezoelectric single crystal substrate is ground by CMP or the like, and the piezoelectric single crystal substrate is adjusted to a desired thickness, whereby the piezoelectric layer 131 is formed.
　本実施形態に係る圧電トランスデューサ２００の製造方法においては、本発明の実施形態１に係る圧電トランスデューサ１００の製造方法と同様に圧電体層１３１をパターニングした後、絶縁層２３５をパターニングする。これにより、絶縁層２３５の外形が画定される。 In the method of manufacturing the piezoelectric transducer 200 according to this embodiment, the insulating layer 235 is patterned after the piezoelectric layer 131 is patterned as in the method of manufacturing the piezoelectric transducer 100 according to the first embodiment of the present invention. This defines the outer shape of the insulating layer 235.
　上記のように、本発明の実施形態２に係る圧電トランスデューサ２００においては、複数の梁部２３０の各々は、下部電極層１３３と活性層１１４との間に配置された絶縁層２３５をさらに有している。これにより、複数の梁部２３０の各々の剛性をより高くできるため、圧電トランスデューサ２００の駆動時において、複数の梁部２３０の各々が屈曲した際の変位量を小さくすることができる。また、下部電極層１３３と活性層１１４との間の電気絶縁性能を高くできるため、圧電体層１３１の圧電特性を向上でき、ひいては、圧電トランスデューサ２００の入出力特性を向上させることができる。 As described above, in the piezoelectric transducer 200 according to the second embodiment of the present invention, each of the plurality of beam portions 230 further includes the insulating layer 235 disposed between the lower electrode layer 133 and the active layer 114. ing. Thereby, the rigidity of each of the plurality of beam portions 230 can be further increased, and thus the amount of displacement when each of the plurality of beam portions 230 is bent can be reduced when the piezoelectric transducer 200 is driven. Moreover, since the electrical insulation performance between the lower electrode layer 133 and the active layer 114 can be improved, the piezoelectric characteristics of the piezoelectric layer 131 can be improved, and the input/output characteristics of the piezoelectric transducer 200 can be improved.
　(実施形態３)
　以下、本発明の実施形態３に係る圧電トランスデューサについて説明する。本発明の実施形態３に係る圧電トランスデューサは、複数の梁部の各々における積層体の構成が、実施形態１に係る圧電トランスデューサ１００と異なる。よって、本発明の実施形態１に係る圧電トランスデューサ１００と同様である構成については説明を繰り返さない。 (Embodiment 3)
Hereinafter, a piezoelectric transducer according to the third embodiment of the present invention will be described. The piezoelectric transducer according to the third embodiment of the present invention is different from the piezoelectric transducer 100 according to the first embodiment in the configuration of the laminated body in each of the plurality of beam portions. Therefore, the description of the same configuration as the piezoelectric transducer 100 according to the first embodiment of the present invention will not be repeated.
　図１５は、本発明の実施形態３に係る圧電トランスデューサの構成を示す断面図である。図１５に示す圧電トランスデューサ３００の断面図は、図２に示す圧電トランスデューサ１００の断面図と同一の断面視にて図示している。 FIG. 15 is a cross-sectional view showing the configuration of the piezoelectric transducer according to the third embodiment of the present invention. The sectional view of the piezoelectric transducer 300 shown in FIG. 15 is illustrated in the same sectional view as the sectional view of the piezoelectric transducer 100 shown in FIG.
　図１５に示すように、本発明の実施形態３に係る圧電トランスデューサ３００においては、複数の梁部３３０の各々は、上部電極層１３２の上側に配置された保護層３３６をさらに有している。保護層３３６は、たとえばＳｉＯ2などの耐湿性を有する材料で構成されている。保護層３３６は、ＣＶＤ法またはＰＶＤ法などにより、上部電極層１３２の上面に設けられる。 As shown in FIG. 15, in the piezoelectric transducer 300 according to the third embodiment of the present invention, each of the plurality of beam portions 330 further includes a protective layer 336 arranged above the upper electrode layer 132. The protective layer 336 is made of a material having moisture resistance such as SiO 2 . The protective layer 336 is provided on the upper surface of the upper electrode layer 132 by a CVD method, a PVD method, or the like.
　これにより、複数の梁部３３０の各々の剛性をより高くできるため、圧電トランスデューサ３００の駆動時において、複数の梁部３３０の各々が屈曲した際の変位量を小さくすることができる。また、圧電体層１３１の上方を耐湿性を有する保護層３３６で覆うことができるため、圧電トランスデューサ３００の信頼性を向上させることができる。 With this, since the rigidity of each of the plurality of beam portions 330 can be further increased, it is possible to reduce the displacement amount when each of the plurality of beam portions 330 is bent when the piezoelectric transducer 300 is driven. Further, since the upper side of the piezoelectric layer 131 can be covered with the protective layer 336 having moisture resistance, the reliability of the piezoelectric transducer 300 can be improved.
　(実施形態４)
　以下、本発明の実施形態４に係る圧電トランスデューサについて説明する。本発明の実施形態４に係る圧電トランスデューサは、上下方向から見たときの複数の梁部の形状が、本発明の実施形態１に係る圧電トランスデューサ１００とは異なる。よって、本発明の実施形態１に係る圧電トランスデューサ１００と同様である構成については説明を繰り返さない。 (Embodiment 4)
The piezoelectric transducer according to the fourth embodiment of the present invention will be described below. The piezoelectric transducer according to the fourth exemplary embodiment of the present invention is different from the piezoelectric transducer 100 according to the first exemplary embodiment of the present invention in the shape of the plurality of beam portions when viewed in the vertical direction. Therefore, the description of the same configuration as the piezoelectric transducer 100 according to the first embodiment of the present invention will not be repeated.
　図１６は、本発明の実施形態４に係る圧電トランスデューサの構成を示す、前方上方からの斜視図である。 FIG. 16 is a perspective view from the front upper side showing the configuration of the piezoelectric transducer according to the fourth embodiment of the present invention.
　図１６に示すように、本発明の実施形態４に係る圧電トランスデューサ４００においては、上下方向から見たときに、複数の梁部４３０の各々の一方端は、基部１１０に接続されている。複数の梁部４３０の各々の他方端は、板状部１２０に接続されている。 As shown in FIG. 16, in the piezoelectric transducer 400 according to the fourth embodiment of the present invention, one end of each of the plurality of beam portions 430 is connected to the base portion 110 when viewed from above and below. The other end of each of the plurality of beam portions 430 is connected to the plate-shaped portion 120.
　複数の梁部４３０の各々の上下方向の最大厚さは、板状部１２０の上下方向の最大厚さより厚くなっている。なお、複数の梁部４３０の各々を構成する材料の複合弾性率は、板状部１２０を構成する材料の複合弾性率より高くなっていることが好ましい。さらに、複数の梁部４３０の各々の単体における最低次の屈曲振動モードの共振周波数は、板状部１２０の単体における最低次の屈曲振動モードの共振周波数より高くなっている。その結果、複数の梁部４３０の各々の曲げ剛性が、板状部１２０の曲げ剛性より高くなっている。なお、上記の最大厚さ、複合弾性率および共振周波数のうちの少なくとも１つの要因によって、複数の梁部４３０の各々の曲げ剛性が、板状部１２０の曲げ剛性より高くなっていればよい。 The maximum vertical thickness of each of the plurality of beam portions 430 is thicker than the maximum vertical thickness of the plate-shaped portion 120. The composite elastic modulus of the material forming each of the plurality of beam portions 430 is preferably higher than the composite elastic modulus of the material forming the plate-shaped portion 120. Further, the resonance frequency of the lowest bending vibration mode of each of the plurality of beam portions 430 is higher than the resonance frequency of the lowest bending vibration mode of the plate portion 120 alone. As a result, the bending rigidity of each of the plurality of beam portions 430 is higher than the bending rigidity of the plate-shaped portion 120. Note that the bending rigidity of each of the plurality of beam portions 430 may be higher than the bending rigidity of the plate-shaped portion 120 due to at least one factor of the maximum thickness, the composite elastic modulus, and the resonance frequency described above.
　図１６に示すように、本実施形態に係る圧電トランスデューサ４００においては、上下方向から見たときに、複数の梁部４３０の各々は、板状部１２０の中心Ｏに関して点対称となるように互いに同一の外形を有し、かつ、外形の少なくとも一部が湾曲している。複数の梁部４３０のうちの周方向において互いに隣接する梁部４３０同士の間には、一定の間隔を維持しつつ延在する隙間４０４が設けられている。 As shown in FIG. 16, in the piezoelectric transducer 400 according to the present embodiment, each of the plurality of beam portions 430 is point-symmetrical with respect to the center O of the plate-shaped portion 120 when viewed from above and below. It has the same outer shape and at least a part of the outer shape is curved. A gap 404 that extends while maintaining a constant interval is provided between the beam portions 430 that are adjacent to each other in the circumferential direction of the plurality of beam portions 430.
　これにより、圧電トランスデューサ４００を駆動させた際、複数の梁部４３０の各々のうち周方向において互いに隣接する梁部４３０同士の変位量が互いに等しくなる。すなわち、板状部１２０の外周側面の周方向から見たときに、互いに隣接する梁部４３０同士の間の隙間が広がらない。このため、圧電トランスデューサ４００の駆動時に、互いに隣接する梁部４３０同士の間から空気が漏れることが抑制され、圧電トランスデューサ４００の入出力特性を向上させることができる。 As a result, when the piezoelectric transducer 400 is driven, the displacement amounts of the beam portions 430 adjacent to each other in the circumferential direction among the plurality of beam portions 430 become equal to each other. That is, when viewed from the circumferential direction of the outer peripheral side surface of the plate-shaped portion 120, the gap between the adjacent beam portions 430 does not widen. Therefore, when the piezoelectric transducer 400 is driven, it is possible to prevent air from leaking from between the beam portions 430 adjacent to each other, and it is possible to improve the input/output characteristics of the piezoelectric transducer 400.
　なお、隙間４０４は、板状部１２０の外周側面から基部１１０の内周側面にかけて延在している。隙間４０４は、板状部１２０の外周側面から基部１１０の内周側面までの全長にわたって、一定の曲率で湾曲している。 Note that the gap 404 extends from the outer peripheral side surface of the plate-shaped portion 120 to the inner peripheral side surface of the base portion 110. The gap 404 is curved with a constant curvature over the entire length from the outer peripheral side surface of the plate-shaped portion 120 to the inner peripheral side surface of the base portion 110.
　また、図１６に示すように、本実施形態に係る圧電トランスデューサ４００においては、互いに隣接する梁部４３０同士の間の隙間４０４が一定の間隔を維持しつつ延在している。 Further, as shown in FIG. 16, in the piezoelectric transducer 400 according to the present embodiment, the gap 404 between the beam portions 430 adjacent to each other extends while maintaining a constant gap.
　これにより、互いに隣接する梁部４３０同士の間の隙間が大きな部分が生じることを抑制できるため、互いに隣接する梁部４３０同士の間の隙間から空気が漏れることを抑制できる。このため、空気振動を介して入出力する圧電トランスデューサ４００において、圧電トランスデューサ４００の入出力特性を向上させることができる。 With this, it is possible to suppress the occurrence of a large gap between the adjacent beam portions 430, so that it is possible to prevent air from leaking from the gap between the adjacent beam portions 430. Therefore, in the piezoelectric transducer 400 that inputs and outputs via air vibration, the input/output characteristic of the piezoelectric transducer 400 can be improved.
　また、本実施形態に係る圧電トランスデューサ４００においては、上下方向から見たときに、複数の梁部４３０の各々は、基部１１０側の部分より、板状部１２０側の部分の方が、板状部１２０の外周側面の径方向を向いている。 Further, in the piezoelectric transducer 400 according to the present embodiment, when viewed from above and below, each of the plurality of beam portions 430 has a plate-like shape on the plate-shaped portion 120 side than on the base 110-side portion. The outer peripheral side surface of the portion 120 faces in the radial direction.
　これにより、上記外周側面の周方向に互いに隣接する梁部４３０同士の、基部１１０からの距離が長く変位量の大きい板状部１２０側の部分における互いの間の隙間が大きくなることを抑制することができる。ひいては、駆動時において、上記外周側面の周方向において互いに隣接する梁部４３０同士の間の隙間の広がりを基部１１０から板状部１２０までの区間全体においてより抑制して、圧電トランスデューサ４００の入出力特性を向上させることができる。 Thereby, it is possible to prevent the gap between the beam portions 430 adjacent to each other in the circumferential direction of the outer peripheral side surface from increasing in the plate-shaped portion 120 side where the distance from the base portion 110 is long and the displacement amount is large. be able to. Consequently, during driving, the expansion of the gap between the beam portions 430 adjacent to each other in the circumferential direction of the outer peripheral side surface is further suppressed in the entire section from the base portion 110 to the plate-shaped portion 120, and the input/output of the piezoelectric transducer 400 is suppressed. The characteristics can be improved.
　上述した実施形態の説明において、組み合わせ可能な構成を相互に組み合わせてもよい。 In the above description of the embodiments, the configurations that can be combined may be combined with each other.
　今回開示された実施形態はすべての点で例示であって制限的なものではないと考えられるべきである。本発明の範囲は上記した説明ではなくて請求の範囲によって示され、請求の範囲と均等の意味および範囲内でのすべての変更が含まれることが意図される。 The embodiments disclosed this time are to be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description but by the scope of the claims, and is intended to include meanings equivalent to the scope of the claims and all modifications within the scope.
　１００，２００，３００，４００，９００　圧電トランスデューサ、１０１，１０２，４０４，９０２　隙間、１０３　凹部、１１０　基部、１１１　ハンドル層、１１２　ボックス層、１１４　活性層、１２０，９２０　板状部、１２０Ｎ，１３０Ｎ　中立面、１３０，２３０，３３０，４３０，９３０　梁部、１３０Ａ　延在部、１３０Ｂ　外側端部、１３０Ｃ　内側端部、１３１　圧電体層、１３２　上部電極層、１３３　下部電極層、２３５　絶縁層、３３６　保護層。 100, 200, 300, 400, 900 Piezoelectric transducer, 101, 102, 404, 902 Gap, 103 recess, 110 base, 111 handle layer, 112 box layer, 114 active layer, 120,920 plate, 120N, 130N Elevation, 130, 230, 330, 430, 930 beam, 130A extension, 130B outer end, 130C inner end, 131 piezoelectric layer, 132 upper electrode layer, 133 lower electrode layer, 235 insulating layer, 336 Protective layer.

Claims (10)

  1. 　上下方向から見て環状の外形を有する基部と、
    　前記基部と離間しつつ前記基部の内側に位置する板状部と、
    　前記基部と前記板状部とを互いに接続し、前記基部の周方向に互いに間隔をあけて配置された複数の梁部とを備え、
    　前記複数の梁部の各々は、圧電体層と、該圧電体層の上側に配置された上部電極層と、前記圧電体層を挟んで前記上部電極層の少なくとも一部に対向するように配置された下部電極層とを有し、
    　前記複数の梁部の各々の曲げ剛性は、前記板状部の曲げ剛性より高い、圧電トランスデューサ。     A base portion having an annular outer shape when viewed from above and below,
    A plate-shaped portion located inside the base portion while being separated from the base portion,
    The base portion and the plate-shaped portion are connected to each other, and a plurality of beam portions arranged at intervals in the circumferential direction of the base portion,
    Each of the plurality of beam portions is arranged so as to face a piezoelectric layer, an upper electrode layer disposed above the piezoelectric layer, and at least a portion of the upper electrode layer with the piezoelectric layer sandwiched therebetween. And a lower electrode layer
    A piezoelectric transducer in which the bending rigidity of each of the plurality of beam portions is higher than the bending rigidity of the plate-shaped portion.
  2. 　前記複数の梁部の各々の上下方向の最大厚さは、前記板状部の上下方向の最大厚さより厚い、請求項１に記載の圧電トランスデューサ。 The piezoelectric transducer according to claim 1, wherein a maximum vertical thickness of each of the plurality of beam portions is greater than a maximum vertical thickness of the plate-shaped portion.
  3. 　前記複数の梁部の各々を構成する材料の複合弾性率は、前記板状部を構成する材料の複合弾性率より高い、請求項１または請求項２に記載の圧電トランスデューサ。 The piezoelectric transducer according to claim 1 or 2, wherein a composite elastic modulus of a material forming each of the plurality of beam portions is higher than a composite elastic modulus of a material forming the plate-shaped portion.
  4. 　前記複数の梁部の各々の単体における最低次の屈曲振動モードの共振周波数は、前記板状部の単体における最低次の屈曲振動モードの共振周波数より高い、請求項１から請求項３のいずれか１項に記載の圧電トランスデューサ。 The resonance frequency of the lowest-order bending vibration mode in each single body of the plurality of beam portions is higher than the resonance frequency of the lowest-order bending vibration mode in the single body of the plate-like portion. The piezoelectric transducer according to item 1.
  5. 　前記板状部は、単結晶シリコンから構成されており、
    　前記板状部の中立面が、前記板状部内に位置している、請求項１から請求項４のいずれか１項に記載の圧電トランスデューサ。     The plate-shaped portion is composed of single crystal silicon,
    The piezoelectric transducer according to any one of claims 1 to 4, wherein the neutral surface of the plate-shaped portion is located inside the plate-shaped portion.
  6. 　前記複数の梁部の各々は、前記下部電極層より下側に配置された活性層をさらに有し、
    　前記活性層は、単結晶シリコンから構成されており、
    　前記複数の梁部の各々の中立面が、前記活性層内に位置している、請求項１から請求項５のいずれか１項に記載の圧電トランスデューサ。     Each of the plurality of beam portions further has an active layer disposed below the lower electrode layer,
    The active layer is composed of single crystal silicon,
    The piezoelectric transducer according to claim 1, wherein a neutral plane of each of the plurality of beam portions is located in the active layer.
  7. 　前記複数の梁部の各々は、前記下部電極層と前記活性層との間に配置された絶縁層をさらに有する、請求項６に記載の圧電トランスデューサ。 The piezoelectric transducer according to claim 6, wherein each of the plurality of beam portions further includes an insulating layer disposed between the lower electrode layer and the active layer.
  8. 　前記複数の梁部の各々は、前記上部電極層の上側に配置された保護層をさらに有する、請求項１から請求項７のいずれか１項に記載の圧電トランスデューサ。 The piezoelectric transducer according to any one of claims 1 to 7, wherein each of the plurality of beam portions further includes a protective layer disposed above the upper electrode layer.
  9. 　前記圧電トランスデューサの駆動時において前記複数の梁部の各々が上下方向に屈曲することによって前記板状部が錐体状に変形するように、構成されている、請求項１から請求項８のいずれか１項に記載の圧電トランスデューサ。 9. Any one of claims 1 to 8 configured such that when the piezoelectric transducer is driven, each of the plurality of beam portions is bent in the vertical direction so that the plate-like portion is deformed into a cone shape. 2. The piezoelectric transducer according to item 1.
  10. 　前記圧電トランスデューサの駆動時において前記板状部の上下方向の最大変位量が前記複数の梁部の各々の上下方向の最大変位量より大きくなるように、構成されている、請求項９に記載の圧電トランスデューサ。 10. The configuration according to claim 9, wherein the maximum displacement amount of the plate-shaped portion in the vertical direction when driving the piezoelectric transducer is larger than the maximum displacement amount of each of the plurality of beam portions in the vertical direction. Piezoelectric transducer.
PCT/JP2019/032102 2018-12-27 2019-08-16 Piezoelectric transducer WO2020136983A1 (en)

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Publication number Priority date Publication date Assignee Title
JP2017022576A (en) * 2015-07-10 2017-01-26 ローム株式会社 Structure for piezoelectric thin film microphone, and manufacturing method

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2017022576A (en) * 2015-07-10 2017-01-26 ローム株式会社 Structure for piezoelectric thin film microphone, and manufacturing method

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