JP6122066B2 - High frequency ultrasonic piezoelectric element, method for manufacturing the same, and high frequency ultrasonic probe including the same - Google Patents
High frequency ultrasonic piezoelectric element, method for manufacturing the same, and high frequency ultrasonic probe including the same Download PDFInfo
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- 238000000034 method Methods 0.000 title claims description 29
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- 239000002131 composite material Substances 0.000 claims description 23
- 239000000843 powder Substances 0.000 claims description 20
- 239000007921 spray Substances 0.000 claims description 19
- 238000005245 sintering Methods 0.000 claims description 7
- 239000010408 film Substances 0.000 description 108
- 239000000463 material Substances 0.000 description 15
- 229910052451 lead zirconate titanate Inorganic materials 0.000 description 9
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- 230000002093 peripheral effect Effects 0.000 description 2
- 238000005498 polishing Methods 0.000 description 2
- 238000005507 spraying Methods 0.000 description 2
- 229910052719 titanium Inorganic materials 0.000 description 2
- 239000010936 titanium Substances 0.000 description 2
- 238000007740 vapor deposition Methods 0.000 description 2
- 229910052726 zirconium Inorganic materials 0.000 description 2
- -1 zirconium alkoxide Chemical class 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000003745 diagnosis Methods 0.000 description 1
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- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 239000010931 gold Substances 0.000 description 1
- 238000003384 imaging method Methods 0.000 description 1
- HFGPZNIAWCZYJU-UHFFFAOYSA-N lead zirconate titanate Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[Ti+4].[Zr+4].[Pb+2] HFGPZNIAWCZYJU-UHFFFAOYSA-N 0.000 description 1
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical group [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 239000000123 paper Substances 0.000 description 1
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- 229920005989 resin Polymers 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000004332 silver Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000004544 sputter deposition Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
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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
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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
- H04R31/00—Apparatus or processes specially adapted for the manufacture of transducers or diaphragms therefor
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- H10N30/00—Piezoelectric or electrostrictive devices
- H10N30/01—Manufacture or treatment
- H10N30/06—Forming electrodes or interconnections, e.g. leads or terminals
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- 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
- H10N30/07—Forming of piezoelectric or electrostrictive parts or bodies on an electrical element or another base
- H10N30/074—Forming of piezoelectric or electrostrictive parts or bodies on an electrical element or another base by depositing piezoelectric or electrostrictive layers, e.g. aerosol or screen printing
- H10N30/077—Forming of piezoelectric or electrostrictive parts or bodies on an electrical element or another base by depositing piezoelectric or electrostrictive layers, e.g. aerosol or screen printing by liquid phase deposition
- H10N30/078—Forming of piezoelectric or electrostrictive parts or bodies on an electrical element or another base by depositing piezoelectric or electrostrictive layers, e.g. aerosol or screen printing by liquid phase deposition by sol-gel deposition
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- 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
- H10N30/09—Forming piezoelectric or electrostrictive materials
- H10N30/093—Forming inorganic materials
- H10N30/097—Forming inorganic materials by sintering
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- 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
- H10N30/20—Piezoelectric or electrostrictive devices with electrical input and mechanical output, e.g. functioning as actuators or vibrators
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- 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
- H10N30/87—Electrodes or interconnections, e.g. leads or terminals
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B8/00—Diagnosis using ultrasonic, sonic or infrasonic waves
- A61B8/13—Tomography
- A61B8/14—Echo-tomography
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Description
本発明は、高周波超音波圧電素子、その製造方法、及びそれを含む高周波超音波プローブに関し、特に、スプレー法を用いて形成された圧電膜を含む高周波超音波圧電素子、その製造方法、及びそれを含む高周波超音波プローブに関する。 The present invention relates to a high-frequency ultrasonic piezoelectric element, a method for manufacturing the same, and a high-frequency ultrasonic probe including the same, and in particular, a high-frequency ultrasonic piezoelectric element including a piezoelectric film formed using a spray method, a method for manufacturing the same. The present invention relates to a high-frequency ultrasonic probe including
従来から、超音波プローブ等を用いて、生体内部等に超音波を照射し、その生体内部からの反射波を得て、得られた反射波に信号処理を施して可視化し、生体の性状を診断することが行われている。超音波の送受信には、圧電素子が用いられ、圧電素子の材料としては、一般に、チタン酸ジルコン酸鉛(Pb(Zr,Ti)O3:PZT)等のペロブスカイト結晶構造を有する酸化系圧電材料が用いられる。圧電素子は、一般に、PZT等からなる粉末を立方体等の所定の形状に成形し、その成形体を焼結してセラミック焼結体を得た後、その焼結体を圧電膜として切削や研磨等により所望の形状に加工し、該圧電膜に電極を取り付けることによって製造される(例えば特許文献1等を参照)。 Conventionally, an ultrasonic probe or the like is used to irradiate the inside of a living body with ultrasonic waves, obtain a reflected wave from the inside of the living body, perform signal processing on the obtained reflected wave, visualize it, and characterize the living body. Diagnosis is done. Piezoelectric elements are used for transmission / reception of ultrasonic waves, and as a material of the piezoelectric elements, generally, an oxidation-type piezoelectric material having a perovskite crystal structure such as lead zirconate titanate (Pb (Zr, Ti) O 3 : PZT). Is used. In general, a piezoelectric element is formed by molding a powder made of PZT or the like into a predetermined shape such as a cube, and sintering the molded body to obtain a ceramic sintered body, and then cutting or polishing the sintered body as a piezoelectric film. It is manufactured by processing into a desired shape by, for example, and attaching electrodes to the piezoelectric film (see, for example, Patent Document 1).
近年、より高精細な超音波画像を取得できるようにすることが求められており、高精細な超音波画像を得るためには、より高い周波数で超音波を送受可能な圧電素子が必要となる。圧電素子の材料として同一の材料を用いた場合、圧電膜の厚みを薄くするに従って高い周波数で超音波を送受可能となる。具体的に、圧電素子の駆動周波数と圧電素子の厚さとは反比例関係にあり、100μmの圧電膜を有する圧電素子が、例えば20MHzで駆動する場合、これと同一材料からなる圧電素子における圧電膜を5分の1の厚さである20μmとすれば、通常、その駆動周波数は5倍である100MHzとなる。このような100MHzの高周波で駆動する圧電素子を用いると、得られる超音波画像の照射方向空間分解能は、駆動周波数が20MHzの場合と比較して5倍となる。従って、より高精細な超音波画像の取得を可能とする圧電素子を得るためには、より膜厚が小さい圧電膜を形成する必要がある。 In recent years, there has been a demand for acquiring a higher-definition ultrasonic image, and in order to obtain a high-definition ultrasonic image, a piezoelectric element capable of transmitting and receiving ultrasonic waves at a higher frequency is required. . When the same material is used as the material of the piezoelectric element, ultrasonic waves can be transmitted and received at a higher frequency as the thickness of the piezoelectric film is reduced. Specifically, the driving frequency of the piezoelectric element and the thickness of the piezoelectric element are inversely proportional to each other, and when a piezoelectric element having a 100 μm piezoelectric film is driven at, for example, 20 MHz, the piezoelectric film in the piezoelectric element made of the same material as this is used. If the thickness is set to 20 μm, which is 1/5 of the thickness, the drive frequency is normally 5 times 100 MHz. When such a piezoelectric element driven at a high frequency of 100 MHz is used, the spatial resolution in the irradiation direction of the obtained ultrasonic image is five times that in the case where the driving frequency is 20 MHz. Therefore, in order to obtain a piezoelectric element that can acquire a higher-definition ultrasonic image, it is necessary to form a piezoelectric film having a smaller film thickness.
しかしながら、上述のようにPZTからなる焼結体を切削や研磨等の機械的加工により薄膜化することは効率的でなく、また、得られる薄膜の薄さにも限界がある。さらに、数十μm〜数百μmの薄さのPZTからなる焼結体に機械的加工を施すと割れ等が生じるおそれもある。 However, as described above, it is not efficient to thin a sintered body made of PZT by mechanical processing such as cutting or polishing, and there is a limit to the thickness of the thin film obtained. Furthermore, when a sintered body made of PZT having a thickness of several tens of μm to several hundreds of μm is subjected to mechanical processing, cracks and the like may occur.
本発明は、前記の問題に鑑みてなされたものであり、その目的は、より薄い圧電膜を簡便な方法によって形成できるようにし、得られた圧電膜を用いて高精細な超音波画像の送受が可能な高周波超音波圧電素子を得ることにある。 The present invention has been made in view of the above problems, and an object of the present invention is to enable a thinner piezoelectric film to be formed by a simple method, and to transmit / receive a high-definition ultrasonic image using the obtained piezoelectric film. The object is to obtain a high-frequency ultrasonic piezoelectric element capable of satisfying the requirements.
前記の目的を達成するために、本発明では、ゾルゲル溶液と圧電粉末との複合体をスプレー法により電極に塗布することによって圧電膜を形成して、高周波超音波圧電素子を製造した。 In order to achieve the above object, in the present invention, a piezoelectric film is formed by applying a composite of a sol-gel solution and a piezoelectric powder to an electrode by a spray method to manufacture a high-frequency ultrasonic piezoelectric element.
具体的に、本発明に係る高周波超音波圧電素子の製造方法は、下部電極を準備するステップと、下部電極の上に、ゾルゲル溶液と圧電粉末とを含む複合体をスプレー法により塗布し、塗布された複合体を焼結して圧電膜を形成するステップと、圧電膜の上に上部電極を形成するステップとを備えていることを特徴とする。 Specifically, in the method for manufacturing a high-frequency ultrasonic piezoelectric element according to the present invention, a step of preparing a lower electrode, and a composite containing a sol-gel solution and a piezoelectric powder is applied on the lower electrode by a spray method. A step of sintering the composite body to form a piezoelectric film; and a step of forming an upper electrode on the piezoelectric film.
本発明に係る高周波超音波圧電素子の製造方法によると、下部電極の上に、ゾルゲル溶液と圧電粉末とを含む複合体をスプレー法により塗布するため、スプレーからの当該複合体の吐出量や吐出時間等を適宜調節することで、所望の膜厚の圧電膜を所望の領域に簡便に形成することができ、数μmの極めて薄い圧電膜を形成することも可能となる。 According to the method for manufacturing a high-frequency ultrasonic piezoelectric element according to the present invention, a composite containing a sol-gel solution and a piezoelectric powder is applied onto the lower electrode by a spray method. By appropriately adjusting the time and the like, a piezoelectric film having a desired film thickness can be easily formed in a desired region, and an extremely thin piezoelectric film having a thickness of several μm can be formed.
本発明に係る高周波超音波圧電素子の製造方法では、上部電極を形成するステップにおいて、圧電膜の上に、アレイ状に配置され且つ圧電膜を露出する複数の開口部を有するマスクを配設し、圧電膜及びマスクを覆うように上部電極を形成した後に、マスクを除去してもよい。 In the method of manufacturing a high-frequency ultrasonic piezoelectric element according to the present invention, in the step of forming the upper electrode, a mask having a plurality of openings arranged in an array and exposing the piezoelectric film is disposed on the piezoelectric film. The mask may be removed after the upper electrode is formed so as to cover the piezoelectric film and the mask.
このようにすると、圧電膜の上に上部電極がアレイ状に形成されるため、得られた圧電素子を、複数の上部電極の直下に位置する圧電膜の各領域が互いに特定の時間差で超音波を発信するように制御されて、電子的な走査により生体内部の断面画像を取得可能な所謂フェーズドアレイ型の超音波プローブに適用することができる。 In this way, since the upper electrode is formed in an array on the piezoelectric film, the obtained piezoelectric element is ultrasonically mixed with each region of the piezoelectric film located immediately below the plurality of upper electrodes at a specific time difference. Can be applied to a so-called phased array type ultrasonic probe that can acquire a cross-sectional image inside a living body by electronic scanning.
この場合、下部電極を準備するステップにおいて、板状であり且つその表面に長さ方向に延びる凹部を有する下部電極を準備し、圧電膜を形成するステップにおいて、凹部の底面に圧電膜を形成し、上部電極を形成するステップにおいて、圧電膜の上に、凹部が延びる方向に沿って整列するように配置された複数の上部電極を形成してもよい。 In this case, in the step of preparing the lower electrode, a lower electrode having a plate-like shape and having a recess extending in the length direction on the surface thereof is prepared, and in the step of forming the piezoelectric film, the piezoelectric film is formed on the bottom surface of the recess. In the step of forming the upper electrode, a plurality of upper electrodes arranged so as to be aligned along the direction in which the recesses extend may be formed on the piezoelectric film.
このようにすると、複数の上部電極が、下部電極の凹部内に、該凹部が延びる方向(下部電極の長さ方向)に沿って整列するため、それらの上部電極の直下に位置する圧電膜の各領域から発信される超音波が、凹部が延びる方向と垂直な方向(下部電極の幅方向)に広がることを抑制して収束することができる。このため、この圧電素子を超音波プローブに適用する場合、音響レンズを設ける必要がなく、部品点数及び製造コストを低減することができる。 In this way, since the plurality of upper electrodes are aligned in the recesses of the lower electrode along the direction in which the recesses extend (the length direction of the lower electrodes), the piezoelectric film positioned immediately below these upper electrodes The ultrasonic wave transmitted from each region can be converged while suppressing spreading in the direction perpendicular to the direction in which the recess extends (the width direction of the lower electrode). For this reason, when this piezoelectric element is applied to an ultrasonic probe, it is not necessary to provide an acoustic lens, and the number of parts and the manufacturing cost can be reduced.
本発明に係る高周波超音波圧電素子の製造方法では、圧電膜を形成するステップにおいて、下部電極の上に、アレイ状に配置され且つ下部電極を露出する複数の開口部を有するマスクを配設した後に、スプレー法により下部電極の上に複合体を塗布し、複合体を焼結してアレイ状に配置された複数の圧電膜を形成してもよい。 In the method of manufacturing a high-frequency ultrasonic piezoelectric element according to the present invention, in the step of forming the piezoelectric film, a mask having a plurality of openings arranged in an array and exposing the lower electrode is disposed on the lower electrode. Later, the composite may be applied on the lower electrode by a spray method, and the composite may be sintered to form a plurality of piezoelectric films arranged in an array.
このようにすると、下部電極の上にアレイ状に配置された複数の薄い圧電膜を簡便に形成することができる。また、複数の薄い圧電膜をアレイ状に形成できるため、得られた圧電素子を、複数の圧電膜が互いに特定の時間差で超音波を発信するように制御されて電子的な走査により生体内部の断面画像を取得可能な所謂フェーズドアレイ型の超音波プローブに適用することができる。 In this way, a plurality of thin piezoelectric films arranged in an array on the lower electrode can be easily formed. In addition, since a plurality of thin piezoelectric films can be formed in an array, the obtained piezoelectric element is controlled so that the plurality of piezoelectric films emit ultrasonic waves at a specific time difference from each other, and electronic scanning is performed inside the living body. The present invention can be applied to a so-called phased array type ultrasonic probe capable of acquiring a cross-sectional image.
この場合、下部電極を準備するステップにおいて、板状であり且つその表面に長さ方向に延びる凹部を有する下部電極を準備し、圧電膜を形成するステップにおいて、下部電極の凹部の底面に、該凹部が延びる方向に沿って整列するように配置された複数の圧電膜を形成してもよい。 In this case, in the step of preparing the lower electrode, a lower electrode having a plate-like shape and having a concave portion extending in the length direction on the surface thereof is prepared, and in the step of forming the piezoelectric film, the bottom surface of the concave portion of the lower electrode is A plurality of piezoelectric films arranged so as to be aligned along the direction in which the recesses extend may be formed.
このようにすると、複数の圧電膜が、下部電極の凹部の底面に、該凹部が延びる方向(下部電極の長さ方向)に沿って整列するため、圧電膜から発信される超音波を凹部が延びる方向と垂直な方向(下部電極の幅方向)に広がることを抑制して収束することができる。このため、この圧電素子を超音波プローブに適用する場合、音響レンズを設ける必要がなく、部品点数及び製造コストを低減することができる。 In this case, since the plurality of piezoelectric films are aligned with the bottom surface of the recesses of the lower electrode along the direction in which the recesses extend (the length direction of the lower electrode), the recesses can transmit ultrasonic waves transmitted from the piezoelectric films. It is possible to converge while suppressing spreading in the direction perpendicular to the extending direction (width direction of the lower electrode). For this reason, when this piezoelectric element is applied to an ultrasonic probe, it is not necessary to provide an acoustic lens, and the number of parts and the manufacturing cost can be reduced.
本発明に係る高周波超音波圧電素子の製造方法では、下部電極を準備するステップにおいて、ロッド状であってその端面に凹部を有する下部電極を準備し、圧電膜を形成するステップにおいて、下部電極の凹部の底面に圧電膜を形成してもよい。 In the method for manufacturing a high-frequency ultrasonic piezoelectric element according to the present invention, in the step of preparing the lower electrode, in the step of preparing a lower electrode having a rod shape and having a recess on its end surface and forming the piezoelectric film, A piezoelectric film may be formed on the bottom surface of the recess.
このようにすると、圧電膜を、ロッド状の下部電極の端面における凹部の底面に形成するため、圧電膜から発信される超音波が、ロッド状の下部電極の軸方向から外側に広がることを抑制して収束することができる。このため、上記の場合と同様に、この圧電素子を超音波プローブに適用する場合、音響レンズを設ける必要がなく、部品点数及び製造コストを低減することができる。また、ロッド状の下部電極の端面に例えば単一の圧電膜を設けることで、上記フェーズドアレイ型ではなく、機械的な走査により生体内部の断面画像を取得可能な、所謂、単振動子型の超音波プローブに適用することができる。 In this way, since the piezoelectric film is formed on the bottom surface of the recess in the end face of the rod-shaped lower electrode, the ultrasonic wave transmitted from the piezoelectric film is prevented from spreading outward from the axial direction of the rod-shaped lower electrode. And can converge. For this reason, similarly to the above case, when this piezoelectric element is applied to an ultrasonic probe, it is not necessary to provide an acoustic lens, and the number of parts and the manufacturing cost can be reduced. In addition, by providing a single piezoelectric film, for example, on the end surface of the rod-shaped lower electrode, a so-called single-vibrator type that can acquire a cross-sectional image inside the living body by mechanical scanning instead of the phased array type described above. It can be applied to an ultrasonic probe.
本発明に係る高周波超音波圧電素子の製造方法において、圧電粉末としては、PZTからなる圧電粉末を用いることができる。 In the method for manufacturing a high-frequency ultrasonic piezoelectric element according to the present invention, a piezoelectric powder made of PZT can be used as the piezoelectric powder.
本発明に係る高周波超音波圧電素子は、上述の製造方法により得られ、下部電極と、下部電極の上にゾルゲル溶液と圧電粉末とを含む複合体がスプレー法により塗布された後に焼結されて形成された圧電膜と、圧電膜の上に形成された上部電極とを備えていることを特徴とする。 The high-frequency ultrasonic piezoelectric element according to the present invention is obtained by the above-described manufacturing method, and is sintered after a lower electrode and a composite containing a sol-gel solution and a piezoelectric powder are applied on the lower electrode by a spray method. A piezoelectric film formed and an upper electrode formed on the piezoelectric film are provided.
本発明に係る高周波超音波圧電素子によると、ゾルゲル溶液と圧電粉末とを含む複合体をスプレー法による塗布によって形成された圧電膜を含むため、圧電膜の膜厚を簡便に調整することができ、薄い膜厚の圧電膜を得ることも容易である。このため、薄い膜厚の圧電膜を有することで、より高い周波数の超音波の送受を可能とする高周波超音波圧電素子を容易に得ることができる。 The high-frequency ultrasonic piezoelectric element according to the present invention includes a piezoelectric film formed by applying a composite containing a sol-gel solution and piezoelectric powder by spraying, so that the thickness of the piezoelectric film can be easily adjusted. It is also easy to obtain a thin piezoelectric film. For this reason, it is possible to easily obtain a high-frequency ultrasonic piezoelectric element that enables transmission and reception of ultrasonic waves with a higher frequency by having a thin piezoelectric film.
本発明に係る高周波超音波圧電素子において、上部電極は、圧電膜の上にアレイ状に複数形成されていてもよい。 In the high frequency ultrasonic piezoelectric element according to the present invention, a plurality of upper electrodes may be formed in an array on the piezoelectric film.
このようにすると、圧電膜の上に上部電極がアレイ状に並んでいるため、得られた圧電素子を、複数の上部電極の直下に位置する圧電膜の各領域が互いに特定の時間差で超音波を発信するように制御されて電子的な走査により生体内部の断面画像を取得可能な所謂フェーズドアレイ型の超音波プローブに適用することができる。 In this way, since the upper electrodes are arranged in an array on the piezoelectric film, the obtained piezoelectric element is ultrasonically moved between each region of the piezoelectric film located immediately below the plurality of upper electrodes with a specific time difference. It can be applied to a so-called phased array type ultrasonic probe that is controlled so as to transmit a cross-sectional image and can acquire a cross-sectional image inside a living body by electronic scanning.
この場合、下部電極は、板状であり且つその表面に長さ方向に延びる凹部を有しており、圧電膜は、凹部の底面上に形成され、複数の上部電極は、圧電膜の上に、凹部が延びる方向に沿って整列するように配置されていてもよい。 In this case, the lower electrode is plate-shaped and has a concave portion extending in the length direction on the surface thereof, the piezoelectric film is formed on the bottom surface of the concave portion, and the plurality of upper electrodes are formed on the piezoelectric film. The recesses may be arranged so as to be aligned along the extending direction.
このようにすると、複数の上部電極が、下部電極の凹部内に、該凹部が延びる方向(下部電極の長さ方向)に沿って整列するため、それらの上部電極の直下に位置する圧電膜の各領域から発信される超音波が、凹部が延びる方向と垂直な方向(下部電極の幅方向)に広がることを抑制して収束することができる。このため、この圧電素子を超音波プローブに適用する場合、音響レンズを設ける必要がなく、部品点数及び製造コストを低減することができる。 In this way, since the plurality of upper electrodes are aligned in the recesses of the lower electrode along the direction in which the recesses extend (the length direction of the lower electrodes), the piezoelectric film positioned immediately below these upper electrodes The ultrasonic wave transmitted from each region can be converged while suppressing spreading in the direction perpendicular to the direction in which the recess extends (the width direction of the lower electrode). For this reason, when this piezoelectric element is applied to an ultrasonic probe, it is not necessary to provide an acoustic lens, and the number of parts and the manufacturing cost can be reduced.
本発明に係る高周波超音波圧電素子において、圧電膜は、下部電極の上にアレイ状に複数形成されていてもよい。 In the high frequency ultrasonic piezoelectric element according to the present invention, a plurality of piezoelectric films may be formed in an array on the lower electrode.
このようにすると、圧電膜がアレイ状に複数形成されているため、複数の圧電膜が互いに特定の時間差で超音波を発信するように制御されて電子的な走査により生体内部の断面画像を取得可能な所謂フェーズドアレイ型の超音波プローブに適用可能となる。 In this way, since a plurality of piezoelectric films are formed in an array, the plurality of piezoelectric films are controlled to emit ultrasonic waves at a specific time difference from each other, and a cross-sectional image inside the living body is obtained by electronic scanning. This can be applied to a so-called phased array type ultrasonic probe.
この場合、下部電極は、板状であり且つその表面に長さ方向に延びる凹部を有しており、複数の圧電膜は、下部電極の凹部の底面に、該凹部が延びる方向に沿って整列するように配置されていてもよい。 In this case, the lower electrode is plate-shaped and has a recess extending in the length direction on the surface thereof, and the plurality of piezoelectric films are aligned on the bottom surface of the recess of the lower electrode along the direction in which the recess extends. It may be arranged to do.
このようにすると、複数の圧電膜が、下部電極の凹部の底面に、該凹部が延びる方向(下部電極の長さ方向)に沿って整列するため、圧電膜から発信される超音波が、凹部が延びる方向と垂直な方向(下部電極の幅方向)に広がることを抑制して収束することができる。このため、この圧電素子を超音波プローブに適用する場合、音響レンズを設ける必要がなく、部品点数及び製造コストを低減することができる。 In this case, since the plurality of piezoelectric films are aligned with the bottom surface of the recess of the lower electrode along the direction in which the recess extends (the length direction of the lower electrode), the ultrasonic wave transmitted from the piezoelectric film is It is possible to converge while suppressing spreading in the direction perpendicular to the extending direction (width direction of the lower electrode). For this reason, when this piezoelectric element is applied to an ultrasonic probe, it is not necessary to provide an acoustic lens, and the number of parts and the manufacturing cost can be reduced.
本発明に係る高周波超音波圧電素子において、下部電極は、ロッド状であり且つその端面に凹部を有し、圧電膜は、凹部の底面に形成されていてもよい。 In the high-frequency ultrasonic piezoelectric element according to the present invention, the lower electrode may be rod-shaped and have a concave portion on its end surface, and the piezoelectric film may be formed on the bottom surface of the concave portion.
このようにすると、圧電膜が、ロッド状の下部電極の端面における凹部の底面に形成されているため、圧電膜から発信される超音波が、ロッド状の下部電極の軸方向から外側に広がることを抑制して収束することができる。このため、上記の場合と同様に、この圧電素子を超音波プローブに適用する場合、音響レンズを設ける必要がなく、部品点数及び製造コストを低減することができる。また、ロッド状の下部電極の端面に例えば単一の圧電膜を設けることで、上記フェーズドアレイ型ではなく、機械的な走査により生体内部の断面画像を取得可能な、所謂、単振動子型の超音波プローブに適用することができる。 In this case, since the piezoelectric film is formed on the bottom surface of the recess in the end surface of the rod-shaped lower electrode, the ultrasonic wave transmitted from the piezoelectric film spreads outward from the axial direction of the rod-shaped lower electrode. Can be suppressed and converged. For this reason, similarly to the above case, when this piezoelectric element is applied to an ultrasonic probe, it is not necessary to provide an acoustic lens, and the number of parts and the manufacturing cost can be reduced. In addition, by providing a single piezoelectric film, for example, on the end surface of the rod-shaped lower electrode, a so-called single-vibrator type that can acquire a cross-sectional image inside the living body by mechanical scanning instead of the phased array type described above. It can be applied to an ultrasonic probe.
本発明に係る高周波超音波圧電素子において、圧電粉末は、PZTからなる圧電粉末とすることができる。 In the high-frequency ultrasonic piezoelectric element according to the present invention, the piezoelectric powder may be a piezoelectric powder made of PZT.
本発明に係る高周波超音波プローブは、上記の高周波超音波圧電素子を含むことを特徴とする。 A high-frequency ultrasonic probe according to the present invention includes the above-described high-frequency ultrasonic piezoelectric element.
本発明に係る高周波超音波プローブによると、上記の作用・効果を有する高周波超音波圧電素子を含むため、より薄い圧電膜を有して高い周波数の超音波を送受可能とすることを容易にでき、その結果、より高精細な画像を取得することができる。 The high-frequency ultrasonic probe according to the present invention includes a high-frequency ultrasonic piezoelectric element having the above-described actions and effects, and thus can easily transmit and receive high-frequency ultrasonic waves with a thinner piezoelectric film. As a result, a higher-definition image can be acquired.
本発明に係る高周波超音波圧電素子、その製造方法、及びそれを含む高周波超音波プローブによると、下部電極の上に、ゾルゲル溶液と圧電粉末とを含む複合体をスプレー法により塗布するため、極めて薄い圧電膜が簡便に得られ、その結果、より高い周波数の超音波を送受可能であり、より高精細な画像を取得することができる高周波超音波プローブを得ることができる。 According to the high-frequency ultrasonic piezoelectric element, the manufacturing method thereof, and the high-frequency ultrasonic probe including the same according to the present invention, the composite containing the sol-gel solution and the piezoelectric powder is applied on the lower electrode by the spray method. A thin piezoelectric film can be easily obtained. As a result, a high-frequency ultrasonic probe that can transmit and receive higher-frequency ultrasonic waves and can acquire a higher-definition image can be obtained.
以下、本発明を実施するための形態を図面に基づいて説明する。以下の好ましい実施形態の説明は、本質的に例示に過ぎず、本発明、その適用方法或いはその用途を制限することを意図するものではない。 Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. The following description of the preferred embodiments is merely exemplary in nature and is not intended to limit the invention, its method of application, or its application.
(第1の実施形態)
以下、本発明の第1の実施形態に係る高周波超音波圧電素子10の製造方法及びその構成について図1(a)〜(f)及び図2を参照しながら説明する。
(First embodiment)
Hereinafter, a method for manufacturing the high-frequency ultrasonic piezoelectric element 10 according to the first embodiment of the present invention and the configuration thereof will be described with reference to FIGS.
まず、図1(a)に示すように、板状の平坦な下部電極11を準備する。下部電極11の材料としては、導電性であり、通常、電極として用いられる金属からなるものであれば特に限定されない。また、下部電極11の厚さも、特に限定はされず、圧電素子の小型化及び強度の観点から適宜選択すればよく、例えば10μm〜150μmである。 First, as shown in FIG. 1A, a plate-like flat lower electrode 11 is prepared. The material of the lower electrode 11 is not particularly limited as long as it is conductive and is usually made of a metal used as an electrode. Further, the thickness of the lower electrode 11 is not particularly limited, and may be appropriately selected from the viewpoint of miniaturization and strength of the piezoelectric element, and is, for example, 10 μm to 150 μm.
次に、図1(b)に示すように、下部電極11の上に圧電膜12を形成する。圧電膜12は、ゾルゲル溶液と圧電粉末とを含む複合体を、スプレー装置を用いて塗布するスプレー法によって下部電極11の上に塗布し、塗布された複合体を焼結することにより得られる。例えば、ゾルゲル溶液は、金属アルコキシドをエタノールやメタノール等の溶剤に溶解することで得られ、特に鉛アルコキシド、ジルコニウムアルコキシド及びチタンアルコキシドを含むPZTゾルゲル溶液を用いることが好ましい。また、圧電粉末の材料としてはPZTを用いることができる。ゾルゲル溶液と圧電粉末との組成比(重量比)は、例えばゾルゲル溶液:圧電粉末=1:1〜2:1とすることができる。また、圧電粉末の粒径としては50〜1000nmとすることが好ましい。スプレー法による複合体の吐出量、吐出時間、及びスプレーから下部電極までの距離等は、形成する圧電膜の膜厚等に従って適宜変更することができる。より高い周波数の超音波を送受できる圧電素子を得るためには、圧電膜を薄膜化することが好ましく、スプレー法を用いると上記複合体の吐出量あるいは吐出時間等を制御することにより、容易に薄膜化することができ、例えば、吐出時間200msの条件では、約10μmの膜厚の複合体層を形成することができる。このスプレー法による塗布後、複合体層を約150℃で5分乾燥し、約450℃で5分仮焼結し、約650℃で5分焼成し、その後、例えばコロナ放電によって分極処理を行うことにより圧電膜12が得られる。 Next, as illustrated in FIG. 1B, a piezoelectric film 12 is formed on the lower electrode 11. The piezoelectric film 12 is obtained by applying a composite containing a sol-gel solution and a piezoelectric powder on the lower electrode 11 by a spraying method using a spray device, and sintering the applied composite. For example, the sol-gel solution is obtained by dissolving a metal alkoxide in a solvent such as ethanol or methanol, and it is particularly preferable to use a PZT sol-gel solution containing lead alkoxide, zirconium alkoxide, and titanium alkoxide. Further, PZT can be used as the material of the piezoelectric powder. The composition ratio (weight ratio) between the sol-gel solution and the piezoelectric powder can be, for example, sol-gel solution: piezoelectric powder = 1: 1 to 2: 1. The particle size of the piezoelectric powder is preferably 50 to 1000 nm. The discharge amount of the composite by the spray method, the discharge time, the distance from the spray to the lower electrode, and the like can be appropriately changed according to the film thickness of the piezoelectric film to be formed. In order to obtain a piezoelectric element capable of transmitting and receiving ultrasonic waves of higher frequency, it is preferable to reduce the thickness of the piezoelectric film. By using the spray method, it is easy to control the discharge amount or discharge time of the composite. For example, a composite layer having a thickness of about 10 μm can be formed under a discharge time condition of 200 ms. After application by this spray method, the composite layer is dried at about 150 ° C. for 5 minutes, pre-sintered at about 450 ° C. for 5 minutes, and fired at about 650 ° C. for 5 minutes, and then subjected to polarization treatment, for example, by corona discharge Thus, the piezoelectric film 12 is obtained.
次に、図1(c)に示すように、圧電膜12の上にマスク層13を配設する。マスク層13の材料としては、例えば樹脂、ガラス、木材又は紙等の材料を用いることができるが、これらに限定されない。 Next, as shown in FIG. 1C, a mask layer 13 is disposed on the piezoelectric film 12. As a material of the mask layer 13, for example, a material such as resin, glass, wood, or paper can be used, but is not limited thereto.
次に、図1(d)に示すように、マスク層13に圧電膜12を露出する複数の開口部14を形成する。開口部14は、後に上部電極15を形成する所望の位置に設け、本実施形態では、下部電極の長さ方向に沿って等間隔に配置される。開口部14の形成は、マスク層13の材料に従って、エッチング法等の化学的処理を用いてもよいし、切削等の機械的処理を用いてもよい。なお、本実施形態では、マスク層13を圧電膜12の上に設けた後に、開口部14を形成したが、圧電膜12の上に設ける前に、マスク層13に予め開口部14を形成し、開口部14が形成されたマスク層13を圧電膜12の上に配置してもよい。 Next, as shown in FIG. 1D, a plurality of openings 14 that expose the piezoelectric film 12 are formed in the mask layer 13. The openings 14 are provided at desired positions where the upper electrode 15 will be formed later. In the present embodiment, the openings 14 are arranged at equal intervals along the length direction of the lower electrode. The opening 14 may be formed by chemical treatment such as an etching method or mechanical treatment such as cutting according to the material of the mask layer 13. In this embodiment, the opening 14 is formed after the mask layer 13 is provided on the piezoelectric film 12. However, the opening 14 is previously formed in the mask layer 13 before being provided on the piezoelectric film 12. The mask layer 13 in which the opening 14 is formed may be disposed on the piezoelectric film 12.
次に、図1(e)に示すように、圧電膜12及びマスク層13の上に上部電極15を形成する。上部電極15の材料としては、導電性材料であり、通常、電極に用いられ得るものであれば特に限定されず、例えば金や銀等の金属が用いられる。また、上部電極15の形成には、蒸着法やスパッタ法等の常法が用いられ得る。上部電極15の厚さも、特に限定はされず、圧電素子の小型化及び強度の観点から適宜選択すればよく、例えば10μm〜150μmである。 Next, as shown in FIG. 1E, the upper electrode 15 is formed on the piezoelectric film 12 and the mask layer 13. The material of the upper electrode 15 is a conductive material and is not particularly limited as long as it can be used for an electrode. For example, a metal such as gold or silver is used. Further, the upper electrode 15 can be formed by a conventional method such as vapor deposition or sputtering. The thickness of the upper electrode 15 is not particularly limited, and may be appropriately selected from the viewpoint of miniaturization and strength of the piezoelectric element, and is, for example, 10 μm to 150 μm.
次に、図1(f)に示すように、マスク層13を除去することにより、開口部14内の圧電膜12の上にのみ上部電極15が残存する。図示はしないが、その後、電源と接続したリード線を下部電極11及び複数の上部電極15のそれぞれに接続することにより、本実施形態に係る高周波超音波圧電素子10を得ることができる。 Next, as shown in FIG. 1F, the upper electrode 15 remains only on the piezoelectric film 12 in the opening 14 by removing the mask layer 13. Although not shown, the high-frequency ultrasonic piezoelectric element 10 according to this embodiment can be obtained by connecting the lead wire connected to the power source to each of the lower electrode 11 and the plurality of upper electrodes 15 thereafter.
図1では、便宜上、マスク層13に開口部14を3つ形成し、上部電極15を3つ形成するように示したが、当然にこれに限られず、図2に示すように上部電極15が5つ形成されてもよいし、それ以上の所望の数の上部電極15を形成することができる。本実施形態では、複数の上部電極15が圧電膜12の上にアレイ状に形成され、具体的に、図1(f)及び図2に示すように、上部電極15は、下部電極11の長さ方向に沿って整列するように配置される。そのように上部電極15が配置された形態の高周波超音波圧電素子10を、生体内部の断面を画像化するための超音波プローブに適用することで、複数の上部電極の直下に位置する圧電膜のそれぞれの領域が互いに特定の時間差で超音波を発信するように、上部電極に電圧が印加されるタイミングを制御することによる電子的な走査によって生体内部の断面画像を取得可能な、所謂フェーズドアレイ型の超音波プローブを得ることができる。本実施形態に係る高周波超音波圧電素子を含む高周波超音波プローブは、従来の超音波プローブと同様にプローブ本体において、基端側から先端側に向かってバッキング材、本実施形態に係る圧電素子、音響整合層及び音響レンズの順に配設して構成される。但し、本実施形態に係る高周波超音波プローブにおいて、バッキング材及び音響整合層を必須の構成としない。 In FIG. 1, for convenience, three openings 14 are formed in the mask layer 13 and three upper electrodes 15 are formed. However, the present invention is not limited to this, and the upper electrode 15 is formed as shown in FIG. Five or more desired numbers of upper electrodes 15 may be formed. In the present embodiment, a plurality of upper electrodes 15 are formed in an array on the piezoelectric film 12. Specifically, as shown in FIGS. 1 (f) and 2, the upper electrode 15 is the length of the lower electrode 11. It arrange | positions so that it may align along a horizontal direction. By applying the high-frequency ultrasonic piezoelectric element 10 having the upper electrode 15 arranged in such a manner to an ultrasonic probe for imaging a cross section inside the living body, the piezoelectric film positioned immediately below the plurality of upper electrodes A so-called phased array that can acquire a cross-sectional image of the inside of a living body by electronic scanning by controlling the timing at which a voltage is applied to the upper electrode so that each of the regions transmits ultrasonic waves at a specific time difference. A type of ultrasonic probe can be obtained. The high-frequency ultrasonic probe including the high-frequency ultrasonic piezoelectric element according to the present embodiment includes a backing material from the proximal end side toward the distal end side in the probe main body as in the conventional ultrasonic probe, the piezoelectric element according to the present embodiment, An acoustic matching layer and an acoustic lens are arranged in this order. However, in the high-frequency ultrasonic probe according to the present embodiment, the backing material and the acoustic matching layer are not essential components.
なお、本実施形態では、上述のとおり、下部電極の上を覆うように形成された圧電膜の上に開口部を有するマスクを用いて複数の上部電極を形成したが、下部電極の上にアレイ状に形成された開口部を有するマスクを用いて、アレイ状に配置する複数の圧電膜を形成し、それら複数の圧電膜の上にそれぞれ上部電極を形成してもよい。このようにすると、圧電膜材料のスプレー塗布時点で複数の圧電膜が互いに分離することとなるため、圧電素子内におけるクロストークを防止するために、圧電膜をダイシングするといった切断処理をする必要がない。特に、薄い圧電膜を切断することは割れ等が生じやすく困難であるため、この点で有利である。 In the present embodiment, as described above, a plurality of upper electrodes are formed using a mask having an opening on a piezoelectric film formed so as to cover the lower electrode, but an array is formed on the lower electrode. A plurality of piezoelectric films arranged in an array may be formed using a mask having openings formed in a shape, and an upper electrode may be formed on each of the plurality of piezoelectric films. In this case, since the plurality of piezoelectric films are separated from each other at the time of spray application of the piezoelectric film material, it is necessary to perform a cutting process such as dicing the piezoelectric film in order to prevent crosstalk in the piezoelectric element. Absent. In particular, cutting a thin piezoelectric film is advantageous in this respect because it is difficult to cause cracks and the like.
本実施形態では、板状の平坦な下部電極11を用いて高周波超音波圧電素子10を作製したが、板状であり且つその表面に長さ方向に延びる凹部を有する下部電極を用いて、その凹部内に圧電膜及び上部電極を形成して高周波超音波圧電素子を形成してもよい。そのような形態の高周波超音波圧電素子を第1の実施形態の一変形例として図3を参照しながら説明する。なお、本実施形態では、第1の実施形態と同一の点については説明を省略し、異なる点についてのみ詳細に説明する。また、図3は、下部電極に凹部を有することを除いて図2に示す高周波超音波圧電素子と同等の超音波圧電素子を示すものであり、特に、その一上部電極上における上部電極の長さ方向に沿った断面を示すものである。すなわち、本変形例に係る高周波超音波圧電素子においては、図3の紙面に垂直な方向に沿って上部電極が複数配列されている。 In the present embodiment, the high-frequency ultrasonic piezoelectric element 10 is manufactured using the plate-like flat lower electrode 11, but the plate-like lower electrode having a concave portion extending in the length direction on the surface thereof is used. A high-frequency ultrasonic piezoelectric element may be formed by forming a piezoelectric film and an upper electrode in the recess. Such a high-frequency ultrasonic piezoelectric element will be described as a modification of the first embodiment with reference to FIG. In the present embodiment, description of the same points as those in the first embodiment will be omitted, and only different points will be described in detail. FIG. 3 shows an ultrasonic piezoelectric element equivalent to the high-frequency ultrasonic piezoelectric element shown in FIG. 2 except that the lower electrode has a recess. In particular, the length of the upper electrode on one upper electrode is shown. A cross section along the vertical direction is shown. That is, in the high-frequency ultrasonic piezoelectric element according to this modification, a plurality of upper electrodes are arranged along a direction perpendicular to the paper surface of FIG.
図3に示すように、本変形例に係る高周波超音波圧電素子20は、表面に凹部26が形成された下部電極21を備えている。凹部26は、下部電極21の長さ方向に沿って延びるように形成されている。また、凹部26の開口の周縁部(下部電極21の表面と凹部26との境界部)は丸みを帯びている。下部電極21の凹部26の底面上には、圧電膜22が形成されている。圧電膜22は凹部26の底面形状に沿って形成されている。圧電膜22の上には上部電極25が形成されている。上部電極25は、上述の第1の実施形態と同様に、下部電極21の長さ方向に沿って、すなわち凹部が延びる方向に沿って複数配設されている。なお、本変形例に係る高周波超音波圧電素子20は、凹部26を有する下部電極21を用いることを除いて、圧電膜22及び上部電極25の形成等は上述の第1の実施形態に係る高周波超音波圧電素子10と同様の方法を用いて行うことができる。 As shown in FIG. 3, the high-frequency ultrasonic piezoelectric element 20 according to this modification includes a lower electrode 21 having a recess 26 formed on the surface. The recess 26 is formed so as to extend along the length direction of the lower electrode 21. In addition, the peripheral edge of the opening of the recess 26 (the boundary between the surface of the lower electrode 21 and the recess 26) is rounded. A piezoelectric film 22 is formed on the bottom surface of the recess 26 of the lower electrode 21. The piezoelectric film 22 is formed along the bottom shape of the recess 26. An upper electrode 25 is formed on the piezoelectric film 22. Similar to the first embodiment, a plurality of upper electrodes 25 are arranged along the length direction of the lower electrode 21, that is, along the direction in which the recesses extend. Note that the high-frequency ultrasonic piezoelectric element 20 according to this modified example uses the high-frequency ultrasonic piezoelectric element 20 according to the above-described first embodiment except that the lower electrode 21 having the concave portions 26 is used. A method similar to that for the ultrasonic piezoelectric element 10 can be used.
なお、本変形例においても、下部電極の上に凹部が延びる方向に沿って整列する複数の圧電膜が形成され、それらの複数の圧電膜の上にそれぞれ上部電極が形成された形態としてもよい。そうすることにより、上述のとおり、圧電膜材料のスプレー塗布時点で複数の圧電膜が互いに分離することとなるため、圧電素子内におけるクロストークを防止するために、圧電膜を切断する等の処理をする必要がなくなる。 In this modification as well, a plurality of piezoelectric films aligned along the direction in which the concave portion extends are formed on the lower electrode, and the upper electrode may be formed on each of the plurality of piezoelectric films. . By doing so, as described above, a plurality of piezoelectric films are separated from each other at the time of spray application of the piezoelectric film material. Therefore, in order to prevent crosstalk in the piezoelectric element, a process such as cutting the piezoelectric film is performed. There is no need to do.
本変形例に係る高周波超音波圧電素子20では、下部電極21の表面に、圧電膜22の配列方向と並行して延びる凹部26が形成されているため、凹部26内に配設された圧電膜22から発信される超音波が、凹部26が延びる方向と垂直な方向(下部電極21の幅方向)に広がることを抑制して収束することができる。その結果、この高周波超音波圧電素子20を超音波プローブに適用する場合、音響レンズを設ける必要がない。 In the high-frequency ultrasonic piezoelectric element 20 according to this modification, since the concave portion 26 extending in parallel with the arrangement direction of the piezoelectric films 22 is formed on the surface of the lower electrode 21, the piezoelectric film disposed in the concave portion 26. The ultrasonic wave transmitted from 22 can be converged while suppressing spreading in the direction perpendicular to the direction in which the recess 26 extends (the width direction of the lower electrode 21). As a result, when this high-frequency ultrasonic piezoelectric element 20 is applied to an ultrasonic probe, it is not necessary to provide an acoustic lens.
(第2の実施形態)
次に、本発明の第2の実施形態に係る高周波超音波圧電素子30について図4を参照しながら説明する。なお、本実施形態では、上記第1の実施形態及びその一変形例と同一の点については説明を省略し、異なる点についてのみ詳細に説明する。本実施形態に係る高周波超音波圧電素子30は、第1の実施形態に係る高周波超音波圧電素子10と比較して、特に下部電極としてロッド状の下部電極31を用いること、及び単一の圧電膜32及び上部電極35を形成することが異なる。
(Second Embodiment)
Next, a high-frequency ultrasonic piezoelectric element 30 according to a second embodiment of the present invention will be described with reference to FIG. In the present embodiment, the description of the same points as those of the first embodiment and the modification thereof will be omitted, and only different points will be described in detail. Compared with the high-frequency ultrasonic piezoelectric element 10 according to the first embodiment, the high-frequency ultrasonic piezoelectric element 30 according to the present embodiment uses a rod-shaped lower electrode 31 as a lower electrode, and a single piezoelectric element. The formation of the film 32 and the upper electrode 35 is different.
図4(a)及び(b)に示すように、本実施形態に係る高周波超音波圧電素子30において、下部電極31は、上述のとおりロッド状であり、特に円柱形状である。また、この下部電極31の一端面には、円形状の開口を有する球欠形状の凹部36が形成されている。凹部36の開口の周縁部(下部電極31の表面と凹部36との境界部)は丸みを帯びている。例えば、下部電極31の横断面の径は10mmであり、凹部36の開口径は6mmであり、凹部36の深さは2mmである。当然に、これらのサイズは一例であり、これらに限定されることはなく、適宜、これらのサイズを選択することができる。 As shown in FIGS. 4A and 4B, in the high-frequency ultrasonic piezoelectric element 30 according to the present embodiment, the lower electrode 31 has a rod shape as described above, and particularly has a cylindrical shape. Further, a spherical recess 36 having a circular opening is formed on one end surface of the lower electrode 31. The peripheral edge of the opening of the recess 36 (the boundary between the surface of the lower electrode 31 and the recess 36) is rounded. For example, the diameter of the cross section of the lower electrode 31 is 10 mm, the opening diameter of the recess 36 is 6 mm, and the depth of the recess 36 is 2 mm. Of course, these sizes are merely examples, and the present invention is not limited to these sizes, and these sizes can be selected as appropriate.
下部電極31の凹部36の底面上には、圧電膜32が形成されている。圧電膜32は凹部36の底面形状に沿って形成されている。本実施形態では、第1の実施形態と同様に、圧電膜32をスプレー法による複合体の塗布及び焼結により形成することができる。圧電膜32の上には上部電極35が形成されている。上部電極35も凹部36の底面形状に沿って形成されている。本実施形態に係る高周波超音波圧電素子30において、上部電極35の形成前に、特に複数の開口部を有するマスク層を形成する必要はなく、圧電膜32の上に蒸着法等の方法を用いて単一の膜からなる上部電極35が形成される。なお、図示はしないが、第1の実施形態と同様に、下部電極31及び上部電極35には、それぞれ電源に接続されたリード線が接続されている。 A piezoelectric film 32 is formed on the bottom surface of the recess 36 of the lower electrode 31. The piezoelectric film 32 is formed along the bottom shape of the recess 36. In the present embodiment, as in the first embodiment, the piezoelectric film 32 can be formed by applying and sintering a composite by a spray method. An upper electrode 35 is formed on the piezoelectric film 32. The upper electrode 35 is also formed along the bottom shape of the recess 36. In the high-frequency ultrasonic piezoelectric element 30 according to the present embodiment, it is not necessary to form a mask layer having a plurality of openings before the upper electrode 35 is formed, and a method such as vapor deposition is used on the piezoelectric film 32. Thus, the upper electrode 35 made of a single film is formed. Although not shown, as in the first embodiment, the lower electrode 31 and the upper electrode 35 are connected to lead wires connected to a power source, respectively.
本実施形態に係る高周波超音波圧電素子30では、ロッド状の下部電極31の端面に圧電膜32及び上部電極35が形成されているため、これを機械的な走査で用いられる単振動子型の超音波プローブに適用することができる。なお、本実施形態に係る高周波超音波圧電素子30を含む高周波超音波プローブは、上記第1の実施形態と同様の構成とすることができる。また、本実施形態に係る高周波超音波圧電素子30では、ロッド状の下部電極31の端面に形成された凹部36内に圧電膜32及び上部電極35が形成されているため、圧電膜32から発信される超音波が下部電極31の軸方向から外側に広がらずに収束される。その結果、この高周波超音波圧電素子30を超音波プローブに適用する場合、音響レンズを設ける必要がない。 In the high-frequency ultrasonic piezoelectric element 30 according to the present embodiment, the piezoelectric film 32 and the upper electrode 35 are formed on the end face of the rod-shaped lower electrode 31, so that this is a single vibrator type used for mechanical scanning. It can be applied to an ultrasonic probe. The high-frequency ultrasonic probe including the high-frequency ultrasonic piezoelectric element 30 according to this embodiment can have the same configuration as that of the first embodiment. Further, in the high-frequency ultrasonic piezoelectric element 30 according to the present embodiment, the piezoelectric film 32 and the upper electrode 35 are formed in the recess 36 formed on the end surface of the rod-shaped lower electrode 31, so that the transmission from the piezoelectric film 32 is performed. The ultrasonic waves to be converged without spreading outward from the axial direction of the lower electrode 31. As a result, when this high-frequency ultrasonic piezoelectric element 30 is applied to an ultrasonic probe, there is no need to provide an acoustic lens.
以上のとおり、本発明に係る高周波超音波圧電素子、その製造方法、及びそれを含む高周波超音波プローブによると、下部電極の上に、ゾルゲル溶液と圧電粉末とを含む複合体をスプレー法により塗布するため、極めて薄い圧電膜が簡便に得られ、その結果、より高い周波数の超音波を送受可能であり、より高精細な画像を取得することができる高周波超音波プローブを得ることができる。 As described above, according to the high-frequency ultrasonic piezoelectric element, the manufacturing method thereof, and the high-frequency ultrasonic probe including the same according to the present invention, the composite containing the sol-gel solution and the piezoelectric powder is applied on the lower electrode by the spray method. Therefore, an extremely thin piezoelectric film can be easily obtained, and as a result, a high-frequency ultrasonic probe that can transmit and receive higher-frequency ultrasonic waves and can acquire higher-definition images can be obtained.
10、20、30 高周波超音波圧電素子
11、21、31 下部電極
12、22、32 圧電膜
13 マスク層
14 開口部
15、25、35 上部電極
26、36 凹部
10, 20, 30 High-frequency ultrasonic piezoelectric elements 11, 21, 31 Lower electrodes 12, 22, 32 Piezoelectric film 13 Mask layer 14 Openings 15, 25, 35 Upper electrodes 26, 36 Recess
Claims (3)
前記下部電極の前記凹部の底面に、ゾルゲル溶液と圧電粉末とを含む複合体をスプレー法により塗布し、前記塗布された複合体を焼結して圧電膜を形成するステップと、
前記圧電膜の上に、前記凹部が延びる方向に沿って整列するように配置された複数の上部電極を形成するステップとを備え、
前記凹部の表面は曲面状であることを特徴とする高周波超音波圧電素子の製造方法。 Preparing a lower electrode that is plate-shaped and has one recess extending in the lengthwise direction on the surface thereof ;
Applying a composite containing a sol-gel solution and piezoelectric powder to the bottom surface of the recess of the lower electrode by a spray method, and sintering the applied composite to form a piezoelectric film;
Forming a plurality of upper electrodes arranged on the piezoelectric film so as to be aligned along a direction in which the recess extends .
The method of manufacturing a high-frequency ultrasonic piezoelectric element, wherein the surface of the recess is curved .
前記下部電極の前記凹部の底面に、ゾルゲル溶液と圧電粉末とを含む複合体をスプレー法により塗布し、前記塗布された複合体を焼結して圧電膜を形成するステップと、Applying a composite containing a sol-gel solution and piezoelectric powder to the bottom surface of the recess of the lower electrode by a spray method, and sintering the applied composite to form a piezoelectric film;
前記圧電膜の上に上部電極を形成するステップとを備え、Forming an upper electrode on the piezoelectric film,
前記圧電膜を形成するステップにおいて、前記下部電極の前記凹部の底面に、該凹部が延びる方向に沿って整列するように配置された複数の圧電膜を形成し、In the step of forming the piezoelectric film, a plurality of piezoelectric films arranged so as to be aligned along a direction in which the concave portion extends are formed on the bottom surface of the concave portion of the lower electrode,
前記凹部の表面は曲面状であることを特徴とする高周波超音波圧電素子の製造方法。The method of manufacturing a high-frequency ultrasonic piezoelectric element, wherein the surface of the recess is curved.
前記下部電極の前記凹部の底面に、ゾルゲル溶液と圧電粉末とを含む複合体をスプレー法により塗布し、前記塗布された複合体を焼結して圧電膜を形成するステップと、Applying a composite containing a sol-gel solution and piezoelectric powder to the bottom surface of the recess of the lower electrode by a spray method, and sintering the applied composite to form a piezoelectric film;
前記圧電膜の上に上部電極を形成するステップとを備え、Forming an upper electrode on the piezoelectric film,
前記圧電膜は前記凹部の内側にのみ形成されていることを特徴とする高周波超音波圧電素子の製造方法。The method of manufacturing a high-frequency ultrasonic piezoelectric element, wherein the piezoelectric film is formed only inside the recess.
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US7449821B2 (en) * | 2005-03-02 | 2008-11-11 | Research Triangle Institute | Piezoelectric micromachined ultrasonic transducer with air-backed cavities |
JP2012011024A (en) * | 2010-07-01 | 2012-01-19 | Konica Minolta Medical & Graphic Inc | Ultrasonic probe and ultrasonic diagnostic apparatus |
JP5540361B2 (en) * | 2011-06-07 | 2014-07-02 | 日立Geニュークリア・エナジー株式会社 | Ultrasonic sensor and manufacturing method thereof |
JP2013168573A (en) * | 2012-02-16 | 2013-08-29 | Mitsubishi Heavy Ind Ltd | Process of manufacturing supersonic thickness sensor |
JP2013207155A (en) * | 2012-03-29 | 2013-10-07 | Mitsubishi Materials Corp | Ferroelectric thin film manufacturing method |
JP6132337B2 (en) * | 2013-04-24 | 2017-05-24 | 国立大学法人電気通信大学 | Ultrasonic diagnostic apparatus and ultrasonic image construction method |
-
2015
- 2015-06-24 JP JP2015126268A patent/JP6122066B2/en active Active
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2016
- 2016-06-10 WO PCT/JP2016/067395 patent/WO2016208425A1/en active Application Filing
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TWI693731B (en) | 2020-05-11 |
JP2017011144A (en) | 2017-01-12 |
WO2016208425A1 (en) | 2016-12-29 |
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