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 PDF

Info

Publication number
JP6122066B2
JP6122066B2 JP2015126268A JP2015126268A JP6122066B2 JP 6122066 B2 JP6122066 B2 JP 6122066B2 JP 2015126268 A JP2015126268 A JP 2015126268A JP 2015126268 A JP2015126268 A JP 2015126268A JP 6122066 B2 JP6122066 B2 JP 6122066B2
Authority
JP
Japan
Prior art keywords
piezoelectric
lower electrode
piezoelectric film
piezoelectric element
frequency ultrasonic
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
JP2015126268A
Other languages
Japanese (ja)
Other versions
JP2017011144A5 (en
JP2017011144A (en
Inventor
牧子 小林
牧子 小林
将之 田邉
将之 田邉
椎名　毅
毅 椎名
剣生 隅田
剣生 隅田
範夫 河口
範夫 河口
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ACADEMIC INDUSTRY RESEARCH INC.
Kyoto University
Kumamoto University NUC
Original Assignee
ACADEMIC INDUSTRY RESEARCH INC.
Kyoto University
Kumamoto University NUC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by ACADEMIC INDUSTRY RESEARCH INC., Kyoto University, Kumamoto University NUC filed Critical ACADEMIC INDUSTRY RESEARCH INC.
Priority to JP2015126268A priority Critical patent/JP6122066B2/en
Priority to PCT/JP2016/067395 priority patent/WO2016208425A1/en
Priority to TW105119414A priority patent/TWI693731B/en
Publication of JP2017011144A publication Critical patent/JP2017011144A/en
Publication of JP2017011144A5 publication Critical patent/JP2017011144A5/ja
Application granted granted Critical
Publication of JP6122066B2 publication Critical patent/JP6122066B2/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • 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
    • 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
    • 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
    • H10N30/06—Forming electrodes or interconnections, e.g. leads or terminals
    • 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
    • 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
    • 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
    • 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
    • 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

Landscapes

  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Chemical & Material Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Dispersion Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Ultra Sonic Daignosis Equipment (AREA)
  • Transducers For Ultrasonic Waves (AREA)
  • Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)

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.

特開平７−４５１２４号公報JP-A-7-45124

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.

（ａ）〜（ｆ）は、本発明の第１の実施形態に係る高周波超音波圧電素子の製造工程を順次示す断面図である。(A)-(f) is sectional drawing which shows the manufacturing process of the high frequency ultrasonic piezoelectric element concerning the 1st Embodiment of this invention sequentially. 本発明の第１の実施形態に係る高周波超音波圧電素子を示す平面図である。It is a top view which shows the high frequency ultrasonic piezoelectric element which concerns on the 1st Embodiment of this invention. 本発明の第１の実施形態の一変形例に係る高周波超音波圧電素子を示す断面図である。It is sectional drawing which shows the high frequency ultrasonic piezoelectric element which concerns on the modification of the 1st Embodiment of this invention. （ａ）は本発明の第２の実施形態に係る高周波超音波圧電素子を示す断面図であり、（ｂ）は本発明の第２の実施形態に係る高周波超音波圧電素子を示す平面図である。(A) is sectional drawing which shows the high frequency ultrasonic piezoelectric element which concerns on the 2nd Embodiment of this invention, (b) is a top view which shows the high frequency ultrasonic piezoelectric element which concerns on the 2nd Embodiment of this invention. is there.

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)

板状であり且つその表面に長さ方向に延びる１つの凹部を有する下部電極を準備するステップと、
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 . 板状であり且つその表面に長さ方向に延びる１つの凹部を有する下部電極を準備するステップと、Preparing a lower electrode that is plate-shaped and has one recess extending in the lengthwise direction on the surface thereof;
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. ロッド状であってその端面に１つの凹部を有する下部電極を準備するステップと、Preparing a lower electrode that is rod-shaped and has one recess on its end face;
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.
JP2015126268A 2015-06-24 2015-06-24 High frequency ultrasonic piezoelectric element, method for manufacturing the same, and high frequency ultrasonic probe including the same Active JP6122066B2 (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
JP2015126268A JP6122066B2 (en) 2015-06-24 2015-06-24 High frequency ultrasonic piezoelectric element, method for manufacturing the same, and high frequency ultrasonic probe including the same
PCT/JP2016/067395 WO2016208425A1 (en) 2015-06-24 2016-06-10 High-frequency ultrasonic piezoelectric element, method for manufacturing same, and high-frequency ultrasonic probe including same
TW105119414A TWI693731B (en) 2015-06-24 2016-06-21 High-frequency ultrasound piezoelectric element, manufacturing method thereof and the high-frequency ultrasound probe comprising the high-frequency ultrasound piezoelectric element

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2015126268A JP6122066B2 (en) 2015-06-24 2015-06-24 High frequency ultrasonic piezoelectric element, method for manufacturing the same, and high frequency ultrasonic probe including the same

Publications (3)

Publication Number Publication Date
JP2017011144A JP2017011144A (en) 2017-01-12
JP2017011144A5 JP2017011144A5 (en) 2017-02-16
JP6122066B2 true JP6122066B2 (en) 2017-04-26

Family

ID=57584920

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2015126268A Active JP6122066B2 (en) 2015-06-24 2015-06-24 High frequency ultrasonic piezoelectric element, method for manufacturing the same, and high frequency ultrasonic probe including the same

Country Status (3)

Country Link
JP (1) JP6122066B2 (en)
TW (1) TWI693731B (en)
WO (1) WO2016208425A1 (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101965171B1 (en) * 2018-08-24 2019-08-13 (주)비티비엘 Method of manufacturing ultrasonic sensor

Family Cites Families (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH071920Y2 (en) * 1988-05-10 1995-01-18 東レ株式会社 Ultrasonic transducer
JP2002008939A (en) * 2000-04-13 2002-01-11 Fujitsu Ltd Method of manufacturing ceramic body by selective coating
JP4759117B2 (en) * 2000-06-22 2011-08-31 日本特殊陶業株式会社 SUBSTRATE WITH METAL OXIDE FILM AND METHOD FOR PRODUCING SUBSTRATE WITH METAL OXIDE FILM
JP2004111835A (en) * 2002-09-20 2004-04-08 Canon Inc Method of manufacturing piezoelectric element, piezoelectric element, and ink jet recording head
JP2005327919A (en) * 2004-05-14 2005-11-24 Seiko Epson Corp Method for manufacturing device and device, electrooptic element and printer
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

Also Published As

Publication number Publication date
TW201705560A (en) 2017-02-01
TWI693731B (en) 2020-05-11
JP2017011144A (en) 2017-01-12
WO2016208425A1 (en) 2016-12-29

Similar Documents

Publication Publication Date Title
US11759175B2 (en) Configurable ultrasonic imager
US9263663B2 (en) Method of making thick film transducer arrays
US10471471B2 (en) Ultrasound transducer and method for making the same
Zhou et al. Piezoelectric films for high frequency ultrasonic transducers in biomedical applications
US7449821B2 (en) Piezoelectric micromachined ultrasonic transducer with air-backed cavities
US8823246B2 (en) High frequency piezocomposite transducer pillars
JP2000050391A (en) Ultrasonic transducer and its manufacture
US7872949B2 (en) Vibrator array, manufacturing method thereof, and ultrasonic probe
CN107534815B (en) Ultrasonic transducer including matching layer having composite structure and method of manufacturing the same
EP2902118A2 (en) Ultrasonic device, probe, electronic device, and ultrasound imaging apparatus
Zhou et al. Micro-machined high-frequency (80 MHz) PZT thick film linear arrays
JP2000028595A (en) Manufacture of piezoelectric structure and combined piezoelectric vibrator
JP2007158467A (en) Ultrasonic probe and manufacturing method thereof
JP2007273584A (en) Laminated piezoelectric element, manufacturing method therefor and ultrasonic probe
JP4528606B2 (en) Ultrasonic probe and ultrasonic diagnostic apparatus
Tipsawat et al. 32 element piezoelectric micromachined ultrasound transducer (pmut) phased array for neuromodulation
JP2000300559A (en) Ultrasonic probe and its manufacture
JP6122066B2 (en) High frequency ultrasonic piezoelectric element, method for manufacturing the same, and high frequency ultrasonic probe including the same
US20100001620A1 (en) Microstructure of perovskite-type oxide single crystal and method of manufacturing the same, composite piezoelectric material, piezoelectric vibrator, ultrasonic probe, and ultrasonic diagnostic apparatus
JP2008048276A (en) Ultrasonic transducer and ultrasonic transducer array
JP5794114B2 (en) Piezoelectric element, manufacturing method thereof, and ultrasonic transmission / reception probe
KR102000689B1 (en) A centrifugal packing apparatus and a manufacturing method of a piezoelectric sensor and a piezoelectric sensor manufactured thereby or an ultrasonic sensor containing the same
JP2013026682A (en) Medical composite single-crystal piezoelectric vibrator, medical ultrasonic probe, method of manufacturing medical composite single-crystal piezoelectric vibrator, and method of manufacturing medical ultrasonic probe
JP2005110116A (en) Ultrasonic-wave transducer array and its manufacturing method
JP2005286444A (en) Ultrasonic transducer

Legal Events

Date Code Title Description
A521 Request for written amendment filed

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20161111

A621 Written request for application examination

Free format text: JAPANESE INTERMEDIATE CODE: A621

Effective date: 20161111

A871 Explanation of circumstances concerning accelerated examination

Free format text: JAPANESE INTERMEDIATE CODE: A871

Effective date: 20161111

A975 Report on accelerated examination

Free format text: JAPANESE INTERMEDIATE CODE: A971005

Effective date: 20161208

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20161220

A521 Request for written amendment filed

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20170217

TRDD Decision of grant or rejection written
A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

Effective date: 20170321

A61 First payment of annual fees (during grant procedure)

Free format text: JAPANESE INTERMEDIATE CODE: A61

Effective date: 20170330

R150 Certificate of patent or registration of utility model

Ref document number: 6122066

Country of ref document: JP

Free format text: JAPANESE INTERMEDIATE CODE: R150

RD04 Notification of resignation of power of attorney

Free format text: JAPANESE INTERMEDIATE CODE: R3D04

S111 Request for change of ownership or part of ownership

Free format text: JAPANESE INTERMEDIATE CODE: R313117

R360 Written notification for declining of transfer of rights

Free format text: JAPANESE INTERMEDIATE CODE: R360

R370 Written measure of declining of transfer procedure

Free format text: JAPANESE INTERMEDIATE CODE: R370

S111 Request for change of ownership or part of ownership

Free format text: JAPANESE INTERMEDIATE CODE: R313117

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R350 Written notification of registration of transfer

Free format text: JAPANESE INTERMEDIATE CODE: R350

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

S111 Request for change of ownership or part of ownership

Free format text: JAPANESE INTERMEDIATE CODE: R313113

R350 Written notification of registration of transfer

Free format text: JAPANESE INTERMEDIATE CODE: R350

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250