JPH0774407A - Piezoelectric high polymer film, surface wave piezoelectric element and ultrasonic transducer - Google Patents
Piezoelectric high polymer film, surface wave piezoelectric element and ultrasonic transducerInfo
- Publication number
- JPH0774407A JPH0774407A JP24063893A JP24063893A JPH0774407A JP H0774407 A JPH0774407 A JP H0774407A JP 24063893 A JP24063893 A JP 24063893A JP 24063893 A JP24063893 A JP 24063893A JP H0774407 A JPH0774407 A JP H0774407A
- Authority
- JP
- Japan
- Prior art keywords
- film
- piezoelectric
- piezoelectricity
- vdf
- vinylidene fluoride
- 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.)
- Granted
Links
Landscapes
- Transducers For Ultrasonic Waves (AREA)
- Surface Acoustic Wave Elements And Circuit Networks Thereof (AREA)
- Piezo-Electric Or Mechanical Vibrators, Or Delay Or Filter Circuits (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、大きなずり圧電性を有
する高分子圧電体を使った、高性能の表面波圧電素子、
およびそれを用いた超音波トランスデューサに関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high performance surface acoustic wave piezoelectric element using a polymer piezoelectric material having a large shear piezoelectricity.
And an ultrasonic transducer using the same.
【０００２】[0002]
【従来の技術】フッ化ビニリデン／３フッ化エチレン共
重合体（以下Ｐ（ＶＤＦ−ＴｒＦＥ）と略す）、および
フッ化ビニリデン／４フッ化エチレン共重合体（以下Ｐ
（ＶＤＦ−ＴｅＦＥ）と略す）が強誘電体であり、これ
らの共重合体が伸び圧電性および厚み圧電性を有するこ
とは公知の事実である。BACKGROUND OF THE INVENTION Vinylidene fluoride / 3-fluorinated ethylene copolymer (hereinafter abbreviated as P (VDF-TrFE)) and vinylidene fluoride / 4-fluorinated ethylene copolymer (hereinafter P
It is a known fact that (abbreviated as VDF-TeFE) is a ferroelectric substance, and that these copolymers have elongation piezoelectricity and thickness piezoelectricity.
【０００３】また、これらの伸び圧電性については、特
開昭５３−２６９９５号公報等に述べられている（伸び
圧電性の定義については後述）。また、特開昭５９−２
３６７８号公報、特開昭６２−４２５６０号公報等に述
べられているように、これらの厚み圧電性を利用した装
置としては、超音波トランスデューサがある。高分子特
有の良好な性質を利用して、無機材料にはない、大口径
のものや１μｍ以下の薄膜を使用した高周波のトランス
デューサが開発されている。The stretching piezoelectricity is described in JP-A-53-26995 (the definition of the stretching piezoelectricity will be described later). Also, JP-A-59-2
As described in Japanese Patent No. 3678, Japanese Unexamined Patent Publication No. 62-42560 and the like, an ultrasonic transducer is used as a device utilizing the thickness piezoelectricity. Utilizing good properties peculiar to polymers, high-frequency transducers using a large-diameter film or a thin film of 1 μm or less, which is not found in inorganic materials, have been developed.
【０００４】以上のように種々の応用が展開されている
Ｐ（ＶＤＦ−ＴｒＦＥ）およびＰ（ＶＤＦ−ＴｅＦＥ）
であるが、これまでに、伸び圧電性と厚み圧電性以外の
全く異なった成分である、ずり圧電性（剪断方向の圧電
性）に関しては、その性能が明らかにされておらず、こ
の性質を利用した素子は開発されていない。As described above, various applications have been developed for P (VDF-TrFE) and P (VDF-TeFE).
However, the performance of shear piezoelectricity (piezoelectricity in the shearing direction), which is a completely different component other than elongation piezoelectricity and thickness piezoelectricity, has not been clarified so far. The device used has not been developed.
【０００５】一方、表面波素子についてみると、セラミ
ック材料が応用されているものには、ずり圧電性を利用
しているものがある。高分子材料中では、唯一、フッ化
ビニリデン（ＰＶＤＦ）で表面波素子の実験例の報告
（ＵＬＴＲＡＳＯＮＩＣＳ ＳＹＭＰＯＳＩＵＭ Ｐ．
５１１（１９７９））があるが、効率が悪く、実用には
至っていない。Ｐ（ＶＤＦ−ＴｒＦＥ）やＰ（ＶＤＦ−
ＴｅＦＥ）について表面波素子の報告例はない。On the other hand, regarding the surface acoustic wave element, some of the applications of the ceramic material utilize shear piezoelectricity. Among the polymeric materials, the only report of an experimental example of a surface acoustic wave device with vinylidene fluoride (PVDF) (ULTRASONICS SYMPOSIUM P.
511 (1979), but the efficiency is poor and it has not been put to practical use. P (VDF-TrFE) and P (VDF-
There are no reports of surface acoustic wave devices for TeFE).
【０００６】[0006]
【発明が解決しようとする課題】本発明の目的は、ずり
圧電性の大きいＰ（ＶＤＦ−ＴｒＦＥ）および／又はＰ
（ＶＤＦ−ＴｅＦＥ）膜を用いることによって、高効率
の横波振動素子を提供することにある。そして、この横
波振動素子の具体的な実施態様として、表面波素子、及
び、超音波トランスデューサを提供することにある。SUMMARY OF THE INVENTION An object of the present invention is to provide P (VDF-TrFE) and / or P having high shear piezoelectricity.
By using a (VDF-TeFE) film, it is to provide a highly efficient transverse wave vibrating element. Then, as a specific embodiment of the transverse wave vibration element, a surface wave element and an ultrasonic transducer are provided.
【０００７】[0007]
【課題を解決するための手段】大きなずり圧電性、好ま
しくはその電気機械結合定数（ｋ15および／又はｋ24）
が０．１以上の値を有する圧電体においては、そのずり
圧電性を利用して優れた横波振動素子を作製することが
できる。Large shear piezoelectricity, preferably its electromechanical coupling constant (k 15 and / or k 24 ).
With a piezoelectric body having a value of 0.1 or more, an excellent transverse wave vibration element can be manufactured by utilizing the shear piezoelectricity.
【０００８】一方、本発明者らは、Ｐ（ＶＤＦ−ＴｒＦ
Ｅ）および／又はＰ（ＶＤＦ−ＴｅＦＥ）を用いて、そ
のずり圧電性の電気機械結合定数が０．１以上である圧
電膜を得ることに成功した。On the other hand, the present inventors have found that P (VDF-TrF
E) and / or P (VDF-TeFE) was used to obtain a piezoelectric film having a shear piezoelectric electromechanical coupling constant of 0.1 or more.
【０００９】したがって、この共重合膜を用い、そのず
り圧電性を利用して、優れた性能の横波振動素子を実現
できることを見出した。Therefore, it has been found that a shear wave vibrating element having excellent performance can be realized by using this copolymer film and utilizing its shear piezoelectricity.
【００１０】すなわち、前記目的に沿う本発明の圧電性
高分子膜は、ずり圧電性を有しており、その電気機械結
合定数（ｋ15および／又はｋ24）が０．１以上のフッ化
ビニリデン／３フッ化エチレン共重合体および／又はフ
ッ化ビニリデン／４フッ化エチレン共重合体からなるこ
とを特徴とするものである。That is, the piezoelectric polymer film of the present invention which meets the above object has shear piezoelectricity, and its electromechanical coupling constant (k 15 and / or k 24 ) is 0.1 or more. It is characterized by comprising a vinylidene / 3-fluorinated ethylene copolymer and / or a vinylidene fluoride / 4-fluorinated ethylene copolymer.
【００１１】このような圧電性高分子膜は、とくに横波
振動素子として利用することができる。Such a piezoelectric polymer film can be used especially as a transverse wave vibration element.
【００１２】本発明に係る表面波圧電素子は、上記のＰ
（ＶＤＦ−ＴｒＦＥ）および／又はＰ（ＶＤＦ−ＴｅＦ
Ｅ）からなる圧電性高分子膜の表面に、金属からなる櫛
状電極が形成されてなるものである。また、この圧電性
高分子膜は、表面波の伝播媒体として高分子よりも減衰
の少ない固体、たとえば、金属体や無機の結晶体などか
らなる基板上に形成できるので、さらに有利である。こ
の場合、金属基板または絶縁体基板上に圧電性高分子膜
を形成し、上記同様の櫛状電極を形成してもよい。ま
た、上記圧電性高分子膜と櫛状電極との間には、絶縁体
薄膜を設けてもよい。The surface acoustic wave piezoelectric element according to the present invention has the above-mentioned P
(VDF-TrFE) and / or P (VDF-TeF)
A comb-shaped electrode made of metal is formed on the surface of the piezoelectric polymer film made of E). Further, this piezoelectric polymer film is more advantageous because it can be formed as a surface wave propagation medium on a solid body having less attenuation than a polymer, for example, a substrate made of a metal body or an inorganic crystal body. In this case, a piezoelectric polymer film may be formed on a metal substrate or an insulating substrate, and a comb-shaped electrode similar to the above may be formed. Further, an insulator thin film may be provided between the piezoelectric polymer film and the comb electrode.
【００１３】また、本発明に係る超音波トランスデュー
サは、膜厚方向にポーリングされた、ずり圧電性を有す
る、電気機械結合定数（ｋ15および／又はｋ24）が０．
１以上のフッ化ビニリデン／３フッ化エチレン共重合体
および／又はフッ化ビニリデン／４フッ化エチレン共重
合体からなる圧電性高分子膜を、膜厚方向に複数枚積
層、接着した後、積層体の膜面に対し垂直な方向に切り
出した薄膜と、該薄膜の上面と下面とに設けられた電極
と、を有する表面波圧電素子を用いたことを特徴とする
ものから成る。In the ultrasonic transducer according to the present invention, the electromechanical coupling constant (k 15 and / or k 24 ) which is poled in the film thickness direction and has shear piezoelectricity is 0.
A plurality of piezoelectric polymer films composed of one or more vinylidene fluoride / 3-fluorinated ethylene copolymer and / or vinylidene fluoride / 4-fluorinated ethylene copolymer are laminated and adhered in the film thickness direction, and then laminated. It is characterized by using a surface acoustic wave piezoelectric element having a thin film cut out in a direction perpendicular to the film surface of the body, and electrodes provided on the upper surface and the lower surface of the thin film.
【００１４】さらに、本発明に係る高分子圧電膜の製造
方法は、膜厚方向にポーリングされた、ずり圧電性を有
する、電気機械結合定数（ｋ15および／又はｋ24）が
０．１以上のフッ化ビニリデン／３フッ化エチレン共重
合体および／又はフッ化ビニリデン／４フッ化エチレン
共重合体からなる圧電性高分子膜を、膜厚方向に複数枚
積層、接着し、積層体の膜面に対し垂直な方向に薄膜を
切り出すことを特徴とする方法からなる。Further, in the method for producing a polymeric piezoelectric film according to the present invention, the electromechanical coupling constant (k 15 and / or k 24 ) having a shear piezoelectric property which is poled in the film thickness direction is 0.1 or more. A plurality of piezoelectric polymer films made of vinylidene fluoride / 3-fluorinated ethylene copolymer and / or vinylidene fluoride / 4-fluorinated ethylene copolymer are laminated and adhered in the film thickness direction to form a laminated film. The method comprises cutting out a thin film in a direction perpendicular to the plane.
【００１５】従来の技術では、もっぱら、伸び圧電性と
厚み圧電性を利用しているのみで、ずり圧電性について
は検討されておらず、いうまでもなく、ずり圧電性を利
用した用途については知られていない。In the prior art, the extension piezoelectricity and the thickness piezoelectricity are exclusively used, and the shear piezoelectricity has not been examined. Needless to say, the applications utilizing the shear piezoelectricity are not considered. unknown.
【００１６】ここで、伸び圧電性及び厚み圧電性なる用
語は次のとおり定義される。高分子圧電膜ではポーリン
グの方向は膜面に垂直な方向であり、この方向をＺ
（３）軸にとる。膜面内の対象軸をＸ（１）軸、Ｙ
（２）軸に選ぶ。ただし、延伸する方向を１軸とする。
この時の圧電ｅ定数の成分は数１で示される。Here, the terms elongation piezoelectricity and thickness piezoelectricity are defined as follows. In the piezoelectric polymer film, the poling direction is perpendicular to the film surface.
(3) Take the axis. The target axis in the film plane is the X (1) axis, Y
(2) Select the axis. However, the stretching direction is uniaxial.
The component of the piezoelectric e constant at this time is expressed by Equation 1.
【００１７】[0017]
【数１】 [Equation 1]
【００１８】ここで、ｅ31、ｅ32をもって示される圧電
性を伸び圧電性、ｅ33をもって示される圧電性を厚み圧
電性といい、両者は、伸縮変形と電場を結合するもので
ある。ｅ15、ｅ24で示される定数がずり圧電性で、膜に
加えられたずり変形と電場を結合させる定数である。Here, the piezoelectricity represented by e 31 and e 32 is referred to as extension piezoelectricity, and the piezoelectricity represented by e 33 is referred to as thickness piezoelectricity, both of which combine expansion and contraction and an electric field. The constants indicated by e 15 and e 24 are shear piezoelectrics, and are constants for coupling the shear deformation applied to the film and the electric field.
【００１９】圧電性を表す定数の一つに、電気エネルギ
ーと機械エネルギーの変換効率を意味する電気機械結合
定数（ｋij；ｉｊは方向を表す。カップリングファクタ
ーとも言う。）があるが、Ｐ（ＶＤＦ−ＴｒＦＥ）やＰ
（ＶＤＦ−ＴｅＦＥ）が大きなｋ33およびｋ31を持つこ
とはこれまでもよく知られている。例えば、Ｐ（ＶＤＦ
−ＴｒＦＥ）の厚み方向の電気機械結合定数では、高分
子中最高のｋ33＞０．３を達成している（Jpn.Appl.Phy
s., 24 ,23(1985)) 。One of the constants representing the piezoelectricity is an electromechanical coupling constant (k ij ; ij represents a direction, also called a coupling factor) which means the conversion efficiency of electric energy and mechanical energy. (VDF-TrFE) and P
It is well known that (VDF-TeFE) has large k 33 and k 31 . For example, P (VDF
In terms of electromechanical coupling constant in the thickness direction of -TrFE, the highest k 33 > 0.3 among polymers was achieved (Jpn.Appl.Phy.
s., 24 , 23 (1985)).
【００２０】ここで、ずり方向の電気機械結合定数ｋ15
は、数２のように定義される。Here, the electromechanical coupling constant in the shear direction k 15
Is defined as Equation 2.
【００２１】[0021]
【数２】 [Equation 2]
【００２２】未延伸膜の場合には、上記ｋ15はｋ24と等
しくなる。In the case of an unstretched film, k 15 is equal to k 24 .
【００２３】まず、本発明では、Ｐ（ＶＤＦ−ＴｒＦ
Ｅ）およびＰ（ＶＤＦ−ＴｅＦＥ）膜において、大きな
ずり方向の電気機械結合定数ｋ15およびｋ24を発現させ
ることに成功した。First, in the present invention, P (VDF-TrF
E) and P (VDF-TeFE) films were successful in developing electromechanical coupling constants k 15 and k 24 in the large shear direction.
【００２４】発現させた値は、Ｐ（ＶＤＦ−ＴｒＦＥ）
の共重合比ＶＤＦ＝０．７５の未延伸膜において、ｋ15
＝０．２（温度；２００Ｋ）で、実質的にｋ15＝ｋ24で
あった。この値は、ＰＶＤＦのｋ31よりも大きく、ＰＶ
ＤＦのｋ33と同程度の大きな値であることが分かった。
そこで、これを用いて、効率のよい表面波素子、及び、
超音波トランスデューサが実現できたものである。The expressed value is P (VDF-TrFE).
In unstretched film of the copolymerization ratio VDF = 0.75, k 15
= 0.2 (temperature; 200K) in was = k 24 substantially k 15. This value is larger than k 31 of PVDF, and PV
It was found to be as large as k 33 of DF.
Therefore, by using this, an efficient surface wave element, and
The ultrasonic transducer was realized.
【００２５】次に、ずり圧電性を有効に利用する効率の
よい表面波素子の作用について説明する。ずり変形によ
って生じた電荷は膜面に平行に生じ、進行方向に対して
垂直な振動を持つ横波である。このような横波振動素子
を表面波素子として利用するには次のような構成によ
る。Next, the operation of the efficient surface acoustic wave element that effectively utilizes the shear piezoelectricity will be described. The electric charge generated by the shear deformation is a transverse wave that is generated parallel to the film surface and has a vibration perpendicular to the traveling direction. To use such a transverse wave vibration element as a surface wave element, the following configuration is used.
【００２６】Ｐ（ＶＤＦ−ＴｒＦＥ）および／又はＰ
（ＶＤＦ−ＴｅＦＥ）からなる圧電性高分子膜の表面
に、金属からなる櫛状電極を形成した。分極した圧電膜
表面に金属をフォトリソグラフィ、エッチング等により
櫛状に形成し電極とした。ここで、櫛状電極の材質は、
通常よく用いられている金属で、例えばアルミニウムな
ど、エッチングできる材質ならば何でもよい。櫛状電極
間に交流電圧を印加して、素子を駆動させると、効率の
よい表面波が発生する。P (VDF-TrFE) and / or P
A comb-shaped electrode made of metal was formed on the surface of the piezoelectric polymer film made of (VDF-TeFE). A metal was formed into a comb shape on the surface of the polarized piezoelectric film by photolithography, etching or the like to form an electrode. Here, the material of the comb-shaped electrode is
Any commonly used metal, such as aluminum, may be used as long as it can be etched. When an AC voltage is applied between the comb electrodes to drive the element, efficient surface waves are generated.
【００２７】さらに、金属基板または絶縁体基板上に、
Ｐ（ＶＤＦ−ＴｒＦＥ）および／又はＰ（ＶＤＦ−Ｔｅ
ＦＥ）からなる圧電性高分子膜を形成し、その表面に金
属からなる櫛状電極を形成して駆動しても、効率のよい
表面波が得られた。また、Ｐ（ＶＤＲ−ＴｒＦＥ）およ
び／又はＰ（ＶＤＦ−ＴｅＦＥ）からなる膜と、櫛状電
極との間に、絶縁体薄膜がある場合にも、効率のよい表
面波が得られた。Furthermore, on a metal substrate or an insulating substrate,
P (VDF-TrFE) and / or P (VDF-Te
Even if a piezoelectric polymer film made of FE) was formed, and a comb-shaped electrode made of metal was formed on the surface of the film, the surface wave was efficiently obtained. Further, even when the insulator thin film was provided between the comb-shaped electrode and the film made of P (VDR-TrFE) and / or P (VDF-TeFE), efficient surface waves were obtained.
【００２８】一般に、高分子固体中では表面波の伝播減
衰が大きいので、Ｐ（ＶＤＦ−ＴｒＦＥ）および／又は
Ｐ（ＶＤＦ−ＴｅＦＥ）からなる表面波素子に、減衰の
小さいセラミック、水晶などの無機材料を組み合わせて
も、有効な表面波素子として利用できることは言うまで
もない。In general, since the propagation attenuation of surface waves is large in a polymer solid, a surface acoustic wave element made of P (VDF-TrFE) and / or P (VDF-TeFE) has a small attenuation of an inorganic material such as ceramic or quartz. It goes without saying that a combination of materials can be used as an effective surface acoustic wave element.
【００２９】Ｐ（ＶＤＦ−ＴｒＦＥ）やＰ（ＶＤＦ−Ｔ
ｅＦＥ）のずり圧電性は、ＰＶＤＦのように延伸あるい
は高電圧下で分極処理を施さなくても、未延伸で発現す
るため、どんな基板上にも容易に形成できる。この未延
伸で使用できる点は、ｋ33を利用した通常の超音波トラ
ンスデューサの場合と同じく、大きな利点である。さら
に、高分子の特徴を生かして、複雑な形状、大面積化や
薄膜化が容易である利点もある。P (VDF-TrFE) and P (VDF-T)
The shear piezoelectricity of eFE) can be easily formed on any substrate because it develops in an unstretched state without being subjected to stretching or polarization treatment under a high voltage like PVDF. The fact that it can be used without being stretched is a great advantage as in the case of a normal ultrasonic transducer utilizing k 33 . Furthermore, there is an advantage that it is easy to make a complicated shape, a large area, and a thin film by utilizing the characteristics of the polymer.
【００３０】次に、ずり圧電性を利用した超音波トラン
スデューサについて説明する。従来のトランスデューサ
においては、厚み方向の圧電性を利用したものであっ
て、膜厚方向に分極した膜を、例えば、バッキング材に
固定し、所定の周波数（膜厚に固有）で駆動する。本発
明では、ずり圧電性の膜面方向の振動を利用するため、
次のような構造とする。Next, an ultrasonic transducer utilizing shear piezoelectricity will be described. The conventional transducer uses piezoelectricity in the thickness direction, and a film polarized in the film thickness direction is fixed to, for example, a backing material and driven at a predetermined frequency (specific to the film thickness). In the present invention, since the vibration in the film surface direction of shear piezoelectric is utilized,
The structure is as follows.
【００３１】膜厚方向にポーリングされたＰ（ＶＤＦ−
ＴｒＦＥ）および／又はＰ（ＶＤＦ−ＴｅＦＥ）からな
る膜を、膜厚方向に複数枚積層し接着した後、膜面に対
し垂直な方向に薄く切り出して薄膜を得、該薄膜の上面
と下面に電極が形成された膜を用いて、超音波トランス
デューサを製作した。つまり、分極方向が面と平行にな
った膜の上面と下面に均一な電極を形成し、交流電源を
用いて駆動すると、効率のよい超音波トランスデューサ
として使用できる。P (VDF-polled in the film thickness direction
After laminating a plurality of films made of TrFE) and / or P (VDF-TeFE) in the film thickness direction and adhering them, a thin film is cut out in a direction perpendicular to the film surface to obtain a thin film. An ultrasonic transducer was manufactured using the film on which the electrodes were formed. That is, when uniform electrodes are formed on the upper and lower surfaces of a film whose polarization direction is parallel to the surface and driven by an AC power source, it can be used as an efficient ultrasonic transducer.
【００３２】以上、本発明に係る圧電性高分子膜の表面
波素子、超音波トランスデューサへの応用例を説明した
が、本発明に係る圧電性高分子膜は、もっと一般的に、
ずり圧電性を利用した装置に広く応用できることは言う
までもない。Although the application examples of the piezoelectric polymer film according to the present invention to the surface wave element and the ultrasonic transducer have been described above, the piezoelectric polymer film according to the present invention is more generally
It goes without saying that it can be widely applied to devices utilizing shear piezoelectricity.
【００３３】[0033]
【実施例】実施例１（表面波素子） フッ化ビニリデン組成０．７５モルのＰ（ＶＤＦ−Ｔｒ
ＦＥ）共重合体、ジメチルホルムアミド溶液をガラス板
に流延し、常温、減圧下で溶媒を気化させ、さらに、１
００℃の熱で溶媒を完全に気化させた。この膜の融点は
１４５℃、厚さ５０μｍであった。ガラス板からはがさ
ずに、１４０℃で熱処理結晶化させたのち、自然冷却さ
せた。膜両面にアルミニウムを蒸着して電極を設け、常
温で外部から±４．５ｋＶのピークを持つ１Ｈｚの交流
電圧（三角波）を膜の上下面に印加してポーリング処理
を施した。ポーリング処理後にアルミニウム電極は水酸
化ナトリウムで溶解剥離した。得られた圧電膜のずり圧
電性ｋ15を測定したところ、温度２００Ｋにおいて、
０．２であった。Examples Example 1 (Surface wave element) P (VDF-Tr) having a vinylidene fluoride composition of 0.75 mol
The FE) copolymer and dimethylformamide solution are cast on a glass plate, and the solvent is vaporized at room temperature under reduced pressure.
The solvent was completely vaporized with heat of 00 ° C. The melting point of this film was 145 ° C. and the thickness was 50 μm. It was not peeled from the glass plate, heat-treated at 140 ° C. for crystallization, and then naturally cooled. Aluminum was vapor-deposited on both surfaces of the film to provide electrodes, and an alternating voltage (triangular wave) of 1 Hz having a peak of ± 4.5 kV was applied to the upper and lower surfaces of the film at room temperature to perform poling treatment. After the poling treatment, the aluminum electrode was dissolved and peeled off with sodium hydroxide. When the shear piezoelectricity k 15 of the obtained piezoelectric film was measured, at a temperature of 200K,
It was 0.2.
【００３４】図１に、得られた圧電膜の電気機械結合定
数（カップリングファクター）ｋ15およびｋ24の特性
を、ｋ31およびｋ33の特性、および比較のためのフッ化
ビニリデン（ＰＶＤＦ）のｋ31、ｋ33とともに示す。図
に示すように、実質的にｋ15＝ｋ24であり、温度２００
Ｋまで、ＰＶＤＦのｋ33と同程度の大きな値をもつこと
が判る。FIG. 1 shows characteristics of electromechanical coupling constants (coupling factors) k 15 and k 24 of the obtained piezoelectric film, characteristics of k 31 and k 33 , and vinylidene fluoride (PVDF) for comparison. Of k 31 and k 33 . As shown in the figure, substantially k 15 = k 24 and the temperature 200
It can be seen that up to K, it has a value as large as k 33 of PVDF.
【００３５】ｋ24またはｋ15の圧電性を横波振動子とし
て用いた、表面波素子を作る場合は、図２に示すよう
に、上記のようにして得られた圧電膜１３を基板１１上
に設け、その表面に櫛状電極１２をフォトリソグラフィ
により形成し表面波圧電素子を得た。櫛状電極間に交流
電源１４から交流電場を印加することにより、表面波を
発生させた。発生した表面波を、１０ｍｍ離して置かれ
た、櫛状電極１２′を有する別の表面波素子１５によっ
て検出器１６を介して検出した。When a surface acoustic wave device using the piezoelectricity of k 24 or k 15 as a transverse wave oscillator is produced, the piezoelectric film 13 obtained as described above is formed on the substrate 11 as shown in FIG. Then, the comb-shaped electrode 12 was formed on the surface by photolithography to obtain a surface acoustic wave piezoelectric element. A surface wave was generated by applying an AC electric field from the AC power supply 14 between the comb electrodes. The generated surface wave was detected via a detector 16 by another surface wave element 15 having a comb-shaped electrode 12 ', which was placed 10 mm apart.
【００３６】実施例２（超音波トランスデューサ） 実施例１の手順で膜厚９５μｍのＰ（ＶＤＦ−ＴｒＦ
Ｅ）膜を得、これを８０枚積層した。接着は圧電性発現
の妨げにならないよう充分注意した。得られた厚さ１０
ｍｍのバルク状の塊を積層体の膜の膜面と垂直の方向に
薄くスライスした。こうして得られた積層圧電膜は、図
３に示すような、１０ｍｍ角で、膜厚が９０μｍの膜３
であった。この高分子圧電膜３を用いて、図４に示すよ
うな超音波トランスデューサに組み立て駆動させたとこ
ろ、４ＭＨｚに動作周波数をもっており、高効率の超音
波トランスデューサが得られた。なお、図４において、
１は支持基板、２は背面側電極、３は高分子圧電膜、４
は動作面側電極、５は保護膜、６は金属ケース、７はプ
ラスチックケース、８は導線を、それぞれ示している。Example 2 (Ultrasonic Transducer) According to the procedure of Example 1, P (VDF-TrF) having a film thickness of 95 μm was used.
E) A film was obtained and 80 sheets were laminated. Careful attention was paid so that the adhesion did not hinder the development of piezoelectricity. The obtained thickness 10
A bulk mass of mm was thinly sliced in a direction perpendicular to the film surface of the film of the laminate. The laminated piezoelectric film thus obtained is a film 3 having a 10 mm square and a film thickness of 90 μm as shown in FIG.
Met. When this polymeric piezoelectric film 3 was used to assemble and drive an ultrasonic transducer as shown in FIG. 4, an ultrasonic transducer having an operating frequency of 4 MHz and a high efficiency was obtained. In addition, in FIG.
1 is a support substrate, 2 is a back side electrode, 3 is a polymer piezoelectric film, 4
Is an operating surface side electrode, 5 is a protective film, 6 is a metal case, 7 is a plastic case, and 8 is a conducting wire.
【００３７】[0037]
【発明の効果】本発明においては、従来応用されていな
かった高分子圧電体のずり圧電性を利用して、効率のよ
い表面波圧電素子、および超音波トランスデューサを得
ることができた。According to the present invention, it is possible to obtain a highly efficient surface acoustic wave piezoelectric element and ultrasonic transducer by utilizing the shear piezoelectricity of a polymer piezoelectric material which has not been applied conventionally.
【図１】フッ化ビニリデン／３フッ化ニチレン共重合体
０．７５モル％の電気機械結合定数と温度との関係図で
ある。FIG. 1 is a relationship diagram between an electromechanical coupling constant and a temperature of 0.75 mol% of vinylidene fluoride / nitylene fluoride copolymer.
【図２】本発明の表面波圧電素子の駆動試験の状態を示
す概略構成図である。FIG. 2 is a schematic configuration diagram showing a driving test state of the surface acoustic wave piezoelectric element of the present invention.
【図３】本発明に係る高分子圧電膜の斜視図である。FIG. 3 is a perspective view of a polymer piezoelectric film according to the present invention.
【図４】本発明に係る超音波トランスデューサの概略構
成図である。FIG. 4 is a schematic configuration diagram of an ultrasonic transducer according to the present invention.
１ 支持基板 ２ 背面側電極 ３ 高分子電圧膜 ４ 動作面側電極 ５ 保護膜 ６ 金属ケース ７ プラスチックケース ８ 導線 １１ 基板 １２、１２′ 櫛状電極 １３ 圧電膜 １４ 交流電源 １５ 検出用の表面波素子 １６ 検出器 1 Support Substrate 2 Back Side Electrode 3 Polymer Voltage Membrane 4 Operating Side Electrode 5 Protective Film 6 Metal Case 7 Plastic Case 8 Conductor 11 Substrate 12, 12 'Comb Electrode 13 Piezoelectric Film 14 AC Power Supply 15 Surface Wave Element for Detection 16 detector
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.6 識別記号 庁内整理番号 ＦＩ 技術表示箇所 Ｈ０３Ｈ 9/25 Ｃ 7259−5Ｊ Ｈ０４Ｒ 17/00 ３３０ Ｅ ─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. 6 Identification number Office reference number FI Technical indication location H03H 9/25 C 7259-5J H04R 17/00 330 E
Claims (7)
結合定数（ｋ15および／又はｋ24）が０．１以上のフッ
化ビニリデン／３フッ化エチレン共重合体および／又は
フッ化ビニリデン／４フッ化エチレン共重合体からなる
圧電性高分子膜。1. A vinylidene fluoride / trifluoroethylene copolymer and / or fluorinated having shear piezoelectricity and having an electromechanical coupling constant (k 15 and / or k 24 ) of 0.1 or more. A piezoelectric polymer film made of vinylidene / 4 fluoroethylene copolymer.
そのずり圧電性を利用してなる横波振動素子。2. A piezoelectric polymer film according to claim 1,
A transverse wave vibration element that utilizes the shear piezoelectricity.
請求項１記載の圧電性高分子膜の表面に、金属からなる
櫛状電極が形成されてなる表面波圧電素子。3. The transverse wave vibration element according to claim 2, wherein
A surface acoustic wave piezoelectric element having a comb-shaped electrode made of metal formed on the surface of the piezoelectric polymer film according to claim 1.
金属基板または絶縁体基板上に、請求項１記載の圧電性
高分子膜を形成してなる、請求項３記載の表面波圧電素
子。4. The transverse wave vibration element according to claim 2, wherein
The surface acoustic wave piezoelectric element according to claim 3, wherein the piezoelectric polymer film according to claim 1 is formed on a metal substrate or an insulating substrate.
請求項１記載の圧電性高分子膜と、その表面に形成され
た櫛状電極との間に、絶縁体薄膜があることを特徴とす
る、請求項３又は４記載の表面波圧電素子。5. The transverse wave vibration element according to claim 2, wherein
The surface acoustic wave piezoelectric element according to claim 3 or 4, wherein an insulating thin film is provided between the piezoelectric polymer film according to claim 1 and the comb-shaped electrode formed on the surface thereof.
性を有する、電気機械結合定数（ｋ15および／又は
ｋ24）が０．１以上のフッ化ビニリデン／３フッ化エチ
レン共重合体および／又はフッ化ビニリデン／４フッ化
エチレン共重合体からなる圧電性高分子膜を、膜厚方向
に複数枚積層、接着した後、積層体の膜面に対し垂直な
方向に切り出した薄膜と、該薄膜の上面と下面とに設け
られた電極と、を有する表面波圧電素子を用いたことを
特徴とする超音波トランスデューサ。6. A vinylidene fluoride / 3-fluorinated ethylene copolymer having an electromechanical coupling constant (k 15 and / or k 24 ) of 0.1 or more, which has a shear piezoelectricity and is poled in the film thickness direction. A thin film obtained by stacking and adhering a plurality of piezoelectric polymer films composed of a vinylidene fluoride / 4 fluoroethylene copolymer in the film thickness direction and adhering the film, and cutting the film in a direction perpendicular to the film surface of the layered product. An ultrasonic transducer comprising a surface acoustic wave piezoelectric element having electrodes provided on an upper surface and a lower surface of the thin film.
性を有する、電気機械結合定数（ｋ15および／又は
ｋ24）が０．１以上のフッ化ビニリデン／３フッ化エチ
レン共重合体および／又はフッ化ビニリデン／４フッ化
エチレン共重合体からなる圧電性高分子膜を、膜厚方向
に複数枚積層、接着し、積層体の膜面に対し垂直な方向
に薄膜を切り出すことを特徴とする、高分子圧電膜の製
造方法。7. A vinylidene fluoride / trifluoroethylene copolymer having an electromechanical coupling constant (k 15 and / or k 24 ) of 0.1 or more, which is poled in the film thickness direction and has shear piezoelectricity. Characterized in that a plurality of piezoelectric polymer films made of vinylidene fluoride / tetrafluoroethylene copolymer are laminated / adhered in the film thickness direction and the thin film is cut out in a direction perpendicular to the film surface of the laminated product. And a method for producing a polymeric piezoelectric film.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP24063893A JP3360371B2 (en) | 1993-08-31 | 1993-08-31 | Shear wave vibration element, surface wave piezoelectric element, and ultrasonic transducer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP24063893A JP3360371B2 (en) | 1993-08-31 | 1993-08-31 | Shear wave vibration element, surface wave piezoelectric element, and ultrasonic transducer |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0774407A true JPH0774407A (en) | 1995-03-17 |
| JP3360371B2 JP3360371B2 (en) | 2002-12-24 |
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ID=17062479
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP24063893A Expired - Fee Related JP3360371B2 (en) | 1993-08-31 | 1993-08-31 | Shear wave vibration element, surface wave piezoelectric element, and ultrasonic transducer |
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| Country | Link |
|---|---|
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003516620A (en) * | 1999-11-10 | 2003-05-13 | フラウンホーファ−ゲゼルシャフト ツァー フォルデルング デア アンゲバンデン フォルシュンク エー． ファオ． | Method of manufacturing piezoelectric transducer |
| JP2011080058A (en) * | 2009-09-14 | 2011-04-21 | Ideal Star Inc | Mixed film of copolymer of vinylidene fluoride and trifluoro ethylene or tetrafluoro ethylene and fullerene and manufacturing method therefor |
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- 1993-08-31 JP JP24063893A patent/JP3360371B2/en not_active Expired - Fee Related
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003516620A (en) * | 1999-11-10 | 2003-05-13 | フラウンホーファ−ゲゼルシャフト ツァー フォルデルング デア アンゲバンデン フォルシュンク エー． ファオ． | Method of manufacturing piezoelectric transducer |
| JP4896331B2 (en) * | 1999-11-10 | 2012-03-14 | フラウンホーファ−ゲゼルシャフト ツァー フォルデルング デア アンゲバンデン フォルシュンク エー． ファオ． | Method for manufacturing piezoelectric transducer |
| JPWO2009113433A1 (en) * | 2008-03-14 | 2011-07-21 | コニカミノルタエムジー株式会社 | Organic piezoelectric material, ultrasonic transducer using the same, manufacturing method thereof, ultrasonic probe, and ultrasonic medical diagnostic imaging apparatus |
| JP5633369B2 (en) * | 2008-03-14 | 2014-12-03 | コニカミノルタ株式会社 | Organic piezoelectric material, ultrasonic transducer using the same, manufacturing method thereof, ultrasonic probe, and ultrasonic medical diagnostic imaging apparatus |
| JP2011080058A (en) * | 2009-09-14 | 2011-04-21 | Ideal Star Inc | Mixed film of copolymer of vinylidene fluoride and trifluoro ethylene or tetrafluoro ethylene and fullerene and manufacturing method therefor |
| JP2013210367A (en) * | 2012-03-01 | 2013-10-10 | Riverbell Kk | Person presence/absence detection method and person presence/absence detection device |
| JP2015534667A (en) * | 2012-09-04 | 2015-12-03 | ヨアノイム リサーチ フォルシュングスゲゼルシャフト エムベーハーＪｏａｎｎｅｕｍ Ｒｅｓｅａｒｃｈ Ｆｏｒｓｃｈｕｎｇｓｇｅｓｅｌｌｓｃｈａｆｔ Ｍｂｈ | Printed piezoelectric pressure sensing foil |
| KR101539050B1 (en) * | 2014-05-12 | 2015-07-23 | 울산대학교 산학협력단 | Ultrasonic transducer using ferroelectric polymer |
| CN107229901A (en) * | 2017-04-05 | 2017-10-03 | 王开安 | Ultrasonic fingerprint recognizer component and preparation method, electronic installation |
| CN107451520A (en) * | 2017-04-05 | 2017-12-08 | 王开安 | The preparation method of ultrasonic fingerprint recognizer component electrode pattern |
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