JP3410893B2 - Piezoelectric element and method of manufacturing the same - Google Patents
Piezoelectric element and method of manufacturing the sameInfo
- Publication number
- JP3410893B2 JP3410893B2 JP01635396A JP1635396A JP3410893B2 JP 3410893 B2 JP3410893 B2 JP 3410893B2 JP 01635396 A JP01635396 A JP 01635396A JP 1635396 A JP1635396 A JP 1635396A JP 3410893 B2 JP3410893 B2 JP 3410893B2
- Authority
- JP
- Japan
- Prior art keywords
- piezoelectric
- piezoelectric element
- piezoelectric body
- glass component
- conductive paste
- 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.)
- Expired - Lifetime
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- 238000004519 manufacturing process Methods 0.000 title claims description 5
- 239000011521 glass Substances 0.000 claims description 31
- 239000013078 crystal Substances 0.000 claims description 16
- 239000004020 conductor Substances 0.000 claims description 10
- 238000000034 method Methods 0.000 claims description 9
- 229910052769 Ytterbium Inorganic materials 0.000 claims description 6
- 229910052738 indium Inorganic materials 0.000 claims description 6
- 229910052759 nickel Inorganic materials 0.000 claims description 6
- 229910052758 niobium Inorganic materials 0.000 claims description 6
- 229910052715 tantalum Inorganic materials 0.000 claims description 6
- 229910052725 zinc Inorganic materials 0.000 claims description 6
- 229910052706 scandium Inorganic materials 0.000 claims description 5
- 238000005245 sintering Methods 0.000 claims description 5
- 230000008878 coupling Effects 0.000 description 12
- 238000010168 coupling process Methods 0.000 description 12
- 238000005859 coupling reaction Methods 0.000 description 12
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 description 11
- 239000000523 sample Substances 0.000 description 10
- 239000000463 material Substances 0.000 description 9
- 230000000052 comparative effect Effects 0.000 description 6
- 150000001875 compounds Chemical class 0.000 description 5
- 229910052749 magnesium Inorganic materials 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
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- 229910004298 SiO 2 Inorganic materials 0.000 description 3
- 230000003628 erosive effect Effects 0.000 description 3
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- OAYXUHPQHDHDDZ-UHFFFAOYSA-N 2-(2-butoxyethoxy)ethanol Chemical compound CCCCOCCOCCO OAYXUHPQHDHDDZ-UHFFFAOYSA-N 0.000 description 2
- 229920005822 acrylic binder Polymers 0.000 description 2
- 230000002411 adverse Effects 0.000 description 2
- 239000011230 binding agent Substances 0.000 description 2
- 229910010293 ceramic material Inorganic materials 0.000 description 2
- 229940028356 diethylene glycol monobutyl ether Drugs 0.000 description 2
- 239000007772 electrode material Substances 0.000 description 2
- 229910052737 gold Inorganic materials 0.000 description 2
- JCGNDDUYTRNOFT-UHFFFAOYSA-N oxolane-2,4-dione Chemical compound O=C1COC(=O)C1 JCGNDDUYTRNOFT-UHFFFAOYSA-N 0.000 description 2
- 229910052709 silver Inorganic materials 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 238000004544 sputter deposition Methods 0.000 description 2
- 238000007740 vapor deposition Methods 0.000 description 2
- VZSRBBMJRBPUNF-UHFFFAOYSA-N 2-(2,3-dihydro-1H-inden-2-ylamino)-N-[3-oxo-3-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)propyl]pyrimidine-5-carboxamide Chemical compound C1C(CC2=CC=CC=C12)NC1=NC=C(C=N1)C(=O)NCCC(N1CC2=C(CC1)NN=N2)=O VZSRBBMJRBPUNF-UHFFFAOYSA-N 0.000 description 1
- -1 B 2 O 3 Inorganic materials 0.000 description 1
- NIPNSKYNPDTRPC-UHFFFAOYSA-N N-[2-oxo-2-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)ethyl]-2-[[3-(trifluoromethoxy)phenyl]methylamino]pyrimidine-5-carboxamide Chemical compound O=C(CNC(=O)C=1C=NC(=NC=1)NCC1=CC(=CC=C1)OC(F)(F)F)N1CC2=C(CC1)NN=N2 NIPNSKYNPDTRPC-UHFFFAOYSA-N 0.000 description 1
- AFCARXCZXQIEQB-UHFFFAOYSA-N N-[3-oxo-3-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)propyl]-2-[[3-(trifluoromethoxy)phenyl]methylamino]pyrimidine-5-carboxamide Chemical compound O=C(CCNC(=O)C=1C=NC(=NC=1)NCC1=CC(=CC=C1)OC(F)(F)F)N1CC2=C(CC1)NN=N2 AFCARXCZXQIEQB-UHFFFAOYSA-N 0.000 description 1
- 229920002472 Starch Polymers 0.000 description 1
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- 229910052788 barium Inorganic materials 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 229920002678 cellulose Polymers 0.000 description 1
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- 238000004021 metal welding Methods 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- 229910052763 palladium Inorganic materials 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
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Landscapes
- Compositions Of Oxide Ceramics (AREA)
- Crystals, And After-Treatments Of Crystals (AREA)
- Transducers For Ultrasonic Waves (AREA)
Description
【０００１】[0001]
【発明の属する技術分野】本発明は単結晶素子に関す
る。TECHNICAL FIELD The present invention relates to a single crystal device.
【０００２】[0002]
【従来の技術】圧電素子は、電圧を印加することで振動
が生じることを利用し、例えば人体内部を検査するため
の医療用診断装置や金属溶接内部の探傷を目的とする検
査装置などの超音波プローブ等に利用されている。2. Description of the Related Art Piezoelectric elements utilize the fact that vibration is generated when a voltage is applied, and are used, for example, in medical diagnostic equipment for inspecting the inside of the human body and inspection equipment for the purpose of flaw detection in metal welding. It is used as a sound wave probe.
【０００３】通常、これらの超音波プローブに使用され
る圧電体としてはペロブスカイト構造のセラミック材料
が使用されているが、セラミック材料は電気機械結合係
数（ｋt 、ｋ33やｋ33´）が低い、すなわち電気から振
動への変換効率が低かった。Usually, a ceramic material having a perovskite structure is used as the piezoelectric body used in these ultrasonic probes, but the ceramic material has a low electromechanical coupling coefficient (k t , k 33 or k 33 ′). That is, the conversion efficiency from electricity to vibration was low.
【０００４】一方、ペロブスカイト構造の単結晶材料は
電気機械結合係数の高い圧電材料として知られている
が、この単結晶材料にスパッタや蒸着により電極を形成
した場合、電極とリード線との接合などが困難であり、
さらには接合面での密着強度にも問題が生じた。On the other hand, a single crystal material having a perovskite structure is known as a piezoelectric material having a high electromechanical coupling coefficient. When an electrode is formed on this single crystal material by sputtering or vapor deposition, the electrode and the lead wire are joined together. Is difficult and
Furthermore, there was a problem with the adhesion strength at the joint surface.
【０００５】[0005]
【発明が解決しようとする課題】上述したように、従来
の圧電素子は外部から接続されるリードとの接合性が悪
いと言う問題があった。本願発明は、このような問題を
解決し、外部電極との接合性が良好であり、簡便に製造
できる電気機械結合係数の高い圧電素子を提供すること
を目的とする。As described above, the conventional piezoelectric element has a problem in that the bondability with the leads connected from the outside is poor. SUMMARY OF THE INVENTION It is an object of the present invention to provide a piezoelectric element which solves such a problem, has a good bondability with an external electrode, and can be easily manufactured with a high electromechanical coupling coefficient.
【０００６】[0006]
【課題を解決するための手段】本願第１の発明は、Ｐｂ
［（Ｂ1 ，Ｂ2 ）1-X ＴｉX ］Ｏ3 （ただし、ｘ＝０〜
０．５５、Ｂ1 はＺｎ、Ｎｉ、Ｍｇ、Ｓｃ、Ｉｎおよび
Ｙｂの群から選ばれる少なくとも一種、Ｂ2 はＮｂおよ
びＴａから選ばれる少なくとも１種）の単結晶からなる
圧電体と、この圧電体表面の一部に形成され、０．０１
〜５ｗｔ％のガラス成分および導電性材料からなる電極
層とを有する圧電素子である。Means for Solving the Problems The first invention of the present application is Pb.
[(B1, B2) 1-X Ti X ] O 3 (where x = 0 to
0.55, B1 is at least one kind selected from the group of Zn, Ni, Mg, Sc, In and Yb, B2 is at least one kind selected from Nb and Ta), and a piezoelectric body made of a single crystal, and the surface of this piezoelectric body Formed in part of
A piezoelectric element having a glass component of ˜5 wt% and an electrode layer made of a conductive material.
【０００７】本願第２の発明は、前記ガラス成分は、５
０ｗｔ％以上がＰｂＯおよびＺｎＯの少なくとも１種で
ある前記第１の発明に記載の圧電素子である。本願第３
の発明は、Ｐｂ［（Ｂ1 ，Ｂ2 ）1-X ＴｉX ］Ｏ3 （た
だし、ｘ＝０〜０．５５、Ｂ1 はＺｎ、Ｎｉ、Ｍｇ、Ｓ
ｃ、ＩｎおよびＹｂの群から選ばれる少なくとも一種、
Ｂ2 はＮｂおよびＴａから選ばれる少なくとも１種）の
単結晶からなる圧電体表面に、０．０１〜５ｗｔ％のガ
ラス成分および導電性材料を含有する導電性ペースト層
を形成する工程と、前記導電性ペーストを焼結し前記圧
電体表面に電極層を形成する工程とを有する圧電素子の
製造方法である。本願第４の発明は、９００℃以下で前
記導電性ペーストを焼結する前記第３の発明に記載の圧
電素子の製造方法である。In the second invention of the present application, the glass component is 5
The piezoelectric element according to the first invention, wherein 0 wt% or more is at least one of PbO and ZnO. Third application
The invention, Pb [(B1, B2) 1-X Ti X] O 3 ( however, x = 0~0.55, B1 is Zn, Ni, Mg, S
at least one selected from the group consisting of c, In and Yb,
B2 is a step of forming a conductive paste layer containing 0.01 to 5 wt% of a glass component and a conductive material on the surface of the piezoelectric body made of a single crystal of at least one selected from Nb and Ta); Of a conductive paste to form an electrode layer on the surface of the piezoelectric body. A fourth invention of the present application is the method for manufacturing a piezoelectric element according to the third invention, wherein the conductive paste is sintered at 900 ° C. or lower.
【０００８】[0008]
【発明の実施の形態】本願発明は、Ｐｂ［（Ｂ1 ，Ｂ2
）1-X ＴｉX ］Ｏ3 （ただし、ｘ＝０〜０．５５、Ｂ1
はＺｎ、Ｎｉ、Ｍｇ、Ｓｃ、ＩｎおよびＹｂの群から
選ばれる少なくとも一種、Ｂ2 はＮｂおよびＴａから選
ばれる少なくとも１種よりなるペロブスカイト化合物の
単結晶からなる圧電体と、この圧電体表面の一部に形成
されたガラス成分の含有率が０．０１〜５ｗｔ％の導体
からなる電極層とを有する圧電素子である。BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, Pb [(B1, B2
) 1-X Ti X ] O 3 (where x = 0 to 0.55, B1
Is a piezoelectric material composed of a single crystal of a perovskite compound consisting of at least one selected from the group of Zn, Ni, Mg, Sc, In and Yb, B2 is at least one selected from Nb and Ta, and one of the piezoelectric surfaces. A piezoelectric element having an electrode layer made of a conductor having a glass component content of 0.01 to 5 wt% formed in the portion.
【０００９】ペロブスカイト化合物などのような酸化物
は、金属との密着力が弱い。そのため、ペロブスカイト
化合物からなる圧電体表面に、導電性ペーストを焼き付
けて、電極層を形成する場合には、導電性ペースト中に
ガラス成分を添加してその密着性を高めることが必須条
件となっており、通常ガラス成分を１０ｗｔ％程度添加
することで十分な密着強度を得ている。Oxides such as perovskite compounds have weak adhesion to metals. Therefore, when a conductive paste is baked on the surface of a piezoelectric body made of a perovskite compound to form an electrode layer, it is an essential condition to add a glass component to the conductive paste to enhance its adhesion. Therefore, a sufficient adhesion strength is usually obtained by adding about 10 wt% of the glass component.
【００１０】本発明者らが電気機械結合係数の高い圧電
体単結晶に、前述の導電性ペーストを塗布、焼き付ける
ことで、スパッタや蒸着などの従来法と違い、簡便な装
置で、リードとの接続性の高い、電極層を形成した。そ
の結果、圧電素子の誘電率は極端に低く、正常な電気機
械結合係数の値が得られなかった。By coating and baking the above-mentioned conductive paste on a piezoelectric single crystal having a high electromechanical coupling coefficient, the inventors of the present invention used a simple device, unlike a conventional method such as sputtering or vapor deposition, to form a lead. An electrode layer having high connectivity was formed. As a result, the dielectric constant of the piezoelectric element was extremely low, and a normal electromechanical coupling coefficient value could not be obtained.
【００１１】この原因について、鋭意研究の結果、導電
性ペースト中のガラス成分が圧電素子に悪影響を与える
という知見を得、本発明に至った。この理由は明確でな
いが、理由の１つとして導電性ペースト中にガラス成分
が添加されていると、ガラス成分が単結晶のペロブスカ
イト化合物の構造を変成させ、圧電性の小さいパイロク
ロア構造となるためであると思われる。また他の理由と
して、導電性ペーストを焼き付ける際に導電性ペースト
中から滲み出るガラス成分が電極と圧電体との界面に層
状に形成されてしまうことが予想される。このような知
見に基づいて、導電性ペースト中のガラス成分を所定量
にすることで誘電率及び電気機械結合係数（ｋ33´、ｋ
33、ｋt など）の高い圧電素子を得ることができるとい
う本発明に至った。As a result of earnest research on this cause, it was found that the glass component in the conductive paste adversely affects the piezoelectric element, and the present invention has been accomplished. The reason for this is not clear, but one of the reasons is that when a glass component is added to the conductive paste, the glass component modifies the structure of the single crystal perovskite compound, resulting in a pyrochlore structure with low piezoelectricity. It appears to be. In addition, as another reason, it is expected that the glass component exuding from the conductive paste when the conductive paste is baked is formed in layers at the interface between the electrode and the piezoelectric body. Based on these findings, the dielectric constant and electromechanical coupling coefficient (k33 ', k
The present invention has made it possible to obtain a piezoelectric element having high (33, kt, etc.).
【００１２】以下、より詳細に本発明について説明す
る。図１は、本発明の圧電素子の概略斜視図である。圧
電体２２の対向する面にそれぞれ電極層２１が形成され
ている。The present invention will be described in more detail below. FIG. 1 is a schematic perspective view of a piezoelectric element of the present invention. Electrode layers 21 are formed on the opposite surfaces of the piezoelectric body 22, respectively.
【００１３】圧電体２２は所定の組成を有する単結晶で
あり、電極層２１は、所定量のガラス成分を含有してい
る。本発明に用いられる単結晶の圧電体は、実質的にＰ
ｂ［（Ｂ1 ，Ｂ2 ）1-X ＴｉX ］Ｏ3 （ただし、ｘ＝０
〜０．５５、Ｂ1 はＺｎ、Ｎｉ、Ｍｇ、Ｓｃ、Ｉｎおよ
びＹｂの群から選ばれる少なくとも一種、Ｂ2 はＮｂお
よびＴａから選ばれる少なくとも１種よりなるペロブス
カイト化合物であればよく、例えば１０ｍｏｌ％以内で
あればＰｂの一部がＢａ、Ｓｒ、ＣａあるいはＬａで置
換されたものであってもよい。The piezoelectric body 22 is a single crystal having a predetermined composition, and the electrode layer 21 contains a predetermined amount of glass component. The single crystal piezoelectric material used in the present invention is substantially composed of P
b [(B1, B2) 1-X Ti X ] O 3 (where x = 0
.About.0.55, B1 is at least one selected from the group consisting of Zn, Ni, Mg, Sc, In and Yb, and B2 is a perovskite compound composed of at least one selected from Nb and Ta. For example, within 10 mol% If so, a part of Pb may be substituted with Ba, Sr, Ca or La.
【００１４】単結晶圧電体の形状は、特に制限されず、
用途によってその形状を任意なものとすることができ
る。また、圧電体の厚さは（電極間の距離）、使用する
周波数帯によって異なり、使用する周波数帯が高くなる
ほど圧電体の厚さは小さく設定される。例えば、超音波
プローブなどに使用する場合には１００μｍ乃至６００
μｍの厚さで使用される。The shape of the single crystal piezoelectric body is not particularly limited,
The shape can be arbitrary depending on the application. The thickness of the piezoelectric body (distance between electrodes) varies depending on the frequency band used, and the thickness of the piezoelectric body is set smaller as the frequency band used increases. For example, when used for an ultrasonic probe or the like, 100 μm to 600 μm
Used in μm thickness.
【００１５】本発明の電極層は、有機溶剤、導電性材料
およびガラス成分からなる導電性ペーストを単結晶の圧
電体表面に塗布した後、焼結することで形成される。前
記導電性材料は、導電性材料であれば特に制限されずに
用いることができるが、Ａｇ、Ｐｄ、ＡｕあるいはＰｔ
等といった金属材料が導電性材料中の５０ｗｔ％以上を
占めることが好ましい。The electrode layer of the present invention is formed by applying a conductive paste composed of an organic solvent, a conductive material and a glass component onto the surface of a single crystal piezoelectric body and then sintering the same. The conductive material can be used without particular limitation as long as it is a conductive material, and Ag, Pd, Au or Pt can be used.
It is preferable that a metal material such as occupies 50 wt% or more of the conductive material.
【００１６】本発明に用いられるガラス成分とは、通常
ガラスに含有される成分の少なくとも１種を含むもので
あれば良く、例えば、ＳｉＯ2 、Ｂ2 Ｏ3 、ＰｂＯやＺ
ｎＯなどの酸化物があげられる。これらガラス成分のう
ち、特に、ＰｂＯやＺｎＯは他のガラス成分に比べ、電
気機械結合係数の値の大きい圧電素子を得ることができ
る。したがって、ガラス成分中のＰｂＯおよびＺｎＯの
総量が５０ｗｔ％以上とすることが好ましい。逆に、Ｓ
ｉＯ2 、Ｂ2 Ｏ3 は、圧電体の特性に与える悪影響が大
きいため、ガラス成分中のＳｉＯ2 、Ｂ2 Ｏ3 の総量は
５０ｗｔ％以下とすることが好ましい。The glass component used in the present invention may be one containing at least one of the components usually contained in glass, for example, SiO 2 , B 2 O 3 , PbO or Z.
Examples thereof include oxides such as nO. Among these glass components, particularly PbO and ZnO can provide a piezoelectric element having a larger electromechanical coupling coefficient than other glass components. Therefore, the total amount of PbO and ZnO in the glass component is preferably 50 wt% or more. Conversely, S
Since iO 2 and B 2 O 3 have a large adverse effect on the characteristics of the piezoelectric body, the total amount of SiO 2 and B 2 O 3 in the glass component is preferably 50 wt% or less.
【００１７】これは、ＳｉＯ2 、Ｂ2 Ｏ3 が本発明に係
わる圧電体のペロブスカイト構造を破壊するためと思わ
れる。電極層中のガラス成分の量が０．０１ｗｔ％未満
であると、圧電体との密着力を十分に取れず、５ｗｔ％
を越えると圧電体の特性を低減させるため、０．０１ｗ
ｔ％以上、５ｗｔ％以下に設定する必要があり、さらに
は０．１ｗｔ％以上、２ｗｔ％以下とすることが好まし
い。It is considered that this is because SiO 2 and B 2 O 3 destroy the perovskite structure of the piezoelectric material according to the present invention. If the amount of the glass component in the electrode layer is less than 0.01 wt%, the adhesive force with the piezoelectric body cannot be sufficiently obtained, and the amount is 5 wt%.
If it exceeds, the characteristics of the piezoelectric body will be reduced, so 0.01w
It is necessary to set t% or more and 5 wt% or less, and more preferably 0.1 wt% or more and 2 wt% or less.
【００１８】ガラス成分の量が多いと圧電体の特性が低
下する理由は、セラミックでは粒界に吸収されるべきガ
ラス成分が結晶格子内部に入り込ことでペロブスカイト
構造を崩し、パイロクロア構造としてしまうため、ある
いは一部のガラス成分により電極層と圧電体との界面に
ガラス層を形成することためと考えられる。The reason why the characteristics of the piezoelectric material deteriorate when the amount of the glass component is large is that in the ceramic, the glass component to be absorbed in the grain boundaries enters the inside of the crystal lattice to destroy the perovskite structure, resulting in a pyrochlore structure. Or, it is considered that the glass layer is formed at the interface between the electrode layer and the piezoelectric body by a part of the glass component.
【００１９】電極層の厚さは、圧電体の特性を低下させ
ないために圧電体の厚さに対して１／２０以下の厚さに
することが望ましい。また圧電体との十分な密着性を得
るためには０．３μｍ以上とすることが望ましい。The thickness of the electrode layer is preferably 1/20 or less of the thickness of the piezoelectric body so as not to deteriorate the characteristics of the piezoelectric body. Further, in order to obtain sufficient adhesion with the piezoelectric body, it is desirable that the thickness be 0.3 μm or more.
【００２０】電極層となる導電性ペーストからなる層を
圧電体表面に形成する方法としてはスクリーン印刷法が
最も一般的である。スクリーン印刷法はスクリーンに塗
られた乳剤厚み及びスクリーンの目の粗さを調整するこ
とにより自由に形成厚みを調整できる。A screen printing method is the most general method for forming a layer made of a conductive paste to be an electrode layer on the surface of a piezoelectric material. In the screen printing method, the formed thickness can be freely adjusted by adjusting the thickness of the emulsion applied to the screen and the roughness of the screen mesh.
【００２１】また、導電性ペーストは、溶剤と導電性物
質とから調整されるが、前記溶剤は、導電性材料やガラ
ス成分などの電極成分を分散し得るものであれば特に制
限されず用いることができ、例えばジエチレングリコー
ルモノブチルエーテルなどの比較的粘性のあるものや、
ブチルカルビトールのような粘性の低いものを用いるこ
ともできる。粘性の低いものではアクリル系バインダー
やセルロース系バインダーなどを混合することもある。
また安全環境保護の立場から澱粉等の水系のバインダー
を用いても良い。The conductive paste is prepared from a solvent and a conductive substance, but the solvent is not particularly limited as long as it can disperse the electrode components such as the conductive material and the glass component. Which is relatively viscous, such as diethylene glycol monobutyl ether,
It is also possible to use one having a low viscosity such as butyl carbitol. If the viscosity is low, an acrylic binder or a cellulose binder may be mixed.
Further, from the viewpoint of safe environment protection, an aqueous binder such as starch may be used.
【００２２】導電性ペーストの層を形成する方法は前述
したスクリーン印刷法に限定されず、現在広く用いられ
ているグラビア印刷、熱転写印刷あるいはスタンプ式の
印刷方法などが例として挙げられる。The method of forming the layer of the conductive paste is not limited to the above-mentioned screen printing method, and examples thereof include gravure printing, thermal transfer printing and stamp printing methods which are widely used at present.
【００２３】また、本発明の圧電素子は、その製造方法
工程において、導電性ペーストを焼結させる際に、でき
る限り低温で焼結することが望ましい。具体的には導電
性ペーストの焼結温度以上で、９００℃以下、より好ま
しくは７００℃以下で焼結することで、電気機械結合係
数の値の大きい圧電素子を得ることができる。Further, the piezoelectric element of the present invention is preferably sintered at a temperature as low as possible when the conductive paste is sintered in the manufacturing method step. Specifically, a piezoelectric element having a large electromechanical coupling coefficient value can be obtained by sintering at a sintering temperature of the conductive paste or higher and 900 ° C. or lower, more preferably 700 ° C. or lower.
【００２４】この理由も、高温で導電性ペーストを焼結
すると、ガラス成分が圧電体のペロブスカイト構造を破
壊しやすい、あるいは電極層と圧電体との界面にガラス
層が形成されやすくなるためと思われる。The reason for this is probably that when the conductive paste is sintered at a high temperature, the glass component easily breaks the perovskite structure of the piezoelectric body or the glass layer is easily formed at the interface between the electrode layer and the piezoelectric body. Be done.
【００２５】本願発明の圧電素子は、超音波プローブ、
結石破砕装置、圧電モーター、圧電ブザーあるいは蒸気
発生装置などに従来の圧電素子と同様に用いることがで
きる。一例として以下に超音波プローブについて説明す
る。The piezoelectric element of the present invention is an ultrasonic probe,
It can be used in a calculus breaking device, a piezoelectric motor, a piezoelectric buzzer, a steam generator, or the like in the same manner as a conventional piezoelectric element. An ultrasonic probe will be described below as an example.
【００２６】図２は、本発明の圧電素子を用いた超音波
プローブの概略斜視図である。図中、圧電体１１の対向
する面に電極層１３、１４を形成した圧電素子がアレイ
状に配置されている。配列された圧電素子の片面には音
響マッチング層１５および音響レンズ１６からなる超音
波送受信面が形成されている。配列された圧電素子の超
音波送受信面と対向する面にはバッキング層が形成され
ている。さらに電極層１３はフレキシブル印刷配線板１
８上の配線に電気的に接続されており、電極層１４はア
ース電極板上の配線に接続されている。FIG. 2 is a schematic perspective view of an ultrasonic probe using the piezoelectric element of the present invention. In the figure, piezoelectric elements having electrode layers 13 and 14 formed on the opposing surfaces of the piezoelectric body 11 are arranged in an array. An ultrasonic wave transmitting / receiving surface including an acoustic matching layer 15 and an acoustic lens 16 is formed on one surface of the arrayed piezoelectric elements. A backing layer is formed on the surface of the arrayed piezoelectric elements that faces the ultrasonic wave transmitting / receiving surface. Further, the electrode layer 13 is a flexible printed wiring board 1
8 is electrically connected to the wiring on the ground electrode plate, and the electrode layer 14 is connected to the wiring on the ground electrode plate.
【００２７】超音波プローブに用いられる圧電体は通常
厚さ１００〜６００μｍ程度で、６０〜３６０μｍ×１
５〜２０ｃｍ程度の物が用いられる。またＡｇ、Ｔｉあ
るいはＡｕなどを電極層として厚さ０．４〜２０μｍ程
度に形成し、これをアレイ状に配列して用いる。The piezoelectric body used for the ultrasonic probe usually has a thickness of about 100 to 600 μm and 60 to 360 μm × 1.
The thing of about 5 to 20 cm is used. Further, Ag, Ti, Au, or the like is formed as an electrode layer to a thickness of about 0.4 to 20 μm, and this is arranged in an array and used.
【００２８】電極層１３、１４間に電圧を印加し、圧電
体を共振させることで超音波送受信面から超音波を送信
する。受信時には、超音波送受信面から受けた超音波に
よって圧電体を振動させ、この振動が電気的に変換され
る。By applying a voltage between the electrode layers 13 and 14 to resonate the piezoelectric body, ultrasonic waves are transmitted from the ultrasonic wave transmitting / receiving surface. Upon reception, the piezoelectric body is vibrated by the ultrasonic waves received from the ultrasonic wave transmitting / receiving surface, and this vibration is electrically converted.
【００２９】[0029]
実施例１
Ｐｂ［（Ｚｎ1/3 Ｎｂ2/3 ）o.91Ｔｉ0.09］Ｏ3 （以下
９１ＰＺＮ−９ＰＴと略す）からなる単結晶ウエハーを
〈１００〉面と平行になるように方位を決めてダイヤモ
ンドカッターにて１ｍｍの厚みに切り出した。これを最
終４００μｍまで研磨した。次に下記表１に示す組成比
（重量比）の電極材料をジエチレングリコールモノブチ
ルエーテルに溶かし、導電性ペーストを得た。この導電
性ペーストを前記ウエハーにスクリーン印刷により塗布
し、導電性ペースト層を形成した後、８００℃にて１０
分間焼結することで５μｍ厚の電極層を形成した。この
試料を４ｍｍ各にカットし、厚さ４００μｍで４ｍｍ×
４ｍｍの圧電素子を作成した。Example 1 A single crystal wafer made of Pb [(Zn 1/3 Nb 2/3 ) o.91 Ti 0.09 ] O 3 (hereinafter abbreviated as 91PZN-9PT) was oriented so that it was parallel to the <100> plane. With a diamond cutter to a thickness of 1 mm. This was polished to a final thickness of 400 μm. Next, an electrode material having a composition ratio (weight ratio) shown in Table 1 below was dissolved in diethylene glycol monobutyl ether to obtain a conductive paste. This conductive paste is applied to the wafer by screen printing to form a conductive paste layer, which is then heated at 800 ° C. for 10 minutes.
An electrode layer having a thickness of 5 μm was formed by sintering for 5 minutes. This sample was cut into 4mm each, 4mm x 400μm thick
A 4 mm piezoelectric element was prepared.
【００３０】得られた圧電素子の容量ＣをＬＣＲメータ
ー（HEWLETT PACKERD 社製 4284A）にて測定したところ
１．４５ｎＦであった。これをεr ＝Ｃｄ／ε0 Ｓ（式
中εr は誘電率、ｄは試料厚さ、ε0 は真空の誘電率、
Ｓは電極面積である）の式にあてはめることで、この圧
電素子の誘電率が４１００であることが分かる。The capacitance C of the obtained piezoelectric element was 1.45 nF when measured with an LCR meter (4284A manufactured by HEWLETT PACKERD). Ε r = Cd / ε 0 S (where ε r is the dielectric constant, d is the sample thickness, ε 0 is the vacuum dielectric constant,
It is understood that the dielectric constant of this piezoelectric element is 4100 by applying the equation (S is the electrode area).
【００３１】次に２００℃、１ｋＶ／ｍｍにてこの圧電
素子の分極処理を行い、ネットワーク・スペクトラムア
ナライザー（HEWLETT PACKERD 社製 4195A）のネットワ
ークモードにて共振、反共振周波数を求めた。共振周波
数４．８２５ＭＨｚ、反共振周波数５．５２５ＭＨｚで
あった。Next, the piezoelectric element was polarized at 200 ° C. and 1 kV / mm, and the resonance and antiresonance frequencies were determined in the network mode of a network spectrum analyzer (4195A manufactured by HEWLETT PACKERD). The resonance frequency was 4.825 MHz and the anti-resonance frequency was 5.525 MHz.
【００３２】電気機械結合係数ｋt は、ｋt 2 ＝０．４
０５×ｆr ／（ｆa −ｆr ）＋０．８１０（式中、ｆr
は共振周波数、ｆa は反共振周波数）で通常表され、こ
の式よりこの圧電素子のｋt が５３．３％であることが
分かる。The electromechanical coupling coefficient k t is k t 2 = 0.4.
05 × f r / (f a -f r) +0.810 ( in the formula, f r
Is a resonance frequency and f a is an anti-resonance frequency). From this equation, it is understood that k t of this piezoelectric element is 53.3%.
【００３３】この圧電素子の電極にリード線をハンダ付
けしたところ、ハンダ食われは生じなかった。また、リ
ード線と圧電素子との接着量も強く、リード線を手で強
く引っ張っても剥がれは起きず、更に強い力を加るとリ
ード線が切れたが、電極の剥がれは生じなかった。When lead wires were soldered to the electrodes of this piezoelectric element, solder erosion did not occur. In addition, the amount of adhesion between the lead wire and the piezoelectric element was strong, and peeling did not occur even if the lead wire was strongly pulled by hand. When a stronger force was applied, the lead wire was broken, but the electrode did not peel.
【００３４】比較例１−１乃至１−３
電極材料の組成比を下記表１の通りにしたことを除き実
施例１と全く同様にして比較例１−１乃至比較例１−３
の圧電素子それぞれ作成した。Comparative Examples 1-1 to 1-3 Comparative Examples 1-1 to 1-3 were performed in exactly the same manner as in Example 1 except that the composition ratios of the electrode materials were as shown in Table 1 below.
Piezoelectric elements were prepared.
【００３５】得られた圧電素子を実施例１と全く同様に
して容量、誘電率を測定した。その結果を表１に併記す
る。さらに得られた各圧電素子を実施例１と同様の処理
でリード線をハンダ付けした。The capacitance and the dielectric constant of the obtained piezoelectric element were measured in exactly the same manner as in Example 1. The results are also shown in Table 1. Further, lead wires were soldered to each of the obtained piezoelectric elements by the same process as in Example 1.
【００３６】比較例１−１の圧電素子はハンダ食われが
生じ、リード線を手で軽く引っ張るとリード線が容易に
圧電素子から剥離してしまった。比較例１−２の圧電素
子はリード線を手で強く引っ張ると圧電体から電極が剥
離してしまった。剥離した圧電体の表面を走査型電子顕
微鏡（ＳＥＭ）で観察したところ正八面体の粒（パイロ
クロア構造）が観測された。電極の剥がれていない部分
の断面を観察したところ、圧電体と電極との間にパイロ
クロア層が生成しておりひび割れが観察された。比較例
１−３の圧電素子はリード線を手で引っ張ると圧電体か
ら電極が剥離してしまった。The piezoelectric element of Comparative Example 1-1 suffered solder erosion, and when the lead wire was lightly pulled by hand, the lead wire was easily separated from the piezoelectric element. In the piezoelectric element of Comparative Example 1-2, when the lead wire was strongly pulled by hand, the electrode peeled off from the piezoelectric body. When the surface of the separated piezoelectric material was observed with a scanning electron microscope (SEM), regular octahedral grains (pyrochlore structure) were observed. When the cross section of the part where the electrode was not peeled off was observed, a pyrochlore layer was formed between the piezoelectric body and the electrode, and cracking was observed. In the piezoelectric element of Comparative Example 1-3, when the lead wire was pulled by hand, the electrode peeled off from the piezoelectric body.
【００３７】[0037]
【表１】 [Table 1]
【００３８】実施例２乃至５
Ａｇ粉末４９ｇ、アクリル系バインダ５０ｇおよび下記
表２に示される組成のガラス成分１ｇをブチルカルビト
ールに溶かして導電性ペーストを調製した。Examples 2 to 5 49 g of Ag powder, 50 g of an acrylic binder and 1 g of a glass component having the composition shown in Table 2 below were dissolved in butyl carbitol to prepare a conductive paste.
【００３９】この導電性ペーストを実施例１と全く同様
の圧電体にスタンプ式で印刷した後、７００℃で１５分
熱処理し、１０μｍ厚の電極層を形成し、圧電素子を作
成した。This electroconductive paste was printed on the same piezoelectric body as in Example 1 by the stamp method and then heat-treated at 700 ° C. for 15 minutes to form an electrode layer having a thickness of 10 μm, and a piezoelectric element was prepared.
【００４０】実施例１と全く同様に測定した結果の誘電
率εr および電気機械結合係数ｋtを表２に併記する。
得られた各圧電素子の電極にリード線をハンダ付けした
ところ、いずれの圧電素子もハンダ食われは生じなかっ
た。また、リード線と圧電素子との接着量も強く、リー
ド線を手で強く引っ張っても剥がれは起きず、更に強い
力を加るとリード線が切れたが、電極の剥がれは生じな
かった。Table 2 also shows the permittivity ε r and the electromechanical coupling coefficient kt obtained as a result of measurement exactly as in Example 1.
When lead wires were soldered to the electrodes of the obtained piezoelectric elements, solder erosion did not occur in any of the piezoelectric elements. In addition, the amount of adhesion between the lead wire and the piezoelectric element was strong, and peeling did not occur even if the lead wire was strongly pulled by hand. When a stronger force was applied, the lead wire was broken, but the electrode did not peel.
【００４１】実施例および比較例から、本発明の圧電素
子は圧電体と電極層との密着力が高く、かつ誘電率、電
気機械結合係数も良好であることが分かる。さらに、実
施例２乃至５から、ガラス成分の中でもＰｂＯあるいは
ＺｎＯの比率を高くすることで、圧電素子の特性を高め
ることが可能となることがわかる。From the examples and comparative examples, it is understood that the piezoelectric element of the present invention has a high adhesion between the piezoelectric body and the electrode layer, and also has a good dielectric constant and electromechanical coupling coefficient. Furthermore, from Examples 2 to 5, it can be seen that the characteristics of the piezoelectric element can be improved by increasing the ratio of PbO or ZnO among the glass components.
【００４２】[0042]
【表２】 [Table 2]
【００４３】[0043]
【発明の効果】上述したように、本願発明によれば誘電
率、電気機械結合係数の良好な圧電素子が得られる。As described above, according to the present invention, a piezoelectric element having a good dielectric constant and a good electromechanical coupling coefficient can be obtained.
【図１】 本発明の圧電素子の概略斜視図。FIG. 1 is a schematic perspective view of a piezoelectric element of the present invention.
【図２】 本発明の圧電素子を用いた超音波プローブの
概略断面図。FIG. 2 is a schematic sectional view of an ultrasonic probe using the piezoelectric element of the present invention.
２１・・・電極層 ２２・・・圧電体 21 ... Electrode layer 22 ... Piezoelectric body
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.7 識別記号 ＦＩ Ｈ０４Ｒ 17/00 ３３０ Ｈ０１Ｌ 41/22 Ｚ (56)参考文献 特開 平６−38963（ＪＰ，Ａ) 特開 平６−60713（ＪＰ，Ａ) 特開 平６−131912（ＪＰ，Ａ) 特開 昭57−180112（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) H01L 41/18 ─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. 7 Identification code FI H04R 17/00 330 H01L 41/22 Z (56) References JP-A-6-38963 (JP, A) JP-A-6-60713 (JP, A) JP-A-6-131912 (JP, A) JP-A-57-180112 (JP, A) (58) Fields investigated (Int.Cl. 7 , DB name) H01L 41/18
Claims (4)
（ただし、ｘ＝０〜０．５５、Ｂ1 はＺｎ、Ｎｉ、Ｍ
ｇ、Ｓｃ、ＩｎおよびＹｂの群から選ばれる少なくとも
一種、Ｂ2 はＮｂおよびＴａから選ばれる少なくとも１
種）の単結晶からなる圧電体と、この圧電体表面の一部
に形成され、０．０１〜５ｗｔ％のガラス成分および導
電性材料からなる電極層とを有することを特徴とする圧
電素子。1. Pb [(B1, B2) 1-X Ti X ] O 3
(However, x = 0 to 0.55, B1 is Zn, Ni, M
at least one selected from the group consisting of g, Sc, In and Yb, and B2 is at least 1 selected from Nb and Ta.
A piezoelectric element comprising a piezoelectric body made of a single crystal of (seed) and an electrode layer formed on a part of the surface of the piezoelectric body and made of a glass component of 0.01 to 5 wt% and a conductive material.
ｂＯおよびＺｎＯの少なくとも１種であることを特徴と
する請求項１記載の圧電素子。2. The glass component comprises 50 wt% or more of P.
The piezoelectric element according to claim 1, which is at least one of bO and ZnO.
（ただし、ｘ＝０〜０．５５、Ｂ1 はＺｎ、Ｎｉ、Ｍ
ｇ、Ｓｃ、ＩｎおよびＹｂの群から選ばれる少なくとも
一種、Ｂ2 はＮｂおよびＴａから選ばれる少なくとも１
種）の単結晶からなる圧電体表面に、０．０１〜５ｗｔ
％のガラス成分および導電性材料を含有する導電性ペー
スト層を形成する工程と、前記導電性ペーストを焼結し
前記圧電体表面に電極層を形成する工程とを有すること
を特徴とする圧電素子の製造方法。3. Pb [(B1, B2) 1-X Ti X ] O 3
(However, x = 0 to 0.55, B1 is Zn, Ni, M
at least one selected from the group consisting of g, Sc, In and Yb, and B2 is at least 1 selected from Nb and Ta.
0.01 to 5 wt% on the surface of the piezoelectric body made of the single crystal of
% Of a glass component and a conductive material, a step of forming a conductive paste layer, and a step of sintering the conductive paste to form an electrode layer on the surface of the piezoelectric body. Manufacturing method.
結することを特徴とする請求項３記載の圧電素子の製造
方法。4. The method for manufacturing a piezoelectric element according to claim 3, wherein the conductive paste is sintered at 900 ° C. or lower.
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|---|---|---|---|
| JP01635396A JP3410893B2 (en) | 1996-02-01 | 1996-02-01 | Piezoelectric element and method of manufacturing the same |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP01635396A JP3410893B2 (en) | 1996-02-01 | 1996-02-01 | Piezoelectric element and method of manufacturing the same |
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|---|---|
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| US7402938B2 (en) * | 2004-10-29 | 2008-07-22 | Jfe Mineral Co., Ltd. | Piezoelectric single crystal device |
| JP2014170795A (en) * | 2013-03-01 | 2014-09-18 | Ngk Insulators Ltd | Laminate and piezoelectric/electrostrictive element |
-
1996
- 1996-02-01 JP JP01635396A patent/JP3410893B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH09214014A (en) | 1997-08-15 |
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