JPH0223035B2 - - Google Patents
Info
- Publication number
- JPH0223035B2 JPH0223035B2 JP57173931A JP17393182A JPH0223035B2 JP H0223035 B2 JPH0223035 B2 JP H0223035B2 JP 57173931 A JP57173931 A JP 57173931A JP 17393182 A JP17393182 A JP 17393182A JP H0223035 B2 JPH0223035 B2 JP H0223035B2
- Authority
- JP
- Japan
- Prior art keywords
- piezoelectric
- voltage
- coercive electric
- piezoelectric element
- displacement
- 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
Links
Classifications
-
- 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
- H10N30/204—Piezoelectric or electrostrictive devices with electrical input and mechanical output, e.g. functioning as actuators or vibrators using bending displacement, e.g. unimorph, bimorph or multimorph cantilever or membrane benders
- H10N30/2041—Beam type
- H10N30/2042—Cantilevers, i.e. having one fixed end
Landscapes
- Piezo-Electric Or Mechanical Vibrators, Or Delay Or Filter Circuits (AREA)
Description
【発明の詳細な説明】
本発明は圧電バイモルフに関し、特に、圧電素
子単位当り高電圧下長時間動作特性の改善に関す
るものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a piezoelectric bimorph, and more particularly to improving long-term operating characteristics under high voltage per piezoelectric element unit.
圧電バイモルフは、周知のように、電気的な信
号により機械的変位を生ずる機能を有しており、
近年微小な位置制御用あるいは駆動用の変位素子
として多方面に実用化されるようになつている。 As is well known, piezoelectric bimorphs have the ability to generate mechanical displacement using electrical signals.
In recent years, they have come to be put to practical use in many fields as displacement elements for minute position control or driving.
従来、この種の圧電バイモルフは、厚さ方向に
分極処理した２枚の同組成の圧電セラミツク素子
を金属電極板の両面に両素子の分極方向の向きを
一致させて貼り合わせた構成となつている。この
様な圧電バイモルフに直流電圧を印加すると、一
方の圧電素子には分極方向と同一方向の電圧がか
かる事になり、圧電素子は長さ方向に対して縮
み、又他方の圧電素子には分極方向と逆方向の電
圧がかかり、圧電素子は長さ方向に対して伸びる
様になる。従つて、圧電バイモルフには上記伸縮
作用による機械的変位が生じる。ところで圧電素
子に生じる機械的変位δは圧電素子の圧電定数
d31（ｍ／Ｖ）に関係があり、圧電素子の長さｌ
（ｍ）、厚みｔ（ｍ）、印加電圧Ｖ（Ｖ）との間には、
近似的に
δ＝3l2・Ｖ・d31／4t2（ｍ）なる関係にある。従
つて圧電定数d31の高い圧電素子を用いる事が機
械的変位を増大させる上で或は圧電バイモルフを
設計する上で有利とされている。 Conventionally, this type of piezoelectric bimorph has a structure in which two piezoelectric ceramic elements of the same composition that have been polarized in the thickness direction are bonded to both sides of a metal electrode plate with the polarization directions of both elements aligned. There is. When a DC voltage is applied to such a piezoelectric bimorph, a voltage in the same direction as the polarization direction is applied to one piezoelectric element, and the piezoelectric element contracts in the length direction, and the other piezoelectric element is polarized. A voltage is applied in the opposite direction, and the piezoelectric element begins to extend in the length direction. Therefore, mechanical displacement occurs in the piezoelectric bimorph due to the above-mentioned expansion and contraction action. By the way, the mechanical displacement δ generated in the piezoelectric element is the piezoelectric constant of the piezoelectric element.
d 31 (m/V), and the length l of the piezoelectric element
(m), thickness t (m), and applied voltage V (V),
Approximately, the relationship is δ=3l 2 ·V · d 31 /4t 2 (m). Therefore, it is considered advantageous to use a piezoelectric element with a high piezoelectric constant d 31 in increasing mechanical displacement or in designing a piezoelectric bimorph.
圧電定数d31は材料の組成によつて異なるが、
同じ系の材料のうち、圧電定数d31の高いものは
比較的軟かく抗電界が低い傾向にある。抗電界が
低い材料は、分極方向と逆方向に高電圧を印加さ
れると脱分極状態あるいは逆方向に分極された状
態になる。 The piezoelectric constant d 31 varies depending on the composition of the material, but
Among materials of the same type, those with a high piezoelectric constant d 31 tend to be relatively soft and have a low coercive electric field. A material with a low coercive electric field becomes depolarized or polarized in the opposite direction when a high voltage is applied in the opposite direction to the polarization direction.
従つて、圧電バイモルフの２枚の圧電素子とし
て圧電定数d31の大きなものを用いると、機械的
変位を大きくとれるが、比較的高い電圧を長時間
印加していると、分極方向と逆方向に電圧を印加
した側の圧電素子が脱分極あるいは逆方向へ分極
された状態となり、変位しなくなるか逆方向に変
位するようになり、この結果、バイモルフ全体と
しては、変位量が小さくなるか、ほとんど変位し
なくなるという恐れがある。 Therefore, if the two piezoelectric elements of the piezoelectric bimorph have a large piezoelectric constant d 31 , a large mechanical displacement can be obtained, but if a relatively high voltage is applied for a long time, the polarization direction will be reversed. The piezoelectric element on the side to which the voltage is applied becomes depolarized or polarized in the opposite direction, and either no longer displaces or begins to displace in the opposite direction.As a result, the amount of displacement of the bimorph as a whole becomes small or almost no. There is a fear that the displacement will no longer occur.
このような欠点を避けるためには、圧電定数
d31と抗電界のいずれも高い材料が望まれるが、
このような材料は、これ迄のところ現れていな
い。 To avoid such drawbacks, the piezoelectric constant
A material with both high d 31 and coercive electric field is desired, but
Such materials have not appeared so far.
本発明はかかる従来の欠点を解消するために成
されたものであり、長時間、比較的高い電圧を印
加しても機械的変位の劣化のない、高信頼性の圧
電バイモルフを提供する事を主な目的とする。 The present invention has been made in order to eliminate such conventional drawbacks, and aims to provide a highly reliable piezoelectric bimorph that does not suffer from deterioration in mechanical displacement even when a relatively high voltage is applied for a long period of time. Main purpose.
本発明は抗電界の異なる二種の圧電セラミツク
素子を貼り合わせたことを特徴とする圧電バイモ
ルフであつて、低い抗電界の素子側には分極方向
と同一方向に電圧を印加し、高い抗電界の素子側
には分極方向と逆方向の電圧を印加することによ
つて高電圧の長時間印加によつても逆方向電圧を
印加された素子の脱分極や逆方向分極の発生を抑
えて、変位量の劣化を防止することができる。 The present invention is a piezoelectric bimorph characterized by bonding together two types of piezoelectric ceramic elements with different coercive electric fields, in which a voltage is applied in the same direction as the polarization direction to the element side with a lower coercive electric field, and By applying a voltage in the opposite direction to the polarization direction to the element side, even if high voltage is applied for a long time, depolarization and reverse polarization of the element to which the reverse voltage is applied can be suppressed. Deterioration of displacement amount can be prevented.
以下本発明の圧電バイモルフにつき、一実施例
を挙げ、具体的に説明する。 Hereinafter, the piezoelectric bimorph of the present invention will be specifically explained using an example.
第１図は本発明圧電バイモルフの一例断面図で
ある。第１図において、１はPb（TiZr）O3系組
成から成る抗電界250V／mmの圧電素子であり、
比較的高いd31定数を有している。２は同じくPb
（TiZr）O3系であるが異なる組成として抗電界
1000／mm以上の圧電素子である。この圧電素子
１，２は、各々長さ40mm、幅10mm、厚さ0.17mmの
形状のもので、両面に真空蒸着法によりAg電極
を付与し、90〜100℃のシリコン油中で厚み方向
に4KV／mmの直流電圧を30分間印加して分極処
理を施したものである。両圧電素子１，２は、厚
さ0.03mmの金属電極板３の両面に分極方向が同一
になる様にして変性アクリレート系接着剤を用い
加圧接着して一体化されている。使用に際して
は、低抗電界の圧電素子１には分極方向と同一方
向の電圧が印加され、高抗電界の圧電素子２には
分極方向と逆方向の電圧が印加される様にする。
尚第１図において矢印は分極方向を示す。 FIG. 1 is a sectional view of an example of the piezoelectric bimorph of the present invention. In Fig. 1, numeral 1 is a piezoelectric element with a coercive electric field of 250 V/mm consisting of a Pb(TiZr)O 3 composition;
It has a relatively high d31 constant. 2 is also Pb
(TiZr) O3 system but with different composition, coercive electric field
It is a piezoelectric element of 1000/mm or more. These piezoelectric elements 1 and 2 each have a shape of 40 mm in length, 10 mm in width, and 0.17 mm in thickness. Ag electrodes are provided on both sides by vacuum evaporation method, and the piezoelectric elements are coated in silicone oil at 90 to 100°C in the thickness direction. Polarization treatment was performed by applying a DC voltage of 4KV/mm for 30 minutes. Both piezoelectric elements 1 and 2 are integrated by pressure bonding using a modified acrylate adhesive on both sides of a metal electrode plate 3 having a thickness of 0.03 mm so that the polarization directions are the same. In use, a voltage in the same direction as the polarization direction is applied to the piezoelectric element 1 with a low coercive electric field, and a voltage in the opposite direction to the polarization direction is applied to the piezoelectric element 2 with a high coercive electric field.
In FIG. 1, arrows indicate polarization directions.
以上の様にして圧電バイモルフを構成すれば、
圧電素子１は低抗電界にもかかわらず分極方向と
同一方向に電圧が印加されるために、高い印加電
圧でも脱分極が起りにくく、機械的変位の劣化も
ない。一方圧電素子２は高抗電界のものであるた
めに、逆方向の電圧が印加されていても比較的大
きな電圧印加時でも脱分極が起こりにくく、従つ
て機械的変位の劣化も極めて少なく、長時間動作
においても安定した変位特性を維持する事ができ
る。又高抗電界の圧電素子２の厚みを薄くする事
が可能であり機械的変位を大きくとる上で好都合
である。更に高抗電界の圧電素子２に合わせて印
加電圧を設定できるため、広範囲の応用が可能で
ある。 If a piezoelectric bimorph is constructed as described above,
Since a voltage is applied to the piezoelectric element 1 in the same direction as the polarization direction despite the low coercive electric field, depolarization is unlikely to occur even with a high applied voltage, and there is no deterioration in mechanical displacement. On the other hand, since the piezoelectric element 2 has a high coercive electric field, it is difficult to depolarize even when a relatively large voltage is applied, even when a voltage in the opposite direction is applied.Therefore, there is extremely little deterioration in mechanical displacement, and it can be used for long periods of time. Stable displacement characteristics can be maintained even during time operation. Furthermore, it is possible to reduce the thickness of the piezoelectric element 2 with a high coercive electric field, which is advantageous for achieving a large mechanical displacement. Furthermore, since the applied voltage can be set according to the piezoelectric element 2 having a high coercive electric field, a wide range of applications is possible.
上記実施例による本発明の圧電バイモルフと、
従来の低抗電界の圧電素子から成る圧電バイモル
フにつき、温度60℃の雰囲気中で長時間負荷試験
（直流電圧50V、1000時間）を行ない、変位量の
変化を測定した。その結果を第２図のグラフに示
す。 A piezoelectric bimorph of the present invention according to the above embodiment,
A piezoelectric bimorph made of a conventional piezoelectric element with a low coercive electric field was subjected to a long-term load test (DC voltage 50V, 1000 hours) in an atmosphere at a temperature of 60°C, and changes in displacement were measured. The results are shown in the graph of FIG.
第２図からも明らかな様に、従来の圧電バイモ
ルフにおいては初期時大きい変位量が得られるも
のの、時間の経過と共に変位量の劣化が生じ、
1000時間後では35％程度の変位量減となり、信頼
性に乏しく好ましくない。これに対し、本発明の
圧電バイモルフは1000時間後でも変位量の減少が
５％以下と極めて少なく、高い信頼性を有してお
り、圧電バイモルフとしての特性上非常に有利で
ある事がわかる。 As is clear from Figure 2, although the conventional piezoelectric bimorph can obtain a large amount of displacement at the initial stage, the amount of displacement deteriorates over time.
After 1000 hours, the amount of displacement decreases by about 35%, which is unfavorable due to poor reliability. On the other hand, the piezoelectric bimorph of the present invention has a very small decrease in displacement of 5% or less even after 1000 hours, and has high reliability, which shows that it is very advantageous in terms of characteristics as a piezoelectric bimorph.
なお、本発明の実施例においては、両圧電素子
を金属電極板の両面に貼り合わせて強度を向上さ
せたが、直接貼り合わせても同様の効果が達成で
きる事は勿論の事である。 In the embodiment of the present invention, both piezoelectric elements were attached to both sides of the metal electrode plate to improve the strength, but it goes without saying that the same effect can be achieved by directly attaching them.
以上詳述した様に、本発明によれば、抗電界の
異なる圧電セラミツク素子を用いるという簡単な
構成で信頼性の高い圧電バイモルフを得る事がで
き、実用上価値大なるものである。 As detailed above, according to the present invention, a highly reliable piezoelectric bimorph can be obtained with a simple configuration using piezoelectric ceramic elements having different coercive electric fields, and is of great practical value.
第１図は本発明圧電バイモルフの一例の断面
図、第２図は、本発明の圧電バイモルフと従来の
圧電バイモルフの変位量の時間変化を示すグラフ
である。
１……低抗電界の圧電素子、２……高抗電界の
圧電素子、３……金属中間電極板。
FIG. 1 is a cross-sectional view of an example of the piezoelectric bimorph of the present invention, and FIG. 2 is a graph showing changes over time in the amount of displacement of the piezoelectric bimorph of the present invention and the conventional piezoelectric bimorph. 1... Piezoelectric element with low coercive electric field, 2... Piezoelectric element with high coercive electric field, 3... Metal intermediate electrode plate.
Claims (1)
る圧電バイモルフにおいて、該２枚の圧電セラミ
ツク素子として互いに抗電界が異なる圧電セラミ
ツクを用いたことを特徴とする圧電バイモルフ。1. A piezoelectric bimorph formed by bonding two piezoelectric ceramic elements together, characterized in that the two piezoelectric ceramic elements are made of piezoelectric ceramics having different coercive electric fields.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57173931A JPS5963782A (en) | 1982-10-05 | 1982-10-05 | Piezoelectric bimorph element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57173931A JPS5963782A (en) | 1982-10-05 | 1982-10-05 | Piezoelectric bimorph element |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5963782A JPS5963782A (en) | 1984-04-11 |
| JPH0223035B2 true JPH0223035B2 (en) | 1990-05-22 |
Family
ID=15969719
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP57173931A Granted JPS5963782A (en) | 1982-10-05 | 1982-10-05 | Piezoelectric bimorph element |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5963782A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04138087U (en) * | 1991-06-18 | 1992-12-24 | 株式会社技研製作所 | Pile mobile work device |
| JPH0592890A (en) * | 1991-09-30 | 1993-04-16 | Giken Seisakusho Co Ltd | On-pile moving device |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0436231Y2 (en) * | 1985-06-28 | 1992-08-26 | ||
| JPS63237044A (en) * | 1987-03-25 | 1988-10-03 | Minolta Camera Co Ltd | Electrostrictive shutter driving device |
| EP1833102A3 (en) | 1999-10-01 | 2009-04-08 | Ngk Insulators, Ltd. | Piezoelectric/electrostrictive device |
| US7164221B1 (en) | 1999-10-01 | 2007-01-16 | Ngk Insulators, Ltd. | Piezoelectric/electrostrictive device and method of manufacturing same |
| US6657364B1 (en) * | 1999-10-01 | 2003-12-02 | Ngk Insulators, Ltd. | Piezoelectric/electrostrictive device |
| CN104213325A (en) * | 2014-09-22 | 2014-12-17 | 福建省鑫港纺织机械有限公司 | Piezoelectric jacquard element applicable to coarse needle pitches |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR1202614A (en) * | 1958-09-30 | 1960-01-12 | Clevite Corp | Electromechanical transducer |
| JPS5772498A (en) * | 1980-10-23 | 1982-05-06 | Sharp Corp | Bimorph type electrostrictive vibrator |
| JPS58139329A (en) * | 1982-02-15 | 1983-08-18 | Hitachi Ltd | Magnetic head driving element |
| JPS6453515A (en) * | 1987-08-25 | 1989-03-01 | Seiko Epson Corp | Rotor magnet for watch use |
-
1982
- 1982-10-05 JP JP57173931A patent/JPS5963782A/en active Granted
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04138087U (en) * | 1991-06-18 | 1992-12-24 | 株式会社技研製作所 | Pile mobile work device |
| JPH0592890A (en) * | 1991-09-30 | 1993-04-16 | Giken Seisakusho Co Ltd | On-pile moving device |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5963782A (en) | 1984-04-11 |
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