JPH0310163A - Piezoelectric type acceleration sensor - Google Patents

Piezoelectric type acceleration sensor

Info

Publication number
JPH0310163A
JPH0310163A JP14557589A JP14557589A JPH0310163A JP H0310163 A JPH0310163 A JP H0310163A JP 14557589 A JP14557589 A JP 14557589A JP 14557589 A JP14557589 A JP 14557589A JP H0310163 A JPH0310163 A JP H0310163A
Authority
JP
Japan
Prior art keywords
piezoelectric element
electrodes
hole
divided
piezoelectric
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.)
Pending
Application number
JP14557589A
Other languages
Japanese (ja)
Inventor
Katsuhiko Takahashi
克彦 高橋
Shiro Nakayama
中山 四郎
Satoshi Kunimura
國村 智
Takayuki Imai
隆之 今井
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.)
Fujikura Ltd
Original Assignee
Fujikura Ltd
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 Fujikura Ltd filed Critical Fujikura Ltd
Priority to JP14557589A priority Critical patent/JPH0310163A/en
Publication of JPH0310163A publication Critical patent/JPH0310163A/en
Pending legal-status Critical Current

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Abstract

PURPOSE:To improve the output of a detected value when electric charges having the different polarities are generated by providing divided electrodes at a piezoelectric element, and collecting the electric charge having the same polarity. CONSTITUTION:Aluminum is deposited by vacuum evaporation on both surfaces of a ceramic-based piezoelectric element 3, and divided electrodes 4A, 4B, 4C and 4D are formed. A circulate hole 5 is provided at the central part. Thus a vibrating body 2 having the laminated structure is provide. The vibrating body 2 is held by a frame- shaped fixing part 5. The center of the hole 5 is arranged coaxially with a vibrating body 6a so as to be stretched. Then, the center of a detecting part 1 is used as the original point, and an arbitrary point (r, theta) in a polar coordinate system is determined on the surface of the element 3. The strain in the direction (r) is made to be epsilonr, and the strain in the direction theta is made to be epsilontheta. The shapes of the electrodes 4A, 4B, 4C and 4D are made to be in planar symmetry which is divided within the ranges where the expression (i) and the expression (ii) hold true. The electrodes are connected in parallel. Then, the generated electric charges are divided and taken out at the surrounding part of the hole 5 and in the vicinity of the fixed part 6. The electric charges Q1 and Q2 can be added and collected with a charge amplifier 8.

Description

【発明の詳細な説明】 「産業上の利用分野」 本発明は、圧電型加速度センサに係り、特に、加速度セ
ンサの検出感度を向上させ、かつ、・焦電効果による出
力変動を低減する技術に関するものである。
DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a piezoelectric acceleration sensor, and particularly relates to a technique for improving the detection sensitivity of an acceleration sensor and reducing output fluctuations due to the pyroelectric effect. It is something.

「従来技術」 物理量である加速度の検出は、 F=mα (ただし、F:力、m:質量、α:加速度)で与えられ
、加えられた力と比例関係にある。
"Prior Art" Detection of acceleration, which is a physical quantity, is given by F=mα (where F: force, m: mass, α: acceleration), and is proportional to the applied force.

加速度センサは、力という機械量を電気量に変換して検
出する乙ので、この変換方式には、圧電型、サーボ型、
歪みゲージ型などがある。この中で加速度センサにおい
ては圧電型が現在最も普及している。
Acceleration sensors convert a mechanical quantity called force into an electrical quantity for detection, so this conversion method includes piezoelectric type, servo type,
There are strain gauge types. Among these acceleration sensors, the piezoelectric type is currently the most popular.

圧電型加速度センサは、検知部に備えられた圧型素子に
外力が加わって歪みを受けると、その力の大きさに比例
した電気量を発生する圧電効果を利用したものである。
A piezoelectric acceleration sensor utilizes a piezoelectric effect that generates an amount of electricity proportional to the magnitude of the force when an external force is applied to a piezoelectric element provided in a detection section and the piezoelectric element is distorted.

そして、その検知部としては、前記圧電素子の歪みの発
生の仕方の違いにより、第4図の(イ)〜(ハ)に示す
ように、大略3種類ある。これらを簡単に説明すると、 (イ)支持体Sの周囲に取り付けられた重りMに力Fが
加わると、重りMと基板との間に配された圧電素子Pが
圧縮され、圧電素子Pの分極軸の軸方向と同じ方向に歪
みが発生する[圧縮型1゜(ロ)支持体Sの周囲に圧電
素子Pを介して取り付けられた重りMに力Fが加わると
、圧電素子Pが剪断力を受け、歪みが圧電素子Pの分極
軸方向と同方向な面に対するずれとして発生する[剪断
型]。
There are approximately three types of detection portions as shown in (a) to (c) of FIG. 4, depending on the way in which distortion occurs in the piezoelectric element. To briefly explain these, (a) When force F is applied to the weight M attached around the support S, the piezoelectric element P placed between the weight M and the substrate is compressed, and the piezoelectric element P is compressed. Strain occurs in the same direction as the axial direction of the polarization axis [compression type 1° (b) When a force F is applied to the weight M attached around the support S via the piezoelectric element P, the piezoelectric element P is sheared. When a force is applied, strain occurs as a deviation from the plane in the same direction as the polarization axis of the piezoelectric element P [shear type].

(ハ)支持体Sに圧電素子Pが片持ち梁状に取り付けら
れ、その先端に取り付けられた重りMに対して力Fが加
わると、歪みが圧電素子の分極軸方向に対し直角方向に
発生する[片持ち粱型]。
(c) When a piezoelectric element P is attached to a support S in the form of a cantilever, and a force F is applied to a weight M attached to the tip of the piezoelectric element P, distortion occurs in a direction perpendicular to the polarization axis direction of the piezoelectric element. [Cantilever type]

のそれぞれである。each of them.

例えば中高周波の振動体の加速度を検出するには、(イ
)の圧縮型、あるいは(ロ)の剪断型が用いられ、低周
波の振動体の加速度を検出する場合には、これらよりも
検出感度が高く微小振動の検出が可能な(ハ)の片持ち
梁型が用いられるなど、周波数、あるいはこの他に加速
度の大きさや測定範囲などによって使い分けられている
For example, to detect the acceleration of a vibrating body at medium and high frequencies, the compression type (a) or the shear type (b) is used, and when detecting the acceleration of a vibrating body at low frequencies, these are used. The cantilever type (C), which has high sensitivity and can detect minute vibrations, is used, and they are used depending on the frequency, the magnitude of acceleration, the measurement range, etc.

「発明が解決しようとする課題J ところで[片持ち梁型コは、低周波、低加速度の検出に
優れているが、この場合、圧電素子の一端を支持体に固
定する場合の固定条件の実現が難しく、このため周波数
特性や感度が安定L7にくいという不具合がある。
``Problem to be solved by the invention J By the way, the cantilever type is excellent in detecting low frequencies and low accelerations, but in this case, the fixing conditions for fixing one end of the piezoelectric element to the support body must be realized. Therefore, there is a problem that it is difficult to maintain stable frequency characteristics and sensitivity L7.

本発明者等は、前に、特願昭62−258780号他に
おいて、第4図の(ニ)に示すように固定枠の中に圧電
素子を支持させる手段に、振動部分の中心部に孔を明け
る手段を付加することにより、検出感度を向上させるこ
との可能な圧電型加速度センサを提案した。
The present inventors previously proposed in Japanese Patent Application No. 62-258780 and others that a means for supporting a piezoelectric element in a fixed frame has a hole in the center of the vibrating part, as shown in FIG. 4(d). We have proposed a piezoelectric acceleration sensor that can improve detection sensitivity by adding a means to clear the area.

その後において、さらに研究を重ねた結果、般の圧電素
子においては、歪みの生じる位置により電荷発生効率が
変化する現象があり、同一表面上においても、発生電荷
の極性が異なる部分が同時に発生する現象が起こること
を知見した。
Subsequently, as a result of further research, it was found that in general piezoelectric elements, there is a phenomenon in which the charge generation efficiency changes depending on the position where distortion occurs, and even on the same surface, parts with different polarities of generated charges are generated at the same time. We found that this occurs.

本発明は、上記知見に鑑みてなされたものであり、発生
電荷の極性を一致させた状態で電荷を取り出して、−層
の高感度化を図り、かつ、検出出力の安定性を得ること
を目的としている。
The present invention has been made in view of the above findings, and aims to increase the sensitivity of the negative layer and obtain stability of the detection output by extracting the charges while matching the polarity of the generated charges. The purpose is

「課題を解決するための手&J 本発明に係る圧電型加速度センサは、第1図及び第2図
に示すように、検知部Iに備えられた圧電素子3の歪み
にともなって発生する電気量から加速度を検出する基本
構成に加えて、前記検知部lは、固定部6における振動
式6aの中に、中心部に孔5が形成された薄膜状の圧電
素子3が張架状態に支持されるとともに、該圧電素子3
の両面に半径方向に間隔を空けた分割電極4A・4B・
4C・4Dが一体に設けられ、該分割電極4A・4B・
4C・4Dは、圧電素子3の表面上に、検知部!の中心
を原点とする極座標系の任意点r、θをとり、該任意点
におけるr軸方向の歪みをεr、θ軸方向の歪みをεθ
としたとき、 εr+εθ〉 0    ・・・・・・(i)およびε
r+εoく 0    ・・・・・(ii)の関係が成
立する部分に分割して面対称状態に設けられてなり、複
数の分割電極4A・4B・4C・4Dの間を並列接続状
態として同一極性の電荷を取り出す構成を具備している
A piezoelectric acceleration sensor according to the present invention has a piezoelectric acceleration sensor according to the present invention, as shown in FIG. 1 and FIG. In addition to the basic configuration for detecting acceleration from the ground, the detection unit l includes a thin film-like piezoelectric element 3 with a hole 5 formed in the center supported in a tensioned state in a vibrating type 6a in the fixed part 6. At the same time, the piezoelectric element 3
Split electrodes 4A, 4B, and radially spaced on both sides of the
4C and 4D are integrally provided, and the divided electrodes 4A, 4B,
4C and 4D are detection parts on the surface of the piezoelectric element 3! Take arbitrary points r and θ in a polar coordinate system whose origin is the center of
When, εr+εθ〉 0 ......(i) and ε
r+εoku 0...It is divided into parts where the relationship (ii) holds and is provided in a plane symmetrical state, and the plurality of divided electrodes 4A, 4B, 4C, and 4D are connected in parallel and have the same polarity. It has a configuration for extracting the electric charge.

「作用」 検知部lの圧電素子3に、その厚さ方向に−様な加速度
が加わったとき、振動部分に歪みを生じて、次式の出力
が得られる。
"Operation" When --like acceleration is applied to the piezoelectric element 3 of the detection part 1 in its thickness direction, distortion occurs in the vibrating part, and the output of the following equation is obtained.

ただし、ε:歪み、S:面積、e:圧電歪定数(pc/
N)、C:静電容量である。
However, ε: strain, S: area, e: piezoelectric strain constant (pc/
N), C: capacitance.

また、圧電素子3に生じる歪みは、場所、方向によって
引っ張り歪みあるいは圧縮歪みとなる。
Moreover, the strain that occurs in the piezoelectric element 3 becomes tensile strain or compressive strain depending on the location and direction.

したがって、圧電素子3の表面には、第3図の電気的等
価回路モデルにおいて、Q、およびQ2で示すように、
圧電素子3の歪みの位置によって、つまり、外側電極4
A・4Bおよび内側電極4C・4Dの位置の違いによっ
て、極性(正負)が反対になる電荷か同時に発生する。
Therefore, on the surface of the piezoelectric element 3, as shown by Q and Q2 in the electrical equivalent circuit model of FIG.
Depending on the strain position of the piezoelectric element 3, that is, the outer electrode 4
Due to the difference in the positions of A and 4B and the inner electrodes 4C and 4D, charges with opposite polarities (positive and negative) are generated at the same time.

この二つの電荷Q、−Q、を第3図に示す電気的等価回
路モデル図に示すように、ヂャージアンプ8で集めるこ
とにより、 総合電荷Q=QI 十〇2 に対応する電気量が得られることになる。
As shown in the electrical equivalent circuit model diagram shown in Figure 3, by collecting these two charges Q and -Q with the charge amplifier 8, an amount of electricity corresponding to the total charge Q = QI 102 can be obtained. become.

ここで、検知部1の中心を原点とした極座標系を考える
と、r軸方向とθ軸方向とで符号の異なる電荷が発生す
ることがあり、圧電素子3の片側表面に発生した全電荷
を同一電極で集めると、電荷の一部が相殺されるために
、見掛は上の発生電荷が少なくなる傾向を生じる。
Here, considering a polar coordinate system with the center of the detection unit 1 as the origin, charges with different signs may be generated in the r-axis direction and the θ-axis direction, and the total charge generated on one surface of the piezoelectric element 3 is When collected at the same electrode, a portion of the charges are canceled out, so that the apparent generated charges tend to decrease.

そこで、面に垂直な一方向の力が加わったときに、εr
+εθ〉0の関係が成立する範囲と、εr+εθ〈0の
関係が成立する範囲とで分割して、外側電極4A・4B
の間、内側電極4C・4Dの間で全電荷を取り出すよう
に、例えば、孔5の周辺部と固定部6の近傍との発生電
荷を分割して取り出して寄せ集めることによって、二つ
の電荷Q1 ・Q2が加算され、発生電荷を無駄なく集
めることか可能となる。
Therefore, when a force in one direction perpendicular to the surface is applied, εr
The outer electrodes 4A and 4B are divided into a range where the relationship +εθ〉0 holds true and a range where the relationship εr+εθ〈0 holds true.
For example, by dividing and extracting the charges generated in the vicinity of the hole 5 and the vicinity of the fixing part 6, the two charges Q1 are collected so that the entire charge is extracted between the inner electrodes 4C and 4D. - Q2 is added, making it possible to collect the generated charges without waste.

一方、圧電素子3の表裏に温度差が生じることに基づい
て電荷が発生した場合(いわゆる焦電効果が生じた場合
)であると、その焦電効果による発生電荷が、例えば外
側電極4A・4Bと同極性であるとすると電荷が加算さ
れることになるが、反対に、内側電極4C・4Dに対し
て相殺し合うので、電荷を総合した状態で考えると、概
略的に外側電極4A・4Bの面積と内側電極4c・4D
の面積とに差カイある分だlす影響を及ぼすことJこな
り、焦電効果による影響が少なくなって誤差の発生を低
減し得るものとなる。
On the other hand, if a charge is generated due to a temperature difference between the front and back surfaces of the piezoelectric element 3 (a so-called pyroelectric effect occurs), the charge generated due to the pyroelectric effect may be transferred to the outer electrodes 4A and 4B, for example. If they have the same polarity, the charges will be added, but on the contrary, they cancel each other out for the inner electrodes 4C and 4D, so if we consider the charges as a whole, roughly speaking, the charges will be added to the outer electrodes 4A and 4B. area and inner electrodes 4c and 4D
Since there is a difference between the area of

「実施例」 以下、本発明に係る圧電型加速度センサの一実施例につ
いて説明する。
"Example" Hereinafter, an example of a piezoelectric acceleration sensor according to the present invention will be described.

第1図および第2図において、符号Iは検知部、2は振
動体、3は圧電素子、4A・4B・4C・−1Dは分割
電極、5は円形状などの孔(円形孔)、6は固定部(固
定枠)、6aは振動穴、7A・7Bは端子導体である。
1 and 2, reference numeral I is a detection unit, 2 is a vibrating body, 3 is a piezoelectric element, 4A, 4B, 4C, -1D are divided electrodes, 5 is a circular hole (circular hole), 6 is a fixed part (fixed frame), 6a is a vibration hole, and 7A and 7B are terminal conductors.

前記振動体2は、厚さ30μmのセラミック系圧電素子
3の両面に、真空蒸着法によってアルミを厚さ0.05
〜O1μm程度蒸着して、分割電極4A・4B・4C・
4Dを形成してなる積層構造体であり、中心部に内径2
.7mmの孔(円形孔)5を明けたものである。そして
、振動体2等は、内径7 mm、外径13mmの円形の
枠状の固定部6で挾むようにして、孔5の中心が円形状
の振動穴6aと同心円状に配置されるとともに、張架状
態に支持されている。
The vibrating body 2 is made by coating aluminum to a thickness of 0.05 μm on both sides of a ceramic piezoelectric element 3 with a thickness of 30 μm using a vacuum evaporation method.
~ About 1 μm of O was deposited to form divided electrodes 4A, 4B, 4C,
It is a laminated structure formed by forming 4D, with an inner diameter of 2 in the center.
.. A hole (circular hole) 5 of 7 mm is drilled. The vibrating body 2 and the like are sandwiched between circular frame-shaped fixing parts 6 with an inner diameter of 7 mm and an outer diameter of 13 mm, and the center of the hole 5 is arranged concentrically with the circular vibration hole 6a. supported by the state.

また、分割電極4A・4B・4C・4Dは、第1図に示
すように、圧電素子3の表裏面に同心円状にかつ面対称
状態に組み合わせて形成される。
Further, as shown in FIG. 1, the divided electrodes 4A, 4B, 4C, and 4D are formed on the front and back surfaces of the piezoelectric element 3 concentrically and in a symmetrical manner.

そして、外側の分割電極4A・4Bは、その外径が約7
mmで振動穴6aの中に収まる程度で、内径が前述した
(i)(ii)式の境界近傍(例えば直径4.8mm程
度)とされ、円環状の一部に切欠部4eが形成さ・れて
、首記端子導体7Bを半径外方向に導いており、その反
対側において前記端子導体7Aと接続されている。さら
に、内側の分割型%4G・4Dは、その外径が外側の分
割電極4A・4Bと小間隙を形成する程度で、その内径
が前記孔5の内径に合わけて形成され、かつ、前記端子
導体7Bと接続されている。このような分割電極4A・
4Bは、前述したように、アルミ蒸着法によって圧電素
子3の表面に一体に形成した蒸着層を、化学エツチング
加工によって、第1図に示すよう?こ、不要部分を除去
することなどの方法によって形成されるとともに、分割
電極4A・4Bの間隙は、10μmに設定されている。
The outer diameter of the outer divided electrodes 4A and 4B is approximately 7
mm and fits within the vibration hole 6a, the inner diameter is near the boundary of the above-mentioned formulas (i) and (ii) (for example, about 4.8 mm in diameter), and a notch 4e is formed in a part of the annular shape. The terminal conductor 7B is guided in a radial outward direction, and is connected to the terminal conductor 7A on the opposite side. Further, the inner divided electrodes 4G and 4D are formed such that their outer diameters form a small gap with the outer divided electrodes 4A and 4B, and their inner diameters match the inner diameters of the holes 5, and It is connected to the terminal conductor 7B. Such a divided electrode 4A・
4B, as described above, the vapor deposited layer integrally formed on the surface of the piezoelectric element 3 by the aluminum vapor deposition method is processed by chemical etching to form the vapor deposition layer as shown in FIG. This is formed by removing unnecessary parts, and the gap between the divided electrodes 4A and 4B is set to 10 μm.

首記固定部6は、ガラス−エポキシ樹脂積層板を切削加
工して、内径7 mm、外径13mmの円形の枠状とし
、振動体2を厚さ方向に挾むようにして、孔5の中心が
円形状の振動穴6aと同心円状になる配置とするととも
に、振動体2を張架状態に支持するようにしている。
The fixing part 6 is made by cutting a glass-epoxy resin laminate to form a circular frame shape with an inner diameter of 7 mm and an outer diameter of 13 mm, and is arranged so that the vibrating body 2 is sandwiched in the thickness direction so that the center of the hole 5 is a circle. The vibration hole 6a is arranged concentrically with the vibrating hole 6a, and the vibrating body 2 is supported in a stretched state.

[実験例コ 第1図および第2図(実施例)に基づくサンプル#1と
、比較のための類似構造の後述するサンプル#2とを作
製し、電極形状による振動特性の差を検討した。
[Experimental Example] Sample #1 based on FIGS. 1 and 2 (Example) and Sample #2, which will be described later and have a similar structure, were prepared for comparison, and differences in vibration characteristics due to electrode shapes were investigated.

〈サンプル#I〉 第1図および第2図例のもの。つまり、外側の分割電極
4A・4Bとして、外径7 mm、内径48mmの環状
のもので、一部に切り離し部4eが形成されているもの
と、内側の分割電極4C・4Dとして、外径4 、8m
m、内径2.7mmの環状のものとを組み合わせ、かつ
、内外の分割電極4A・4B・4C・4Dの間隙を50
μmとし、圧電素子3の中心部に 2.7mmの孔5を
明けたもの。
<Sample #I> The example shown in Figures 1 and 2. In other words, the outer divided electrodes 4A and 4B are annular ones with an outer diameter of 7 mm and an inner diameter of 48 mm, and have a cutaway part 4e formed in a part, and the inner divided electrodes 4C and 4D are annular ones with an outer diameter of 48 mm. ,8m
m, annular one with an inner diameter of 2.7 mm, and the gaps between the inner and outer divided electrodes 4A, 4B, 4C, and 4D are 50 mm.
μm, with a 2.7 mm hole 5 in the center of the piezoelectric element 3.

〈サンプル#2〉 サンプル#lにおける表面側で外側の分割電極4Aの部
分のみを環状に設け、圧電素子3の裏側−面に一様に電
極を設け、中心部に2.7mmの孔を明けたもの。
<Sample #2> Only the outer divided electrode 4A on the front side of sample #l was provided in a ring shape, electrodes were uniformly provided on the back side of the piezoelectric element 3, and a 2.7 mm hole was made in the center. Something.

これらのサンプル#1および#2について、次の試験A
および試験Bを行なった。
For these samples #1 and #2, the following test A
And Test B was conducted.

「試験A] 100Hz、 I Gの正弦波振動加速度を加えたとき
の出力を測定した。
"Test A" The output was measured when a 100 Hz, IG, sine wave vibration acceleration was applied.

試験Aの結果 サンプル#Iの出力を100としたとき、サンプル#2
の相対出力比は72であった。
As a result of test A, when the output of sample #I is 100, sample #2
The relative power ratio was 72.

「試験B] 100HZ、 I Gの正弦波振動加速度を加えた状態
で、試験雰囲気を室温(20℃)から30秒後に50℃
になるように急速加熱し、30秒間温度を保った後、再
び室温に戻すように放熱(放冷)(また。そのときの出
力変化を測定した。
“Test B” The test atmosphere was changed from room temperature (20°C) to 50°C after 30 seconds with 100Hz and IG sinusoidal vibration acceleration applied.
After rapidly heating to a temperature of

試験Bの結果 それぞれサンプル#Iおよびサンプル#2において、初
期出力を1としたときの相対出力比を第1表に示す。
Table 1 shows the relative output ratios of Sample #I and Sample #2 of Test B when the initial output is set to 1.

第1表 これらの比較結果を整理して説明すると、サンプル#1
、つまり、発明の一実施例の条件を満たすものは、サン
プル#2と比較して、発生出力そのものが数IO%程度
大きくなり、検出感度を高くできることが明らかである
Table 1 To organize and explain these comparison results, sample #1
In other words, it is clear that in a sample that satisfies the conditions of one embodiment of the invention, the generated output itself is increased by several IO% compared to sample #2, and the detection sensitivity can be increased.

また、第1表により、雰囲気温度が過渡的に変化する条
件下で検討すると、サンプル#1は、特性変化が少なく
、、温度特性上有利であるとともに、焦電効果か現れに
くいことを意味しているが、サンプル#2では、過渡的
な温度変化によって特性差、つまり、焦電効果が現れて
、特性変化が大きくなる傾向を示した。
In addition, according to Table 1, when examined under conditions where the ambient temperature changes transiently, sample #1 has little change in characteristics, which means that it is advantageous in terms of temperature characteristics and that pyroelectric effects are less likely to appear. However, in sample #2, a characteristic difference, that is, a pyroelectric effect appeared due to a transient temperature change, and the characteristic change tended to increase.

したがって、試験Aおよび試験Bとで得られた結果を総
合すると、サンプル#1は、検出出力を十分に高めて高
感度化を達成でき、かつ、温度特性”および焦電効果の
点でも有利となる。
Therefore, combining the results obtained in Test A and Test B, sample #1 can sufficiently increase the detection output and achieve high sensitivity, and is also advantageous in terms of temperature characteristics and pyroelectric effect. Become.

[他の実施態様コ 本発明にあっては、次の実施態様を採用することができ
る。
[Other Embodiments] The following embodiments can be adopted in the present invention.

(a)圧電素子をセラミック系以外のものとすること。(a) The piezoelectric element should be made of something other than ceramic.

(b)圧電素子における弾性率の温度依存性が大きい場
合に、圧電素子に裏打ち材を貼付L7て、振動体として
の性能を改良すること。
(b) When the temperature dependence of the elastic modulus of the piezoelectric element is large, a backing material L7 is attached to the piezoelectric element to improve its performance as a vibrating body.

(c)裏打ち材を貼付する場合、次式の条件を満足させ
ること。
(c) When attaching a backing material, the conditions of the following formula must be satisfied.

EvTv3/EpTp3≧5−−−−−− (iv )
ただし、 Ev:共通電極の弾性率 Tv:共通電極の厚さ Ep;圧電素子の弾性率 Tp:圧電素子の厚さ (d)各電極4A・4B・4Cを例えばスパッタリング
法や真空蒸着等でマスクを用いて形成するこ七。あるい
は化学的エツチング等の手段により形成すること。
EvTv3/EpTp3≧5---(iv)
However, Ev: Elastic modulus of the common electrode Tv: Thickness of the common electrode Ep; Elastic modulus of the piezoelectric element Tp: Thickness of the piezoelectric element (d) Each electrode 4A, 4B, 4C is masked by, for example, sputtering or vacuum evaporation. This is formed using . Alternatively, it may be formed by means such as chemical etching.

(e)分割電極4A・4Bの間隙を小さくする場合、そ
の限度を5μm以上として、電極間の電流漏洩を防止す
ること。
(e) When reducing the gap between the divided electrodes 4A and 4B, set the limit to 5 μm or more to prevent current leakage between the electrodes.

「発明の効果」 以上説明したように、本発明に係る圧電型加速度センサ
によれば、 ■振動体に孔を明けることによって、加速度検出出力を
増大させることができる。
"Effects of the Invention" As explained above, according to the piezoelectric acceleration sensor according to the present invention, (1) the acceleration detection output can be increased by making holes in the vibrating body.

■圧電素子の両面に、分割電極を設けて両極性の電荷を
同時に集めて利用するようにしているから、極性の相異
する電荷が発生した場合における検出出力を向上させる
ことができるとともに、両極性の電荷が同時に発生した
場合に打ち消し合う現象の発生を防止して、検出感度を
向上させることができる。
■Since split electrodes are provided on both sides of the piezoelectric element to collect and utilize charges of both polarities at the same time, it is possible to improve the detection output when charges of different polarities are generated, and also to The detection sensitivity can be improved by preventing the occurrence of a phenomenon in which polar charges cancel each other out when they are generated at the same time.

■圧電素子の両面に分割電極を設けて、圧電素子の一表
面に同時に発生した極性の異なる両電荷を集合させるよ
うにしているため、焦電効果によりて圧電素子の一表面
に誤差となる電荷が生じた場合において、その誤差とな
る電荷が一表面の正電荷および負電荷に対してそれぞれ
増減する方向となって結果的に相殺されるので、焦電効
果の影響を受けることが少なくなる。
■Separated electrodes are provided on both sides of the piezoelectric element to collect charges of different polarities that are generated simultaneously on one surface of the piezoelectric element, so the charge that causes an error on one surface of the piezoelectric element due to the pyroelectric effect When this occurs, the erroneous charge increases or decreases with respect to the positive charge and negative charge on one surface, and as a result they cancel each other out, so that the influence of the pyroelectric effect is reduced.

■上記により、圧電素子の表裏に過渡的な温度差が生じ
た場合に、表裏の圧電素子特性差による誤差の発生を低
減し、検出出力を安定させることができる。
(2) With the above, when a transient temperature difference occurs between the front and back sides of the piezoelectric element, it is possible to reduce the occurrence of errors due to the difference in piezoelectric element characteristics between the front and back sides, and to stabilize the detection output.

などの効果を奏するものである。It has the following effects.

【図面の簡単な説明】[Brief explanation of drawings]

第1図は本発明に係る圧電型加速度センサの一実施例を
示す一部を切欠した平面図、第2図は第1図の■−■線
矢視図、第3図は本発明に係る圧電型加速度センサの電
気的等価回路モデル図、第4図の(イ)〜(ニ)は圧電
型加速度センサの従来構造例を示す正断面図である。 !・・・・・検知部、 2・・・・・・振動体、 e 4r・・ 4g ・ 5 ・・・ 6 ・・ a  A ・・・・・圧電素子、 A・4B・4C・4D・・・・・・分割電極、・・・・
切り離し部、 接続導体、 ・・扇形部分、 ・・孔(円形孔)、 ・固定部(固定枠)、 振動穴、 ・7B・・・・・・端子導体、 ・・・・チャージアンプ。 第1図
Fig. 1 is a partially cutaway plan view showing an embodiment of the piezoelectric acceleration sensor according to the present invention, Fig. 2 is a view taken along the line ■-■ in Fig. 1, and Fig. 3 is a plan view according to the present invention. An electrical equivalent circuit model diagram of a piezoelectric acceleration sensor, (a) to (d) of FIG. 4 are front sectional views showing an example of a conventional structure of a piezoelectric acceleration sensor. ! ...Detection section, 2... Vibrating body, e 4r... 4g, 5... 6... a A... Piezoelectric element, A, 4B, 4C, 4D... ...Split electrode, ...
Separation part, connection conductor, ... fan-shaped part, ... hole (circular hole), - fixed part (fixed frame), vibration hole, 7B...terminal conductor, ... charge amplifier. Figure 1

Claims (1)

【特許請求の範囲】 検知部に備えられた圧電素子の歪みにともなって発生す
る電気量から加速度を検出する圧電型加速度センサにお
いて、前記検知部(1)は、固定部(6)における振動
穴(6a)の中に、中心部に孔(5)が形成された薄膜
状の圧電素子(3)が張架状態に支持されるとともに、
該圧電素子の両面に半径方向に間隔を空けた分割電極(
4A・4B・4C・4D)が一体に設けられ、該分割電
極は、圧電素子の表面上に、検知部の中心を原点とする
極座標系の任意点(r,θ)をとり、該任意点における
r軸方向の歪みをεr,θ軸方向の歪みをεθとしたと
き、 εr+εθ>0(i) およびεr+εθ<0(ii) の関係が成立する部分に分割して両面対称状態に設けら
れてなり、複数の分割電極の間を並列接続状態として同
一極性の電荷を取り出すことを特徴とする圧電型加速度
センサ。
[Claims] In a piezoelectric acceleration sensor that detects acceleration from an amount of electricity generated due to distortion of a piezoelectric element provided in the detection section, the detection section (1) includes a vibration hole in a fixed section (6). A thin film piezoelectric element (3) with a hole (5) formed in the center is supported in a stretched state in (6a), and
Split electrodes spaced radially on both sides of the piezoelectric element (
4A, 4B, 4C, 4D) are integrally provided, and the divided electrode takes an arbitrary point (r, θ) on the surface of the piezoelectric element in a polar coordinate system with the origin at the center of the detection part, and When the strain in the r-axis direction at A piezoelectric acceleration sensor characterized in that a plurality of divided electrodes are connected in parallel to extract charges of the same polarity.
JP14557589A 1989-06-08 1989-06-08 Piezoelectric type acceleration sensor Pending JPH0310163A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP14557589A JPH0310163A (en) 1989-06-08 1989-06-08 Piezoelectric type acceleration sensor

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP14557589A JPH0310163A (en) 1989-06-08 1989-06-08 Piezoelectric type acceleration sensor

Publications (1)

Publication Number Publication Date
JPH0310163A true JPH0310163A (en) 1991-01-17

Family

ID=15388281

Family Applications (1)

Application Number Title Priority Date Filing Date
JP14557589A Pending JPH0310163A (en) 1989-06-08 1989-06-08 Piezoelectric type acceleration sensor

Country Status (1)

Country Link
JP (1) JPH0310163A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0882987A1 (en) * 1997-06-04 1998-12-09 Matsushita Electric Industrial Co., Ltd. Piezoelectric acceleration sensor
JP2010249658A (en) * 2009-04-15 2010-11-04 Tokkyokiki Corp Piezoelectric acceleration sensor
KR20150109899A (en) * 2014-03-21 2015-10-02 주식회사 녹인 Amphbian and reptile capturing apparatus considering season condition

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0882987A1 (en) * 1997-06-04 1998-12-09 Matsushita Electric Industrial Co., Ltd. Piezoelectric acceleration sensor
US6050144A (en) * 1997-06-04 2000-04-18 Matsushita Electric Industrial Co., Ltd. Acceleration sensor
US6227051B1 (en) 1997-06-04 2001-05-08 Matsushita Electric Industrial Co., Ltd. Acceleration sensor
JP2010249658A (en) * 2009-04-15 2010-11-04 Tokkyokiki Corp Piezoelectric acceleration sensor
KR20150109899A (en) * 2014-03-21 2015-10-02 주식회사 녹인 Amphbian and reptile capturing apparatus considering season condition

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