JPS6055798A - Ultrasonic wave transmitting and receiving device - Google Patents
Ultrasonic wave transmitting and receiving deviceInfo
- Publication number
- JPS6055798A JPS6055798A JP16441083A JP16441083A JPS6055798A JP S6055798 A JPS6055798 A JP S6055798A JP 16441083 A JP16441083 A JP 16441083A JP 16441083 A JP16441083 A JP 16441083A JP S6055798 A JPS6055798 A JP S6055798A
- Authority
- JP
- Japan
- Prior art keywords
- diaphragm
- piezoelectric element
- ultrasonic transducer
- resonance frequency
- resonant frequency
- 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
Links
- 230000002093 peripheral effect Effects 0.000 claims abstract 2
- 239000000463 material Substances 0.000 claims description 7
- 230000001052 transient effect Effects 0.000 abstract description 8
- 230000005540 biological transmission Effects 0.000 abstract description 3
- 239000010408 film Substances 0.000 abstract 2
- 239000010409 thin film Substances 0.000 abstract 1
- 230000035945 sensitivity Effects 0.000 description 10
- 238000005259 measurement Methods 0.000 description 5
- 230000008878 coupling Effects 0.000 description 4
- 238000010168 coupling process Methods 0.000 description 4
- 238000005859 coupling reaction Methods 0.000 description 4
- 239000000919 ceramic Substances 0.000 description 3
- 239000011358 absorbing material Substances 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000013013 elastic material Substances 0.000 description 1
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
Classifications
-
- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K9/00—Devices in which sound is produced by vibrating a diaphragm or analogous element, e.g. fog horns, vehicle hooters or buzzers
- G10K9/12—Devices in which sound is produced by vibrating a diaphragm or analogous element, e.g. fog horns, vehicle hooters or buzzers electrically operated
- G10K9/122—Devices in which sound is produced by vibrating a diaphragm or analogous element, e.g. fog horns, vehicle hooters or buzzers electrically operated using piezoelectric driving means
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Acoustics & Sound (AREA)
- Multimedia (AREA)
- Transducers For Ultrasonic Waves (AREA)
Abstract
Description
【発明の詳細な説明】
産業上の利用分野
本発明は、空中での超音波応用計測に必要な超音波送受
波器に関するものである。DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an ultrasonic transducer necessary for ultrasonic applied measurement in the air.
従来例の構成とその問題点
空気中での超音波を送受波するだめの装置には、圧電セ
ラミクスの貼り合せ型素子が多く用いられており、上記
貼り合せ型素子のたわみ振動の共振点・***振点で使用
するように作られている・また、空気の機械的インピー
ダンスは圧電セラミクスのそれに比して著しく小さいた
め、貼り合せ型圧電素子を振動板と結合させて機械的イ
ンピーダンスの低下を図っている。Conventional configurations and their problems Many piezoelectric ceramic bonded elements are used in devices that transmit and receive ultrasonic waves in the air. The mechanical impedance of air is significantly smaller than that of piezoelectric ceramics, so a bonded piezoelectric element is combined with a diaphragm to reduce the mechanical impedance. I'm trying.
従来の超音波送受波器の構造と特性を第１図および第２
図にそれぞれ示す。第１図に示すように、貼り合せ型圧
電素子１の中心部に結合軸２が貫通固定され、この結合
軸２に振動板３が取付けられている。そして、貼シ合せ
型圧電素子１の振動の節部が支持台４の先端に弾性接着
剤５をもって固定されている。なお、６，６′は端子、
７は貼り合せ型圧電素子１等を覆うケース、８はケース
７の上部に形成された透孔に取り付けられた保獲用メツ
シュ、９，９′は、貼り合せ型圧電素子１と端子６，６
′を電気的に接続しているリード線である。The structure and characteristics of a conventional ultrasonic transducer are shown in Figures 1 and 2.
Each is shown in the figure. As shown in FIG. 1, a coupling shaft 2 is fixed through the center of the bonded piezoelectric element 1, and a diaphragm 3 is attached to this coupling shaft 2. The vibration nodes of the laminated piezoelectric element 1 are fixed to the tip of the support base 4 with an elastic adhesive 5. In addition, 6, 6' are terminals,
7 is a case that covers the bonded piezoelectric element 1, etc.; 8 is a retention mesh attached to a through hole formed in the upper part of the case 7; 9 and 9' are the bonded piezoelectric element 1 and the terminal 6; 6
This is the lead wire that electrically connects .
第２図は、上記構造の超音波送受波器を複数個のパルス
で駆動したときの送受波形を示したもので、立上がり、
立下がり時間が遅く、２ミリ秒以」二にも及ぶものであ
った。Figure 2 shows the transmission and reception waveforms when the ultrasonic transducer with the above structure is driven with multiple pulses.
The fall time was slow, reaching more than 2 milliseconds.
このような従来の超音波送受波器を用いて、短い時間間
隔で測定情報を得る必要がある場合、受波器によって受
信された信号は、立上がり、立下がり時間が長いために
、受信信号がピーク値になる寸での時間がかかる。ある
いは受信信号が立下がる前に次の信号が受信される等、
正確な測定情報が得られなかった。When it is necessary to obtain measurement information at short time intervals using such a conventional ultrasonic transducer, the signal received by the receiver has long rise and fall times, so the received signal is It takes time to reach the peak value. Or the next signal is received before the received signal falls, etc.
Accurate measurement information could not be obtained.
また、送受波を単体の素子で行なわせる場合、送波させ
てただちに受信可能な状態になるまで、かなりの時間を
要し、その間、測定消￥には得られなかった。In addition, when transmitting and receiving waves using a single element, it takes a considerable amount of time until the wave can be immediately received after transmitting the wave, and during that time, no measurements can be made.
さらに圧電セラミクスを用いた超音波送受波器に尖鋭な
指向特性を要求すると、振動板、貼り合せ型圧電素子お
よび貼り合せ型圧電素子を支持するだめの支持台が著し
く大きくなるという欠点があった。たとえ大きな振動板
を用いても、ピストン振動させることは困難であるため
、指向特性を著しく尖鋭にすることは不可能であった。Furthermore, when ultrasonic transducers using piezoelectric ceramics are required to have sharp directivity characteristics, there is a drawback that the diaphragm, the bonded piezoelectric element, and the support base for supporting the bonded piezoelectric element become significantly large. . Even if a large diaphragm is used, it is difficult to cause the piston to vibrate, so it has been impossible to make the directivity characteristics extremely sharp.
そこで、ホーンを用いて指向特性を尖鋭にしようとする
と、機械的Ｑを低下させてパルス特性を改善することは
一層困難となった。Therefore, when trying to sharpen the directional characteristics by using a horn, it became even more difficult to reduce the mechanical Q and improve the pulse characteristics.
発明の目的
本発明は過渡特性と送受波感度特性の良好な超音波送受
波器を提供しようとするものである。OBJECTS OF THE INVENTION The present invention seeks to provide an ultrasonic transducer with good transient characteristics and wave transmitting/receiving sensitivity characteristics.
発明の構成
本発明は、貼り合せ型圧電素子の中心部に振動板を設け
、機械的振動を抑制するように振動板の周囲を弾性ゴム
等の弾性材でケースに弾性的に固定することによシ、急
峻な過渡特性を有する超音波送受波器を実現し、送受波
感度特性と温度特性を改善したものである。Structure of the Invention The present invention provides a diaphragm in the center of a bonded piezoelectric element, and elastically fixes the periphery of the diaphragm to a case with an elastic material such as elastic rubber so as to suppress mechanical vibration. We have achieved an ultrasonic transducer with sharp transient characteristics, and improved the transmitting/receiving sensitivity characteristics and temperature characteristics.
実施Ｖりの説明
以下、本発明の一実施例について、図を用いて説明する
。第３図はこの実施例の超音波送受波器の断面図である
。DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 3 is a sectional view of the ultrasonic transducer of this embodiment.
貼り合せ型圧電素子１１の中心部に配した結合軸１２に
金属あるいは樹脂より形成された振動板１３が取り付け
られている。振動板１３０周辺部（は、機械的振動を抑
制するように円環状に形成された弾性ゴム等の緩衝材２
０を介して、円筒状のケース１７の内側面に弾性的に固
定されている。A vibration plate 13 made of metal or resin is attached to a coupling shaft 12 arranged at the center of the bonded piezoelectric element 11. The periphery of the diaphragm 130 (is a cushioning material 2 such as elastic rubber formed in an annular shape to suppress mechanical vibrations)
0, and is elastically fixed to the inner surface of the cylindrical case 17.
ケース１７の底部には吸音材２１が設けられている。振
動板１３の前方には、中心部に円状の開口部２２と、結
合軸１２を通過する直線を中心にした同心円周上に設け
た他の開口部２２’、２２’とを有する薄板２３が設置
されている。薄板２３と貼り合せ型圧電素子１１等を覆
うケース１７とは、放物面ホーン２４の喉部に嵌入され
保持されている。１９．１９’は貼り合せ型圧電素子１
１と端子１ｅ、１６′を電気的に接続しているリード線
である。A sound absorbing material 21 is provided at the bottom of the case 17. In front of the diaphragm 13 is a thin plate 23 having a circular opening 22 in the center and other openings 22', 22' provided on a concentric circumference centered on a straight line passing through the coupling shaft 12. is installed. A case 17 that covers the thin plate 23, the bonded piezoelectric element 11, etc. is fitted into the throat of the parabolic horn 24 and held there. 19.19' is bonded piezoelectric element 1
1 and terminals 1e and 16'.
上記薄板２３の開口部２２．２２’ 、２２″は、貼り
合せ型圧電素子１１の大きさ・厚さ、振動板１３の大き
さ・厚さ・中心角、緩衝材２０の内径等に依存し、最適
形状が異なる。その代表的なものを第４図に示す。The openings 22, 22' and 22'' of the thin plate 23 depend on the size and thickness of the bonded piezoelectric element 11, the size, thickness and central angle of the diaphragm 13, the inner diameter of the cushioning material 20, etc. , the optimum shape is different. A typical one is shown in FIG.
なお、上記薄板２３の開口部２２．２２’ 、２２”の
大きさ・形状、薄板２３の厚さ、薄板２３と振動板１３
の間の容積等によって決定される共振周波数ｆ。は、緩
衝材２ｏによシ弾性的に固定された振動板１３を中心部
に有する貼り合せ型圧電素子１１の共振周波数ｆｒ か
ら***振周波数へ までの範囲の値に設定されている。The size and shape of the openings 22, 22' and 22'' of the thin plate 23, the thickness of the thin plate 23, and the thin plate 23 and the diaphragm 13
Resonant frequency f determined by the volume between. is set to a value in the range from the resonant frequency fr of the bonded piezoelectric element 11 having the diaphragm 13 elastically fixed to the buffer material 2o at the center to the anti-resonant frequency.
次に上記本発明の構造による超音波送受波器の過渡特性
を第５図に示す。パルスの立上り・立下り時間は０．２
ミリ秒以下を示すようになった。Next, FIG. 5 shows the transient characteristics of the ultrasonic transducer having the structure of the present invention. Pulse rise/fall time is 0.2
Now indicates milliseconds or less.
第６図に、緩衝材２０により弾性的に固定された振動板
１３を中心部に有する貼り合せ型圧電素子１１の共振周
波数ｆｌ＋***振周波数ｆａ と、開口部２２．２２’
、２２’、薄板２３と振動板１３の同の容積等によっ
て決定される共振周波数ｆｏ との関係を変化したとき
、本超音波送受波器の送波音圧レベルと受波感度の周波
数特性を示す。FIG. 6 shows the resonant frequency fl + anti-resonant frequency fa of the bonded piezoelectric element 11 having the diaphragm 13 in the center which is elastically fixed by the buffer material 20, and the opening 22, 22'.
, 22', shows the frequency characteristics of the transmitted sound pressure level and reception sensitivity of the ultrasonic transducer when the relationship between the resonance frequency fo determined by the same volume of the thin plate 23 and the diaphragm 13 is changed. .
ｆ＜ｆｒ’！、たはｆ。＞へ のとき、それぞれの最大
周波数で、送波音圧レベルが約１２３ｄＢ、受波感度が
−ｓ ｅｉ ｄＢ程度であった。f<fr'! , or f. >, the transmitted sound pressure level was approximately 123 dB and the receiving sensitivity was approximately -sei dB at each maximum frequency.
ｆｏをｆｒ≦ｆｃ≦ｆａとなるように設定することによ
り、送波音圧レベノペ受波感度が増大したことが明確と
なった。It has become clear that by setting fo so that fr≦fc≦fa, the transmitted sound pressure level reception sensitivity is increased.
また周囲温度の変化とともに送波音圧レベル及び受波感
度の周波数特性が変化している。Furthermore, the frequency characteristics of the transmitted sound pressure level and the receiving sensitivity change with changes in the ambient temperature.
この変化は、開口部２２．２２’ 、２２”、薄板２３
と振動板１３０間の容量等によって共振する波長λ。が
温度に依存しなくほぼ一定であるのに対し、音速■は変
化するため、その共振周波数ｆｏ は、ｆ０＝■／λ０
で示される式にしたがって変化することに起因している
からである。This change is caused by openings 22, 22', 22'', thin plates 23
The wavelength λ that resonates due to the capacitance between the diaphragm 130 and the diaphragm 130. is almost constant regardless of temperature, whereas the sound speed ■ changes, so its resonant frequency fo is f0=■/λ0
This is because it changes according to the formula shown below.
しかしながら、第６図（−）、（時、（→から明確なよ
うに、本超音波送受波器をほぼＣｆｏ−３）ｋｌｋから
Ｃｆｃ−ｊ）ｋｌｚの設定周波数で使用することにより
、送波音圧レベルと受波感度の温度特性は、いちじるし
く改善された。なお、図の曲線Ａ、Ｂは送波音圧レベル
を、また同Ｃ，Ｄは受波感度をそれぞれ示す。However, as is clear from Fig. 6(-), The temperature characteristics of pressure level and reception sensitivity have been significantly improved. Note that curves A and B in the figure indicate the transmitted sound pressure level, and curves C and D indicate the receiving sensitivity, respectively.
発明の効果
以上のように、本発明の超音波送受波器は、良好な過渡
特性と高い送受波感度特性を有し、音波を用いた距離計
等、超音波応用計測にはきわめて有用なものである。Effects of the Invention As described above, the ultrasonic transducer of the present invention has good transient characteristics and high wave transmitting and receiving sensitivity characteristics, and is extremely useful for ultrasonic applied measurements such as distance meters using sound waves. It is.
第１図は従来の超音波送受波器の一例を示す断面図、第
２図はその過渡特性を示す図、第３図は本発明の超音波
送受波器の一実施例を示す断面図、第４図は同超音波送
受波器の薄板の一実施例を示す正面図、第６図は同超音
波送受波器の過渡特性を示す図、第６図は同超音波送受
波器の感度周波数特性の温度変化と、共振周波数ｆ。の
設定条件との関係を示す図である。。
１１・・・・・・貼り合せ型圧電素子、１３・・・・・
・振動板２０・・・・・・緩衝材、２１・・・・・・吸
音材、２２ 、２ｉ。
２２′・・・・・・開口部、２３・・・・・・薄板、２
４・・・・・・ホーン。
代理人の氏名 弁理士 中 尾 敏 男 ほか１名第１
図
第２図
第３図
第５図FIG. 1 is a sectional view showing an example of a conventional ultrasonic transducer, FIG. 2 is a diagram showing its transient characteristics, and FIG. 3 is a sectional view showing an embodiment of the ultrasonic transducer of the present invention. Fig. 4 is a front view showing an example of the thin plate of the ultrasonic transducer, Fig. 6 is a diagram showing the transient characteristics of the ultrasonic transducer, and Fig. 6 is the sensitivity of the ultrasonic transducer. Temperature change in frequency characteristics and resonance frequency f. FIG. . 11... Bonded piezoelectric element, 13...
- Vibration plate 20...Buffer material, 21...Sound absorbing material, 22, 2i. 22'...opening, 23...thin plate, 2
4...Horn. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 3 Figure 5
Claims (3)
合わせ型圧電素子を封入するケースとから少なくとも構
成される電気音響変換部を有し、前記ケースの開口部と
前記ケース内でかつ前記振動板前面の容積によって決定
される共振周波数を、前記電気音響変換部の共振周波数
から***振周波数までの範囲内に設定したことを特徴と
する超音波送受波器。(1) It has an electroacoustic transducer including at least a laminated piezoelectric element provided with a diaphragm and a case enclosing the laminated piezoelectric element, and has An ultrasonic transducer characterized in that the resonant frequency determined by the volume of the front surface of the diaphragm is set within a range from the resonant frequency to the anti-resonant frequency of the electroacoustic transducer.
る薄板を設置し、前記電気音響変換部と前記薄板とをホ
ーンに絹み込んだことを特徴とする特許請求の範囲第１
項記載の超音波送受波器。(2) A thin plate having a plurality of openings is installed in front of the electroacoustic converter, and the electroacoustic converter and the thin plate are embedded in the horn.
Ultrasonic transducer described in section.
側面とに接触するように配されている緩衝材により、機
械的振動を抑制するように前記振動板を前記緩衝材によ
り前記ケースに弾性的に固定したことを特徴とする特許
請求の範囲第２項記載の超音波送受波器。(3) The electroacoustic transducer connects the diaphragm to the diaphragm using the cushioning material so as to suppress mechanical vibrations using the cushioning material disposed so as to contact the peripheral portion of the diaphragm and the inner surface of the case. 3. The ultrasonic transducer according to claim 2, wherein the ultrasonic transducer is elastically fixed to the case.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16441083A JPS6055798A (en) | 1983-09-06 | 1983-09-06 | Ultrasonic wave transmitting and receiving device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16441083A JPS6055798A (en) | 1983-09-06 | 1983-09-06 | Ultrasonic wave transmitting and receiving device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS6055798A true JPS6055798A (en) | 1985-04-01 |
Family
ID=15792609
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP16441083A Pending JPS6055798A (en) | 1983-09-06 | 1983-09-06 | Ultrasonic wave transmitting and receiving device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6055798A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0679907A2 (en) * | 1994-04-29 | 1995-11-02 | The Whitaker Corporation | Short distance ultrasonic distance meter |
| WO1999010874A1 (en) * | 1997-08-23 | 1999-03-04 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | Acoustic transducer |
-
1983
- 1983-09-06 JP JP16441083A patent/JPS6055798A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0679907A2 (en) * | 1994-04-29 | 1995-11-02 | The Whitaker Corporation | Short distance ultrasonic distance meter |
| EP0679907A3 (en) * | 1994-04-29 | 1996-03-13 | Whitaker Corp | Short distance ultrasonic distance meter. |
| WO1999010874A1 (en) * | 1997-08-23 | 1999-03-04 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | Acoustic transducer |
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