JPH0462519B2 - - Google Patents
Info
- Publication number
- JPH0462519B2 JPH0462519B2 JP22279884A JP22279884A JPH0462519B2 JP H0462519 B2 JPH0462519 B2 JP H0462519B2 JP 22279884 A JP22279884 A JP 22279884A JP 22279884 A JP22279884 A JP 22279884A JP H0462519 B2 JPH0462519 B2 JP H0462519B2
- Authority
- JP
- Japan
- Prior art keywords
- honeycomb
- ceramic body
- piezoelectric ceramic
- holes
- shaped vibrator
- 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
Links
Classifications
-
- G—PHYSICS
- G06—COMPUTING OR CALCULATING; COUNTING
- G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
- G06K17/00—Methods or arrangements for effecting co-operative working between equipments covered by two or more of main groups G06K1/00 - G06K15/00, e.g. automatic card files incorporating conveying and reading operations
- G06K17/0022—Methods or arrangements for effecting co-operative working between equipments covered by two or more of main groups G06K1/00 - G06K15/00, e.g. automatic card files incorporating conveying and reading operations arrangements or provisions for transferring data to distant stations, e.g. from a sensing device
- G06K17/0029—Methods or arrangements for effecting co-operative working between equipments covered by two or more of main groups G06K1/00 - G06K15/00, e.g. automatic card files incorporating conveying and reading operations arrangements or provisions for transferring data to distant stations, e.g. from a sensing device the arrangement being specially adapted for wireless interrogation of grouped or bundled articles tagged with wireless record carriers
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01H—MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
- G01H11/00—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by detecting changes in electric or magnetic properties
- G01H11/06—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by detecting changes in electric or magnetic properties by electric means
- G01H11/08—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by detecting changes in electric or magnetic properties by electric means using piezoelectric devices
-
- 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
- G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/02—Mechanical acoustic impedances; Impedance matching, e.g. by horns; Acoustic resonators
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- Multimedia (AREA)
- Computer Networks & Wireless Communication (AREA)
- General Engineering & Computer Science (AREA)
- Theoretical Computer Science (AREA)
- Piezo-Electric Transducers For Audible Bands (AREA)
- Transducers For Ultrasonic Waves (AREA)
Description
【発明の詳細な説明】
産業上の利用分野
本発明は、魚群探知機、音響測深機、音響探信
機、地下埋設物探索機、超音波探傷機、超音波診
断装置などパルス状超音波の送受波を目的とする
超音波送受波振動子またランジユバン振動子等と
に使用されるハニカム状振動子に関する。DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is applicable to fish finders, echo sounders, acoustic detectors, underground buried object searchers, ultrasonic flaw detectors, ultrasonic diagnostic devices, etc. The present invention relates to a honeycomb-shaped vibrator used in an ultrasonic wave transmitting/receiving vibrator or a Languevent vibrator for the purpose of transmitting and receiving waves.
従来技術
従来のこの種の圧電振動子は、一般に、第３図
に示すように、チタン酸バリウム系あるいはジル
コン酸鉛系圧電磁器等により、円板状または角板
状等の平板状に形成された圧電磁器素体１の厚み
あるいは縦方向の両面に電極２，３を形成した構
造となつていた。圧電磁器素体１の分極方向P1
は、通常は、電極２，３による電界方向と一致す
る方向、即ち厚みあるいは縦方向となり、厚みあ
るいは縦方向の振動モードを利用する構成となつ
ていた。Prior Art This type of conventional piezoelectric vibrator is generally formed into a flat plate shape, such as a disk shape or a square plate shape, using barium titanate-based or lead zirconate-based piezoelectric ceramics, as shown in FIG. The piezoelectric ceramic body 1 had a structure in which electrodes 2 and 3 were formed on both sides in the thickness or longitudinal direction. Polarization direction P 1 of piezoelectric ceramic body 1
Normally, the direction corresponds to the direction of the electric field from the electrodes 2 and 3, that is, the thickness or longitudinal direction, and the vibration mode in the thickness or longitudinal direction is utilized.
従来技術の欠点
しかしながら、第３図に示した従来のハニカム
状振動子においては、厚みあるいは縦振動モード
の外に、横振動モードもしくは径振動モード及び
その高調波振動モードが大きくなることと、これ
らのスプリアスによる振動負荷時における機械的
品質係数Ｑが小さくならないこととにより、パル
ス超音波の送受波形の尾引きが長くなり距離分解
能が低下するという問題があつた。Disadvantages of the Prior Art However, in the conventional honeycomb-shaped vibrator shown in FIG. There was a problem in that the mechanical quality factor Q did not become small during the vibration load due to spurious waves, and the tail of the transmitted and received waveform of the pulsed ultrasonic wave became long, resulting in a decrease in distance resolution.
一方、共振周波数が高い振動子では制動容量が
大きくなりインピーダンスが低下して、送受信器
との電気的整合が良くないという問題を有してい
た。 On the other hand, a vibrator with a high resonant frequency has a problem in that the damping capacity increases and the impedance decreases, resulting in poor electrical matching with the transmitter/receiver.
本発明の目的
本発明は上述する従来からの問題点を解決し、
横振動モードもしくは径振動モード及びその高調
波振動モードを小さくし、スプリアスを低減させ
ると共に、音響インピーダンスを水の音響インピ
ーダンスとの整合条件にできるだけ近づけ、超音
波送受信の感度を向上させたハニカム状振動子を
提供することを目的とする。Purpose of the present invention The present invention solves the above-mentioned conventional problems,
A honeycomb-shaped vibration that reduces the transverse vibration mode, radial vibration mode, and its harmonic vibration mode to reduce spurious vibrations, brings the acoustic impedance as close as possible to matching the acoustic impedance of water, and improves the sensitivity of ultrasonic transmission and reception. The purpose is to provide children.
本発明の構成
上記目的を達成するため、本発明に係るハニカ
ム状振動子は、圧電磁器素体の厚みあるいは縦方
向に多数の空孔を設け、この空孔の断面積比率を
50％以上としたことを特徴とする。Structure of the Present Invention In order to achieve the above object, the honeycomb vibrator according to the present invention has a large number of holes in the thickness or longitudinal direction of the piezoelectric ceramic body, and the cross-sectional area ratio of the holes is increased.
It is characterized by being 50% or more.
実施例
第１図は本発明に係るハニカム状振動子の平面
図、第２図は同じく正面断面図である。図におい
て、第３図と同一の参照符号は同一性ある構成部
分を示している。この実施例では、円板状に形成
された圧電磁器素体１の厚みあるいは縦方向に、
多数の貫通孔状の空孔４を形成してある。この実
施例では空孔４は、円形状となつているが、例え
ば六角状等の角形状に形成してもよい。また、圧
電磁器素体１は円板状に限らず、角板状であつて
もよい。Embodiment FIG. 1 is a plan view of a honeycomb-shaped vibrator according to the present invention, and FIG. 2 is a front sectional view of the same. In the figure, the same reference numerals as in FIG. 3 indicate the same components. In this embodiment, the thickness or longitudinal direction of the piezoelectric ceramic body 1 formed in the shape of a disk is
A large number of through holes 4 are formed. Although the holes 4 are circular in this embodiment, they may be formed in a rectangular shape such as a hexagonal shape. Further, the piezoelectric ceramic body 1 is not limited to a disk shape, but may be a square plate shape.
上述のような空孔４を設けると、当該ハニカム
状振動子に対して、異方性に類似した特性を持た
せ、横振動モードまたは径振動モードを少なく
し、スプリアスを低減させることができる。 By providing the holes 4 as described above, it is possible to impart characteristics similar to anisotropy to the honeycomb-shaped vibrator, reduce transverse vibration mode or radial vibration mode, and reduce spurious waves.
前記空孔４は、断面積比率が50％以上となるよ
うに形成する。即ち、空孔４の数をｎ個とし、空
孔４の各々の体積をV1とした場合、空孔４の総
体積〓Ｖは
〓Ｖ＝n.V1
となる。 The holes 4 are formed so that the cross-sectional area ratio is 50% or more. That is, when the number of holes 4 is n and the volume of each hole 4 is V1 , the total volume of the holes 4 〓V=V=nV 1 .
一方、この実施例のように、円板状の圧電磁器
素体１を使用した場合において、圧電磁器素体１
の半径をｒ、厚みをｔとした場合、圧電磁器素体
１の体積V2は、
V2＝π.r.t−〓Ｖ
となる。本発明においては、空孔４の総体積〓Ｖ
と、圧電磁器素体１の体積V2との関係を、
（〓Ｖ／V2）×100％＞50％となるように選定
するのである。 On the other hand, when the disk-shaped piezoelectric ceramic body 1 is used as in this embodiment, the piezoelectric ceramic body 1
When the radius is r and the thickness is t, the volume V 2 of the piezoelectric ceramic body 1 is as follows: V 2 =π.rt−〓V. In the present invention, the total volume of the holes 4〓V
The relationship between this and the volume V 2 of the piezoelectric ceramic body 1 is selected so that (〓V/V 2 )×100%>50%.
この種のハニカム状振動子においては、一般
に、空孔４の体積を大きくし、その断面積比率を
上げると、ハニカム状振動子の見かけ上の密度が
下つてその音響インピーダンスが低下し、水の音
響インピーダンスに近づく。そして、ハニカム状
振動子の音響インピーダンスと水の音響インピー
ダンスのインピーダンス整合が完全にとられたと
きに、超音波送受信感度が最大となる。次に、イ
ンピーダンス整合条件を求める。 In this type of honeycomb-shaped vibrator, when the volume of the pores 4 is increased and the cross-sectional area ratio thereof is increased, the apparent density of the honeycomb-shaped vibrator decreases, and its acoustic impedance decreases. Close to acoustic impedance. When the acoustic impedance of the honeycomb-shaped vibrator and the acoustic impedance of water are perfectly matched, the ultrasonic transmission and reception sensitivity becomes maximum. Next, find impedance matching conditions.
まず、ハニカム状振動子の機械的インピーダン
スは次のように求められる。 First, the mechanical impedance of the honeycomb-shaped vibrator is determined as follows.
ρ0.C0.S0
ただし、ρ0は圧電磁器素体の密度で
ρ0≒7.5×103Kg／m3
C0は圧電磁器素体中の音速
C0≒４×103ｍ／ｓ
S0は圧電磁器素体の放射面積m2
次に水の機械的インピーダンスは次のように求
められる。ρ 0 .C 0 .S 0 However, ρ 0 is the density of the piezoelectric ceramic body, ρ 0 ≒7.5×10 3 Kg/m 3 C 0 is the sound velocity in the piezoelectric ceramic body, C 0 ≒4×10 3 m/ s S 0 is the radiation area of the piezoelectric ceramic body m 2 Next, the mechanical impedance of water is determined as follows.
ρa.Ca.Sa
ただし、ρaは水の密度で
ρa≒１×103Kg／m3
Caは水の音速で
Ca≒1.5×103ｍ／ｓ
Saは圧電磁器素体の放射面積m2
ハニカム状振動子と水とのインピーダンス整合が
とられたとすると、
ρ0.C0.S0＝ρa.Ca.Sa
なる整合条件式が得られる。この条件式に、
ρ0≒7.5×103Kg／m3
C0≒４×103ｍ／ｓ
ρa≒１×103Kg／m3
Ca≒1.5×103ｍ／ｓ
なる数値を代入すると、
S0≒Sa／20
つまり、圧電磁器素体の断面積比率を約５％
（従つて空孔４の断面積比率を95％）にすれば、
ハニカム状振動子と水とのインピーダンスが整合
し、理想的な超音波送受信感度が得られる。実際
上は、圧電磁器素体の機械的強度を確保する必要
があるから、空孔４の断面積比率は、前述したよ
うに50％以上の範囲で、できるだけ理想値95％に
近づくように選定することが望ましい。 ρa.Ca.Sa where ρa is the density of water ρa≒1×10 3 Kg/m 3 Ca is the sound speed of water Ca≒1.5×10 3 m/s Sa is the radiation area of the piezoelectric ceramic body m 2 Honeycomb Assuming that impedance matching is achieved between the shaped vibrator and water, the matching conditional expression ρ 0 .C 0 .S 0 =ρa.Ca.Sa is obtained. Substituting the following values into this conditional expression: ρ 0 ≒7.5×10 3 Kg/m 3 C 0 ≒4×10 3 m/s ρa≒1×10 3 Kg/m 3 Ca≒1.5×10 3 m/s , S 0 ≒Sa/20 In other words, the cross-sectional area ratio of the piezoelectric ceramic body is approximately 5%.
(Therefore, if the cross-sectional area ratio of hole 4 is set to 95%),
The impedances of the honeycomb-shaped vibrator and water match, and ideal ultrasonic transmission and reception sensitivity can be obtained. In practice, it is necessary to ensure the mechanical strength of the piezoelectric ceramic body, so the cross-sectional area ratio of the holes 4 is selected to be as close to the ideal value of 95% as possible within the range of 50% or more as described above. It is desirable to do so.
前記空孔４は、その最大口径が当該ハニカム状
振動子の持つ厚み縦振動の固有共振周波数f0によ
る音場媒質の音波の波長λより小さくなるように
設定することが望ましい。即ち、空孔４の口形を
円形状とした場合には、その直径ｌが共振周波数
f0の波長λより小さくなるように選定し、また空
孔４の口形を角形状に形成した場合には、対角線
長ｌを最大口径とし、ｌ＜λとなるように選定す
る。 It is desirable that the maximum diameter of the holes 4 is set to be smaller than the wavelength λ of the sound wave of the sound field medium at the natural resonant frequency f 0 of the thickness longitudinal vibration of the honeycomb-shaped vibrator. That is, when the mouth shape of the hole 4 is circular, its diameter l is the resonance frequency.
The diameter is selected so that it is smaller than the wavelength λ of f 0 , and when the opening of the hole 4 is formed into a square shape, the diameter is selected so that the diagonal length l is the maximum diameter, and l<λ.
上述のように、空孔４を、その最大口径ｌが共
振周波数f0による音場媒質の音波の波長λより小
さくなるように形成すると、音響負荷が見掛け上
大きくなり、水中へ超音波を放射するに当つてパ
ルス駆動した場合、水中での機械的品質係数Qm
が従来の圧電振動子より小さくなり、超音波パル
ス幅が短くなつて、距離分解能が向上する
本発明の効果
以上述べたように、本発明に係るハニカム状振
動子は、圧電磁器素体の厚みあるいは縦方向に多
数の空孔を設け、この空孔の断面積比率を50％以
上としたことを特徴とするから、横振動モードも
しくは径振動モード及びその高調波振動モードを
小さくし、スプリアスを低減させると共に、音響
インピーダンスを水の音響インピーダンスとの整
合条件にできるだけ近づけ、水中における超音波
送受信の感度を向上させたハニカム状振動子を提
供することができる。 As mentioned above, if the hole 4 is formed so that its maximum aperture l is smaller than the wavelength λ of the sound wave in the sound field medium due to the resonance frequency f 0 , the acoustic load will apparently increase and the ultrasonic wave will be emitted into the water. Mechanical quality factor Qm in water when pulse driven
is smaller than that of a conventional piezoelectric vibrator, the ultrasonic pulse width is shortened, and the distance resolution is improved.As described above, the honeycomb-shaped vibrator according to the present invention has Alternatively, since a large number of holes are provided in the vertical direction, and the cross-sectional area ratio of these holes is set to 50% or more, the transverse vibration mode or radial vibration mode and its harmonic vibration mode are reduced, and spurious It is possible to provide a honeycomb-shaped vibrator in which the acoustic impedance is reduced, the acoustic impedance is brought as close as possible to matching conditions with the acoustic impedance of water, and the sensitivity of ultrasonic transmission and reception in water is improved.
第１図は本発明に係るハニカム状振動子の平面
図、第２図は同じく正面断面図、第３図は従来の
圧電振動子の斜視図である。
１…圧電磁器素体、２，３…電極、４…空孔。
FIG. 1 is a plan view of a honeycomb-shaped vibrator according to the present invention, FIG. 2 is a front sectional view of the same, and FIG. 3 is a perspective view of a conventional piezoelectric vibrator. 1... Piezoelectric ceramic body, 2, 3... Electrode, 4... Hole.
Claims (1)
空孔を設け、この空孔の断面積比率を50％以上と
したことを特徴とするハニカム状振動子。 ２ 前記空孔は、前記圧電磁器素体の厚みあるい
は縦方向に貫通させたことを特徴とする特許請求
の範囲第１項に記載のハニカム状振動子。 ３ 前記圧電磁器素体の厚みあるいは縦方向の両
面に電極を有することを特徴とする特許請求の範
囲第１項または第２項に記載のハニカム状振動
子。[Scope of Claims] 1. A honeycomb-shaped vibrator characterized in that a large number of holes are provided in the thickness or longitudinal direction of a piezoelectric ceramic body, and the cross-sectional area ratio of the holes is 50% or more. 2. The honeycomb-shaped vibrator according to claim 1, wherein the holes penetrate through the piezoelectric ceramic body in the thickness or longitudinal direction. 3. The honeycomb-shaped vibrator according to claim 1 or 2, characterized in that the piezoelectric ceramic body has electrodes on both sides in the thickness or longitudinal direction.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22279884A JPS61101198A (en) | 1984-10-23 | 1984-10-23 | Honeycomb-like vibrator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22279884A JPS61101198A (en) | 1984-10-23 | 1984-10-23 | Honeycomb-like vibrator |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS61101198A JPS61101198A (en) | 1986-05-20 |
| JPH0462519B2 true JPH0462519B2 (en) | 1992-10-06 |
Family
ID=16788058
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP22279884A Granted JPS61101198A (en) | 1984-10-23 | 1984-10-23 | Honeycomb-like vibrator |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS61101198A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61196700A (en) * | 1985-02-26 | 1986-08-30 | Toshiba Corp | Piezoelectric ceramic vibrator |
-
1984
- 1984-10-23 JP JP22279884A patent/JPS61101198A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS61101198A (en) | 1986-05-20 |
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