JPH0951599A - Ultrasonic vibrator - Google Patents
Ultrasonic vibratorInfo
- Publication number
- JPH0951599A JPH0951599A JP20079495A JP20079495A JPH0951599A JP H0951599 A JPH0951599 A JP H0951599A JP 20079495 A JP20079495 A JP 20079495A JP 20079495 A JP20079495 A JP 20079495A JP H0951599 A JPH0951599 A JP H0951599A
- Authority
- JP
- Japan
- Prior art keywords
- matching layer
- acoustic matching
- ultrasonic
- ultrasonic transducer
- acoustic
- 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
- 239000000463 material Substances 0.000 claims abstract description 11
- 229920005989 resin Polymers 0.000 claims abstract description 10
- 239000011347 resin Substances 0.000 claims abstract description 10
- 229920001207 Noryl Polymers 0.000 claims abstract description 5
- 239000004727 Noryl Substances 0.000 claims abstract description 5
- 230000035945 sensitivity Effects 0.000 abstract description 16
- 239000000853 adhesive Substances 0.000 abstract description 2
- 230000001070 adhesive effect Effects 0.000 abstract description 2
- 229910052782 aluminium Inorganic materials 0.000 abstract description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 abstract description 2
- 229910052751 metal Inorganic materials 0.000 abstract description 2
- 239000002184 metal Substances 0.000 abstract description 2
- 230000002093 peripheral effect Effects 0.000 abstract description 2
- 241001237728 Precis Species 0.000 abstract 1
- 238000004519 manufacturing process Methods 0.000 abstract 1
- 238000005259 measurement Methods 0.000 description 6
- XECAHXYUAAWDEL-UHFFFAOYSA-N acrylonitrile butadiene styrene Chemical compound C=CC=C.C=CC#N.C=CC1=CC=CC=C1 XECAHXYUAAWDEL-UHFFFAOYSA-N 0.000 description 4
- 229920000122 acrylonitrile butadiene styrene Polymers 0.000 description 4
- 239000004676 acrylonitrile butadiene styrene Substances 0.000 description 4
- 230000005540 biological transmission Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000003822 epoxy resin Substances 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 238000011835 investigation Methods 0.000 description 2
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical group [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 description 2
- 229920000647 polyepoxide Polymers 0.000 description 2
- 239000000758 substrate Substances 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 229920006026 co-polymeric resin Polymers 0.000 description 1
- 230000003111 delayed effect Effects 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 229920002379 silicone rubber Polymers 0.000 description 1
- 239000004945 silicone rubber Substances 0.000 description 1
Landscapes
- Transducers For Ultrasonic Waves (AREA)
- Measurement Of Velocity Or Position Using Acoustic Or Ultrasonic Waves (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は超音波振動子にかか
り、特には、音響整合層の作製材料に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic vibrator, and particularly to a material for producing an acoustic matching layer.
【０００２】[0002]
【従来の技術】超音波振動子は距離測定用の超音波セン
サなどを構成する際に使用されるものであり、超音波振
動子のうちには、図示省略しているが、音響整合層と、
この音響整合層の一面に対して接合された圧電振動素子
及び支持用筒体とを具備したものがある。そして、この
際における音響整合層としては、特開昭５９−１７１２
９５号公報や実公平１−４１２７９号公報で開示されて
いるように、ガラスやカーボンなどからなる微小中空球
が混合されたエポキシ樹脂やシリコン樹脂などを平板形
状として固めたものが一般的となっている。2. Description of the Related Art Ultrasonic transducers are used when constructing ultrasonic sensors for distance measurement and the like. Among the ultrasonic transducers, although not shown, there are acoustic matching layers. ,
Some include a piezoelectric vibrating element and a supporting cylinder that are bonded to one surface of the acoustic matching layer. Then, as the acoustic matching layer at this time, there is disclosed in JP-A-59-1712.
As disclosed in Japanese Patent Publication No. 95 and Japanese Utility Model Publication No. 1-41279, it is common to solidify epoxy resin or silicon resin mixed with minute hollow spheres made of glass, carbon or the like into a flat plate shape. ing.
【０００３】ところで、従来においては、空気の音響イ
ンピーダンスＺ１＝０．０００４×１０6ｋｇ／ｍ2ｓ、
また、セラミックからなる圧電振動子の音響インピーダ
ンスＺ２＝３０×１０6ｋｇ／ｍ2ｓであるのに対し、音
響整合層の音響インピーダンスＺ３＝（Ｚｌ×Ｚ２）
1/2＝０．１１×ｌ０6ｋｇ／ｍ2ｓである場合における
空気中ヘの超音波の伝達効率が最も大きくなる、つま
り、超音波振動子の感度が最も高いことになるので、音
響インピーダンスが０．９〜１．４×１０6ｋｇ／ｍ2ｓ
程度となるような材料を用いたうえで音響整合層を作製
するとともに、この際における音響整合層の厚みを超音
波の１／４波長としておくことが行われている。By the way, in the prior art, the acoustic impedance of air Z1 = 0.004 × 10 6 kg / m 2 s,
Also, while the acoustic impedance Z2 of the piezoelectric vibrator made of ceramic is 30 × 10 6 kg / m 2 s, the acoustic impedance of the acoustic matching layer Z3 = (Zl × Z2).
In the case of 1/2 = 0.11 × 10 6 kg / m 2 s, the transmission efficiency of ultrasonic waves into the air is the highest, that is, the sensitivity of the ultrasonic transducer is the highest, so Impedance is 0.9 to 1.4 × 10 6 kg / m 2 s
The acoustic matching layer is manufactured by using a material having a certain degree, and the thickness of the acoustic matching layer at this time is set to ¼ wavelength of ultrasonic waves.
【０００４】[0004]
【発明が解決しようとする課題】しかしながら、ガラス
製の微小中空球をエポキシ樹脂でもって固めることによ
って作製され、かつ、音響インピーダンスＺ＝１．４×
１０6ｋｇ／ｍ2ｓ程度とされた音響整合層を用意したう
え、この音響整合層を用いて構成された超音波振動子に
おける受信感度を調査してみたところ、図２中の実線で
示すような調査結果が得られた。すなわち、この調査結
果によれば、超音波振動子の有する音響インピーダンス
が理想値に近ければ近いほど、使用周波数がずれた際に
おける超音波振動子の感度変化が大きいことが分かる。However, it is produced by solidifying glass micro hollow spheres with an epoxy resin, and has an acoustic impedance Z = 1.4 ×.
An acoustic matching layer of about 10 6 kg / m 2 s was prepared, and the receiving sensitivity of the ultrasonic transducer configured using this acoustic matching layer was investigated, and it is shown by the solid line in FIG. The survey results are as follows. That is, according to this investigation result, it is understood that the closer the acoustic impedance of the ultrasonic transducer is to the ideal value, the greater the change in sensitivity of the ultrasonic transducer when the operating frequency shifts.
【０００５】そして、超音波振動子の感度の変化が大き
いと、距離測定対象である反射物からの反射時間の変化
が長くなる結果、反射時間に基づいて反射物までの距離
を算出した際の精度が低下することにもなってしまう。
つまり、図３で示すように、送信側の超音波振動子から
反射物に対して超音波信号Ａを出力した際、感度が低下
していなければ、受信側の超音波振動子に対して大きな
反射信号Ｂが入力し、この反射信号Ｂが短い反射時間Ｔ
の経過後にしきい値Ｓを越えて検知されるはずであるの
に対し、感度が低下している場合には、小さな反射波
Ｂ′しか得られず、この反射波Ｂ′がしきい値Ｓを越え
るまでの反射時間Ｔ′が遅れてしまうのである。If the change in the sensitivity of the ultrasonic transducer is large, the change in the reflection time from the reflection object, which is the object of distance measurement, becomes long. As a result, when the distance to the reflection object is calculated based on the reflection time. The accuracy is also reduced.
That is, as shown in FIG. 3, when the ultrasonic signal A is output from the ultrasonic transducer on the transmitting side to the reflector, if the sensitivity is not lowered, it is larger than that on the ultrasonic transducer on the receiving side. The reflection signal B is input, and this reflection signal B has a short reflection time T
When the sensitivity is lowered, only a small reflected wave B'is obtained, and this reflected wave B'is detected as the threshold value S '. The reflection time T'beyond is delayed.
【０００６】そこで、従来構造の超音波振動子において
距離測定精度の向上を図るには、音響整合層の厚みに
対する加工精度を向上させることにより超音波振動子に
おける周波数のバラツキを小さくする、送信側の超音
波振動子を駆動する送信回路の周波数を超音波振動子の
特性に合わせて調整する、温度変化によって超音波セ
ンサの周波数がずれた時には送信回路及び受信回路でも
って周波数のずれを検知して補正する、といった対策を
実行する必要があり、結果として超音波振動子あるいは
送信回路及び受信回路が高価になるという不都合が生じ
ることになっていた。Therefore, in order to improve the accuracy of distance measurement in the ultrasonic transducer having the conventional structure, the variation in frequency in the ultrasonic transducer is reduced by improving the processing accuracy with respect to the thickness of the acoustic matching layer. The frequency of the transmitting circuit that drives the ultrasonic transducer is adjusted according to the characteristics of the ultrasonic transducer.When the frequency of the ultrasonic sensor shifts due to temperature change, the transmitting circuit and the receiving circuit detect the frequency shift. Therefore, it is necessary to take a countermeasure such as correction, and as a result, the ultrasonic transducer or the transmitting circuit and the receiving circuit become expensive.
【０００７】本発明は、これらの不都合に鑑みて創案さ
れたものであって、感度変化が小さくて距離算出精度の
向上を図ることが容易な超音波振動子の提供を目的とす
る。The present invention was devised in view of these inconveniences, and an object thereof is to provide an ultrasonic transducer in which the sensitivity change is small and the distance calculation accuracy can be easily improved.
【０００８】[0008]
【課題を解決するための手段】本発明にかかる超音波振
動子は、音響整合層と、この音響整合層の一面上に接合
された圧電振動素子及び支持用筒体とを具備してなるも
のであって、音響整合層は、音響インピーダンスが１．
５〜１．８×１０6Ｋｇ／ｍ2ｓ程度となる樹脂材料を用
いて作製されたものであることを特徴とする。なお、こ
のような樹脂材料としては、ノリルもしくはＡＢＳ（ア
クリルニトリル−ブタジエン−スチレン共重合樹脂）が
ある。An ultrasonic transducer according to the present invention comprises an acoustic matching layer, a piezoelectric vibrating element bonded to one surface of the acoustic matching layer, and a supporting cylinder. The acoustic matching layer has an acoustic impedance of 1.
It is characterized by being manufactured using a resin material having a weight of about 5 to 1.8 × 10 6 Kg / m 2 s. As such a resin material, there is Noryl or ABS (acrylonitrile-butadiene-styrene copolymer resin).
【０００９】[0009]
【発明の実施の形態】以下、本発明にかかる超音波振動
子の実施の形態を図面に基づいて説明する。BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of an ultrasonic transducer according to the present invention will be described below with reference to the drawings.
【００１０】図１は超音波振動子の全体構造を簡略化し
て示す断面図であり、この超音波振動子は、音響整合層
１と、この音響整合層１の一面（図では、裏面）上に接
着剤（図示せず）を用いて接合された圧電振動素子２及
び支持用筒体３とを具備している。そして、この際にお
ける音響整合層１は、その表面が超音波送受波面として
機能するものであり、１．５〜１．８×１０6Ｋｇ／ｍ2
ｓ程度の音響インピーダンスを有する樹脂材料、例え
ば、ノリルやＡＢＳなどのような樹脂材料を用いること
によって作製されている。FIG. 1 is a sectional view showing a simplified overall structure of an ultrasonic transducer. This ultrasonic transducer has an acoustic matching layer 1 and one surface (back surface in the figure) of the acoustic matching layer 1. The piezoelectric vibrating element 2 and the supporting cylindrical body 3 which are bonded to each other with an adhesive (not shown). The surface of the acoustic matching layer 1 at this time functions as an ultrasonic wave transmitting / receiving surface, and is 1.5 to 1.8 × 10 6 Kg / m 2.
It is manufactured by using a resin material having an acoustic impedance of about s, for example, a resin material such as Noryl or ABS.
【００１１】また、この音響整合層１の厚みが超音波の
１／４波長と合致させられており、かつ、アルミニウム
などの金属を用いて作製された支持用筒体３が音響整合
層１の周縁を支持していることは従来例と同じである。
なお、図中の符号４は支持用筒体３内に配設されたベー
ス基板、５は圧電振動素子１の表面電極（図示せず）に
対して接続された負（−）側のリード線、６は圧電振動
素子１の裏面電極（図示せず）に接続された正（＋）側
のリード線、７は配線ケーブル、８はベース基板４の裏
面側に充填されたシリコーンゴムである。The thickness of the acoustic matching layer 1 is matched with the quarter wavelength of ultrasonic waves, and the supporting cylinder 3 made of a metal such as aluminum is used as the acoustic matching layer 1. Supporting the peripheral edge is the same as the conventional example.
In the figure, reference numeral 4 is a base substrate arranged in the supporting cylinder 3, and reference numeral 5 is a negative (-) side lead wire connected to a surface electrode (not shown) of the piezoelectric vibrating element 1. , 6 is a positive (+) side lead wire connected to a back surface electrode (not shown) of the piezoelectric vibrating element 1, 7 is a wiring cable, and 8 is a silicone rubber filled on the back surface side of the base substrate 4.
【００１２】ところで、音響インピーダンスＺ＝１．７
×１０6Ｋｇ／ｍ2ｓ程度である音響整合層１を用いてな
る超音波振動子の受信感度を調査したところ、図２中の
破線で示すような調査結果が得られた。そして、この調
査結果によれば、音響インピーダンスが１．４×１０6
Ｋｇ／ｍ2ｓ程度であった従来例に比べ、１．７×１０6
Ｋｇ／ｍ2ｓ程度の音響インピーダンスを有する音響整
合層１を用いた際には超音波振動子における感度変化が
少なくなることが明らかとなっている。By the way, acoustic impedance Z = 1.7
When the receiving sensitivity of the ultrasonic transducer using the acoustic matching layer 1 having a density of about 10 6 Kg / m 2 s was investigated, the investigation result shown by the broken line in FIG. 2 was obtained. And, according to this survey result, the acoustic impedance is 1.4 × 10 6.
Compared with the conventional example which was about Kg / m 2 s, 1.7 × 10 6
It has been clarified that when the acoustic matching layer 1 having an acoustic impedance of about Kg / m 2 s is used, the sensitivity change in the ultrasonic transducer is reduced.
【００１３】すなわち、ノリルもしくはＡＢＳのような
樹脂材料を用いることによって音響整合層１を作製した
場合には、周波数のずれによる超音波センサの感度変化
が小さくなり、従来例で説明したようなないしの対
策を実行しなくても距離算出精度が向上していることに
なる。なお、近距離の測定では超音波の減衰が少ないた
めに感度が若干程度低くても問題にはならず、逆に、反
射時間が短くなるために同じ時間誤差であっても相対的
な誤差率が大きくなるから、本発明にかかる超音波振動
子、つまり、フラット（平坦）な感度を有する超音波振
動子の方が、特定の周波数において高いピーク感度を持
つ従来例構造の超音波振動子よりも好ましいことは明ら
かである。That is, when the acoustic matching layer 1 is manufactured by using a resin material such as Noryl or ABS, the sensitivity change of the ultrasonic sensor due to the frequency shift becomes small, which is not described in the conventional example. This means that the distance calculation accuracy is improved without taking the measures described in (1). It should be noted that in short-distance measurement, there is little attenuation of ultrasonic waves, so there is no problem even if sensitivity is somewhat low, and conversely, even if the same time error occurs because the reflection time becomes shorter, the relative error rate Therefore, the ultrasonic vibrator according to the present invention, that is, the ultrasonic vibrator having a flat sensitivity is higher than that of the conventional structure having a high peak sensitivity at a specific frequency. Obviously, is also preferable.
【００１４】[0014]
【発明の効果】以上説明したように、本発明にかかる超
音波振動子によれば、周波数ずれに伴う感度変化を少な
くでき、距離測定精度の向上を図ることができるという
効果が得られる。また、従来例におけるような距離測定
精度の向上を図るための周波数調整や温度補正を行う必
要がなくなる結果、送信回路及び受信回路の構成に要す
るコストを低減することもできる。As described above, according to the ultrasonic vibrator of the present invention, it is possible to reduce the sensitivity change due to the frequency shift and to improve the distance measurement accuracy. Further, since it is not necessary to perform frequency adjustment or temperature correction for improving the distance measurement accuracy as in the conventional example, it is possible to reduce the cost required for the configuration of the transmission circuit and the reception circuit.
【図１】実施形態にかかる超音波振動子の全体構造を簡
略化して示す断面図である。FIG. 1 is a sectional view showing a simplified overall structure of an ultrasonic transducer according to an embodiment.
【図２】実施形態及び従来形態の例超音波振動子におけ
る受信感度の調査結果を示す説明図である。FIG. 2 is an explanatory diagram showing a result of a survey on reception sensitivity of an ultrasonic transducer according to an embodiment and an example of a related art.
【図３】従来形態において反射時間の遅れが生じる状態
の説明図である。FIG. 3 is an explanatory diagram of a state in which a reflection time delay occurs in the conventional form.
１ 音響整合層 ２ 圧電振動素子 ３ 支持用筒体 1 Acoustic Matching Layer 2 Piezoelectric Vibrating Element 3 Supporting Cylindrical Body
Claims (2)
（１）の一面上に接合された圧電振動素子（２）及び支
持用筒体（３）とを具備してなる超音波振動子であっ
て、 音響整合層（１）は、音響インピーダンスが１．５〜
１．８×１０6Ｋｇ／ｍ2ｓ程度となる樹脂材料を用いて
作製されたものであることを特徴とする超音波振動子。1. An ultrasonic vibration comprising an acoustic matching layer (1), a piezoelectric vibrating element (2) and a supporting cylinder (3) bonded to one surface of the acoustic matching layer (1). The acoustic matching layer (1) has a sound impedance of 1.5 to
An ultrasonic transducer manufactured using a resin material having a weight of about 1.8 × 10 6 Kg / m 2 s.
ることを特徴とする請求項１記載の超音波振動子。2. The ultrasonic transducer according to claim 1, wherein the resin material is Noryl or ABS.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20079495A JPH0951599A (en) | 1995-08-07 | 1995-08-07 | Ultrasonic vibrator |
| US08/668,386 US5907521A (en) | 1995-06-23 | 1996-06-21 | Ultrasonic range finder using ultrasonic sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20079495A JPH0951599A (en) | 1995-08-07 | 1995-08-07 | Ultrasonic vibrator |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0951599A true JPH0951599A (en) | 1997-02-18 |
Family
ID=16430306
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP20079495A Pending JPH0951599A (en) | 1995-06-23 | 1995-08-07 | Ultrasonic vibrator |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0951599A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110987041A (en) * | 2019-12-31 | 2020-04-10 | 广东奥迪威传感科技股份有限公司 | Ultrasonic sensor and shell thereof |
-
1995
- 1995-08-07 JP JP20079495A patent/JPH0951599A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110987041A (en) * | 2019-12-31 | 2020-04-10 | 广东奥迪威传感科技股份有限公司 | Ultrasonic sensor and shell thereof |
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| JPH07198827A (en) | Speed detector | |
| JPH09307998A (en) | Tilt angle sensor |