JPS62188599A - Ultrasonic probe - Google Patents
Ultrasonic probeInfo
- Publication number
- JPS62188599A JPS62188599A JP3014786A JP3014786A JPS62188599A JP S62188599 A JPS62188599 A JP S62188599A JP 3014786 A JP3014786 A JP 3014786A JP 3014786 A JP3014786 A JP 3014786A JP S62188599 A JPS62188599 A JP S62188599A
- Authority
- JP
- Japan
- Prior art keywords
- piezoelectric element
- current
- ultrasonic probe
- housing
- probe
- 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
- 239000000523 sample Substances 0.000 title claims abstract description 25
- 239000011810 insulating material Substances 0.000 claims description 5
- 229910052710 silicon Inorganic materials 0.000 claims description 3
- 239000010703 silicon Substances 0.000 claims description 3
- 239000013013 elastic material Substances 0.000 claims description 2
- 230000006378 damage Effects 0.000 abstract description 8
- 239000000463 material Substances 0.000 abstract description 4
- 239000002184 metal Substances 0.000 abstract description 2
- 229910001220 stainless steel Inorganic materials 0.000 abstract description 2
- 239000010935 stainless steel Substances 0.000 abstract description 2
- 238000010438 heat treatment Methods 0.000 abstract 1
- 229920001296 polysiloxane Polymers 0.000 abstract 1
- 238000013016 damping Methods 0.000 description 6
- 238000007789 sealing Methods 0.000 description 5
- 230000000694 effects Effects 0.000 description 4
- 230000020169 heat generation Effects 0.000 description 3
- 230000006835 compression Effects 0.000 description 2
- 238000007906 compression Methods 0.000 description 2
- 230000001066 destructive effect Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000007689 inspection Methods 0.000 description 2
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 description 2
- 238000002604 ultrasonography Methods 0.000 description 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000003745 diagnosis Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 229920006332 epoxy adhesive Polymers 0.000 description 1
- 238000007429 general method Methods 0.000 description 1
- 230000017525 heat dissipation Effects 0.000 description 1
- 238000001727 in vivo Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000009659 non-destructive testing Methods 0.000 description 1
- 230000002250 progressing effect Effects 0.000 description 1
- 238000012827 research and development Methods 0.000 description 1
- 239000003566 sealing material Substances 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 238000005476 soldering Methods 0.000 description 1
- 229910052845 zircon Inorganic materials 0.000 description 1
- GFQYVLUOOAAOGM-UHFFFAOYSA-N zirconium(iv) silicate Chemical compound [Zr+4].[O-][Si]([O-])([O-])[O-] GFQYVLUOOAAOGM-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Transducers For Ultrasonic Waves (AREA)
- Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
- Ultra Sonic Daignosis Equipment (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は過電流による圧電素子の破壊を防止した超音波
探触子に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ultrasonic probe that prevents destruction of piezoelectric elements due to overcurrent.
近年、各種構造物の非破壊検査９体内医療診断等に超音
波が一般的な方法として用いられるようになってきたが
、これらの非破壊検査に用いられる超音波探触子は被検
体の広い領域にわたって高感度・高分解能であることが
望ましく、そのために通常数００Ｖの電圧が印加される
。このような超音波探触子に用いられる圧電素子は、電
気機械結合係数の大きいジルコン・チタン酸鉛（ＰＺＴ
）より構成されるが、この材料は同時に強誘電体でもあ
るため、上記のような高い電圧を印加することによって
ヒステリシスループを描き、通常の誘電率損失（ｔａｎ
δ喪失）による発熱とヒステリシス損失による発熱とが
重畳されている。In recent years, ultrasound has come to be used as a general method for non-destructive inspection of various structures9, in-vivo medical diagnosis, etc., but the ultrasonic probes used for these non-destructive inspections can be used for a wide range of objects. It is desirable to have high sensitivity and high resolution over the area, and for this purpose, a voltage of several hundred volts is usually applied. The piezoelectric elements used in such ultrasonic probes are made of lead zircon titanate (PZT), which has a large electromechanical coupling coefficient.
), but this material is also a ferroelectric material, so by applying the high voltage mentioned above, it creates a hysteresis loop and reduces the normal dielectric loss (tan).
The heat generation due to δ loss) and the heat generation due to hysteresis loss are superimposed.
（発明が解決しようとする問題点）
一方、最近では超音波の研究開発も進んでおり、その一
つにパルス圧縮技術がある。ところが、このパルス圧縮
技術を利用する場合、探触子の発熱がさらに大きくなり
、放熱対策が不十分であると圧電素子が破壊されるおそ
れがある。特に超音波内視鏡のように探触子を体内へ挿
入する場合には、圧電素子の破壊が探触子全体の構造的
破壊を招く場合もあり、単に探触子の機能が停止するだ
けではなく、安全上好ましくない状態に陥ることになる
。また、構造物の非破壊検査においても圧電素子の破壊
によって構造物への電流のリークが発生し、種々の弊害
を及ぼすおそれがある。(Problems to be Solved by the Invention) On the other hand, research and development of ultrasonic waves has been progressing recently, and one of them is pulse compression technology. However, when this pulse compression technique is used, the probe generates even more heat, and if heat dissipation measures are insufficient, the piezoelectric element may be destroyed. Particularly when a probe is inserted into the body, such as in an ultrasound endoscope, destruction of the piezoelectric element may lead to structural destruction of the entire probe, or simply cause the probe to stop functioning. Instead, you will end up in a situation that is unfavorable from a safety standpoint. Furthermore, in non-destructive testing of structures, current leakage to the structure may occur due to destruction of the piezoelectric element, which may cause various adverse effects.
本発明はこのような事情にもとづいてなされたもので、
その目的は、過電流による圧電素子の破壊を防止し、信
頼性および安全性の高い超音波探触子を提供することに
ある。The present invention was made based on these circumstances, and
The purpose is to prevent destruction of the piezoelectric element due to overcurrent and to provide an ultrasonic probe with high reliability and safety.
上記目的を達成するために本発明は、圧ｉ！素子が収容
されたハウジング内に温度に応じて電流値を制限する電
流制限素子を設け、この電流制限素子を前記圧電素子に
直列接続したことを特徴としている。In order to achieve the above object, the present invention provides pressure i! The present invention is characterized in that a current limiting element that limits the current value according to temperature is provided in a housing in which the element is housed, and this current limiting element is connected in series to the piezoelectric element.
本発明においては、探触子の発熱層が大きくなると電流
制限素子が作動して圧電素子への供給電流がＩ１１限さ
れるので圧電素子の破壊を防止できる。In the present invention, when the heat generating layer of the probe becomes large, the current limiting element is activated and the current supplied to the piezoelectric element is limited by I11, so that destruction of the piezoelectric element can be prevented.
以下、本発明を図面に示す実施例にもとづいて説明する
。The present invention will be described below based on embodiments shown in the drawings.
第１図は本発明に係る超音波探触子の一実施例を示すも
ので、探触子の一部分を断面で示したものである。同図
において符号１はＰＺＴ等からなる圧電素子で、この圧
電素子１はステンレス鋼等の金属を円筒（または角筒）
状に形成したハウジング２内に収容されている。そして
、圧電素子１の超音波送受側には音響整合層３が配置さ
れ、その反対側にはダンピング層４およびシール層５が
重なり合った状態で配置されている。なお、ダンピング
層４とハウジング２との間には絶縁層６が設けられてい
る。FIG. 1 shows an embodiment of an ultrasonic probe according to the present invention, and shows a portion of the probe in cross section. In the figure, reference numeral 1 is a piezoelectric element made of PZT or the like, and this piezoelectric element 1 is made of metal such as stainless steel in a cylindrical (or rectangular) shape.
It is housed in a housing 2 formed in a shape. An acoustic matching layer 3 is arranged on the ultrasonic transmitting/receiving side of the piezoelectric element 1, and a damping layer 4 and a sealing layer 5 are arranged in an overlapping state on the opposite side. Note that an insulating layer 6 is provided between the damping layer 4 and the housing 2.
前記圧電素子１の両面は電極となっており、超音波送受
側の電極にはリード線７が接続されている。このリード
４１７はハウジング２に接続しており、圧電素子１をハ
ウジング２にアースさせた構造となっている。また、超
音波送受側と反対の電極にはり−ド１１１８が接続され
ている。このリードｌａ８は前記ダンピング層４および
シール層５内を通り、ハウジング２の下部に設けられた
同軸ケーブル９に接続しており、同軸ケーブル９とリー
ド＄１８との間には正特性サーミスタ１ｏが介挿されて
いる。この正特性サーミスタ１０は前記シール１Ｉ１５
内に設けられ、シール層５はシリコン等の絶縁性シール
材から形成されている。Both surfaces of the piezoelectric element 1 are electrodes, and a lead wire 7 is connected to the electrode on the ultrasonic transmitting/receiving side. This lead 417 is connected to the housing 2, so that the piezoelectric element 1 is grounded to the housing 2. Further, a beam 1118 is connected to the electrode opposite to the ultrasonic wave transmitting/receiving side. This lead la8 passes through the damping layer 4 and sealing layer 5 and is connected to a coaxial cable 9 provided at the bottom of the housing 2, and a positive temperature coefficient thermistor 1o is connected between the coaxial cable 9 and the lead $18. It is interposed. This positive temperature coefficient thermistor 10 has the seal 1I15
The sealing layer 5 is formed from an insulating sealing material such as silicon.
次に正特性サーミスタ１ｏの作用について説明する。Next, the operation of the positive temperature coefficient thermistor 1o will be explained.
第２図は正特性サーミスタの抵抗値と温度の関係を示し
たもので、同図から正特性サーミスタ１０はある一定温
度（Ｔｃ）以上になると、その抵抗値が急激に上昇する
ことがわかる。従って、第３因の如く圧電素子１に正特
性サーミスタ１０を直列に接続することにより、圧電素
子１への供給電流を探触子の発熱！（温度）に応じて制
限することができる。なお、上記実施例では正特性サー
ミスタ１ｏをシール層５内に設けたが、第４図のように
ダンピング層４内に設けてもよい。ただし、その場合に
は正特性サーミスタ１０全体を絶縁材１１で被包する必
要がある。FIG. 2 shows the relationship between the resistance value of a positive temperature coefficient thermistor and temperature, and it can be seen from the figure that the resistance value of the positive coefficient thermistor 10 increases rapidly when the temperature exceeds a certain temperature (Tc). Therefore, by connecting the positive temperature coefficient thermistor 10 in series with the piezoelectric element 1 as in the third factor, the current supplied to the piezoelectric element 1 can be adjusted to reduce the heat generation of the probe. (temperature). In the above embodiment, the positive temperature coefficient thermistor 1o is provided within the sealing layer 5, but it may also be provided within the damping layer 4 as shown in FIG. However, in that case, it is necessary to cover the entire positive temperature coefficient thermistor 10 with the insulating material 11.
また、第５図の如く正特性サーミスタ１０を圧電素子１
とほぼ同じ直径のディスク状に形成し、その裏表のディ
スク面に電極を設けてエポキシ接着剤、導電性接着剤、
半田付は等により圧電素子１に直接接合してもよい。こ
のようにすれば正特性サーミスタ１０の音響インピーダ
ンスは圧電素子１のそれに近い値を示すため、超音波の
周波数は正特性サーミスタの厚みに相当する分だけ低下
する反面、音響整合１３にガラス等の非圧電性材料を用
いた場合に発生する屈自振動を防止できるとともに、電
気的ダンピング効果によるリンギング現像を抑圧できる
という効果がある。In addition, as shown in FIG.
It is formed into a disk shape with approximately the same diameter as the disk, and electrodes are provided on the front and back surfaces of the disk, and epoxy adhesive, conductive adhesive,
The piezoelectric element 1 may be directly joined to the piezoelectric element 1 by soldering or the like. In this way, the acoustic impedance of the PTC thermistor 10 shows a value close to that of the piezoelectric element 1, so the frequency of the ultrasonic wave decreases by an amount corresponding to the thickness of the PTC thermistor. This has the effect of being able to prevent the bending vibration that occurs when a non-piezoelectric material is used, as well as suppressing ringing development due to the electrical damping effect.
なお、第１図に示した第１実施例のシール１１５および
第４図に示した第２実施例の絶縁材１１は、シリコン等
の弾力性のある材料を用いるのが望ましい。これは正特
性サーミスタが急激に瀉度上昇した時の熱膨張による応
力をシール層５または絶縁材１１で吸収するためである
。The seal 115 of the first embodiment shown in FIG. 1 and the insulating material 11 of the second embodiment shown in FIG. 4 are preferably made of an elastic material such as silicon. This is because the sealing layer 5 or the insulating material 11 absorbs stress due to thermal expansion when the temperature of the PTC thermistor suddenly increases.
以上のように本発明によれば、圧電素子が収容されたハ
ウジング内に温度に応じて電流値を制限する電流制限素
子を設け、この電流制限素子を前記圧電素子に直列接続
することにより圧電素子への供給電流を探触子の発熱量
に応じて制限できるので、過電流による圧電素子の破壊
を防止でき、信頼性および安全性の高い超音波探触子を
提供できる。As described above, according to the present invention, a current limiting element that limits a current value according to temperature is provided in a housing in which a piezoelectric element is housed, and this current limiting element is connected in series with the piezoelectric element. Since the current supplied to the probe can be limited according to the amount of heat generated by the probe, destruction of the piezoelectric element due to overcurrent can be prevented, and a highly reliable and safe ultrasonic probe can be provided.
第１図は本発明の第１実施例を示す超音波探触子の断面
図、第２図は正特性サーミスタの温度−抵抗値特性を示
す線図、第３図は第１実施例の回路図、第４図は本発明
の第２実施例を示す超音波探触子の断面図、第５図は本
発明の第３実施例を示す超音波探触子の断面図である。
１・・・圧電素子、２・・・ハウジング、３・・・音響
整合層、４・・・ダンピング層、５・・・シール層、６
・・・絶縁層、７．８・・・リード線、９・・・同軸ケ
ーブル、１０・・・正特性サーミスタ。
出願人代理人 弁理士 坪井 淳
第１図
第２図 第３図′２４ 図
第５図Fig. 1 is a sectional view of an ultrasonic probe showing a first embodiment of the present invention, Fig. 2 is a diagram showing temperature-resistance characteristics of a positive temperature coefficient thermistor, and Fig. 3 is a circuit of the first embodiment. 4 are cross-sectional views of an ultrasonic probe showing a second embodiment of the present invention, and FIG. 5 is a cross-sectional view of an ultrasonic probe showing a third embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Piezoelectric element, 2... Housing, 3... Acoustic matching layer, 4... Damping layer, 5... Seal layer, 6
...Insulating layer, 7.8...Lead wire, 9...Coaxial cable, 10...Positive characteristic thermistor. Applicant's Representative Patent Attorney Jun Tsuboi Figure 1 Figure 2 Figure 3 '24 Figure 5
Claims (4)
して超音波を発生させる超音波探触子において、前記ハ
ウジング内に温度に応じて電流値を制限する電流制限素
子を設け、この電流制限素子を前記圧電素子に直列接続
したことを特徴とする超音波探触子。(1) In an ultrasonic probe that generates ultrasonic waves by applying a voltage to a piezoelectric element housed in a housing, a current limiting element that limits a current value according to temperature is provided in the housing, and the current An ultrasonic probe characterized in that a limiting element is connected in series to the piezoelectric element.
許請求の範囲第（１）項記載の超音波探触子。(2) The ultrasonic probe according to claim (1), wherein the current limiting element is a positive temperature coefficient thermistor.
で被覆されていることを特徴とする特許請求の範囲第（
２）項記載の超音波探触子。(3) The positive temperature coefficient thermistor is characterized in that its entire surface is coated with an insulating material.
The ultrasonic probe described in section 2).
らなる特許請求の範囲第（３）項記載の超音波探触子。(4) The ultrasonic probe according to claim (3), wherein the insulating material is made of an elastic material such as silicon.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3014786A JPS62188599A (en) | 1986-02-14 | 1986-02-14 | Ultrasonic probe |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3014786A JPS62188599A (en) | 1986-02-14 | 1986-02-14 | Ultrasonic probe |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS62188599A true JPS62188599A (en) | 1987-08-18 |
Family
ID=12295649
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3014786A Pending JPS62188599A (en) | 1986-02-14 | 1986-02-14 | Ultrasonic probe |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS62188599A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63156609U (en) * | 1987-04-02 | 1988-10-14 | ||
| JPH021247A (en) * | 1988-03-02 | 1990-01-05 | Toshiba Corp | Ultrasonic diagnostic apparatus |
-
1986
- 1986-02-14 JP JP3014786A patent/JPS62188599A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63156609U (en) * | 1987-04-02 | 1988-10-14 | ||
| JPH021247A (en) * | 1988-03-02 | 1990-01-05 | Toshiba Corp | Ultrasonic diagnostic apparatus |
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