JP3325305B2 - Ultrasonic probe - Google Patents
Ultrasonic probeInfo
- Publication number
- JP3325305B2 JP3325305B2 JP26779992A JP26779992A JP3325305B2 JP 3325305 B2 JP3325305 B2 JP 3325305B2 JP 26779992 A JP26779992 A JP 26779992A JP 26779992 A JP26779992 A JP 26779992A JP 3325305 B2 JP3325305 B2 JP 3325305B2
- Authority
- JP
- Japan
- Prior art keywords
- thin film
- film material
- acoustic
- piezoelectric vibrator
- ultrasonic 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.)
- Expired - Lifetime
Links
Landscapes
- Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
- Ultra Sonic Daignosis Equipment (AREA)
- Transducers For Ultrasonic Waves (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は超音波診断装置用の超音
波探触子に係り、特に多数の棒状圧電振動子をアレー状
に配列して成る電子走査型超音波探触子における振動子
の配列方向と直交する方向での超音波の指向性を改善す
る技術に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic probe for an ultrasonic diagnostic apparatus, and more particularly to a transducer in an electronic scanning ultrasonic probe in which a large number of rod-shaped piezoelectric transducers are arranged in an array. The present invention relates to a technique for improving the directivity of ultrasonic waves in a direction orthogonal to the arrangement direction.
【０００２】[0002]
【従来の技術】電子走査型超音波探触子は、各種文献で
も公知のように、細長い棒状の圧電振動子を吸音材（バ
ッキング材ともいう）の上にアレー状に配置し、その圧
電振動子の上面に複数層の音響整合層を設け、さらにそ
の音響整合層の上を音響レンズで覆って構成されている
のが一般的である。2. Description of the Related Art As is well known in various documents, an electronic scanning ultrasonic probe has an elongated rod-shaped piezoelectric vibrator arranged in an array on a sound absorbing material (also referred to as a backing material). In general, a plurality of acoustic matching layers are provided on the upper surface of the element, and the acoustic matching layer is covered with an acoustic lens.
【０００３】上記探触子の構成要素のうち、音響レンズ
は圧電振動子の配列方向と直交する方向（以下、短軸方
向という）へ超音波を集束する目的で設けられている。
そして、通常、音響レンズによる短軸方向への超音波集
束は超音波の伝播速度を利用して行うこと、及び、探触
子を被検体の体表へ密着させ易くすること等から、その
形状は横断面中央部が厚い蒲鉾状に形成されている。こ
の形状によって、細長い棒状の圧電振動子の端部からの
超音波は早く被検体内へ、そして中央部からの超音波は
遅く被検体内へ伝播され、結果的に短軸方向への超音波
ビームの集束が行われるというものである。[0003] Among the components of the above-mentioned probe, an acoustic lens is provided for the purpose of focusing ultrasonic waves in a direction perpendicular to the arrangement direction of the piezoelectric vibrators (hereinafter, referred to as a short axis direction).
Usually, the ultrasound is focused by the acoustic lens in the short axis direction using the propagation speed of the ultrasound, and the shape of the probe is easily adjusted because the probe is easily brought into close contact with the body surface of the subject. Is formed in a thick kamaboko shape at the center of the cross section. Due to this shape, ultrasonic waves from the end of the elongated rod-shaped piezoelectric vibrator are quickly propagated into the subject, and ultrasonic waves from the central part are slowly propagated into the subject, resulting in ultrasonic waves in the short axis direction. Beam focusing is performed.
【０００４】[0004]
【発明が解決しようとする課題】上記従来技術によれ
ば、短軸方向への超音波ビームの集束がなされはする
が、他面、音響レンズの厚みによる減衰により被検体中
での短軸方向での音圧分布が音響レンズの凸形とは逆に
凹形となってしまい、ビーム指向性の面では良い結果を
もたらしているとは言えないものであった。According to the above prior art, the ultrasonic beam is focused in the short axis direction, but on the other hand, in the short axis direction in the subject due to attenuation due to the thickness of the acoustic lens. The sound pressure distribution becomes concave in contrast to the convex shape of the acoustic lens, and it cannot be said that good results are obtained in terms of beam directivity.
【０００５】本発明は上記に鑑みて成されたもので、被
検体へ密着させ易い従来の凸形音響レンズの形状を変え
ることなく、短軸方向への音圧分布を改良し、結果とし
超音波ビームの指向性を改善し良好な超音波像が得られ
る超音波探触子を提供することを目的としている。The present invention has been made in view of the above, and has improved the sound pressure distribution in the short axis direction without changing the shape of a conventional convex acoustic lens which is easily adhered to a subject. It is an object of the present invention to provide an ultrasonic probe capable of improving the directivity of a sound beam and obtaining a good ultrasonic image.
【０００６】[0006]
【課題を解決するための手段】本発明は、上記目的を達
成するために、吸音材と、この吸音材の上面に配列され
た圧電振動子群と、この圧電振動子群の上面に配置され
た音響整合層と、この音響整合層の上面に配置され前記
圧電素子群の配列方向と直交する方向に両端部を薄くか
つ中央部を厚くした形状の音響レンズとを備えた超音波
振動子において、前記吸音材と前記圧電振動子群の間
に、厚みがλ／４（λは超音波の波長）の薄膜材であっ
て所定の音響インピーダンスである第１の薄膜材を前記
直交方向の中央部に、前記第１の薄膜材と同じ厚みであ
ってそれより大きい音響インピーダンスである第２の薄
膜材を前記直交方向に挟むように、それぞれ配置される
ことを特徴とするものである。また、前記第１の薄膜材
と前記第２の薄膜材との間に配置され、それらの薄膜材
と同じ厚みであってそれらの薄膜材の中間の音響インピ
ーダンスである少なくとも一つの薄膜材を備えたことを
特徴とするものである。 SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a sound absorbing material and a sound absorbing material arranged on an upper surface of the sound absorbing material.
Piezoelectric vibrator group and the piezoelectric vibrator group
An acoustic matching layer, and the acoustic matching layer
Are both ends thin in the direction perpendicular to the direction of arrangement of the piezoelectric elements?
With an acoustic lens with a thick central part
In the vibrator, between the sound absorbing material and the piezoelectric vibrator group
In addition, a thin film material having a thickness of λ / 4 (where λ is the wavelength of the ultrasonic wave) is used.
The first thin film material having a predetermined acoustic impedance
At the center in the orthogonal direction, the same thickness as the first thin film material
The second thin film having a higher acoustic impedance
The film material is disposed so as to sandwich the film material in the orthogonal direction . Further, the first thin film material
And the second thin film material, and the thin film materials
Of the same acoustic impedance as that of the thin film material.
That it has at least one thin film material
It is a feature.
【０００７】[0007]
【作用】バッキング材と上記薄膜材と圧電振動子とを積
層した場合、圧電振動子から見たバッキング材の実効イ
ンピーダンスが短軸方向の中央部から端部へ行くにした
がって大きくなるため、棒状の圧電振動子の振動効率
(送波効率と言っても良い)は中央部が高く、端部へ行く
にしたがって低下する。したがって、音響レンズが中央
部で凸状となっていることによる音圧分布の中央部での
凹形が補償される。When the backing material, the thin film material, and the piezoelectric vibrator are laminated, the effective impedance of the backing material viewed from the piezoelectric vibrator increases from the center to the end in the short-axis direction. Vibration efficiency of piezoelectric vibrator
(It may be said that the transmission efficiency is high) at the center, and decreases toward the end. Therefore, the concave shape at the center of the sound pressure distribution due to the convex shape of the acoustic lens at the center is compensated.
【０００８】[0008]
【実施例】以下、本発明の一実施例を図１を用いて説明
する。図１は電子走査型超音波探触子の内部構成を説明
するために一部を省略及び断面にして示している。図１
において、１はＰＺＴより成り音響インピーダンスが２
０×１０6ｋｇ／ｍ2・secの圧電振動子１１をアレー状に
多数配列して成る振動子部、３はバッキング材で圧電振
動子１１の励振時に振動子の背面へ放射される超音波を
吸収・減衰させるもので、材料としては例えば、音響イ
ンピーダンスがＺB＝７.５×１０6ｋｇ／ｍ2・secのフェ
ライトゴムが用いられるもの、４は音響整合層で超音波
の波長をλとしたとき膜厚がλ／４のものを複数積層し
て超音波が生体へ侵入し易くするもの、５は前にも述べ
た音響レンズである。以上の構成は従来の探触子と同様
である。An embodiment of the present invention will be described below with reference to FIG. FIG. 1 is a partly omitted and cross-sectional view for explaining the internal configuration of the electronic scanning ultrasonic probe. FIG.
Where 1 is PZT and the acoustic impedance is 2
A vibrator portion in which a number of piezoelectric vibrators 11 of 0 × 10 6 kg / m 2 · sec are arranged in an array, 3 is a backing material, and an ultrasonic wave radiated to the back of the vibrator when the piezoelectric vibrator 11 is excited. intended to absorb and attenuate, as a material such as those acoustic impedance ferrite rubber Z B = 7.5 × 10 6 kg / m 2 · sec is used, 4 the wavelength of the ultrasonic wave in the acoustic matching layer When λ is used, a plurality of layers having a film thickness of λ / 4 are laminated to facilitate penetration of ultrasonic waves into a living body. Reference numeral 5 denotes the acoustic lens described above. The above configuration is the same as the conventional probe.
【０００９】次に本発明の特徴点を説明する。図１にお
いて、２は３種の材料で複合構成された薄膜材で、圧電
振動子から見たバッキング材の実効インピーダンスを短
軸方向に対する位置に応じて変化させるものである。薄
膜材２は厚みがλ／４で、短軸方向の中央部に位置する
ポリウレタン樹脂部２１と、その両隣に位置するエポキ
シ樹脂部２２と、両端部に位置するフェライトゴム部２
３とから構成している。それらの音響インピーダンスＺ
21，Ｚ22，Ｚ23は、Ｚ21＜Ｚ22＜Ｚ23となるように、例
えばＺ21＝２.２×１０6ｋｇ／ｍ2・sec，Ｚ22＝３.３×
１０6ｋｇ／ｍ2・sec，Ｚ23＝７.５×１０6ｋｇ／ｍ2・se
cとする。Next, the features of the present invention will be described. In FIG. 1, reference numeral 2 denotes a thin film material composed of three kinds of materials, which changes the effective impedance of the backing material viewed from the piezoelectric vibrator according to the position in the short axis direction. The thin film material 2 has a thickness of λ / 4, a polyurethane resin portion 21 located at the center in the short axis direction, an epoxy resin portion 22 located on both sides thereof, and a ferrite rubber portion 2 located at both ends.
3. Their acoustic impedance Z
21, Z 22, Z 23 is such that Z 21 <Z 22 <Z 23 , for example, Z 21 = 2.2 × 10 6 kg / m 2 · sec, Z 22 = 3.3 ×
10 6 kg / m 2 · sec, Z 23 = 7.5 × 10 6 kg / m 2 · se
c.
【００１０】この場合、圧電振動子１１から見たバッキ
ング材の実効インピーダンスはそれぞれの部分で、(Ｚ
21)2／ＺB ，(Ｚ22)2／ＺB ，(Ｚ23)2／ＺBで表わさ
れ、（Ｚ21)2／ＺB＝０.６×１０6ｋｇ／ｍ2・sec，(Ｚ
22)2＝１.５×１０6ｋｇ／ｍ2・sec，(Ｚ23)2＝７.５×
１０6ｋｇ／ｍ2・secとなる。これにより、各部分での圧
電振動子の振動効率は、中央部においては２０／(２０
＋０.６)＝０.９７＝９７％、中央部に隣接する部分で
は２０／(２０＋１.５)＝０.９３＝９３％、両端部では
２０／(２０＋７.５)＝０.７２７＝７２.７％となる。In this case, the effective impedance of the backing material viewed from the piezoelectric vibrator 11 is (Z
21 ) 2 / Z B , (Z 22 ) 2 / Z B , and (Z 23 ) 2 / Z B , where (Z 21 ) 2 / Z B = 0.6 × 10 6 kg / m 2 · sec. , (Z
22 ) 2 = 1.5 × 10 6 kg / m 2 · sec, (Z 23 ) 2 = 7.5 ×
It is 10 6 kg / m 2 · sec. Thereby, the vibration efficiency of the piezoelectric vibrator in each part is 20 / (20
+0.6) = 0.97 = 97%, 20 / (20 + 1.5) = 0.93 = 93% at the portion adjacent to the center, and 20 / (20 + 7.5) = 0.727 = 72 at both ends. .7%.
【００１１】したがって、単一の細長い棒状圧電振動子
を励振させた場合音圧分布は、中央部では音圧が高く、
端部へ行くにしたがって音圧は低下する。これによっ
て、音響レンズ５から被検体へ侵入する超音波の音圧分
布が従来の凹形から逆に凸形にすることができる。これ
は言葉を替えれば、短軸方向への超音波ビームが細く鋭
くなり、指向性が改善されたことと等価である。Therefore, when a single elongated rod-shaped piezoelectric vibrator is excited, the sound pressure distribution is high at the center,
The sound pressure decreases toward the end. As a result, the sound pressure distribution of the ultrasonic wave that enters the subject from the acoustic lens 5 can be changed from a conventional concave shape to a convex shape. In other words, this is equivalent to the ultrasonic beam in the short-axis direction becoming thinner and sharper, and the directivity being improved.
【００１２】以上、本発明の一実施例を説明したが、本
発明は上記実施例に限定されることなく、要旨を逸脱し
ない範囲で変形が可能である。例えば、上記実施例では
音圧分布を変えるための薄膜材を３種類の異なる音響イ
ンピーダンス部材の複合部材としたが、音圧分布をより
滑らかにするために４種類以上の部材の複合材としても
良い。Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and can be modified without departing from the scope of the invention. For example, in the above embodiment, the thin film material for changing the sound pressure distribution is a composite member of three kinds of different acoustic impedance members. However, in order to make the sound pressure distribution smoother, a composite material of four or more members may be used. good.
【００１３】[0013]
【発明の効果】以上述べたように本発明によれば、振動
子部とバッキング材との間に短軸方向に音響インピーダ
ンスが変化する薄膜材を設けたことにより、探触子から
の超音波の短軸方向への音圧分布を従来の凹形から凸形
へ変えられ、これにより超音波ビームの短軸方向への指
向性を改善することができる。したがって超音波画像は
被検体の薄いスライス厚のものが得られ、画質も良くな
る。更に付随的効果として、サイドローブの減少ももた
らされ、Ｓ／Ｎ向上も計れる。As described above, according to the present invention, by providing a thin film material whose acoustic impedance changes in the short axis direction between the vibrator portion and the backing material, the ultrasonic wave from the probe can be obtained. Can be changed from a conventional concave shape to a convex shape in the short axis direction, thereby improving the directivity of the ultrasonic beam in the short axis direction. Therefore, an ultrasonic image having a small slice thickness of the subject is obtained, and the image quality is improved. Further, as an incidental effect, the side lobe is reduced, and the S / N ratio can be improved.
【図１】本発明の一実施例の超音波探触子の内部構造を
一部断面して示した斜視図。FIG. 1 is a perspective view showing an internal structure of an ultrasonic probe according to an embodiment of the present invention in a partially sectional view.
１ 振動子部 ２ 薄膜材 ３ バッキング材 ４ 音響整合層 ５ 音響レンズ DESCRIPTION OF SYMBOLS 1 Oscillator part 2 Thin film material 3 Backing material 4 Acoustic matching layer 5 Acoustic lens
───────────────────────────────────────────────────── フロントページの続き (72)発明者 河野 敏彦 千葉県柏市新十余二２番１号 株式会社 日立メディコ 大阪工場柏分工場内 審査官 門田 宏 (56)参考文献 特開 平４−250799（ＪＰ，Ａ) 特開 昭61−210795（ＪＰ，Ａ) 特開 平４−352950（ＪＰ，Ａ) 特開 平３−254739（ＪＰ，Ａ) 特開 昭59−138948（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) A61B 8/00 - 8/15 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Toshihiko Kono 2-1 Shinjyuyo, Kashiwa-shi, Chiba Investigator, Hiroshi Kadota, Hitachi Medical Corporation Osaka Plant Kashiwa Branch Plant (56) References JP-A-4-250799 ( JP, A) JP-A-61-210795 (JP, A) JP-A-4-352950 (JP, A) JP-A-3-254739 (JP, A) JP-A-59-138948 (JP, A) (58) ) Surveyed field (Int.Cl. 7 , DB name) A61B 8/00-8/15
Claims (2)
た圧電振動子群と、この圧電振動子群の上面に配置され
た音響整合層と、この音響整合層の上面に配置され前記
圧電素子群の配列方向と直交する方向に両端部を薄くか
つ中央部を厚くした形状の音響レンズとを備えた超音波
振動子において、前記吸音材と前記圧電振動子群の間
に、厚みがλ／４（λは超音波の波長）の薄膜材であっ
て所定の音響インピーダンスである第１の薄膜材を前記
直交方向の中央部に、前記第１の薄膜材と同じ厚みであ
ってそれより大きい音響インピーダンスである第２の薄
膜材を前記直交方向に挟むように、それぞれ配置される
ことを特徴とする超音波探触子。1. A sound absorbing material, and arranged on an upper surface of the sound absorbing material.
Piezoelectric vibrator group and the piezoelectric vibrator group
An acoustic matching layer, and the acoustic matching layer
Are both ends thin in the direction perpendicular to the direction of arrangement of the piezoelectric elements?
With an acoustic lens with a thick central part
In the vibrator, between the sound absorbing material and the piezoelectric vibrator group
In addition, a thin film material having a thickness of λ / 4 (where λ is the wavelength of the ultrasonic wave) is used.
The first thin film material having a predetermined acoustic impedance
At the center in the orthogonal direction, the same thickness as the first thin film material
The second thin film having a higher acoustic impedance
An ultrasonic probe, which is arranged so as to sandwich a film material in the orthogonal direction .
の間に配置され、それらの薄膜材と同じ厚みであってそAnd the same thickness as those thin film materials
れらの薄膜材の中間の音響インピーダンスである少なくThe acoustic impedance between these thin film materials is
とも一つの薄膜材を備えたことを特徴とする請求項１に2. The method according to claim 1, wherein the first and second thin film members are provided.
記載の超音波探触子。The described ultrasonic probe.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP26779992A JP3325305B2 (en) | 1992-09-11 | 1992-09-11 | Ultrasonic probe |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP26779992A JP3325305B2 (en) | 1992-09-11 | 1992-09-11 | Ultrasonic probe |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0690950A JPH0690950A (en) | 1994-04-05 |
| JP3325305B2 true JP3325305B2 (en) | 2002-09-17 |
Family
ID=17449762
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP26779992A Expired - Lifetime JP3325305B2 (en) | 1992-09-11 | 1992-09-11 | Ultrasonic probe |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3325305B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2871963B2 (en) * | 1992-08-05 | 1999-03-17 | 三菱電機株式会社 | Engine exhaust gas purification device |
| JP4134911B2 (en) | 2003-02-27 | 2008-08-20 | 株式会社村田製作所 | Ultrasonic transducer and method for manufacturing the same |
-
1992
- 1992-09-11 JP JP26779992A patent/JP3325305B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0690950A (en) | 1994-04-05 |
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