JPH04250799A - Ultrasonic vibrator - Google Patents
Ultrasonic vibratorInfo
- Publication number
- JPH04250799A JPH04250799A JP3025654A JP2565491A JPH04250799A JP H04250799 A JPH04250799 A JP H04250799A JP 3025654 A JP3025654 A JP 3025654A JP 2565491 A JP2565491 A JP 2565491A JP H04250799 A JPH04250799 A JP H04250799A
- Authority
- JP
- Japan
- Prior art keywords
- piezoelectric element
- powder
- acoustic impedance
- load material
- resin
- 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.)
- Withdrawn
Links
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- 239000011347 resin Substances 0.000 claims abstract description 33
- 239000000843 powder Substances 0.000 claims abstract description 28
- 238000009826 distribution Methods 0.000 claims abstract description 17
- 239000000919 ceramic Substances 0.000 claims abstract description 6
- 239000000463 material Substances 0.000 claims description 93
- 229910052751 metal Inorganic materials 0.000 claims description 7
- 239000002184 metal Substances 0.000 claims description 7
- 230000035945 sensitivity Effects 0.000 abstract description 11
- 230000002093 peripheral effect Effects 0.000 abstract description 10
- 230000010355 oscillation Effects 0.000 abstract description 3
- 230000005540 biological transmission Effects 0.000 abstract 1
- 238000004519 manufacturing process Methods 0.000 description 13
- 238000000034 method Methods 0.000 description 12
- 229920001187 thermosetting polymer Polymers 0.000 description 8
- 238000010586 diagram Methods 0.000 description 7
- 239000007788 liquid Substances 0.000 description 7
- 238000013459 approach Methods 0.000 description 6
- 230000000694 effects Effects 0.000 description 6
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 6
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 5
- 239000004593 Epoxy Substances 0.000 description 4
- 230000004048 modification Effects 0.000 description 4
- 238000012986 modification Methods 0.000 description 4
- 230000010287 polarization Effects 0.000 description 4
- 229920005992 thermoplastic resin Polymers 0.000 description 4
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- ISWSIDIOOBJBQZ-UHFFFAOYSA-N phenol group Chemical group C1(=CC=CC=C1)O ISWSIDIOOBJBQZ-UHFFFAOYSA-N 0.000 description 3
- 239000000853 adhesive Substances 0.000 description 2
- 230000001070 adhesive effect Effects 0.000 description 2
- 230000002238 attenuated effect Effects 0.000 description 2
- 238000005520 cutting process Methods 0.000 description 2
- 238000013016 damping Methods 0.000 description 2
- 230000002542 deteriorative effect Effects 0.000 description 2
- 239000004850 liquid epoxy resins (LERs) Substances 0.000 description 2
- 239000011159 matrix material Substances 0.000 description 2
- 150000002739 metals Chemical class 0.000 description 2
- 230000001105 regulatory effect Effects 0.000 description 2
- -1 their oxides Substances 0.000 description 2
- 239000010937 tungsten Substances 0.000 description 2
- 229910052721 tungsten Inorganic materials 0.000 description 2
- KXGFMDJXCMQABM-UHFFFAOYSA-N 2-methoxy-6-methylphenol Chemical compound [CH]OC1=CC=CC([CH])=C1O KXGFMDJXCMQABM-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910010293 ceramic material Inorganic materials 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 229920006332 epoxy adhesive Polymers 0.000 description 1
- 239000003822 epoxy resin Substances 0.000 description 1
- 238000005304 joining Methods 0.000 description 1
- 229920001568 phenolic resin Polymers 0.000 description 1
- 239000005011 phenolic resin Substances 0.000 description 1
- 229920000647 polyepoxide Polymers 0.000 description 1
- 239000000523 sample Substances 0.000 description 1
- 230000004304 visual acuity Effects 0.000 description 1
Abstract
Description
【０００１】0001
【産業上の利用分野】本発明は、医療用超音波内視鏡等
に使用される超音波探触子用の超音波振動子に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic transducer for an ultrasonic probe used in a medical ultrasonic endoscope or the like.
【０００２】0002
【従来の技術】一般に、超音波振動子から発振される超
音波ビームをシャープにし、解像力・Ｓ／Ｎ比が高い良
好な観測画像を得るために、超音波振動子に音響レンズ
を接合すること、凹面の振動子としてビームを収束する
こと、振動子周縁部で生じている縦振動以外の複雑な振
動により発生する不用音波を低減させて相対的に中心部
の音波を強くすること等が行われている。[Prior Art] Generally, an acoustic lens is bonded to an ultrasonic transducer in order to sharpen the ultrasonic beam emitted from the ultrasonic transducer and obtain a good observation image with high resolution and S/N ratio. , converging the beam as a concave vibrator, reducing unnecessary sound waves generated by complex vibrations other than longitudinal vibrations occurring at the periphery of the vibrator, and making the sound waves at the center relatively stronger. It is being said.
【０００３】これらのうち、振動子周縁部からの不用音
波を低減させる方法として、従来、圧電素子の分極状態
が、中心部が最も強く周縁部に近づくに連れて弱くなる
ように分極する方法が知られている。また、特開昭５８
−２０１６０号公報に開示されるように、圧電素子表面
電極が、中心部が全面電極であって周縁部に近づくに連
れて電極が粗になるかまたは電極が作成されないように
する方法が知られている。さらに，特開昭５６−６５５
９９号公報に開示されるように、不用な振動を生じる部
分に遮蔽板を設ける方法が知られている。Among these methods, a conventional method for reducing unnecessary sound waves from the periphery of the vibrator is to polarize the piezoelectric element in such a way that the polarization state of the piezoelectric element is strongest at the center and becomes weaker as it approaches the periphery. Are known. Also, JP-A-58
As disclosed in Japanese Patent No. 20160, a method is known in which the surface electrode of a piezoelectric element is a full-surface electrode at the center, and the electrode becomes rougher or no electrode is formed as it approaches the periphery. ing. Furthermore, JP-A-56-655
As disclosed in Japanese Patent No. 99, a method is known in which a shielding plate is provided in a portion where unnecessary vibrations occur.
【０００４】0004
【発明が解決しようとする課題】しかし、上記従来の技
術では、分極や電極形成等の工程が非常に複雑になり、
製造コストの上昇は避けられなかった。また、受信時に
は、分極が弱い部分や遮蔽された部分は、そうでない部
分と比較して受信感度が低いかまたは全く受信に寄与し
ないため、超音波振動子全体の感度が低下してしまった
。[Problems to be Solved by the Invention] However, in the above-mentioned conventional technology, the steps such as polarization and electrode formation are extremely complicated.
An increase in manufacturing costs was inevitable. Furthermore, during reception, weakly polarized parts or shielded parts have lower reception sensitivity than non-polarized parts or do not contribute to reception at all, resulting in a decrease in the sensitivity of the entire ultrasonic transducer.
【０００５】本発明は、上記従来の問題点に鑑みてなさ
れたもので、不用な振動成分が少なく、シャープな超音
波ビームを得ることができ、かつ発振出力と受信感度は
低下しない超音波振動子を提供することを目的とする。The present invention has been made in view of the above-mentioned conventional problems, and it is possible to obtain a sharp ultrasonic beam with few unnecessary vibration components, and to produce an ultrasonic vibration that does not reduce the oscillation output and receiving sensitivity. The purpose is to provide children.
【０００６】[0006]
【課題を解決するための手段】上記目的を達成するため
に、本発明は、圧電素子を挟んで音響整合層および背面
負荷材を接合した超音波振動子において、上記背面負荷
材の音響インピーダンスを、周縁部では圧電素子に近く
、中央部では異なるようにした。背面負荷材の音響イン
ピーダンスを、周縁部では圧電素子に近く、中央部では
異なるようにするには、例えば基材となる樹脂に金属ま
たはセラミックスの少なくとも一方の粉体を混入して上
記背面負荷材を作成し、該粉体の分布状態を不均一とす
る。[Means for Solving the Problems] In order to achieve the above object, the present invention provides an ultrasonic transducer in which an acoustic matching layer and a backside load material are bonded to each other with a piezoelectric element sandwiched therebetween, in which the acoustic impedance of the backside load material is reduced. , the peripheral part is close to the piezoelectric element, and the central part is different. In order to make the acoustic impedance of the back loading material close to that of the piezoelectric element at the periphery and different at the center, for example, powder of at least one of metal or ceramic is mixed into the resin serving as the base material. , and the distribution state of the powder is made non-uniform.
【０００７】図１は、本発明の概念図で、圧電素子１を
挟んで音響整合層２と背面負荷材３とが接合されている
。そして、背面負荷材３の音響インピーダンスの分布４
は、周縁部では圧電素子１に近く、中央部では周縁部よ
りも小さくなるように形成されている。FIG. 1 is a conceptual diagram of the present invention, in which an acoustic matching layer 2 and a back load material 3 are bonded with a piezoelectric element 1 in between. Then, the acoustic impedance distribution 4 of the back load material 3
is formed so that it is close to the piezoelectric element 1 at the periphery and smaller at the center than at the periphery.
【０００８】[0008]
【作用】上記構成の本発明の超音波振動子では、背面負
荷材３内における音響インピーダンスの分布４は不均一
である。このため、超音波発振時には、背面負荷材３の
音響インピーダンスが圧電素子とは異なる中心部では、
圧電素子１の背面側に発振される振動は背面負荷材３と
の界面においてある程度反射され、送信波の一部として
放射される。これに対し、背面負荷材３の音響インピー
ダンスが圧電素子に近い周縁部については、圧電素子１
背面側に発振される振動は十分に吸振される。このため
、周縁部で生じている縦振動以外の複雑な振動は、外部
には放射されない。したがって、放射される超音波の出
力（強度）分布５は、図１に示すように、中央部では強
くかつ周縁部では弱くなり、シャープな超音波ビームと
なる。[Operation] In the ultrasonic transducer of the present invention having the above structure, the acoustic impedance distribution 4 within the back load material 3 is non-uniform. Therefore, during ultrasonic oscillation, at the center of the back load material 3 where the acoustic impedance is different from that of the piezoelectric element,
The vibrations oscillated on the back side of the piezoelectric element 1 are reflected to some extent at the interface with the back load material 3, and are radiated as part of the transmitted wave. On the other hand, regarding the peripheral portion of the back load material 3 where the acoustic impedance is close to the piezoelectric element, the piezoelectric element 1
Vibrations oscillated on the back side are sufficiently absorbed. Therefore, complex vibrations other than longitudinal vibrations occurring at the peripheral portion are not radiated to the outside. Therefore, as shown in FIG. 1, the output (intensity) distribution 5 of the emitted ultrasonic waves is strong at the center and weak at the periphery, resulting in a sharp ultrasonic beam.
【０００９】また、観測物から反射してくる超音波を受
信する場合は、圧電素子１の形状・分極状態とその表面
電極は均一であるので、圧電素子１の受信感度が全体で
均一かつ高感度のままである。[0009] Furthermore, when receiving ultrasonic waves reflected from an observation object, since the shape and polarization state of the piezoelectric element 1 and its surface electrode are uniform, the reception sensitivity of the piezoelectric element 1 is uniform and high throughout. Sensitivity remains the same.
【００１０】0010
【実施例１】図２は、本実施例の超音波振動子６を示す
もので、圧電素子１を挟んで音響整合層２と背面負荷材
７とが整合されている。背面負荷材７の材質とては、樹
脂をマトリックスとし、粉体を分散させたものが用いら
れる。本実施例では、粉体にはタングステンを、樹脂に
はエポキシ系の熱硬化性樹脂を用いた。粉体は樹脂中に
不均一に分布されており、これにより、図２に示すよう
に、背面負荷材７内部の音響インピーダンスの分布８は
、中心部に近い部分では圧電素子１と異なって音響イン
ピーダンスが小さくなるように、また周縁部に近づくに
連れて圧電素子１に近い値になるように設定されている
。Embodiment 1 FIG. 2 shows an ultrasonic transducer 6 of this embodiment, in which an acoustic matching layer 2 and a back load material 7 are matched with a piezoelectric element 1 in between. The material used for the back load material 7 is a resin matrix with powder dispersed therein. In this example, tungsten was used as the powder and an epoxy thermosetting resin was used as the resin. The powder is unevenly distributed in the resin, and as a result, as shown in FIG. The impedance is set so that it becomes smaller and becomes closer to the value of the piezoelectric element 1 as it approaches the periphery.
【００１１】本実施例の超音波振動子によれば、背面負
荷材７内において音響インピーダンスの分布８が不均一
であるため、発振される超音波の出力分布は、背面負荷
材７の音響インピーダンスが圧電素子１に近い周縁部に
ついては、両者の音響インピーダンスが異なる中心軸近
傍よりも減衰される。また、観測物から反射してくる超
音波を受信する場合は、圧電素子１の受信感度が全体で
均一かつ高感度になる。According to the ultrasonic transducer of this embodiment, the distribution 8 of acoustic impedance within the back load material 7 is non-uniform, so the output distribution of the oscillated ultrasonic waves depends on the acoustic impedance of the back load material 7. The peripheral portion near the piezoelectric element 1 is attenuated more than the vicinity of the central axis where the acoustic impedances of the two are different. Furthermore, when receiving ultrasonic waves reflected from an observation object, the reception sensitivity of the piezoelectric element 1 becomes uniform and high throughout.
【００１２】すなわち、超音波振動子６から発振される
超音波ビームは、中心軸上が強く、中心から離れるに連
れて弱くなるシャープなビームになる。また、受信時に
は、圧電素子１全体が寄与するため、受信感度は低下し
ない。受信時の振動の減衰は、周縁部の背面負荷材７の
減衰作用により，効果的に行われる。したがって、分解
能が高い観測画像を、高感度であってＳ／Ｎ比を劣化す
ることなく得られる高性能の超音波振動子を、容易かつ
廉価に製造できる。That is, the ultrasonic beam emitted from the ultrasonic transducer 6 becomes a sharp beam that is strong on the central axis and becomes weaker as it moves away from the center. Furthermore, during reception, since the entire piezoelectric element 1 contributes, the reception sensitivity does not decrease. Vibrations during reception are effectively damped by the damping action of the back load material 7 at the peripheral edge. Therefore, it is possible to easily and inexpensively manufacture a high-performance ultrasonic transducer that can obtain observation images with high resolution and high sensitivity without deteriorating the S/N ratio.
【００１３】なお、本実施例では、粉体としてダングス
テンを、樹脂としてエポキシ系の熱硬化性樹脂を用いた
が、これらに限定されるものではない。粉体としては、
他の金属やその酸化物またはアルミナ等のセラミック粉
体を用いることができ、２種以上の粉体を混同してもよ
い。また、樹脂としては、フェノール系等の熱硬化性樹
脂やアクリル，ＡＢＳ等の熱可塑性樹脂を用いることが
できる。さらに、樹脂単体とセラミックス材単体とを組
み合わせてなる板材により背面負荷材７を形成してもよ
い。In this embodiment, dungsten was used as the powder and an epoxy thermosetting resin was used as the resin, but the present invention is not limited to these. As a powder,
Other metals, their oxides, or ceramic powders such as alumina can be used, and two or more types of powders may be mixed. Further, as the resin, a thermosetting resin such as a phenolic resin or a thermoplastic resin such as acrylic or ABS can be used. Furthermore, the back load material 7 may be formed of a plate material made of a combination of a single resin and a single ceramic material.
【００１４】また、背面負荷材７の音響インピーダンス
の分布パターンも上記実施例に限定されるものではなく
、図３および図４に示すように設定してもよい。すなわ
ち、図３に示す超音波振動子は、同心状に嵌合する複数
の背面負荷材分割片により背面負荷材９を形成し、段階
的に音響インピーダンスの分布１０を設定したものであ
る。また、図４に示す超音波振動子は、背面負荷材１１
の中央部に音響インピーダンスが周縁部よりも小さくな
る厚肉円板部１１ａを設け、中心部だけ部分的に音響イ
ンピーダンスが小さくなるように音響インピーダンスの
分布１２を設定したものである。Furthermore, the acoustic impedance distribution pattern of the backside load material 7 is not limited to the above embodiment, and may be set as shown in FIGS. 3 and 4. That is, in the ultrasonic transducer shown in FIG. 3, a back load material 9 is formed by a plurality of concentrically fitted back load material segments, and an acoustic impedance distribution 10 is set in stages. Further, the ultrasonic transducer shown in FIG.
A thick disk portion 11a is provided in the center of the disk, and the acoustic impedance distribution 12 is set so that the acoustic impedance is partially reduced only in the center.
【００１５】[0015]
【実施例２】図５は、本実施例の超音波振動子の製造工
程を示すもので、まず、圧電素子１をケース１３内に載
置した。圧電素子１の外面とケース１３の内面とは密着
させ、水密状態とした。一方、液状の背面負荷材の材料
１４として、硬化前のフェノール系の熱硬化性樹脂とア
ルミナの粉体とを予め混合し、脱泡したものを作製した
。この背面負荷材の材料１４は、硬化後の音響インピー
ダンスが圧電素子１に近くなるように組成を設定してあ
る。また、これとは別に、硬化前のフェノール系の液状
熱硬化性樹脂からなる液状の樹脂材料１５を脱泡して作
製しておいた。この樹脂材料１５は、硬化後の音響イン
ピーダンスが圧電素子１とは大きく異なるように設定し
てある。[Embodiment 2] FIG. 5 shows the manufacturing process of the ultrasonic transducer of this embodiment. First, the piezoelectric element 1 was placed in the case 13. As shown in FIG. The outer surface of the piezoelectric element 1 and the inner surface of the case 13 were brought into close contact to form a watertight state. On the other hand, as material 14 of the liquid backside load material, a phenolic thermosetting resin before curing and alumina powder were mixed in advance and defoamed. The composition of the backside load material 14 is set so that the acoustic impedance after curing is close to that of the piezoelectric element 1. Separately, a liquid resin material 15 made of a phenol-based liquid thermosetting resin before curing was prepared by defoaming. This resin material 15 is set so that its acoustic impedance after curing is significantly different from that of the piezoelectric element 1.
【００１６】ケース１３内に載置した圧電素子１の中央
部に液状の樹脂材料１５を滴下し、硬化させた。その後
、ケース１３内に前記アルミナ粉体を混入した液状の背
面負荷材の材料１４を充填し、硬化させて背面負荷材１
６を得た。この工程が終了した後、ケース１３を取り除
き、図示を省略した音響整合層を圧電素子１に接合し、
超音波振動子を得た。A liquid resin material 15 was dropped onto the center of the piezoelectric element 1 placed in the case 13 and cured. Thereafter, the liquid back load material 14 mixed with the alumina powder is filled into the case 13 and hardened to form the back load material 1.
I got 6. After this step is completed, the case 13 is removed, an acoustic matching layer (not shown) is bonded to the piezoelectric element 1,
An ultrasonic transducer was obtained.
【００１７】本実施例の超音波振動子によれば、実施例
１と同様の効果に加え、背面負荷材１６を圧電素子１上
に直接形成できる。このため、接合工程が不用であり、
接合時の接合層への気泡の混入・接合層の不均一等によ
る性能のバラツキや低下、長時間使用した場合の接合層
の剥がれ等による信頼性の低下が生じない。According to the ultrasonic vibrator of this embodiment, in addition to the same effects as in the first embodiment, the back loading material 16 can be formed directly on the piezoelectric element 1. Therefore, the joining process is unnecessary,
There is no variation or deterioration in performance due to the inclusion of air bubbles in the bonding layer during bonding, non-uniformity of the bonding layer, etc., and there is no decrease in reliability due to peeling of the bonding layer when used for a long time.
【００１８】なお、本実施例において、アルミナ粉体の
代わりに、他のセラミックス粉体、タングステン等の金
属やその酸化物を用いてもよく、２種以上の粉体を混合
することも可能である。また、背面負荷材の材料１４や
樹脂材料１５として、エポキシ系の熱硬化性樹脂やアク
リル，ＡＢＳ等の熱可塑性樹脂を用いることもできる。
さらに、背面負荷材の材料１４または樹脂材料１５を、
硬化後の音響インピーダンスが段階的に圧電素子１に近
づくように樹脂・粉体等の材料や両者の混合比を複数種
選定し、滴下および硬化を複数回繰り返すことで、硬化
後の背面負荷材１６の音響インピーダンスの変化を連続
段階的にすることも可能である。このように、音響イン
ピーダンスの変化を連続的にした場合には、ビームの質
が高まると同時に、受信時の減衰特性が高まり、深さ方
向の解像力が階段状の場合よりも向上する。In this example, instead of alumina powder, other ceramic powders, metals such as tungsten, or their oxides may be used, and it is also possible to mix two or more types of powders. be. Furthermore, as the material 14 and the resin material 15 of the backside load material, an epoxy thermosetting resin, a thermoplastic resin such as acrylic, ABS, etc. can also be used. Furthermore, the material 14 or resin material 15 of the back load material,
By selecting multiple types of materials such as resin and powder and the mixing ratio of the two so that the acoustic impedance after curing gradually approaches that of the piezoelectric element 1, and repeating dropping and curing multiple times, the back load material after curing is It is also possible to change the acoustic impedance of 16 in continuous steps. In this way, when the acoustic impedance is changed continuously, the quality of the beam is improved, and at the same time, the attenuation characteristics at the time of reception are improved, and the resolving power in the depth direction is improved more than when the acoustic impedance is changed in a step-like manner.
【００１９】[0019]
【実施例３】図６は、本実施例の超音波振動子の製造工
程を示すもので、背面負荷材１７は板状であり、圧電素
子１との接合面における中央部には、平面楕円形状の凹
部１７ａが形成されている。背面負荷材１７は、エポキ
シ系の熱硬化性樹脂にタングステンの粉体を混合し、こ
れを脱泡、硬化して形成されている。音響整合層２と背
面負荷材１７とは、圧電素子１を挟んでエポキシ系の接
着剤１８により接合した。この時、背面負荷材１７の凹
部１７ａに接着剤１８を充填しながら接合した。また、
音響整合層２と圧電素子１との間の接合層は、数μｍ以
下になるように極力薄くした。１９は音響インピーダン
スの分布を示す。[Embodiment 3] FIG. 6 shows the manufacturing process of the ultrasonic transducer of this embodiment. The back load material 17 is plate-shaped, and the center part of the joint surface with the piezoelectric element 1 has a planar ellipse. A shaped recess 17a is formed. The back load material 17 is formed by mixing tungsten powder with an epoxy thermosetting resin, defoaming the mixture, and hardening the mixture. The acoustic matching layer 2 and the back load material 17 were bonded with an epoxy adhesive 18 with the piezoelectric element 1 in between. At this time, the adhesive 18 was filled into the concave portion 17a of the backside load material 17 while the bonding was performed. Also,
The bonding layer between the acoustic matching layer 2 and the piezoelectric element 1 was made as thin as possible to several μm or less. 19 shows the distribution of acoustic impedance.
【００２０】本実施例の超音波振動子によれば、背面負
荷材１７には事前に作成された板材等を使用することが
できるため、圧電素子１の分極を損なう材質、例えば熱
可塑性樹脂や硬化時に高熱を必要としたり発生したりす
る樹脂等をマトリックスとすることが可能になり、材料
の選定範囲が広がる。According to the ultrasonic vibrator of this embodiment, since a plate material prepared in advance can be used as the back load material 17, it is possible to use a material that impairs the polarization of the piezoelectric element 1, such as thermoplastic resin or the like. It is now possible to use resins that require or generate high heat during curing as a matrix, expanding the range of material selection.
【００２１】なお、本実施例において、タングステン粉
体の代わりに、他の金属粉体やその酸化物またはアルミ
ナ等のセラミックス粉体を用いてもよく、２種以上の粉
体を混合することも可能である。また、背面負荷材１７
および接着剤１８の材料には、フェノール系の熱硬化性
樹脂やアクリル，ＡＢＳ等の熱可塑性樹脂を用いること
もできる。一方、背面負荷材１７に凹部１７ａを形成す
る代わりに、図７に示すように背面負荷材１７の中心部
に貫通孔１７ｂを形成してもよい。また、凹部１７ａ，
貫通孔１７ｂの平面形状は、真円、多角形状等でもよい
。In this example, instead of tungsten powder, other metal powders, their oxides, or ceramic powders such as alumina may be used, or two or more types of powders may be mixed. It is possible. In addition, the back load material 17
As the material of the adhesive 18, phenolic thermosetting resin, acrylic, ABS, or other thermoplastic resin can also be used. On the other hand, instead of forming the recess 17a in the back load material 17, a through hole 17b may be formed in the center of the back load material 17, as shown in FIG. Moreover, the recessed portion 17a,
The planar shape of the through hole 17b may be a perfect circle, a polygon, or the like.
【００２２】[0022]
【実施例４】図８は、本実施例の超音波振動子の製造工
程を示すもので、音響インピーダンスが圧電素子１と大
きく異なるエポキシ系樹脂等の材質で、その断面形状が
背面負荷材中心部の断面形状と同一のロッド２０を作成
した。ロッド２０の形状は、本実施例では円柱としたが
、これとは別に、実施例１と同様に、液状のエポキシ系
樹脂材とタングステンの粉体を予め混合、脱泡し、液状
の背面負荷材の材料２１を１種以上作成した。材料２１
は、硬化後の音響インピーダンスが段階的に圧電素子に
近づくように樹脂・粉体等の材料や両者の混合比を複数
種選定した。そして、ケース２２内に収容した材料２１
内にロッド２０を浸した。この状態で、樹脂成分を硬化
させ、ケース２２を除去し、背面負荷材の中心よりも１
段外側の部分を作成した。上記の工程を材料２１を硬化
後の音響インピーダンスが段階的に圧電素子に近づくよ
うに交換しながら行い、ロッド２０の軸に関して同芯状
の背面負荷材２３を作成した。この後、必要に応じて適
当な厚さに裁断し、所定の背面負荷材２３を得た。[Example 4] Fig. 8 shows the manufacturing process of the ultrasonic transducer of this example. The material is made of an epoxy resin or the like whose acoustic impedance is significantly different from that of the piezoelectric element 1, and its cross-sectional shape is centered on the back load material. A rod 20 having the same cross-sectional shape as the section was created. The shape of the rod 20 was a cylinder in this example, but apart from this, as in Example 1, a liquid epoxy resin material and tungsten powder were mixed in advance, defoamed, and a liquid back load was prepared. One or more types of materials 21 were created. Material 21
selected multiple materials such as resin and powder and the mixing ratio of the two so that the acoustic impedance after curing gradually approaches that of the piezoelectric element. Then, the material 21 housed in the case 22
The rod 20 was immersed inside. In this state, the resin component is cured, the case 22 is removed, and the
I created the outside part of the step. The above steps were performed while exchanging the material 21 so that the acoustic impedance after curing gradually approached that of the piezoelectric element, thereby creating a back load material 23 that was concentric with the axis of the rod 20. Thereafter, it was cut to an appropriate thickness as necessary to obtain a predetermined back load material 23.
【００２３】本実施例では、実施例３と比較して、背面
負荷材２３の音響インピーダンスの分布２４が段階的で
、結果としてより緩やかであり、ビームの質が高まると
同時に、受信時の減衰特性が高まり、深さ方向の解像力
が向上する。また、実施例３に示した例と同様な理由に
より、背面負荷材２３の材料選定範囲が広がる。In this example, compared to Example 3, the distribution 24 of the acoustic impedance of the back loading material 23 is gradual and, as a result, more gradual, improving beam quality and at the same time reducing attenuation during reception. The characteristics are improved, and the resolution in the depth direction is improved. Furthermore, for the same reason as the example shown in Example 3, the range of material selection for the back load material 23 is expanded.
【００２４】なお、本実施例においても、粉体や樹脂等
の材料は前記実施例１〜３と同様に他の材料を用いるこ
とができる。また、ロッド２０の形状は、断面が楕円、
多角形状等でもよく、テーパを設けて円錐、楕円錐、角
錐等としてもよい。一方、樹脂部分の外形の規制は、本
実施例のようにケース２２の形状で定める方法の他、浸
したロッド２０を材料２１の外に引き上げた場合に材料
２１が自らの粘性によりロッド２０の表面に残ることを
利用すること等の手段を用いてもよい。[0024] Also in this example, other materials such as powder and resin can be used as in Examples 1 to 3 above. Moreover, the shape of the rod 20 has an elliptical cross section,
It may have a polygonal shape, or may be tapered to form a cone, elliptical cone, pyramid, etc. On the other hand, the outer shape of the resin part can be regulated by the shape of the case 22 as in this embodiment, or when the immersed rod 20 is pulled out of the material 21, the material 21 is regulated by its own viscosity. You may also use means such as utilizing the fact that it remains on the surface.
【００２５】[0025]
【実施例５】図９は、本実施例の超音波振動子の製造工
程を示すもので、まず、圧電素子１を、ケース２５内に
載置した。圧電素子１の外面とケース２５の内面とは密
着させ、水密状態とした。ケース２５は、図示しない回
転軸に固定されている。ケース２５の断面形状は、本実
施例では円形とした。これとは別に、実施例１と同様に
、液状のエポキシ系樹脂材と金属タングステンの粉体を
予め混合、脱泡し、液状の背面負荷材の材料２６を作成
しておいた。そして、ケース２５内に材料２６を充填し
た。その後、ケース２５を高速で回転させ、回転により
生ずる遠心力の作用により、材料２６内の粉体の分布が
ケース２５壁面近傍になるほど密になるようにした後、
硬化させて背面負荷材２７を得た。この工程終了後、ケ
ース２５を除き、圧電素子１に図示を省略した音響整合
層を接合して超音波振動子を得た。[Embodiment 5] FIG. 9 shows the manufacturing process of the ultrasonic transducer of this embodiment. First, the piezoelectric element 1 was placed in the case 25. As shown in FIG. The outer surface of the piezoelectric element 1 and the inner surface of the case 25 were brought into close contact to form a watertight state. Case 25 is fixed to a rotating shaft (not shown). The case 25 has a circular cross-sectional shape in this embodiment. Separately, in the same manner as in Example 1, liquid epoxy resin material and metal tungsten powder were mixed in advance and degassed to prepare liquid back load material material 26. Then, the material 26 was filled into the case 25. After that, the case 25 is rotated at high speed, and the distribution of the powder inside the material 26 becomes denser as it approaches the wall surface of the case 25 due to the centrifugal force generated by the rotation.
A back loading material 27 was obtained by curing. After this process was completed, the case 25 was removed and an acoustic matching layer (not shown) was bonded to the piezoelectric element 1 to obtain an ultrasonic vibrator.
【００２６】本実施例によれば、実施例２に示した効果
加え、実施例４に示した例と比較して発振されるビーム
の強度分布および背面負荷材２７の減衰特性の変化が滑
らかになり、ビームの質が高まると同時に、受信時の減
衰特性が高まり、深さ方向の解像力が向上する。According to this embodiment, in addition to the effects shown in the second embodiment, the intensity distribution of the oscillated beam and the attenuation characteristics of the back load material 27 change smoothly compared to the example shown in the fourth embodiment. This improves the quality of the beam, improves the attenuation characteristics during reception, and improves the resolution in the depth direction.
【００２７】なお、本実施例においても、粉体や樹脂等
の材料は前記実施例１〜４と同様に他の材料を用いるこ
とができる。また、ケース２５の断面形状は、楕円、多
角形状等としてもよい。[0027] Also in this example, other materials such as powder and resin can be used as in Examples 1 to 4 above. Further, the cross-sectional shape of the case 25 may be an ellipse, a polygon, or the like.
【００２８】[0028]
【実施例６】図１０は、本実施例の超音波振動子の製造
工程を示すので、背面負荷材２８の材料は実施例２と同
様の材料１４および樹脂材料１５を用いた。ただ、本実
施例では音響インピーダンスが圧電素子１とは異なる樹
脂材料１５からなる部分は、帯状に形成されている。圧
電素子１を挟んで音響整合層２と背面負荷材２８とを接
合した後、上記帯状の領域に直交させて裁断し、複数個
の超音波振動子を得た。本実施例によれば、前記実施例
の効果に加え、超音波振動子の量産性が向上する。[Embodiment 6] Since FIG. 10 shows the manufacturing process of the ultrasonic transducer of this embodiment, the same material 14 and resin material 15 as in Embodiment 2 were used for the back load material 28. However, in this embodiment, the portion made of the resin material 15 whose acoustic impedance is different from that of the piezoelectric element 1 is formed into a band shape. After bonding the acoustic matching layer 2 and the back load material 28 with the piezoelectric element 1 in between, it was cut perpendicularly to the band-shaped region to obtain a plurality of ultrasonic transducers. According to this embodiment, in addition to the effects of the embodiments described above, mass productivity of ultrasonic transducers is improved.
【００２９】なお、本実施例においても、粉体や樹脂等
の材料は前記実施例１〜５と同様に他の材料を用いるこ
とができる。また、帯状の領域を予め形成した背面負荷
材２８を用いるのではなく、前記実施例のように、接合
時に形成する方法や圧電素子１上に直接形成する方法を
採用することができる。さらに、本実施例のように裁断
するのではなく、図１１に示すように溝切りを行うこと
により、振動子アレイ２９を容易に製造できる。[0029] Also in this embodiment, other materials such as powder and resin can be used as in Examples 1 to 5 above. Furthermore, instead of using the back load material 28 in which a band-shaped region is formed in advance, it is possible to adopt a method in which it is formed at the time of bonding or a method in which it is formed directly on the piezoelectric element 1, as in the previous embodiment. Furthermore, the vibrator array 29 can be easily manufactured by cutting grooves as shown in FIG. 11 instead of cutting as in this embodiment.
【００３０】以上の各実施例では、背面負荷材の中央部
を樹脂にして、圧電素子１よりも音響インピーダンスを
低く形成したが、背面負荷材の中央部分に例えば金属等
の素材を配置することにより、圧電素子よりも音響イン
ピーダンスを高くしても同様の効果を得ることができる
。In each of the above embodiments, the center portion of the back load material is made of resin to form a lower acoustic impedance than the piezoelectric element 1, but it is also possible to arrange a material such as metal in the center portion of the back load material. Therefore, the same effect can be obtained even if the acoustic impedance is made higher than that of the piezoelectric element.
【００３１】[0031]
【発明の効果】以上のように、本発明の超音波振動子に
よれば、超音波振動子から発振される超音波ビームは、
中心軸上が強く、中心から離れるに連れて弱くなるシャ
ープなモードになる。加えて、圧電素子の周縁部から放
射される縦振動以外の不用な振動が減衰されているため
、特に超音波ビームの周縁部で生じやすいノイズが非常
に少なくなる。また、受信時には、圧電素子全体が寄与
するため、受信感度は低下しない。受信時の振動の減衰
は、周縁部の背面負荷材の減衰作用により、効果的に行
われる。したがって、分解能が高い観測画像を高感度で
あってＳ／Ｎ比を劣化することなく得られる高性能の超
音波振動子を容易かつ廉価に製造できる。[Effects of the Invention] As described above, according to the ultrasonic vibrator of the present invention, the ultrasonic beam oscillated from the ultrasonic vibrator is
It becomes a sharp mode that is strong on the center axis and becomes weaker as you move away from the center. In addition, since unnecessary vibrations other than longitudinal vibrations radiated from the peripheral edge of the piezoelectric element are attenuated, noise that tends to occur particularly at the peripheral edge of the ultrasonic beam is greatly reduced. Furthermore, during reception, since the entire piezoelectric element contributes, the reception sensitivity does not decrease. Vibrations during reception are effectively damped by the damping effect of the back load material on the peripheral edge. Therefore, it is possible to easily and inexpensively manufacture a high-performance ultrasonic transducer that can obtain observation images with high resolution and high sensitivity without deteriorating the S/N ratio.
【図１】本発明の超音波振動子をその特性とともに示す
概念図である。FIG. 1 is a conceptual diagram showing an ultrasonic transducer of the present invention together with its characteristics.
【図２】本発明の実施例１の超音波振動子をその特性と
ともに示す縦断面図である。FIG. 2 is a longitudinal cross-sectional view showing the ultrasonic transducer of Example 1 of the present invention together with its characteristics.
【図３】本発明の実施例１の変形例の超音波振動子をそ
の特性ととともに示す縦断面図である。FIG. 3 is a longitudinal sectional view showing an ultrasonic transducer according to a modification of the first embodiment of the present invention, together with its characteristics.
【図４】本発明の実施例１の変形例の超音波振動子をそ
の特性とともに示す縦断面図である。FIG. 4 is a longitudinal cross-sectional view showing an ultrasonic transducer according to a modification of the first embodiment of the present invention together with its characteristics.
【図５】本発明の実施例２の製造工程を示す工程図であ
る。FIG. 5 is a process diagram showing the manufacturing process of Example 2 of the present invention.
【図６】本発明の実施例３の製造工程を示す工程図であ
る。FIG. 6 is a process diagram showing the manufacturing process of Example 3 of the present invention.
【図７】本発明の実施例３における背面負荷材の変形例
を示す縦断面図である。FIG. 7 is a longitudinal sectional view showing a modification of the back load material in Example 3 of the present invention.
【図８】本発明の実施例４の製造工程を示す工程図であ
る。FIG. 8 is a process diagram showing the manufacturing process of Example 4 of the present invention.
【図９】本発明の実施例５の製造工程を示す工程図であ
る。FIG. 9 is a process diagram showing the manufacturing process of Example 5 of the present invention.
【図１０】本発明の実施例６の製造工程を示す工程図で
ある。FIG. 10 is a process diagram showing the manufacturing process of Example 6 of the present invention.
【図１１】本発明の実施例６の変形例を示す斜視図であ
る。FIG. 11 is a perspective view showing a modification of the sixth embodiment of the present invention.
１ 圧電素子
２ 音響整合層
３，７，９，１１，１６，１７，２３，２７，２８
背面負荷材
４，８，１０，１２，１９，２４ 音響インピーダン
スの分布
６ 超音波振動子1 Piezoelectric element 2 Acoustic matching layer 3, 7, 9, 11, 16, 17, 23, 27, 28
Back load material 4, 8, 10, 12, 19, 24 Acoustic impedance distribution 6 Ultrasonic vibrator
Claims (2)
面負荷材を接合した超音波振動子において、上記背面負
荷材の音響インピーダンスが、周縁部では圧電素子に近
く、中央部では異なることを特徴とする超音波振動子。1. An ultrasonic transducer in which an acoustic matching layer and a back-loading material are bonded to each other with a piezoelectric element in between, characterized in that the acoustic impedance of the back-loading material is close to that of the piezoelectric element at the periphery and different at the center. Ultrasonic transducer.
面負荷材を接合した超音波振動子において、基材となる
樹脂に金属またはセラミックスの少なくとも一方の粉体
を混入して上記背面負荷材を作成し、該粉体の分布状態
を不均一とすることにより、背面負荷材の音響インピー
ダンスを、周縁部では圧電素子に近く、中央部では異な
るようにした超音波振動子。2. In an ultrasonic transducer in which an acoustic matching layer and a back-loading material are bonded to each other with a piezoelectric element in between, the back-loading material is formed by mixing powder of at least one of metal or ceramics into a resin serving as a base material. An ultrasonic vibrator in which the acoustic impedance of the back load material is close to that of a piezoelectric element at the periphery and different at the center by making the distribution state of the powder non-uniform.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3025654A JPH04250799A (en) | 1991-01-25 | 1991-01-25 | Ultrasonic vibrator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3025654A JPH04250799A (en) | 1991-01-25 | 1991-01-25 | Ultrasonic vibrator |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH04250799A true JPH04250799A (en) | 1992-09-07 |
Family
ID=12171807
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3025654A Withdrawn JPH04250799A (en) | 1991-01-25 | 1991-01-25 | Ultrasonic vibrator |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH04250799A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04352950A (en) * | 1991-05-30 | 1992-12-08 | Matsushita Electric Ind Co Ltd | Ultrasonic probe |
| JPH1127798A (en) * | 1997-07-04 | 1999-01-29 | S C:Kk | Method for generating ultrasonic vibration |
| JP2007195584A (en) * | 2006-01-23 | 2007-08-09 | Ge Medical Systems Global Technology Co Llc | Ultrasonic probe and ultrasonic diagnostic device |
-
1991
- 1991-01-25 JP JP3025654A patent/JPH04250799A/en not_active Withdrawn
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04352950A (en) * | 1991-05-30 | 1992-12-08 | Matsushita Electric Ind Co Ltd | Ultrasonic probe |
| JPH1127798A (en) * | 1997-07-04 | 1999-01-29 | S C:Kk | Method for generating ultrasonic vibration |
| JP2007195584A (en) * | 2006-01-23 | 2007-08-09 | Ge Medical Systems Global Technology Co Llc | Ultrasonic probe and ultrasonic diagnostic device |
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| A300 | Application deemed to be withdrawn because no request for examination was validly filed |
Free format text: JAPANESE INTERMEDIATE CODE: A300 Effective date: 19980514 |