WO2023095884A1 - Acoustic matching layer - Google Patents

Acoustic matching layer Download PDF

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WO2023095884A1
WO2023095884A1 PCT/JP2022/043584 JP2022043584W WO2023095884A1 WO 2023095884 A1 WO2023095884 A1 WO 2023095884A1 JP 2022043584 W JP2022043584 W JP 2022043584W WO 2023095884 A1 WO2023095884 A1 WO 2023095884A1
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matching layer
acoustic matching
carbon
mass
carbon particles
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PCT/JP2022/043584
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French (fr)
Japanese (ja)
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俊樹 大野
厚則 佐竹
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三菱鉛筆株式会社
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R1/00—Details of transducers, loudspeakers or microphones
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R17/00—Piezoelectric transducers; Electrostrictive transducers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R31/00—Apparatus or processes specially adapted for the manufacture of transducers or diaphragms therefor

Definitions

  • the present invention relates to an acoustic matching layer.
  • Medical ultrasonic diagnostic equipment and ultrasonic imaging equipment transmit ultrasonic signals to an object, receive reflected signals (echo signals) from inside the object, and image the inside of the object.
  • An array-type ultrasonic probe having an ultrasonic signal transmission/reception function is mainly used in these ultrasonic diagnostic apparatuses and ultrasonic image inspection apparatuses.
  • Various acoustic matching layers have been proposed for use in such ultrasonic probes.
  • Patent Document 1 discloses an acoustic matching layer containing amorphous carbon and particles having a higher density than the amorphous carbon and uniformly dispersed in the amorphous carbon.
  • the present invention provides a novel acoustic matching layer that can control the balance between sound velocity and density while reducing changes in acoustic impedance.
  • the present invention is as follows: ⁇ Aspect 1> An acoustic matching layer, It contains amorphous carbon and carbon particles dispersed in the amorphous carbon, and the content of the carbon particles is 40% by mass or less with respect to the total mass of the acoustic matching layer. Acoustic matching layer. ⁇ Aspect 2> The acoustic matching layer according to Aspect 1, wherein the carbon particles are scaly carbon particles. ⁇ Aspect 3> The acoustic matching layer according to Aspect 2, wherein the scaly carbon particles are at least one selected from the group consisting of graphite and graphene.
  • FIG. 1 is a side sectional view of the ultrasonic diagnostic apparatus of the present invention.
  • the acoustic matching layer of the present invention is Amorphous carbon and carbon particles dispersed in the amorphous carbon are contained, and the content of the carbon particles is 40% by mass or less with respect to the total mass of the acoustic matching layer.
  • the present inventors found that the balance between sound velocity and density can be controlled without significantly changing acoustic impedance by including carbon particles in amorphous carbon. Without wishing to be bound by theory, this is believed to be due to the large difference in elastic modulus between amorphous carbon and carbon particles, while their densities are relatively close.
  • the acoustic impedance of the acoustic matching layer of the present invention may be 3.5 Mrayl or more, 4.0 Mrayl or more, 4.5 Mrayl or more, 5.0 Mrayl or more, or 5.5 Mrayl or more, or 7.0 Mrayl or less, or6. It may be 5 Mrayl or less.
  • the speed of sound mentioned above may be the speed of sound measured according to JIS Z 2353-2003, for example.
  • the density of the acoustic matching layer of the present invention may be 1.1 g/cm 3 or more, 1.2 g/cm 3 or more, 1.3 g/cm 3 or more, or 1.4 g/cm 3 or more. 0 g/cm 3 or less, 2.8 g/cm 3 or less, 2.5 g/cm 3 or less, 2.4 g/cm 3 or less, 2.2 g/cm 3 or less, 2.0 g/cm 3 or less, or 1.9 g /cm 3 or less.
  • This density may be a density measured according to JIS Z 8807.
  • Amorphous carbon can be obtained, for example, by carbonizing a carbon-containing resin.
  • a method for manufacturing an acoustic matching layer will be described.
  • the amorphous carbon may be porous amorphous carbon, ie having pores dispersed in a matrix of amorphous carbon.
  • the pores may or may not communicate.
  • Carbon particles are carbon particles dispersed in amorphous carbon.
  • carbon particles examples include scale-like carbon particles such as graphite and graphene, linear carbon particles such as carbon nanotubes, milled fibers, and chopped fibers, and spherical carbon particles such as fullerene and carbon black. These may be used alone or in combination. Among them, it is preferable to use scale-like carbon particles from the viewpoint of facilitating control of the speed of sound.
  • the average particle diameter of the carbon particles is 10 nm or more, 20 nm or more, 30 nm or more, 50 nm or more, 70 nm or more, 100 nm or more, 200 nm or more, 300 nm or more, 500 nm or more, 700 nm or more, 1 ⁇ m or more, 2 ⁇ m or more, 3 ⁇ m or more, 4 ⁇ m or more, or 5 ⁇ m or more, and can be 20 ⁇ m or less, 18 ⁇ m or less, 15 ⁇ m or less, 13 ⁇ m or less, 10 ⁇ m or less, or 7 ⁇ m or less.
  • the carbon particles have an average particle size of 1 ⁇ m or more from the viewpoint of facilitating the control of the sound velocity.
  • the average particle size of the carbon particles is 20 ⁇ m or less, sedimentation of the carbon particles themselves can be suppressed, and as a result, dispersion can be facilitated.
  • the average particle size means the median size (D50) calculated on a volume basis in the laser diffraction method.
  • the content of carbon particles in the acoustic matching layer is 40% by mass or less, 35% by mass or less, 30% by mass or less, 27% by mass or less, 25% by mass or less, or 23% by mass or less, based on the mass of the acoustic matching layer. , 20% by weight or less, 17% by weight or less, or 15% by weight or less. According to this, it is possible to suppress internal defects in the obtained acoustic matching layer.
  • This content is 1% by mass or more, 3% by mass or more, 5% by mass or more, 7% by mass or more, 10% by mass or more, 12% by mass or more, 15% by mass or more, 17% by mass or more, 20% by mass or more, It can be 23% by mass or more, or 25% by mass or more.
  • an ultrasonic diagnostic apparatus 10 of the present invention comprises an acoustic lens 12, the above acoustic matching layer 14, a piezoelectric element 16, and a backing material 18 in this order.
  • the ultrasonic diagnostic apparatus of the present invention may have an adhesive layer between each of the above components.
  • the adhesive layer a known adhesive such as a urethane-based adhesive can be used.
  • Acoustic lenses are commonly arranged to use refraction to focus the ultrasound beam and improve resolution.
  • materials constituting the acoustic lens include, for example, conventionally known homopolymers such as silicone rubber, fluorosilicone rubber, polyurethane rubber, and epichlorohydrin rubber, and ethylene-propylene copolymers obtained by copolymerizing ethylene and propylene.
  • Copolymer rubber such as rubber can be used.
  • a piezoelectric element generally has electrodes and a piezoelectric material, and is an element that can convert an electrical signal into mechanical vibration and a mechanical vibration into an electrical signal, and can transmit and receive ultrasonic waves.
  • a piezoelectric material may be a material that can convert electrical signals into mechanical vibrations and mechanical vibrations into electrical signals.
  • Piezoelectric materials include, for example, lead zirconate titanate (PZT)-based ceramics, PbTiO3 - based ceramics and other piezoelectric ceramics, vinylidene fluoride (VDF)-based polymers, vinylidene cyanide (VDCN)-based polymers, and other organic polymeric piezoelectric materials. , quartz, Rochelle salt, and the like can be used.
  • VDF-based polymers examples include polyvinylidene fluoride (PVDF) and polyvinylidene fluoride-trifluoroethylene (P(VDF-TrFE)).
  • Vinylidene cyanide (VDCN)-based polymers include polyvinylidene cyanide (PVDCN) and vinylidene cyanide-based copolymers.
  • Electrode examples of electrodes that can be used include gold (Au), platinum (Pt), silver (Ag), palladium (Pd), copper (Cu), aluminum (Al), nickel (Ni), tin (Sn), and the like. .
  • acoustic matching layer As the acoustic matching layer, the above acoustic matching layer can be used.
  • the backing material is generally a member provided on the opposite side of the piezoelectric element from the direction in which the ultrasonic waves are transmitted to the object.
  • a known backing material can be used as the backing material.
  • the backing material may contain amorphous carbon and carbon particles dispersed in the amorphous carbon, similarly to the acoustic matching layer of the present invention.
  • the description of the acoustic matching layer can be referred to.
  • the amorphous carbon in the backing material may be porous amorphous carbon.
  • the content of carbon particles in the backing material may be 30% by mass or less, 25% by mass or less, 20% by mass or less, or 15% by mass or less, or 5% by mass or more, relative to the mass of the entire backing material. , 7 wt % or more, or 10 wt % or more.
  • the carbon particles are 30% by mass or less, the carbon particles can be molded more easily.
  • the content of carbon particles is 5% by mass or more, good mechanical properties of the backing material can be ensured.
  • the acoustic impedance of the backing material may be 2.0 Mrayl or more, 2.5 Mrayl or more, 3.0 Mrayl or more, or 3.5 Mrayl or more; It may be 8 Mrayl or less, 4.5 Mrayl or less, or 4.0 Mrayl or less.
  • the density of the backing material may be 1.55 g/cm 3 or less.
  • the density may be 1.50 g/cm 3 or less, 1.45 g/cm 3 or less, or 1.40 g/cm 3 or less, and 0.90 g/cm 3 or more, 0.95 g/cm 3 or more, It may be 1.00 g/cm 3 or more, 1.10 g/cm 3 or more, or 1.15 g/cm 3 or more.
  • the method of the present invention for manufacturing an acoustic matching layer comprises: mixing carbon particles with a carbon-containing resin to prepare a precursor composition; and heat-treating the precursor composition in a non-oxidizing atmosphere to carbonize the carbon-containing resin; A content of the carbon particles is 40% by mass or less with respect to the total mass of the acoustic matching layer.
  • the method of the present invention may further comprise curing the prepared precursor composition.
  • the precursor composition can be produced by mixing carbon particles with a carbon-containing resin.
  • the amount of the carbon-containing resin to be added depends on the residual carbon content of the carbon-containing resin, that is, the mass ratio of the carbon-containing resin after carbonization to the carbon-containing resin before carbonization, and the carbon particles in the acoustic matching layer mentioned above. can be adjusted to satisfy the desired content of
  • the residual carbon content of the carbon-containing resin can be changed by changing the type, molecular weight, substituents, etc. of the carbon-containing resin.
  • the residual carbon content of the carbon-containing resin may be obtained by heat-treating the carbon-containing resin alone to carbonize it, or may refer to the numerical value described in the catalog.
  • the precursor composition may further have a pore former.
  • the pore-forming material disappears by heat treatment, thereby forming pores in the resulting acoustic matching layer.
  • Mixing can be performed by a known stirring means such as a disper.
  • Curing of the precursor composition can be performed, for example, by adding a curing agent to the precursor composition.
  • Carbonization of the carbon-containing resin can be performed by heat-treating the precursor composition in a non-oxidizing atmosphere.
  • the non-oxidizing atmosphere may be, for example, an atmosphere such as nitrogen or argon.
  • the heat treatment temperature is, for example, 600°C or higher, 650°C or higher, 700°C or higher, 750°C or higher, or 800°C or higher, 850°C or higher, or 900°C or higher, and 1200°C or lower, 1150°C or lower, 1100°C or lower. , 1050° C. or less, or 1000° C. or less.
  • Carbon-containing resins include phenol resins, furan resins, imide resins, epoxy resins, polyvinyl chloride (PVC), unsaturated polyester resins, and derivatives thereof such as chlorinated polyvinyl chloride (CPVC). can be done. These may be used alone or in combination of two or more.
  • Carbon particles As the carbon particles, the above carbon particles can be used.
  • pore-forming material for example, alcohols, ethers, polymers, and the like can be used. These may be used alone or in combination.
  • alcohols examples include monohydric alcohols such as methanol, ethanol, propanol, and vinyl alcohol, and polyols such as ethylene glycol.
  • ethers for example, dimethyl ether, diethyl ether, and diethylene glycol can be used.
  • polymers examples include alcohol-based polymers, ether-based polymers, and acrylic polymers.
  • polyvinyl alcohol and butyral resin can be used as the alcohol-based polymer.
  • polyethylene glycol polypropylene glycol, polybutylene glycol, etc. can be used.
  • acrylic polymers include poly(meth)acrylic acid, polymethyl(meth)acrylate, polyethyl(meth)acrylate, polypropyl(meth)acrylate, polybutyl(meth)acrylate, polyisobutylacrylate, polypentyl(meth)acrylate, polyhexyl (Meth)acrylate, poly-2-ethylhexyl (meth)acrylate, and the like can be used, and among them, polymethyl methacrylate is preferably used from the viewpoint of pore formation efficiency.
  • ⁇ Curing agent> for example, p-toluenesulfonic acid or the like can be used.
  • the precursor composition may contain other ingredients.
  • Other components that can be used include, for example, dispersants.
  • a dispersing agent for example, sodium stearate or the like can be used.
  • Example 1 95 parts by mass of furan resin (VF-303, Showa Denko Materials Co., Ltd., residual carbon content of 45%) as a carbon-containing resin and 5 parts by mass of flake graphite (Nippon Graphite Industry, average particle size 5 ⁇ m) are stirred, and a curing agent is added. 1 part of p-toluenesulfonic acid was added as a solution and thoroughly stirred with a stirrer to prepare a precursor composition.
  • furan resin VF-303, Showa Denko Materials Co., Ltd., residual carbon content of 45%
  • flake graphite Nippon Graphite Industry, average particle size 5 ⁇ m
  • the precursor composition was cured and then heat-treated in nitrogen gas to carbonize the precursor composition. was made.
  • the mass of the obtained acoustic matching layer was measured, and the density was calculated.
  • ⁇ Internal defect> The presence or absence of internal defects was visually observed. Evaluation criteria are as follows. A: No internal defects were observed. B: Some internal defects were observed. C: Many internal defects were observed.
  • Table 1 shows the configurations and evaluation results of Examples, Comparative Examples, and Reference Examples.
  • the asterisks (*) in the density, sound velocity, and acoustic impedance indicate that there were large variations due to a non-uniform structure due to the presence of internal defects.
  • Comparative Example 2 in which the same mass of tungsten was used instead of flake graphite as in Comparative Example 1, although there were no internal defects, the sound velocity decreased and the acoustic impedance significantly increased. Moreover, in Comparative Example 3 in which the mass of tungsten was increased, the sound velocity was further reduced and the acoustic impedance was further increased. From this, it can be seen that it is difficult to independently control the speed of sound by adjusting the content of particles that are significantly denser than amorphous carbon.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
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Abstract

An acoustic matching layer of the present invention contains amorphous carbon and carbon particles dispersed in the amorphous carbon, wherein the content of the carbon particles is no more than 40% by mass with respect to the total mass of the acoustic matching layer.

Description

音響整合層Acoustic matching layer
　本発明は、音響整合層に関する。 The present invention relates to an acoustic matching layer.
　医療用の超音波診断装置や超音波画像検査装置は、対象物に対し超音波信号を送信し、その対象物内からの反射信号（エコー信号）を受信して当該対象物内を画像化する。これらの超音波診断装置や超音波画像検査装置には、超音波信号送受信機能を有するアレイ式の超音波探触子が主に用いられている。このような超音波探触子に用いられる種々の音響整合層が提案されている。 Medical ultrasonic diagnostic equipment and ultrasonic imaging equipment transmit ultrasonic signals to an object, receive reflected signals (echo signals) from inside the object, and image the inside of the object. . An array-type ultrasonic probe having an ultrasonic signal transmission/reception function is mainly used in these ultrasonic diagnostic apparatuses and ultrasonic image inspection apparatuses. Various acoustic matching layers have been proposed for use in such ultrasonic probes.
　特許文献１では、アモルファス炭素と、前記アモルファス炭素よりも高い密度を有し、前記アモルファス炭素中に均一に分散した粒子とを含む音響整合層が開示されている。 Patent Document 1 discloses an acoustic matching layer containing amorphous carbon and particles having a higher density than the amorphous carbon and uniformly dispersed in the amorphous carbon.
特許第６２１４３３３号公報Japanese Patent No. 6214333
　本発明では、音響インピーダンスの変化を小さくしつつ、音速と密度とのバランスを制御できる、新規な音響整合層を提供する。 The present invention provides a novel acoustic matching layer that can control the balance between sound velocity and density while reducing changes in acoustic impedance.
　本発明者らは、鋭意検討したところ、以下の手段により上記課題を解決できることを見出して、本発明を完成させた。すなわち、本発明は、下記のとおりである：
〈態様１〉音響整合層であって、
　アモルファス炭素、及び前記アモルファス炭素中に分散している炭素粒子を含有しており、かつ
　前記炭素粒子の含有率が、前記音響整合層の全質量に対して４０質量％以下である、
音響整合層。
〈態様２〉前記炭素粒子が、鱗片状炭素粒子である、態様１に記載の音響整合層。
〈態様３〉前記鱗片状炭素粒子が、グラファイト、グラフェンからなる群より選択される少なくとも一種である、態様２に記載の音響整合層。
〈態様４〉態様１～３のいずれか一項に記載の音響整合層を有する超音波診断装置。
〈態様５〉音響整合層の製造方法であって、
　炭素含有樹脂に、炭素粒子を混合させて、前駆体組成物を作製すること、並びに
　前記前駆体組成物を非酸化雰囲気下で熱処理して、前記炭素含有樹脂を炭素化させること
を含み、
　前記炭素粒子の含有率が、前記音響整合層の全質量に対して４０質量％以下である、
音響整合層の製造方法。 As a result of intensive studies, the present inventors have found that the above problems can be solved by the following means, and completed the present invention. That is, the present invention is as follows:
<Aspect 1> An acoustic matching layer,
It contains amorphous carbon and carbon particles dispersed in the amorphous carbon, and the content of the carbon particles is 40% by mass or less with respect to the total mass of the acoustic matching layer.
Acoustic matching layer.
<Aspect 2> The acoustic matching layer according to Aspect 1, wherein the carbon particles are scaly carbon particles.
<Aspect 3> The acoustic matching layer according to Aspect 2, wherein the scaly carbon particles are at least one selected from the group consisting of graphite and graphene.
<Aspect 4> An ultrasonic diagnostic apparatus having the acoustic matching layer according to any one of aspects 1 to 3.
<Mode 5> A method for manufacturing an acoustic matching layer, comprising:
mixing carbon particles with a carbon-containing resin to prepare a precursor composition; and heat-treating the precursor composition in a non-oxidizing atmosphere to carbonize the carbon-containing resin;
The content of the carbon particles is 40% by mass or less with respect to the total mass of the acoustic matching layer.
A method for manufacturing an acoustic matching layer.
　音響インピーダンスの変化を小さくしつつ、音速と密度とのバランスを制御できる、新規な音響整合層を提供する。 To provide a novel acoustic matching layer that can control the balance between sound velocity and density while reducing changes in acoustic impedance.
図１は、本発明の超音波診断装置の側面断面図である。FIG. 1 is a side sectional view of the ultrasonic diagnostic apparatus of the present invention.
　《音響整合層》
　本発明の音響整合層は、
　アモルファス炭素、及び前記アモルファス炭素中に分散している炭素粒子を含有しており、かつ
　前記炭素粒子の含有率が、前記音響整合層の全質量に対して４０質量％以下である。 《Acoustic matching layer》
The acoustic matching layer of the present invention is
Amorphous carbon and carbon particles dispersed in the amorphous carbon are contained, and the content of the carbon particles is 40% by mass or less with respect to the total mass of the acoustic matching layer.
　音響整合層の用途によっては、音響インピーダンスを維持しつつ、音速を制御する要望も存在する。しかしながら、特許文献１に開示されている粒子を用いて音速を変化させようとした場合、音響インピーダンスまで変化することから、上記の要望を満足できないことがあった。 Depending on the application of the acoustic matching layer, there is also a demand to control the speed of sound while maintaining the acoustic impedance. However, when an attempt is made to change the speed of sound using the particles disclosed in Patent Document 1, even the acoustic impedance changes, so there have been cases where the above demands cannot be satisfied.
　これに対し、本発明者らは、アモルファス炭素に炭素粒子を含有させることにより、音響インピーダンスを大きく変化させることなく、音速と密度とのバランスを制御できることを見出した。理論に拘束されることを望まないが、これは、アモルファス炭素と、炭素粒子とを比較すると、密度が比較的近い一方で、弾性率の差異が大きいことに起因すると考えられる。 On the other hand, the present inventors found that the balance between sound velocity and density can be controlled without significantly changing acoustic impedance by including carbon particles in amorphous carbon. Without wishing to be bound by theory, this is believed to be due to the large difference in elastic modulus between amorphous carbon and carbon particles, while their densities are relatively close.
　本発明の音響整合層の音響インピーダンスは、３．５Ｍｒａｙｌ以上、４．０Ｍｒａｙｌ以上、４．５Ｍｒａｙｌ以上、５．０Ｍｒａｙｌ以上、又は５．５Ｍｒａｙｌ以上であってよく、また７．０Ｍｒａｙｌ以下、又は６．５Ｍｒａｙｌ以下であってよい。 The acoustic impedance of the acoustic matching layer of the present invention may be 3.5 Mrayl or more, 4.0 Mrayl or more, 4.5 Mrayl or more, 5.0 Mrayl or more, or 5.5 Mrayl or more, or 7.0 Mrayl or less, or6. It may be 5 Mrayl or less.
　上記の音響インピーダンスは、以下の式により求められるものである。
　音響インピーダンス（Ｚ：Ｍｒａｙｌ）＝密度（ρ：ｇ／ｃｍ３）×音速（Ｃ：ｍ／ｓｅｃ）／１０３ The above acoustic impedance is obtained by the following formula.
Acoustic impedance (Z: Mrayl) = density (ρ: g/cm 3 ) x speed of sound (C: m/sec)/10 3
　ここで、上記の音速は、例えばＪＩＳ　Ｚ　２３５３－２００３に準拠して測定した音速であってよい。 Here, the speed of sound mentioned above may be the speed of sound measured according to JIS Z 2353-2003, for example.
　本発明の音響整合層の密度は、１．１ｇ／ｃｍ３以上、１．２ｇ／ｃｍ３以上、１．３ｇ／ｃｍ３以上、又は１．４ｇ／ｃｍ３以上であってよく、また３．０ｇ／ｃｍ３以下、２．８ｇ／ｃｍ３以下、２．５ｇ／ｃｍ３以下、２．４ｇ／ｃｍ３以下、２．２ｇ／ｃｍ３以下、２．０ｇ／ｃｍ３以下、又は１．９ｇ／ｃｍ３以下であってよい。この密度は、ＪＩＳ　Ｚ　８８０７に準拠して測定した密度であってよい。 The density of the acoustic matching layer of the present invention may be 1.1 g/cm 3 or more, 1.2 g/cm 3 or more, 1.3 g/cm 3 or more, or 1.4 g/cm 3 or more. 0 g/cm 3 or less, 2.8 g/cm 3 or less, 2.5 g/cm 3 or less, 2.4 g/cm 3 or less, 2.2 g/cm 3 or less, 2.0 g/cm 3 or less, or 1.9 g /cm 3 or less. This density may be a density measured according to JIS Z 8807.
　以下では、本発明の各構成要素について説明する。 Each component of the present invention will be described below.
　〈アモルファス炭素〉
　アモルファス炭素は、例えば炭素含有樹脂を炭素化させることにより得ることができる。詳細には、音響整合層の製造方法に関して説明する。 <Amorphous carbon>
Amorphous carbon can be obtained, for example, by carbonizing a carbon-containing resin. In detail, a method for manufacturing an acoustic matching layer will be described.
　アモルファス炭素は、多孔質アモルファス炭素であってよく、すなわちアモルファス炭素のマトリックス中に分散している細孔を有していてよい。この細孔は、連通していてもしていなくてもよい。 The amorphous carbon may be porous amorphous carbon, ie having pores dispersed in a matrix of amorphous carbon. The pores may or may not communicate.
　〈炭素粒子〉
　炭素粒子は、アモルファス炭素中に分散している炭素粒子である。 <Carbon particles>
Carbon particles are carbon particles dispersed in amorphous carbon.
　炭素粒子としては、例えばグラファイト、グラフェン等の鱗片状炭素粒子、カーボンナノチューブ、ミルドファイバー、及びチョップドファイバー等の線状炭素粒子、並びにフラーレン、カーボンブラック等の球状炭素粒子等が挙げられる。これらは単独で使用してもよく、また組み合わせて使用してもよい。中でも、鱗片状炭素粒子を用いることが、音速の制御を容易にする観点から好ましい。 Examples of carbon particles include scale-like carbon particles such as graphite and graphene, linear carbon particles such as carbon nanotubes, milled fibers, and chopped fibers, and spherical carbon particles such as fullerene and carbon black. These may be used alone or in combination. Among them, it is preferable to use scale-like carbon particles from the viewpoint of facilitating control of the speed of sound.
　炭素粒子の平均粒子径は、１０ｎｍ以上、２０ｎｍ以上、３０ｎｍ以上、５０ｎｍ以上、７０ｎｍ以上、１００ｎｍ以上、２００ｎｍ以上、３００ｎｍ以上、５００ｎｍ以上、７００ｎｍ以上、１μｍ以上、２μｍ以上、３μｍ以上、４μｍ以上、又は５μｍ以上であることができ、また２０μｍ以下、１８μｍ以下、１５μｍ以下、１３μｍ以下、１０μｍ以下、又は７μｍ以下であることができる。中でも、炭素粒子の平均粒子径が１μｍ以上であることが、音速の制御を容易にする観点から好ましい。また、炭素粒子の平均粒子径が２０μｍ以下であることにより、炭素粒子自体の沈降を抑制し、その結果、分散を容易にすることができる。 The average particle diameter of the carbon particles is 10 nm or more, 20 nm or more, 30 nm or more, 50 nm or more, 70 nm or more, 100 nm or more, 200 nm or more, 300 nm or more, 500 nm or more, 700 nm or more, 1 μm or more, 2 μm or more, 3 μm or more, 4 μm or more, or 5 μm or more, and can be 20 μm or less, 18 μm or less, 15 μm or less, 13 μm or less, 10 μm or less, or 7 μm or less. Among them, it is preferable that the carbon particles have an average particle size of 1 μm or more from the viewpoint of facilitating the control of the sound velocity. In addition, when the average particle size of the carbon particles is 20 μm or less, sedimentation of the carbon particles themselves can be suppressed, and as a result, dispersion can be facilitated.
　なお、本明細書において、平均粒子径は、レーザー回折法において体積基準により算出されたメジアン径（Ｄ５０）を意味するものである。 In this specification, the average particle size means the median size (D50) calculated on a volume basis in the laser diffraction method.
　音響整合層中の炭素粒子の含有率は、音響整合層の質量を基準として、４０質量％以下、３５質量％以下、３０質量％以下、２７質量％以下、２５質量％以下、２３質量％以下、２０質量％以下、１７質量％以下、又は１５質量％以下であることができる。これによれば、得られる音響整合層の内部欠陥を抑制することができる。この含有率は、１質量％以上、３質量％以上、５質量％以上、７質量％以上、１０質量％以上、１２質量％以上、１５質量％以上、１７質量％以上、２０質量％以上、２３質量％以上、又は２５質量％以上であることができる。 The content of carbon particles in the acoustic matching layer is 40% by mass or less, 35% by mass or less, 30% by mass or less, 27% by mass or less, 25% by mass or less, or 23% by mass or less, based on the mass of the acoustic matching layer. , 20% by weight or less, 17% by weight or less, or 15% by weight or less. According to this, it is possible to suppress internal defects in the obtained acoustic matching layer. This content is 1% by mass or more, 3% by mass or more, 5% by mass or more, 7% by mass or more, 10% by mass or more, 12% by mass or more, 15% by mass or more, 17% by mass or more, 20% by mass or more, It can be 23% by mass or more, or 25% by mass or more.
　《超音波診断装置》
　図１に示すように、本発明の超音波診断装置１０は、音響レンズ１２、上記の音響整合層１４、圧電素子１６、及びバッキング材１８をこの順で具備している。 《Ultrasound diagnostic device》
As shown in FIG. 1, an ultrasonic diagnostic apparatus 10 of the present invention comprises an acoustic lens 12, the above acoustic matching layer 14, a piezoelectric element 16, and a backing material 18 in this order.
　また、図示していないが、本発明の超音波診断装置は、上記の各構成の間に接着層を有していてもよい。接着層としては、ウレタン系接着剤等の公知の接着剤を用いることができる。 Also, although not shown, the ultrasonic diagnostic apparatus of the present invention may have an adhesive layer between each of the above components. As the adhesive layer, a known adhesive such as a urethane-based adhesive can be used.
　〈音響レンズ〉
　音響レンズは、一般に、屈折を利用して超音波ビームを集束し分解能を向上するために配置されている。 <Acoustic lens>
Acoustic lenses are commonly arranged to use refraction to focus the ultrasound beam and improve resolution.
　本発明において、音響レンズを構成する素材としては、例えば従来公知のシリコーンゴム、フッ素シリコーンゴム、ポリウレタンゴム、エピクロルヒドリンゴム等のホモポリマー、エチレンとプロピレンとを共重合させてなるエチレン－プロピレン共重合体ゴム等の共重合体ゴム等を用いることができる。 In the present invention, materials constituting the acoustic lens include, for example, conventionally known homopolymers such as silicone rubber, fluorosilicone rubber, polyurethane rubber, and epichlorohydrin rubber, and ethylene-propylene copolymers obtained by copolymerizing ethylene and propylene. Copolymer rubber such as rubber can be used.
　〈圧電素子〉
　圧電素子は、一般に、電極及び圧電材料を有し、電気信号を機械的な振動に、また機械的な振動を電気信号に変換可能で超音波の送受信が可能な素子である。 <Piezoelectric element>
A piezoelectric element generally has electrodes and a piezoelectric material, and is an element that can convert an electrical signal into mechanical vibration and a mechanical vibration into an electrical signal, and can transmit and receive ultrasonic waves.
　（圧電材料）
　圧電材料は、電気信号を機械的な振動に、また機械的な振動を電気信号に変換可能な材料であってよい。圧電材料としては、例えばチタン酸ジルコン酸鉛（ＰＺＴ）系セラミックス、ＰｂＴｉＯ３系セラミック等の圧電セラミックス、フッ化ビニリデン（ＶＤＦ）系ポリマー、シアン化ビニリデン（ＶＤＣＮ）系ポリマー等の有機高分子圧電材料、水晶、ロッシェル塩等を用いることができる。 (piezoelectric material)
A piezoelectric material may be a material that can convert electrical signals into mechanical vibrations and mechanical vibrations into electrical signals. Piezoelectric materials include, for example, lead zirconate titanate (PZT)-based ceramics, PbTiO3 - based ceramics and other piezoelectric ceramics, vinylidene fluoride (VDF)-based polymers, vinylidene cyanide (VDCN)-based polymers, and other organic polymeric piezoelectric materials. , quartz, Rochelle salt, and the like can be used.
　フッ化ビニリデン（ＶＤＦ）系ポリマーとしては、例えばポリフッ化ビニリデン（ＰＶＤＦ）、ポリフッ化ビニリデン－３フッ化エチレン（Ｐ（ＶＤＦ－ＴｒＦＥ））等が挙げられる。シアン化ビニリデン（ＶＤＣＮ）系ポリマーとしては、ポリシアン化ビニリデン（ＰＶＤＣＮ）、シアン化ビニリデン系共重合体が挙げられる。 Examples of vinylidene fluoride (VDF)-based polymers include polyvinylidene fluoride (PVDF) and polyvinylidene fluoride-trifluoroethylene (P(VDF-TrFE)). Vinylidene cyanide (VDCN)-based polymers include polyvinylidene cyanide (PVDCN) and vinylidene cyanide-based copolymers.
　（電極）
　電極としては、例えば金（Ａｕ）、白金（Ｐｔ）、銀（Ａｇ）、パラジウム（Ｐｄ）、銅（Ｃｕ）、アルミニウム（Ａｌ）、ニッケル（Ｎｉ）、スズ（Ｓｎ）等を用いることができる。 (electrode)
Examples of electrodes that can be used include gold (Au), platinum (Pt), silver (Ag), palladium (Pd), copper (Cu), aluminum (Al), nickel (Ni), tin (Sn), and the like. .
　〈音響整合層〉
　音響整合層としては、上記の音響整合層を用いることができる。 <Acoustic matching layer>
As the acoustic matching layer, the above acoustic matching layer can be used.
　〈バッキング材〉
　バッキング材は、概して、圧電素子に対し、対象への超音波の送波方向とは反対側に設けられる部材である。 <Backing material>
The backing material is generally a member provided on the opposite side of the piezoelectric element from the direction in which the ultrasonic waves are transmitted to the object.
　バッキング材としては、公知のバッキング材を用いることができる。また、バッキング材は、本発明の音響整合層と同様に、アモルファス炭素、並びにアモルファス炭素中に分散している炭素粒子を含有していてよい。この場合のバッキング材の各成分については、音響整合層の記載を参照することができる。 A known backing material can be used as the backing material. Further, the backing material may contain amorphous carbon and carbon particles dispersed in the amorphous carbon, similarly to the acoustic matching layer of the present invention. For each component of the backing material in this case, the description of the acoustic matching layer can be referred to.
　バッキング材におけるアモルファス炭素は、多孔質アモルファス炭素であってよい。 The amorphous carbon in the backing material may be porous amorphous carbon.
　バッキング材における炭素粒子の含有率は、バッキング材全体の質量に対して、３０質量％以下、２５質量％以下、２０質量％以下、又は１５質量％以下であってよく、また、５質量％以上、７質量％以上、又は１０質量％以上であることができる。炭素粒子が３０質量％以下であることにより、炭素粒子の成形をより容易に行うことができる。また、炭素粒子の含有量が５質量％以上であることにより、バッキング材の良好な機械的性質を確保することができる。 The content of carbon particles in the backing material may be 30% by mass or less, 25% by mass or less, 20% by mass or less, or 15% by mass or less, or 5% by mass or more, relative to the mass of the entire backing material. , 7 wt % or more, or 10 wt % or more. When the carbon particles are 30% by mass or less, the carbon particles can be molded more easily. In addition, when the content of carbon particles is 5% by mass or more, good mechanical properties of the backing material can be ensured.
　バッキング材の音響インピーダンスは、２．０Ｍｒａｙｌ以上、２．５Ｍｒａｙｌ以上、３．０Ｍｒａｙｌ以上、又は３．５Ｍｒａｙｌ以上であってよく、また５．５Ｍｒａｙｌ以下、５．３Ｍｒａｙｌ以下、５．０Ｍｒａｙｌ以下、４．８Ｍｒａｙｌ以下、４．５Ｍｒａｙｌ以下、又は４．０Ｍｒａｙｌ以下であってよい。 The acoustic impedance of the backing material may be 2.0 Mrayl or more, 2.5 Mrayl or more, 3.0 Mrayl or more, or 3.5 Mrayl or more; It may be 8 Mrayl or less, 4.5 Mrayl or less, or 4.0 Mrayl or less.
　バッキング材の密度は、１．５５ｇ／ｃｍ３以下であってよい。この密度は、１．５０ｇ／ｃｍ３以下、１．４５ｇ／ｃｍ３以下、又は１．４０ｇ／ｃｍ３以下であってよく、また０．９０ｇ／ｃｍ３以上、０．９５ｇ／ｃｍ３以上、１．００ｇ／ｃｍ３以上、１．１０ｇ／ｃｍ３以上、又は１．１５ｇ／ｃｍ３以上であってよい。 The density of the backing material may be 1.55 g/cm 3 or less. The density may be 1.50 g/cm 3 or less, 1.45 g/cm 3 or less, or 1.40 g/cm 3 or less, and 0.90 g/cm 3 or more, 0.95 g/cm 3 or more, It may be 1.00 g/cm 3 or more, 1.10 g/cm 3 or more, or 1.15 g/cm 3 or more.
　《音響整合層の製造方法》
　音響整合層を製造する本発明の方法は、
　炭素含有樹脂に、炭素粒子を混合させて、前駆体組成物を作製すること、並びに
　前記前駆体組成物を非酸化雰囲気下で熱処理して、前記炭素含有樹脂を炭素化させること
を含み、
　前記炭素粒子の含有率が、前記音響整合層の全質量に対して４０質量％以下である。 <<Manufacturing Method of Acoustic Matching Layer>>
The method of the present invention for manufacturing an acoustic matching layer comprises:
mixing carbon particles with a carbon-containing resin to prepare a precursor composition; and heat-treating the precursor composition in a non-oxidizing atmosphere to carbonize the carbon-containing resin;
A content of the carbon particles is 40% by mass or less with respect to the total mass of the acoustic matching layer.
　本発明の方法は、作成した前駆体組成物を硬化させることを更に含んでもよい。 The method of the present invention may further comprise curing the prepared precursor composition.
　〈前駆体組成物の作製〉
　前駆体組成物は、炭素含有樹脂に、炭素粒子を混合させることにより作製することができる。 <Preparation of precursor composition>
The precursor composition can be produced by mixing carbon particles with a carbon-containing resin.
　炭素含有樹脂の添加量は、炭素含有樹脂の残炭率、すなわち炭素化後の炭素含有樹脂の、炭素化前の炭素含有樹脂に対する質量比に応じ、上記で言及した音響整合層中の炭素粒子の所望の含有率を満足するようにして調節することができる。なお、炭素含有樹脂の残炭率は、炭素含有樹脂の種類、分子量、置換基等を変更することによって変化し得る。炭素含有樹脂の残炭率は、炭素含有樹脂を単独で熱処理して炭素化することによって得たものであってもよく、又はカタログに記載の数値を参照してもよい。 The amount of the carbon-containing resin to be added depends on the residual carbon content of the carbon-containing resin, that is, the mass ratio of the carbon-containing resin after carbonization to the carbon-containing resin before carbonization, and the carbon particles in the acoustic matching layer mentioned above. can be adjusted to satisfy the desired content of The residual carbon content of the carbon-containing resin can be changed by changing the type, molecular weight, substituents, etc. of the carbon-containing resin. The residual carbon content of the carbon-containing resin may be obtained by heat-treating the carbon-containing resin alone to carbonize it, or may refer to the numerical value described in the catalog.
　前駆体組成物は、気孔形成材を更に有していてよい。気孔形成材は、熱処理をすることによって消失し、それによって、得られる音響整合層に気孔を形成することができる。 The precursor composition may further have a pore former. The pore-forming material disappears by heat treatment, thereby forming pores in the resulting acoustic matching layer.
　混合は、ディスパー等の公知の攪拌手段で行うことができる。 Mixing can be performed by a known stirring means such as a disper.
　〈前駆体組成物の硬化〉
　前駆体組成物の硬化は、例えば前駆体組成物に硬化剤を添加することにより行うことができる。 <Curing of Precursor Composition>
Curing of the precursor composition can be performed, for example, by adding a curing agent to the precursor composition.
　〈炭素含有樹脂の炭素化〉
　炭素含有樹脂の炭素化は、前駆体組成物を非酸化雰囲気下で熱処理することにより行うことができる。 <Carbonization of carbon-containing resin>
Carbonization of the carbon-containing resin can be performed by heat-treating the precursor composition in a non-oxidizing atmosphere.
　非酸化雰囲気は、例えば窒素又はアルゴン等の雰囲気であってよい。 The non-oxidizing atmosphere may be, for example, an atmosphere such as nitrogen or argon.
　熱処理の温度は、例えば６００℃以上、６５０℃以上、７００℃以上、７５０℃以上、又は８００℃以上、８５０℃以上、又は９００℃以上であり、かつ１２００℃以下、１１５０℃以下、１１００℃以下、１０５０℃以下、又は１０００℃以下であってよい。 The heat treatment temperature is, for example, 600°C or higher, 650°C or higher, 700°C or higher, 750°C or higher, or 800°C or higher, 850°C or higher, or 900°C or higher, and 1200°C or lower, 1150°C or lower, 1100°C or lower. , 1050° C. or less, or 1000° C. or less.
　以下では、本発明の方法において用いる物について説明する。 The items used in the method of the present invention are described below.
　〈炭素含有樹脂〉
　炭素含有樹脂としては、例えばフェノール樹脂、フラン樹脂、イミド樹脂、エポキシ樹脂、ポリ塩化ビニル（ＰＶＣ）、及び不飽和ポリエステル樹脂、並びにこれらの誘導体、例えば塩素化ポリ塩化ビニル（ＣＰＶＣ）等を用いることができる。これらは単独で用いてもよく、また２種以上を混合して用いてもよい。 <Carbon-containing resin>
Examples of carbon-containing resins include phenol resins, furan resins, imide resins, epoxy resins, polyvinyl chloride (PVC), unsaturated polyester resins, and derivatives thereof such as chlorinated polyvinyl chloride (CPVC). can be done. These may be used alone or in combination of two or more.
　〈炭素粒子〉
　炭素粒子としては、上記の炭素粒子を用いることができる。 <Carbon particles>
As the carbon particles, the above carbon particles can be used.
　〈気孔形成材〉
　気孔形成材としては、例えばアルコール類、エーテル類、及びポリマー等を用いることができる。これらは単独で用いてもよく、又は混合して用いてもよい。 <Pore forming material>
As the pore-forming material, for example, alcohols, ethers, polymers, and the like can be used. These may be used alone or in combination.
　アルコール類としては、例えばメタノール、エタノール、プロパノール、及びビニルアルコール等の一価アルコール、エチレングリコール等のポリオール等を用いることができる。 Examples of alcohols that can be used include monohydric alcohols such as methanol, ethanol, propanol, and vinyl alcohol, and polyols such as ethylene glycol.
　エーテル類としては、例えばジメチルエーテル、ジエチルエーテル、及びジエチレングリコール等を用いることができる。 As ethers, for example, dimethyl ether, diethyl ether, and diethylene glycol can be used.
　ポリマーとしては、例えばアルコール系ポリマー、エーテル系ポリマー、及びアクリル系ポリマー等を用いることができる。 Examples of polymers that can be used include alcohol-based polymers, ether-based polymers, and acrylic polymers.
　アルコール系ポリマーとしては、例えばポリビニルアルコール、及びブチラール樹脂等を用いることができる。 For example, polyvinyl alcohol and butyral resin can be used as the alcohol-based polymer.
　エーテル系ポリマーとしては、ポリエチレングリコール、ポリプロピレングリコール、ポリブチレングリコール等を用いることができる。 　As the ether-based polymer, polyethylene glycol, polypropylene glycol, polybutylene glycol, etc. can be used.
　アクリル系ポリマーとしては、例えばポリ（メタ）アクリル酸、ポリメチル（メタ）アクリレート、ポリエチル（メタ）アクリレート、ポリプロピル（メタ）アクリレート、ポリブチル（メタ）アクリレート、ポリイソブチルアクリレート、ポリペンチル（メタ）アクリレート、ポリヘキシル（メタ）アクリレート、ポリ－２－エチルヘキシル（メタ）アクリレート等を用いることができ、中でもポリメチルメタクリレートを用いることが、気孔の形成効率の観点から好ましい。 Examples of acrylic polymers include poly(meth)acrylic acid, polymethyl(meth)acrylate, polyethyl(meth)acrylate, polypropyl(meth)acrylate, polybutyl(meth)acrylate, polyisobutylacrylate, polypentyl(meth)acrylate, polyhexyl (Meth)acrylate, poly-2-ethylhexyl (meth)acrylate, and the like can be used, and among them, polymethyl methacrylate is preferably used from the viewpoint of pore formation efficiency.
　〈硬化剤〉
　硬化剤としては、例えばｐ－トルエンスルホン酸等を用いることができる。 <Curing agent>
As a curing agent, for example, p-toluenesulfonic acid or the like can be used.
　〈他の成分〉
　前駆体組成物は、他の成分を含有していてもよい。他の成分としては例えば分散剤を用いることができる。分散剤としては、例えばステアリン酸ナトリウム等を用いることができる。 <Other ingredients>
The precursor composition may contain other ingredients. Other components that can be used include, for example, dispersants. As a dispersing agent, for example, sodium stearate or the like can be used.
　実施例及び比較例により本発明を具体的に説明するが、本発明は、これらに限定されるものではない。
　《音響整合層の作製》
　〈実施例１〉
　炭素含有樹脂としてのフラン樹脂（ＶＦ－３０３、昭和電工マテリアルズ社、残炭率４５％）９５質量部、鱗片状黒鉛（日本黒鉛工業、平均粒子径５μｍ）５質量部を撹拌し、硬化剤としてｐ－トルエンスルホン酸１部を添加して、攪拌機を用いて充分撹拌させて、前駆体組成物を作製した。 EXAMPLES The present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to these.
<<Fabrication of Acoustic Matching Layer>>
<Example 1>
95 parts by mass of furan resin (VF-303, Showa Denko Materials Co., Ltd., residual carbon content of 45%) as a carbon-containing resin and 5 parts by mass of flake graphite (Nippon Graphite Industry, average particle size 5 μm) are stirred, and a curing agent is added. 1 part of p-toluenesulfonic acid was added as a solution and thoroughly stirred with a stirrer to prepare a precursor composition.
　次いで、この前駆体組成物を硬化させた後に窒素ガス中で熱処理することにより、前駆体組成物を炭素化させた、これを３０ｍｍ×３０ｍｍ×１ｍｍに切断して、実施例１の音響整合層を作製した。得られた音響整合層の質量を測定し、密度を算出した。 Next, the precursor composition was cured and then heat-treated in nitrogen gas to carbonize the precursor composition. was made. The mass of the obtained acoustic matching layer was measured, and the density was calculated.
　〈実施例２～４、比較例１～３及び参考例１～２〉
　用いた材料の種類及び添加量を表１に示すように変更したことを除き、実施例１と同様にして、実施例２～４、比較例１～３及び参考例１～２の音響整合層を作製した。 <Examples 2-4, Comparative Examples 1-3 and Reference Examples 1-2>
Acoustic matching layers of Examples 2 to 4, Comparative Examples 1 to 3, and Reference Examples 1 and 2 were prepared in the same manner as in Example 1, except that the types and amounts of materials used were changed as shown in Table 1. was made.
　なお、表１で言及している材料の詳細は以下のとおりである：
　Ｗ：アライドマテリアル社、平均粒子径１．１μｍ、密度、１９．３ｇ／ｃｍ３
　ＰＭＭＡ：ポリメチルメタクリレート
　フェノール樹脂：旭有機材社、残炭率５０％ Details of the materials referred to in Table 1 are as follows:
W: Allied Material Co., average particle size 1.1 μm, density 19.3 g/cm 3
PMMA: Polymethyl methacrylate Phenolic resin: Asahi Organic Chemicals Co., Ltd., residual carbon rate of 50%
　《評価》
　〈音速の測定及び音響インピーダンスの算出〉
　ＪＩＳ　Ｚ　２３５３－２００３に従い、シングアラウンド式音速式測定装置を用いて、２５℃で、得られた音響整合層の音速を測定した。得られた音速及び密度から、音響インピーダンスを測定した。 "evaluation"
<Measurement of sound velocity and calculation of acoustic impedance>
According to JIS Z 2353-2003, the sound velocity of the obtained acoustic matching layer was measured at 25° C. using a sing-around sound velocity measuring device. Acoustic impedance was measured from the obtained sound velocity and density.
　〈内部欠陥〉
　内部欠陥の有無を、目視により観察した。評価基準は以下のとおりである。
　Ａ：内部欠陥が見られなかった。
　Ｂ：内部欠陥が少し見られた。
　Ｃ：内部欠陥が多数見られた。 <Internal defect>
The presence or absence of internal defects was visually observed. Evaluation criteria are as follows.
A: No internal defects were observed.
B: Some internal defects were observed.
C: Many internal defects were observed.
　実施例、比較例及び参考例の構成及び評価結果を表１に示す。なお、密度、音速、及び音響インピーダンスにおける「※」は、内部欠陥の存在による不均一な構造により、大きなばらつきが存在していたことを示している。 Table 1 shows the configurations and evaluation results of Examples, Comparative Examples, and Reference Examples. The asterisks (*) in the density, sound velocity, and acoustic impedance indicate that there were large variations due to a non-uniform structure due to the presence of internal defects.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　実施例１～３でのように、参考例１のアモルファス炭素の一部を炭素粒子に置き換えると、音響インピーダンスが大きく変化しない一方で、音速を有意に変化させることができた。しかしながら、炭素粒子の含有率が４８．７８質量％であった比較例１では、内部欠陥が生じており、その結果、密度の測定ができなかった。 As in Examples 1 to 3, when part of the amorphous carbon in Reference Example 1 was replaced with carbon particles, the acoustic impedance did not change significantly, but the sound velocity could be changed significantly. However, in Comparative Example 1 in which the carbon particle content was 48.78% by mass, internal defects occurred, and as a result, the density could not be measured.
　一方、比較例１の鱗片状黒鉛の代わりに、同質量のタングステンを用いた比較例２では、内部欠陥はなかったものの、音速が低下するとともに、音響インピーダンスが有意に増加していた。また、タングステンの質量を増加させた比較例３では、音速が更に低減し、音響インピーダンスが更に増加していた。このことから、アモルファス炭素よりも密度が有意に高い粒子の含有率を調節することによっては、音速を独立して制御することが困難であることが理解できよう。 On the other hand, in Comparative Example 2 in which the same mass of tungsten was used instead of flake graphite as in Comparative Example 1, although there were no internal defects, the sound velocity decreased and the acoustic impedance significantly increased. Moreover, in Comparative Example 3 in which the mass of tungsten was increased, the sound velocity was further reduced and the acoustic impedance was further increased. From this, it can be seen that it is difficult to independently control the speed of sound by adjusting the content of particles that are significantly denser than amorphous carbon.
　また、樹脂を変更し、かつ気孔形成材を用いて得た音響整合層である参考例２のアモルファス炭素の一部を、実施例４でのように炭素粒子に置き換えた場合も、音響インピーダンスが大きく変化しない一方で、音速を有意に変化させることができた。 Also, when a part of the amorphous carbon in Reference Example 2, which is an acoustic matching layer obtained by changing the resin and using a pore-forming material, is replaced with carbon particles as in Example 4, the acoustic impedance is reduced. While not changing significantly, the sound velocity could be changed significantly.
　１０　　超音波診断装置
　１２　　音響レンズ
　１４　　音響整合層
　１６　　圧電素子
　１８　　バッキング材 REFERENCE SIGNS LIST 10 ultrasonic diagnostic apparatus 12 acoustic lens 14 acoustic matching layer 16 piezoelectric element 18 backing material

Claims (5)

  1. 　音響整合層であって、
    　アモルファス炭素、及び前記アモルファス炭素中に分散している炭素粒子を含有しており、かつ
    　前記炭素粒子の含有率が、前記音響整合層の全質量に対して４０質量％以下である、
    音響整合層。     an acoustic matching layer,
    It contains amorphous carbon and carbon particles dispersed in the amorphous carbon, and the content of the carbon particles is 40% by mass or less with respect to the total mass of the acoustic matching layer.
    Acoustic matching layer.
  2. 　前記炭素粒子が、鱗片状炭素粒子である、請求項１に記載の音響整合層。 The acoustic matching layer according to claim 1, wherein the carbon particles are scaly carbon particles.
  3. 　前記鱗片状炭素粒子が、グラファイト、グラフェンからなる群より選択される少なくとも一種である、請求項２に記載の音響整合層。 The acoustic matching layer according to claim 2, wherein the scale-like carbon particles are at least one selected from the group consisting of graphite and graphene.
  4. 　請求項１～３のいずれか一項に記載の音響整合層を有する超音波診断装置。 An ultrasonic diagnostic apparatus having the acoustic matching layer according to any one of claims 1 to 3.
  5. 　音響整合層の製造方法であって、
    　炭素含有樹脂に、炭素粒子を混合させて、前駆体組成物を作製すること、並びに
    　前記前駆体組成物を非酸化雰囲気下で熱処理して、前記炭素含有樹脂を炭素化させること
    を含み、
    　前記炭素粒子の含有率が、前記音響整合層の全質量に対して４０質量％以下である、
    音響整合層の製造方法。     A method for manufacturing an acoustic matching layer, comprising:
    mixing carbon particles with a carbon-containing resin to prepare a precursor composition; and heat-treating the precursor composition in a non-oxidizing atmosphere to carbonize the carbon-containing resin;
    The content of the carbon particles is 40% by mass or less with respect to the total mass of the acoustic matching layer.
    A method for manufacturing an acoustic matching layer.
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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004032425A (en) * 2002-06-26 2004-01-29 Mitsubishi Pencil Co Ltd Composite carbon diaphragm and its manufacturing method
JP2013236262A (en) * 2012-05-09 2013-11-21 Mitsubishi Pencil Co Ltd Carbonaceous acoustic plate and method for manufacturing the same
JP2015093012A (en) * 2013-11-11 2015-05-18 三菱鉛筆株式会社 Composite plate, and method for producing the same
WO2015194602A1 (en) * 2014-06-18 2015-12-23 三菱鉛筆株式会社 Carbonaceous acoustic matching layer and method for producing same

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004032425A (en) * 2002-06-26 2004-01-29 Mitsubishi Pencil Co Ltd Composite carbon diaphragm and its manufacturing method
JP2013236262A (en) * 2012-05-09 2013-11-21 Mitsubishi Pencil Co Ltd Carbonaceous acoustic plate and method for manufacturing the same
JP2015093012A (en) * 2013-11-11 2015-05-18 三菱鉛筆株式会社 Composite plate, and method for producing the same
WO2015194602A1 (en) * 2014-06-18 2015-12-23 三菱鉛筆株式会社 Carbonaceous acoustic matching layer and method for producing same

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