JP2012034160A - Backing material for ultrasonic probe, ultrasonic probe using the same, and ultrasonic medical image diagnosis device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a backing material for an ultrasonic probe in which an attenuation factor of a needless ultrasonic wave radiated backward from an ultrasonic vibrator which constitutes an ultrasonic probe is high, and which in addition, has an appropriate acoustic impedance and is excellent in a yield during dicing, and an ultrasonic probe using the same and ultrasonic medical image diagnosis device using it.SOLUTION: The backing material for ultrasonic probes is provided behind an ultrasonic vibrator constituting an ultrasonic probe, and attenuates an ultrasonic wave radiated backward from the ultrasonic vibrator. In the backing material for ultrasonic probes, the backing material contains a base material and a filler mixture, and as the filler mixture, contains a filler composite particle where an elastomer and a filler are compounded at least, and where an average particle diameter of the filler composite particle is within the range of 50-200 μm, and among the filler composite particles, the content of a micro-particle with a particle size of 30 μm or less is not more than 20 vol%.

Description

  The present invention relates to a backing material for an ultrasound probe, an ultrasound probe using the same, and an ultrasound medical image diagnostic apparatus. Specifically, the attenuation rate of unnecessary ultrasonic waves radiated backward from the ultrasonic transducers constituting the ultrasonic probe is high, and it has an appropriate acoustic impedance and has little thermal deformation when dicing. The present invention relates to a backing material for an ultrasonic probe.

  In an ultrasonic probe used in an ultrasonic medical image diagnostic apparatus or the like, one having higher sensitivity is required in order to improve the image quality by improving the S / N ratio.

  In order to increase the sensitivity of an ultrasonic probe, it is necessary to improve the ultrasonic wave transmission capability and the reception sensitivity. As one of the methods, a backing material (backside load) provided on the back side of the ultrasonic transducer (piezoelectric transducer) to attenuate and absorb unnecessary ultrasonic waves radiated from the ultrasonic transducer backward There is a method of reducing the acoustic impedance of the member.

  Reducing the acoustic impedance of the backing material not only reduces the ultrasonic wave radiated to the backing material side, but also effectively transmits and receives the ultrasonic wave from the ultrasonic wave transmitting / receiving surface in front of the probe. It also improves the receiving sensitivity by reducing the acoustic impedance of the wave system.

  Among the constituent members of the ultrasonic probe, the backing material plays a role of improving the resolution by the damping effect, supporting the ultrasonic transducer, and absorbing the ultrasonic wave radiated to the backing material side.

  In recent years, in an ultrasonic probe, an acoustic matching layer (matching layer) provided on the ultrasonic wave transmitting / receiving surface side of an ultrasonic transducer is multilayered, or a composite piezoelectric material is used for a piezoelectric body constituting the ultrasonic transducer. For example, since the pulse echo waveform is improved, a method for reducing the acoustic impedance of the backing material has become more effective.

  For example, in an ultrasonic probe of an ultrasonic diagnostic apparatus, sensitivity is improved by setting the acoustic impedance of the backing material to about 2 to 5 Mrayls. However, even when trying to obtain a backing material having an acoustic impedance of about 2 to 4 Mrayls required for high sensitivity, it is necessary to have sufficient hardness and absorption attenuation. It has been difficult to obtain in the past.

  If the acoustic properties (physical properties) of the backing material are not good, the backing material cannot sufficiently absorb and attenuate ultrasonic waves, and as a result, the image quality of the ultrasonic image is degraded. In particular, it is desirable that the acoustic impedance of the backing material is as designed, and that the acoustic impedance is uniform as a whole. That is, the backing material needs to match the acoustic impedance and attenuation uniformly to desired values as a whole.

  Conventionally, a rubber material in which ferrite powder is mixed is used as a backing material. However, such a backing material has a problem that it is difficult to increase the attenuation rate of ultrasonic waves. In addition, such a backing material is too soft when making a high-frequency probe, so it cannot be finely diced when dicing to a fine pitch, and is cut to a uniform depth especially when trying to provide a sub-die. It can not be a problem. Further, there is a problem that when dicing, it is easily deformed by heat. Furthermore, in the case of rubber materials, it is difficult to arbitrarily adjust the acoustic impedance and attenuation, and there is no particularly low acoustic impedance of 2 to 5 Mrayls.

  Conventionally, a backing material in which powder (particles) such as tungsten and glass microballoons (particles) are mixed as fillers with epoxy resin is also known (see, for example, Patent Document 1). According to this backing material, high rigidity and high damping characteristics can be obtained.

  However, in this case, there is no problem during dicing due to the flexibility of using rubber, but filler particles such as tungsten have a very large mass (density) per unit volume. When it is mixed, the particles settle to the lower part, and the number of particles per unit volume becomes non-uniform in the vertical direction (in the thickness direction). That is, there is a problem that the acoustic properties (especially acoustic impedance) of the backing cannot be made uniform in the vertical direction. For this reason, it is difficult to obtain high attenuation. In particular, since it is difficult to disperse the filler for damping, it was difficult to add a necessary amount of filler.

  In order to solve the above problems, a technique of combining a filler with silicone rubber or the like and mixing it is also disclosed. (For example, see Patent Documents 2 and 3.) However, when making composite particles in this way, the adhesion between the silicone rubber and the filler is poor, and when forming composite particles, the filler is sufficiently covered with silicone rubber. There is a problem that the silicone rubber part and the filler part are separated and cannot function as composite particles. Therefore, sufficient attenuation cannot be obtained unless the amount of the composite particles is large, and as a result, there is a problem that strength as a backing material and adhesiveness when assembling the transducer are insufficient. When an epoxy adhesive is used for bonding, there is a significant decrease in bonding strength, and in the subsequent processes, problems such as peeling occur and the yield decreases.

JP-A-3-284100 JP 62-118700 A JP 2003-190162 A

  The present invention has been made in view of the above problems and situations, and the problem to be solved is a high attenuation rate of unnecessary ultrasonic waves radiated backward from the ultrasonic transducers constituting the ultrasonic probe. Another object is to provide a backing material for an ultrasonic probe that has an appropriate acoustic impedance and is excellent in yield when dicing. It is another object of the present invention to provide an ultrasonic probe and an ultrasonic medical image diagnostic apparatus using the same.

  The above-mentioned problem according to the present invention is solved by the following means.

  1. An ultrasonic probe backing material that is provided behind an ultrasonic transducer constituting an ultrasonic probe and attenuates ultrasonic waves radiated backward from the ultrasonic transducer, wherein the backing material is Containing a base material and a filler mixture, as the filler mixture, containing filler composite particles comprising at least an elastomer and a filler, and having an average particle size of the filler composite particles in the range of 50 to 200 μm, A backing material for an ultrasound probe, wherein the content of fine particles having a particle size of 30 μm or less among the composite particles is 20 vol% or less.

  2. The backing material for an ultrasonic probe according to item 1, wherein the filler composite particles contain a silane coupling agent or a reaction product thereof.

3. The density of the filler composite particles is in the range of 5.0 × 10 ³ to 15 × 10 ³ kg / m ^3. The ultrasonic probe according to item 1 or 2, Backing material.

  4). The ultrasonic probe according to any one of Items 1 to 3, wherein the filler contained in the filler composite particles has been subjected to surface treatment with the coupling agent in advance. Backing material.

  5. An ultrasonic probe using the backing material for an ultrasonic probe according to any one of items 1 to 4 above.

  6). An ultrasonic medical diagnostic imaging apparatus comprising an ultrasonic probe using the ultrasonic probe backing material according to any one of items 1 to 4.

  By the above means of the present invention, the attenuation rate of unnecessary ultrasonic waves radiated backward from the ultrasonic transducer constituting the ultrasonic probe is high, and also has an appropriate acoustic impedance and is used when dicing. It is possible to provide a backing material for an ultrasonic probe that is excellent in yield. Also, an ultrasonic probe and an ultrasonic medical image diagnostic apparatus using the same can be provided.

  Although the manifestation mechanism of the effect of the present invention is not clear, the average particle size of the filler composite particles is in the range of 50 to 200 μm, and among the filler composite particles, the inclusion of fine particles having a particle size of 30 μm or less. When the condition that the amount is 20 vol% or less is not satisfied, it is presumed that the number of fillers in the filler composite particles and the ratio of the elastomer change, and the strength of the backing material is not sufficiently obtained. Further, when the filler composite particles contain a silane coupling agent or a reaction product thereof, and the filler is subjected to surface treatment with the coupling agent in advance, the number of fillers in the filler composite particles is an appropriate number. It is presumed to be.

Schematic diagram showing the configuration of the ultrasound probe Schematic diagram of an ultrasonic probe diced into each element at a constant pitch Schematic diagram showing the external configuration of an ultrasonic medical diagnostic imaging apparatus Block diagram showing the electrical configuration of the ultrasonic medical diagnostic imaging apparatus The figure which shows the relationship (particle size distribution) of the particle size and content of filler composite particle-1 The figure which shows the relationship (particle size distribution) of the particle size and content of the filler composite particle-2 The figure which shows the relationship (particle size distribution) of the particle size and content of filler composite particle-3 The figure which shows the relationship (particle size distribution) of the particle size and content of the filler composite particle -4 The figure which shows the relationship (particle size distribution) of the particle size and content of filler composite particle-5 The figure which shows the relationship (particle size distribution) of the particle size and content of filler composite particle-6

  The backing material for an ultrasonic probe of the present invention is provided behind the ultrasonic transducer constituting the ultrasonic probe and attenuates the ultrasonic wave radiated backward from the ultrasonic transducer. It is a backing material for tentacles, the backing material contains a base material and a filler mixture, the filler mixture contains filler composite particles in which at least an elastomer and a filler are combined, and the average particle size of the filler composite particles The diameter is in the range of 50 to 200 μm, and the content of fine particles having a particle diameter of 30 μm or less among the filler composite particles is 20 vol% or less. This feature is a technical feature common to the inventions according to claims 1 to 6.

  Note that “behind the ultrasonic transducer” refers to a space located on the opposite side (rear side) to the side (front side) that transmits and receives ultrasonic waves of the ultrasonic transducer.

As an embodiment of the present invention, it is preferable that the filler composite particles contain a silane coupling agent or a reaction product thereof from the viewpoint of manifesting the effects of the present invention. The density of the filler composite particles is preferably in the range of ^{5.0 × 10 3 ~15 × 10 3} kg / m 3. Furthermore, it is preferable that the filler contained in the filler composite particles has been surface-treated with the coupling agent in advance.

  The backing material for an ultrasonic probe of the present invention can be suitably used for an ultrasonic probe and an ultrasonic medical image diagnostic apparatus.

  Hereinafter, the present invention, its components, and modes and modes for carrying out the present invention will be described in detail. In addition, in this application, "-" is used in the meaning which includes the numerical value described before and behind that as a lower limit and an upper limit.

(Backing material for ultrasonic probe)
The backing material for an ultrasonic probe of the present invention is provided behind the ultrasonic transducer constituting the ultrasonic probe and attenuates the ultrasonic wave radiated backward from the ultrasonic transducer. It is a backing material for tentacles, the backing material contains a base material and a filler mixture, the filler mixture contains filler composite particles in which an elastomer and a filler are combined, and the average particle diameter of the filler composite particles Is in the range of 50 to 200 μm, and among the filler composite particles, the content of fine particles having a particle size of 30 μm or less is 20 vol% or less.

  The acoustic impedance of the ultrasonic probe backing material is preferably in the range of 1.8 to 6.0 MRayls.

  Hereinafter, detailed description will be given of the components necessary for this purpose.

<Base material for backing material>
In the present invention, the base material of the backing material is natural rubber, ferrite rubber, epoxy resin, vinyl chloride, polyvinyl butyral (PVB), ABS resin, polyurethane (PUR), polyvinyl alcohol (PVAL), polyethylene (PE), polypropylene. Thermoplastic resins such as (PP), polyacetal (POM), polyethylene terephthalate (PETP), fluororesin (PTFE) polyethylene glycol, and polyethylene terephthalate-polyethylene glycol copolymer can be used.

  A preferable backing material is made of a rubber-based composite material and / or an epoxy resin composite material, and the shape thereof can be appropriately selected according to the shape of the piezoelectric body or the probe head including the piezoelectric body.

  As the rubber-based composite material, a material containing a rubber component and a filler is preferable, and hardness from A70 with a type A durometer to D70 with a type D durometer in a spring hardness tester (durometer hardness) according to JIS K6253. In addition, various other compounding agents can be added as necessary. Examples of rubber components include ethylene propylene rubber (EPDM or EPM), hydrogenated nitrile rubber (HNBR), chloroprene rubber (CR), silicone rubber, blend rubber of EPDM and HNBR, and blend rubber of EPDM and nitrile rubber (NBR). NBR and / or HNBR and high styrene rubber (HSR) blend rubber, EPDM and HSR blend rubber, and the like are preferable.

  More preferably, ethylene propylene rubber (EPDM or EPM), hydrogenated nitrile rubber (HNBR), EPDM and HNBR blend rubber, EPDM and nitrile rubber (NBR) blend rubber, NBR and / or HNBR and high styrene rubber (HSR) ) Blend rubber, EPDM and HSR blend rubber, and the like. As the rubber component according to the present invention, one kind of rubber component such as vulcanized rubber and thermoplastic elastomer may be used alone, but a blend rubber obtained by blending two or more rubber components such as a blend rubber is used. Also good.

  Compounding agents can be added to rubber-based composite materials as needed. Such compounding agents include vulcanizing agents, cross-linking agents, curing agents, auxiliary agents, deterioration inhibitors, and antioxidants. Agents, coloring agents and the like. For example, carbon black, silicon dioxide, process oil, sulfur (vulcanizing agent), dicumyl peroxide (Dicup, crosslinking agent), stearic acid and the like can be blended. These compounding agents are used as necessary, but the amount used is generally about 1 to 100 parts by mass with respect to 100 parts by mass of the rubber component, but may be appropriately changed depending on the overall balance and characteristics. You can also.

  As an epoxy resin composite agent, it is preferable to contain an epoxy resin component and a filler, and various compounding agents can be added as necessary. Examples of the epoxy resin component include bisphenol A type, bisphenol F type, resol novolak type, novolac type epoxy resin such as phenol-modified novolak type, naphthalene structure-containing type, anthracene structure-containing type, fluorene structure-containing type, etc. Type epoxy resin, hydrogenated alicyclic epoxy resin, liquid crystalline epoxy resin and the like. Although the epoxy resin component which concerns on this invention may be used independently, you may mix and use two or more types of epoxy resin components like a blend resin.

  In the present invention, a nanocomposite epoxy resin can also be used as the base material.

  The “nanocomposite epoxy resin” according to the present invention is a new functional property obtained by dispersing nano-sized fine particles having an average particle size of 10 to 1000 nm in advance together with a curing agent or a curing agent and a curing accelerator in an epoxy resin. An epoxy resin that expresses

  The epoxy resin as the nanocomposite epoxy resin that can be used in the present invention is particularly of a type as long as it is liquid at room temperature in the range of about 5 ° C to 28 ° C, and further in the temperature range up to about 100 ° C. There may be various things without being limited.

  For example, diglycidyl ether based on bisphenol A, bisphenol F or resorcin; polyglycidyl ether of phenol novolac resin or cresol novolac resin; diglycidyl ether of hydrogenated bisphenol A; glycidyl amine type; linear aliphatic epoxide type And diglycidyl ester of phthalic acid, hexahydrophthalic acid or tetrahydrophthalic acid.

  The epoxy equivalent of these liquid epoxy resins is preferably in the range of 100 to 500, and more preferably in the range of 150 to 250.

  These liquid epoxy resins may be used individually by 1 type, and may be used in combination of 2 or more types.

  Among the liquid epoxy resins, diglycidyl ether based on bisphenol A or bisphenol F having a low viscosity is preferable.

  In addition, in order to impart toughness and tackiness to the molded product obtained using the liquid epoxy resin composition, the liquid epoxy resin is added with ethylene oxide or propylene oxide-added bisphenol A type epoxy resin, dimer acid type epoxy resin, epoxy modified A modified epoxy resin such as NBR may be used in combination.

  The epoxy resin curing agent (B) used in the present invention has a function of causing a crosslinking reaction with the epoxy group of the epoxy resin by being heated to 50 to 200 ° C. and curing the epoxy resin composition.

  As the curing agent, those conventionally used as curing agents for epoxy resins can be used.

  Specific examples thereof include dicyandiamide; 4,4′-diaminohyphenylsulfone; imidazole derivatives such as 2-n-heptadecylimidazole; isophthalic acid dihydrazide; N, N-dialkylurea derivatives; N, N-dialkylthiourea. Derivatives; Acid anhydrides such as tetrahydrophthalic anhydride; Polyphores such as isophoronediamine, m-phenylenediamine, ethylenediamine, hexamethylenediamine, m-xylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine; bis (aminomethyl) Aminoal such as cyclohexane, N-aminoethylpiperazine, trisdimethylaminomethylphenol, 3,9-bis (3-aminopropyl) -2,4,8,10-tetraoxaspiro (5,5) undecane Le cyclic compound; melamine; boron fluoride complex compounds; consisting adducts of various dimer acid and a diamine polyamide amine; and the like.

  These curing agents for epoxy resins may be used alone or in combination of two or more.

  Examples of the curing aid for the epoxy resin component include tertiary amine compounds such as 1,8-diaza-bicyclo (5,4,0) undecene-7, triethylenediamine, benzyldimethylamine, and 2-methylimidazole. , Imidazoles such as 2-ethyl-4-methylimidazole, 2-phenylimidazole and 2-phenyl-4-methylimidazole, and organic phosphine compounds such as triphenylphosphine and tributylphosphine.

  About the compounding ratio with respect to the whole quantity of a liquid epoxy resin composition, normally with respect to 100 mass parts of epoxy resins, a hardening | curing agent shall be in the range of 3-100 mass parts, and about a hardening accelerator, it is a hardening agent. A ratio of about 1/5 or less can be considered.

  Examples of the fine particles according to the present invention include inorganic compounds and organic compounds.

  The primary average particle diameter of the fine particles is preferably 1000 nm (1 μm) or less, more preferably 500 nm or less, particularly preferably from the viewpoint of nanocompositing, stably mixing in an epoxy resin, and improving acoustic characteristics. Is 200 nm or less.

  Inorganic compounds include silicon-containing compounds, silicon dioxide, aluminum oxide, zirconium oxide, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, magnesium silicate, calcium phosphate, etc. More preferably, there are inorganic compounds containing silicon and zirconium oxide.

  Examples of the fine particles of silicon dioxide according to the present invention include, for example, Aerosil R972, R974, R812, 200, 300, R202, OX50, TT600 (manufactured by Nippon Aerosil Co., Ltd.), MEK-ST (manufactured by Nissan Chemical Co., Ltd.). A commercial product having a trade name such as OSCAL (manufactured by Catalytic Chemicals Co., Ltd.) can be used. Furthermore, as smectite, Lucentite SWN, SAN, STN, SEN, SPN (Coop Chemical Co., Ltd.) and as Bennite, Sven, C, E, W, WX, N-400, NX, NX80, NZ, NZ70 , NE, NEZ, NO12S, NO12 and the like, organite, D, T (manufactured by Hojun Co., Ltd.) and the like. As the zirconium oxide fine particles according to the present invention, for example, those commercially available under trade names such as Aerosil R976 and R811 (manufactured by Nippon Aerosil Co., Ltd.) and QUEEN TITANIC (Catalyst Chemical Co., Ltd.) can be used. .

  As the organic compound, for example, polymers such as acrylic resin, urethane resin, silicone resin, fluorine resin, and the like are preferable. Among these, acrylic resins, butadiene resins and silicone resins can be preferably used. Among the acrylic resins and silicone resins described above, those having a three-dimensional network structure are particularly preferable. For example, as the acrylic resin, resin fine particles, MG-151, MG-152, MG-153, MG-154, MG -251, S-1200, S-0597, S-1500, S-4100, 4000 (manufactured by Nippon Paint Co., Ltd.), Riosphere (manufactured by Toyo Ink Co., Ltd.) and the like are preferable.

  A higher apparent specific gravity is preferable because a high-concentration nanocomposite epoxy resin can be produced, aggregates are reduced, and target acoustic characteristics are improved.

  Silicon dioxide fine particles having an average primary particle diameter of 200 nm or less and an apparent specific gravity of 70 g / liter or more are, for example, a mixture of vaporized silicon tetrachloride and hydrogen burned in air at 1000 to 1200 ° C. Can be obtained. Further, for example, they are commercially available under the trade names of Aerosil 200V and Aerosil R972V (manufactured by Nippon Aerosil Co., Ltd.), and these can be used.

  A commercially available product can also be preferably used for such a nanocomposite epoxy resin. For example, Nanopox F400, F440, F520, F630, F640, ALBIPOX F080, F081, etc. as silica nanocomposites, ALBIPOX 1000, 2000, 2002, 3001, etc. as NBR nanocomposites, ALBIDURE EP2240 as silicone rubber nanocomposites, etc. EP5340, PU5640, 6240UP, VE3320 (manufactured by NANORESIN), ACRYSET BPA328, and BPF307 (manufactured by Nippon Shokubai).

<Filler mixture: Filler composite particles>
The backing material for an ultrasonic probe of the present invention contains a base material and a filler mixture, and contains at least two kinds of filler composite particles in which an elastomer and a filler are combined as the filler mixture.

  The filler mixture according to the present invention is a mixture formed by mixing and dispersing a filler and an elastomer, which will be described later, and an elastomer film formed on the filler, or a filler is impregnated with an elastomer to form a composite. Refers to the combined material.

  In the present invention, a particulate filler composite material, that is, a filler composite particle is preferable.

  As filler composite particles that can be used in the present invention, composite particles of elastomer and ferrite, and composite particles of elastomer, ferrite, and glass balloon are particularly preferably used.

In the present invention, the density of the filler composite particles is preferably ^{5.0 × 10 3 ~15 × 10 3} kg / m 3.

  The density of the filler composite particles was measured using an electronic hydrometer SD-200L (manufactured by Alpha Mirage) in accordance with the density measurement method of Method A (underwater substitution method) described in JIS-K711002.

  Adjustment to bring the density within the above range is made by optimizing the selection of the chemical species of the elastomer and filler constituting the filler composite particles, the amount used, the composition, the temperature and concentration conditions in the method for preparing the filler composite particles. It can be performed by optimizing the above.

  In the present invention, the average particle size of the filler composite particles is in the range of 50 to 200 μm, and among the filler composite particles, the content of fine particles having a particle size of 30 μm or less is 20 vol% or less. To do.

  In this invention, the said average particle diameter was measured using the laser type particle size distribution measuring device (LMS-30 (made by Seishin Enterprise)).

<Elastomer>
The filler composite particles according to the present invention are particles formed by combining an elastomer and a filler.

  In the present application, “elastomer” refers to a substance having rubber elasticity at room temperature. In the present invention, a thermosetting elastomer or a thermoplastic elastomer can be used. For example, thermosetting properties such as a flexible epoxy resin, silicone rubber, isoprene rubber, ethylene propylene rubber, butadiene rubber, chloroprene rubber, and natural rubber. It is preferable to use an elastomer.

《Flexible epoxy resin》
The “flexible epoxy resin” that can be used in the present invention has an epoxy group at both ends of a molecule constituting the resin, and a number average molecular weight of 50 between one epoxy group and the other epoxy group. An epoxy resin having a flexible skeleton of 10000 to 10000.

  By using such a flexible epoxy compound, the filler composite particles according to the present invention are excellent in acoustic characteristics and adhesiveness.

  In the present specification, the “flexible skeleton” means a skeleton having a glass transition temperature of 25 ° C. or lower of a resin composed only of the skeleton. The flexible skeleton portion has a lower limit of number average molecular weight of 50 and an upper limit of 10,000 from the viewpoints of flexibility and adhesiveness of the cured product of the adhesive for electronic components at room temperature. The preferable lower limit of the number average molecular weight is 100, and the preferable upper limit is 2000.

  The flexible epoxy compound is not particularly limited. For example, 1,2-polybutadiene modified bisphenol A glycidyl ether, 1,4-polybutadiene modified bisphenol A glycidyl ether, polypropylene oxide modified bisphenol A glycidyl ether, polyethylene oxide modified bisphenol A Glycidyl ether, acrylic rubber modified bisphenol A glycidyl ether, urethane resin modified bisphenol A glycidyl ether, polyester resin modified bisphenol A glycidyl ether, 1,2-polybutadiene modified glycidyl ether, 1,4-polybutadiene modified glycidyl ether, polypropylene oxide modified glycidyl ether , Polyethylene oxide modified glycidyl ether, acrylic rubber Sex glycidyl ether, urethane resin modified glycidyl ether, polyester resin modified glycidyl ether, and the like of these hydrogenated products thereof.

  These epoxy compounds may be used independently and 2 or more types may be used together. Among them, an epoxy compound in which the flexible skeleton is derived from at least one compound selected from the group consisting of butadiene rubber, propylene oxide, ethylene oxide, acrylic rubber, and these water additives is preferably used. More preferably, an epoxy compound having a flexible skeleton derived from butadiene rubber or a water additive thereof is preferable.

  As the flexible epoxy compound, one having an aromatic skeleton in the molecule is preferable because of its high reaction rate. The epoxy compound having such an aromatic skeleton is not particularly limited. For example, 1,2-polybutadiene modified bisphenol A glycidyl ether, 1,4-polybutadiene modified bisphenol A glycidyl ether, polypropylene oxide modified bisphenol A glycidyl ether, polyethylene Examples thereof include oxide-modified bisphenol A glycidyl ether, acrylic rubber-modified bisphenol A glycidyl ether, urethane resin-modified bisphenol A glycidyl ether, and polyester resin-modified bisphenol A glycidyl ether. Among them, those having a structure in which a glycidyl group is directly bonded to an aromatic skeleton have a particularly high reaction rate.

  Examples of commercially available resins that can be used include EPICLON EXA-4816, EXA-4822, EXA-4850-150, EXA-4850-1000, TSR-960, TSR-601 (manufactured by DIC), Adeka Resin EBR series EPU series, C-1116A / B (manufactured by Tesque), Duralco 4583 (manufactured by Cotronics), Albiflex 296, 348, XP544, 712 (manufactured by Nanoresin) Epofriend AT501, CT310 (manufactured by Daicel Chemical), ER 732 (made by Dow Chemical), EPB-13 (made by Nippon Soda Co., Ltd.) can be mentioned.

<Filler>
As the filler that can be used in the present invention, various conventionally known fillers that can be contained in the resin can be used. In the present invention, it is preferable to use a filler having a specific gravity of 5.0 or more or 1 or less.

  As the filler having a specific gravity of 5.0 or more, the following inorganic particles can be preferably used. The numerical value in the parenthesis below represents the specific gravity of each substance.

  Ferrite (5.6), tungsten oxide (7.2), yttrium oxide (9.2), bismuth oxide (8.9), zinc oxide (5.6), tungsten (19.3), zirconium oxide (5 .9), tin oxide (7.0), nickel oxide (6.7), barium oxide (5.7), manganese oxide (5.0), yttrium oxide (5.0), indium oxide (7.2) ), Tantalum oxide (8.2), barium titanate (6.1), and the like.

  As the filler having a specific gravity of 1 or less, hollow particles are preferable. Hollow particles include hollow resin particles and hollow inorganic particles, both of which can be preferably used, but hollow inorganic particles are more preferred. The hollow particle is a particle having a cavity inside, and may have one cavity inside the particle, or may have a plurality of cavities in the particle. The hollow particles may be porous hollow particles. Examples of the hollow particles include hollow resin particles such as acrylic resins such as acrylic or acrylonitrile, synthetic resins such as polystyrene resins, and hollow inorganic particles such as silica and alumina.

  Glass balloon, hollow silica (0.30), cenolite (0.76), phenol resin microballoon (0.15) urea resin microballoon (0.13), polymethyl methacrylate balloon (0.40), etc. be able to.

  The average particle diameter of the filler is preferably 100 nm to 500 μm, particularly 500 nm to 100 μm, more preferably 5 to 50 μm.

  In addition, the average particle diameter of the filler is obtained by using a number average value obtained by slicing the backing layer thinly and observing with a transmission electron microscope at a magnification of about 1,000,000 times and obtaining an area circle equivalent diameter of at least 100 hollow particles. More simply, it can be measured using a laser type particle size distribution analyzer (for example, LMS-30 (manufactured by Seishin Enterprise)).

  Among the fillers, ferrite, tungsten oxide, zinc oxide, tungsten, hollow silica, and glass balloon are particularly preferable from the viewpoints of cost, specific gravity, and the like.

(Silane coupling agent)
The filler composite particles according to the present invention preferably contain a silane coupling agent or a reaction product thereof.

  “Silane coupling agent” as used herein has two or more different reactive groups (methoxy group, ethoxy group, silanol group, vinyl group, epoxy group, methacryl group, acrylic group, amino group, etc.) in the molecule. An organosilicon monomer.

  Examples of the silane coupling agent used in the present invention include 3-glycidoxypropyltrimethoxysilane, methylmethoxysilane, 3-methacryloxypropyltrimethoxysilane, vinyltrichlorosilane, vinyltris (β-methoxyethoxy) silane, vinyltri Ethoxysilane, vinyltrimethoxysilane, γ- (methacryloxypropyl) trimethoxysilane, γ- (methacryloxypropyl) triethoxysilane, γ- (methacryloxypropyl) methyldimethoxysilane, γ- (methacryloxypropyl) ethyldimethoxy Silane, γ- (acryloxypropyl) trimethoxysilane, γ- (acryloxypropyl) methyldimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxy Propylmethyldiethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) ) -Γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-phenyl-γ-amino Examples include, but are not limited to, propyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, and γ-chloropropyltrimethoxysilane. These silane coupling agents may be used alone or in combination of two or more.

(surface treatment)
In the present invention, it is preferable that the filler contained in the filler composite particles has been surface-treated with the silane coupling agent in advance. As the surface treatment method, various conventionally known methods can be employed.

  For example, a predetermined amount of the silane coupling agent is dissolved in a mixed solvent of acetic acid, methanol or the like and water to prepare a surface treatment solution. A filler is put into this surface treatment liquid, and the surface treatment is performed by sufficiently stirring. Thereafter, after the filler and the treatment liquid are separated, the treated filler is subjected to a heat treatment in a dryer to obtain a surface-treated filler.

<Method for producing filler composite particles>
As a method for producing the filler composite particles according to the present invention, various conventionally known methods can be adopted. For example, they are disclosed in JP-A Nos. 62-118700 and 2003-190162. The method can be adopted.

  Specifically, for example, after immersing the filler powder in a solution of a thermosetting elastomer diluted with a solvent and stirring well, discard the excess solution, dry at room temperature, evaporate the solvent, and then in the electric furnace The elastomer can be heat-cured and the filler powder coated with the elastomer can be obtained as filler composite particles.

  As another production method, first, in order to produce an elastomer as a fluid, an elastomer and a curing agent are mixed in advance and sufficiently stirred. A fixed amount is added, and after the addition, the elastomer is sufficiently stirred. In this case, for example, ultrasonic vibration may be applied together with stirring.

  “Density of filler composite particles” according to the present invention refers to the density of a test piece prepared by mixing and solidifying filler and elastomer at the same ratio when preparing filler composite particles, as described in JIS-K711212. The density was measured using an electronic hydrometer SD-200L (manufactured by Alpha Mirage) in accordance with the density measurement method of Method A (in-water substitution method).

(Ultrasonic probe)
The ultrasonic probe according to the present invention is a main component of an ultrasonic diagnostic imaging apparatus and has a function of generating ultrasonic waves and transmitting / receiving ultrasonic beams. The internal configuration of the ultrasonic probe may take various forms, but as a general configuration, from the tip (surface contacting the living body that is the subject), the “acoustic lens”, “acoustic matching layer”, It is possible to adopt a configuration of an aspect in which “ultrasonic transducer (piezoelectric element)” and “backing” are juxtaposed in order (see FIG. 1).

  An ultrasonic probe according to the present invention is a probe for an ultrasonic medical image diagnostic apparatus including an ultrasonic transmission transducer and an ultrasonic reception transducer. The ultrasonic receiving transducer according to the invention is used.

  In the present invention, both transmission and reception of ultrasonic waves may be performed by a single transducer, but more preferably, the transducers are configured separately for transmission and reception in the probe.

  The piezoelectric material constituting the transmitting vibrator may be a conventionally known ceramic inorganic piezoelectric material or an organic piezoelectric material.

  In the ultrasonic probe according to the present invention, the ultrasonic receiving transducer according to the present invention can be arranged on or in parallel with the transmitting transducer.

  As a more preferred embodiment, the structure for laminating the ultrasonic receiving transducer according to the present invention on the ultrasonic transmitting transducer is good, and in this case, the ultrasonic receiving transducer according to the present invention is other It may be laminated on the transmitting vibrator in a form of being joined to the above polymer material (the polymer (resin) film having a relatively low relative dielectric constant as a support, for example, a polyester film). In this case, it is preferable that the film thickness of the receiving vibrator and the other polymer material be matched to a preferable receiving frequency band in terms of probe design. In view of a practical ultrasonic medical diagnostic imaging apparatus and biological information collection from a practical frequency band, the film thickness is preferably 5 to 200 μm.

  The probe may be provided with a backing layer, an acoustic matching layer, an acoustic lens, and the like. Also, a probe in which vibrators having a large number of piezoelectric materials are two-dimensionally arranged can be used. A plurality of two-dimensionally arranged probes can be sequentially scanned to form a scanner.

(Backing layer)
The backing layer is an ultrasonic absorber that supports an ultrasonic transducer (piezoelectric element) and can absorb unnecessary ultrasonic waves.

  In the present invention, as the backing material used for the backing layer, the backing material is used.

(Ultrasonic vibrator: piezoelectric element)
The ultrasonic transducer according to the present invention is an element having electrodes and a piezoelectric material, capable of converting electrical signals into mechanical vibrations and converting mechanical vibrations into electrical signals and capable of transmitting and receiving ultrasonic waves.

  The piezoelectric material is a material containing a piezoelectric body capable of converting an electrical signal into mechanical vibration and converting mechanical vibration into an electrical signal. Piezoelectric ceramics such as lead zirconate titanate (PZT) ceramics, lead titanate, lead metaniobate, etc., lithium niobate, lead zinc niobate and lead titanate, lead magnesium niobate and lead titanate, etc. Piezoelectric single crystal, crystal, Rochelle salt, polyvinylidene fluoride (PVDF), or VDF and a copolymer of, for example, ethylene trifluoride (TrFE), made of a solid solution single crystal of PVDF copolymer such as (P (VDF-TrFE)), polyvinylidene cyanide (PVDCN) which is a polymer of vinylidene cyanide (VDCN), or vinylidene cyanide-based copolymer such as nylon 9, nylon 11, etc. Odd-numbered nylon, aromatic nylon, alicyclic nylon, polylactic acid, Polyhydroxycarboxylic acids such as hydroxy butyrate, cellulose derivatives, such as organic polymer piezoelectric materials such as polyurea can be used.

  The thickness of the piezoelectric material is generally in the range of 100 to 500 μm. A piezoelectric material is used as an ultrasonic vibrator with electrodes attached to both sides thereof.

(electrode)
Materials used for electrodes applied to piezoelectric materials include gold (Au), platinum (Pt), silver (Ag), palladium (Pd), copper (Cu), aluminum (Al), nickel (Ni), tin (Sn) etc. are mentioned.

  As a method for attaching an electrode to a piezoelectric material, for example, a base metal such as titanium (Ti) or chromium (Cr) is formed to a thickness of 0.02 to 1.0 μm by sputtering, and then the above metal element is mainly used. Examples thereof include a method of forming a metal material made of a metal to be used and an alloy thereof, and further forming a partially insulating material to a thickness of 1 to 10 μm by a sputtering method or other appropriate methods as necessary.

  Electrodes can be formed by screen printing, dipping, or thermal spraying using a conductive paste in which fine metal powder and low-melting glass are mixed, as well as sputtering. The electrode is provided on the entire surface of the piezoelectric body or a part of the piezoelectric body surface on the piezoelectric material according to the shape of the probe.

  In a preferred embodiment, the ultrasonic transducer and the backing material are laminated via an adhesive layer. As an adhesive for forming the adhesive layer, an epoxy-based adhesive can be used.

  An electrode is in contact with a part of the surface on the backing material side of the ultrasonic vibrator and a part of the surface on the acoustic matching layer side, and the part where the backing material and the electrode are laminated via the adhesive layer May include.

(Acoustic matching layer)
The acoustic matching layer according to the present invention matches the acoustic impedance between the ultrasonic transducer and the subject and is made of a material having an intermediate acoustic impedance between the ultrasonic transducer and the subject.

  Materials used for the acoustic matching layer include aluminum, aluminum alloy (for example, AL-Mg alloy), magnesium alloy, Macor glass, glass, fused quartz, copper graphite, polyethylene (PE), polypropylene (PP), and polycarbonate (PC). , ABC resin, polyphenylene ether (PPE), ABS resin, AAS resin, AES resin, nylon (PA6, PA6-6), PPO (polyphenylene oxide), PPS (polyphenylene sulfide: glass fiber can be included), PPE (polyphenylene ether) ), PEEK (polyetheretherketone), PAI (polyamideimide), PETP (polyethylene terephthalate), PC (polycarbonate), epoxy resin, urethane resin, and the like. Preferably, use is made of a thermosetting resin such as an epoxy resin, which contains zinc oxide, titanium oxide, silica, alumina, bengara, ferrite, tungsten oxide, yttrium oxide, barium sulfate, tungsten, molybdenum, etc. as a filler. Can do.

  The acoustic matching layer may be a single layer or may be composed of a plurality of layers, but is preferably 2 layers or more, more preferably 4 layers or more. The thickness of the acoustic matching layer is preferably determined to be λ / 4 where λ is the wavelength of the ultrasonic wave. If this is not satisfied, a plurality of unnecessary spurious noises may appear at a frequency point different from the original resonance frequency, and the basic acoustic characteristics may vary greatly. As a result, reverberation time increases and sensitivity and S / N decrease due to waveform distortion of the reflected echo are undesirable. The thickness of such an acoustic matching layer is generally in the range of 20 to 500 μm.

  In the ultrasonic probe of the present invention, both transmission and reception of ultrasonic waves may be performed by a single ultrasonic transducer. However, as an ultrasonic transducer, an ultrasonic transducer for transmission, an ultrasonic transducer for reception, What comprises is preferably used. The arrangement of the ultrasonic transducer for transmission and the ultrasonic transducer for reception may be either an arrangement arranged one above the other or an arrangement arranged in parallel, but a structure in which the arrangement is arranged one above the other is preferable.

  The thickness of the ultrasonic transducer for transmission and the ultrasonic transducer for reception in the case of stacking is preferably 40 to 150 μm.

  The ultrasonic probe according to the present invention can be used in various modes of ultrasonic image detection devices.

  FIG. 2 is a conceptual diagram showing the configuration of the main part of an example of an ultrasonic image detection apparatus including the ultrasonic probe of the present invention.

  For example, the ultrasonic image detection apparatus transmits an ultrasonic wave to a subject such as a living body, and an ultrasonic probe in which ultrasonic transducers that receive ultrasonic waves reflected by the subject as echo signals are arranged. (Probe). Also, an electric signal is supplied to the ultrasonic probe to generate an ultrasonic wave, and a transmission / reception circuit that receives an echo signal received by each ultrasonic transducer of the ultrasonic probe, and transmission / reception control of the transmission / reception circuit A transmission / reception control circuit is provided.

  Furthermore, an image data conversion circuit that converts echo signals received by the transmission / reception circuit into ultrasonic image data of the subject is provided. Further, a display control circuit for controlling and displaying a monitor with the ultrasonic image data converted by the image data conversion circuit and a control circuit for controlling the entire ultrasonic image detection apparatus are provided.

  A transmission / reception control circuit, an image data conversion circuit, and a display control circuit are connected to the control circuit, and the control circuit controls operations of these units. Then, an electrical signal is applied to each piezoelectric material of the ultrasonic probe, ultrasonic waves are transmitted to the subject, and reflected waves generated by acoustic impedance mismatch inside the subject are received by the ultrasonic probe. To do.

(Acoustic lens)
The acoustic lens according to the present invention is arranged to focus an ultrasonic beam using refraction and improve resolution.

  In the present invention, the material constituting the acoustic lens includes conventionally known homopolymers such as silicone rubber, fluorosilicone rubber, polyurethane rubber, epichlorohydrin rubber, and ethylene-propylene copolymer rubber obtained by copolymerizing ethylene and propylene. Copolymer rubber etc. can be used. Of these, it is preferable to use silicone rubber.

  Examples of the silicone rubber used in the present invention include silicone rubber and fluorine silicone rubber. In particular, it is preferable to use silicone rubber because of the characteristics of the lens material. Silicone rubber is an organopolysiloxane having a molecular skeleton composed of Si—O bonds, and having a plurality of organic groups mainly bonded to the Si atoms. Usually, the main component is methylpolysiloxane, and the entire organic group is organic. 90% or more of the groups are methyl groups. A material in which a hydrogen atom, a phenyl group, a vinyl group, an allyl group or the like is introduced instead of the methyl group can be used. The silicone rubber can be obtained, for example, by kneading a curing agent (vulcanizing agent) such as benzoyl peroxide with organopolysiloxane having a high degree of polymerization, followed by heat vulcanization and curing. If necessary, organic or inorganic fillers such as silica and nylon powder, and vulcanization aids such as sulfur and zinc oxide may be added.

  Examples of the butadiene rubber used in the present invention include butadiene alone or a copolymer rubber mainly composed of butadiene and copolymerized with a small amount of styrene or acrylonitrile. In particular, it is preferable to use butadiene rubber because of the characteristics of the lens material. The butadiene rubber refers to a synthetic rubber obtained by polymerization of butadiene having a conjugated double bond. Butadiene rubber can be obtained by 1.4 or 1.2 polymerization of butadiene alone having a conjugated double bond. A butadiene rubber vulcanized with sulfur or the like can be used.

  The acoustic lens according to the present invention can be obtained by mixing and curing and curing silicone rubber and butadiene rubber. For example, it can be obtained by mixing silicone rubber and butadiene rubber in an appropriate ratio by a kneading roll, adding a vulcanizing agent such as benzoyl peroxide, and heat vulcanizing and crosslinking (curing). At that time, it is preferable to add zinc oxide as a vulcanization aid. Zinc oxide can accelerate vulcanization and shorten the vulcanization time without deteriorating lens characteristics. In addition, other additives may be added as long as the characteristics of the colorant and the acoustic lens are not impaired. The mixing ratio of the silicone rubber and the butadiene rubber is preferably 1: 1 in order to obtain a material whose acoustic impedance is close to that of the human body and whose sound speed is smaller than that of the human body and less attenuated. The mixing ratio can be changed as appropriate.

  Silicone rubber can be obtained as a commercial product. For example, KE742U, KE752U, KE931U, KE941U, KE951U, KE961U, KE850U, KE555U, KE575U, etc. manufactured by Shin-Etsu Chemical Co., Ltd., TSE221-3U, TE221 manufactured by Momentive Performance Materials, Inc. -4U, TSE2233U, XE20-523-4U, TSE27-4U, TSE260-3U, TSE-260-4U, SH35U, SH55UA, SH831U, SE6749U, SE1120USE4704U manufactured by Dow Corning Toray can be used.

  In the present invention, an inorganic filler such as silica, alumina, titanium oxide, nylon, etc., depending on the purpose of adjusting the speed of sound, adjusting the density, etc., based on the rubber material such as the above-mentioned silicone rubber (main component) An organic resin or the like can also be blended.

(Ultrasonic medical diagnostic imaging equipment)
The ultrasonic probe according to the present invention can be used for various types of ultrasonic medical image diagnostic apparatuses (also referred to as “ultrasonic diagnostic apparatuses”).

  FIG. 3 is a schematic diagram illustrating an external configuration of the ultrasonic diagnostic apparatus according to the embodiment. FIG. 4 is a block diagram illustrating an electrical configuration of the ultrasonic diagnostic apparatus according to the embodiment.

  As shown in FIGS. 3 and 4, the ultrasound diagnostic apparatus S transmits an ultrasound signal (hereinafter also referred to as “first ultrasound signal”) to a subject H such as a living body (not shown). The ultrasonic probe 2a that receives the reflected wave of the ultrasonic signal reflected by the subject H (hereinafter also referred to as “second ultrasonic signal”), and is connected via the ultrasonic probe 2a and the cable 3a. The ultrasonic probe 2a transmits the first ultrasonic signal to the subject H by transmitting an electric signal transmission signal to the ultrasonic probe 2a via the cable 3a, and at the same time, the ultrasonic probe Based on the received signal of the electrical signal generated by the ultrasonic probe 2a in accordance with the second ultrasonic signal from the subject H received by the child 2a, the internal state in the subject H is converted into an ultrasonic image. And an ultrasonic diagnostic apparatus main body 1a for imaging a medical image. The ultrasonic diagnostic apparatus main body 1a is provided with an ultrasonic probe folder 4a that holds the ultrasonic probe 2a when the ultrasonic probe 2a is not used.

  For example, as shown in FIG. 4, the ultrasonic diagnostic apparatus main body 1a includes an operation input unit 11a, a transmission unit 12a, a reception unit 13a, a signal processing unit 14a, an image processing unit 15a, a display unit 16a, The control part 17a, the memory | storage part 19a, and the voltage control means 18a are provided and comprised.

  The operation input unit 11a is for inputting data such as a command for instructing the start of diagnosis and personal information of the subject H, for example, an operation panel or a keyboard provided with a plurality of input switches.

  The transmission unit 12a is a circuit having a function of generating a transmission signal of an electrical signal that drives a first piezoelectric unit and a second piezoelectric unit, which will be described later, under the control of the control unit 17a. The transmitting unit 12a supplies a transmission signal to the first piezoelectric unit and the second piezoelectric unit in the ultrasonic probe 2a via the voltage control unit 18a and the cable 3a, and the first probe is supplied to the ultrasonic probe 2a. An ultrasonic signal is generated. The transmission unit 12a includes, for example, a high voltage pulse generator that generates a high voltage pulse.

  The receiving unit 13a is a circuit that receives a reception signal of an electrical signal from the ultrasonic probe 2a via the cable 3a according to the control of the control unit 17a, and outputs the received signal to the signal processing unit 14a. The reception unit 13a includes, for example, an amplifier that amplifies the reception signal with a predetermined amplification factor set in advance, an analog-digital converter that converts the reception signal amplified by the amplifier from an analog signal to a digital signal, and the like. Configured.

  The signal processing unit 14a is a circuit that performs predetermined signal processing on the electrical signal from the receiving unit 13a in accordance with the control of the control unit 17a, and outputs the reflected reception signal subjected to the signal processing to the image processing unit 15a.

  Under the control of the control unit 17a, the image processing unit 15a generates an ultrasonic image of the internal state in the subject H using, for example, a harmonic imaging technique based on the reflected reception signal signal-processed by the signal processing unit 14a. Circuit. For example, a B-mode signal corresponding to the amplitude intensity of the second ultrasonic signal is generated by performing envelope detection processing on the reflected reception signal.

  The storage unit 19a is constituted by a RAM or a ROM, in which programs used for the control unit 17a are recorded, and various image templates to be displayed on the display unit 16a are recorded.

  The voltage control unit 18a has a function of controlling how the transmission signal of the electrical signal from the transmission unit 12a is applied to the first piezoelectric unit and the second piezoelectric unit in accordance with the control of the control unit 17a. .

  The display unit 16a is a device that displays the ultrasonic image generated by the image processing unit 15a under the control of the control unit 17a. The display unit 16a is, for example, a display device such as a CRT display, LCD, EL display, or plasma display, or a printing device such as a printer.

  The control unit 17a includes, for example, a microprocessor, a storage element, and peripheral circuits thereof. The operation input unit 11a, the transmission unit 12a, the reception unit 13a, the signal processing unit 14a, the image processing unit 15a, voltage control means, and the like. This is a circuit that performs overall control of the ultrasonic diagnostic apparatus S by controlling the 18a and the storage unit 19a in accordance with the function.

  On the other hand, the ultrasound probe 2a includes a vibrating unit 30a. The vibrating unit 30a transmits a first ultrasonic signal to a subject H such as a living body (not shown), and from the subject H. The second ultrasonic signal is received. For example, as illustrated in FIG. 1, the vibration unit 30 a includes a backing layer (acoustic braking member) 4, a piezoelectric layer 5, acoustic matching layers 6 and 7, and an acoustic lens 8.

  The backing layer (acoustic braking member) 4 is a flat plate member made of a material that absorbs ultrasonic waves, and absorbs ultrasonic waves radiated from the piezoelectric layer 5 toward the backing layer (acoustic braking member) 4. It is.

  The piezoelectric layer 5 includes a piezoelectric material, and converts signals between an electric signal and an ultrasonic signal by using a piezoelectric phenomenon. Electrodes are formed on both surfaces of the piezoelectric layer 5. The piezoelectric layer 5 may have a configuration in which two layers of a first piezoelectric layer and a second piezoelectric layer are stacked.

  The piezoelectric layer 5 converts a transmission electrical signal input from the transmission unit 12a of the ultrasonic diagnostic apparatus main body 1a via the cable 3a into a first ultrasonic signal and transmits and receives the first ultrasonic signal. The second ultrasonic signal is converted into an electric signal, and this electric signal (received signal) is output to the receiving unit 13a of the ultrasonic diagnostic apparatus main body 1a via the cable 3a. When the ultrasonic probe 2a is brought into contact with the subject H, the first ultrasonic signal generated by the piezoelectric layer 5 is transmitted into the subject H, and the second ultrasonic signal from within the subject H is transmitted. Received by the piezoelectric layer 5.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

Example 1
(Preparation of filler composite particle-1)
(surface treatment)
A surface treatment solution is prepared by dissolving 100 parts by mass of 3-glycidoxypropyltrimethoxysilane (A-187, manufactured by Momentive Performance Materials) in 225 parts by mass of a 1% by mass acetic acid aqueous solution and 675 parts by mass of methanol. 1000 parts by mass of tungsten powder (manufactured by Nippon Tungsten Co., Ltd.) having an average particle diameter of 8 μm is put in this, and stirring is sufficiently performed at 25 ° C. for 1 hr.

  Thereafter, after separating the tungsten and the treatment liquid, the treated tungsten was heat-treated in a sufficient dryer at 80 ° C. for 1 hour to obtain surface-treated tungsten.

The infrared spectrum was measured by the diffuse reflection method, and the peculiar silanol group observed in the vicinity of 3750 cm ⁻¹ disappeared. Therefore, it was judged that the silicon oxide surface was surface-treated with the silane coupling agent.

(Production of composite particles)
Into 90 parts by mass of liquid silicone rubber YE5822 (A) (made by Momentive Performance Materials), 2000 parts by mass of the surface-treated tungsten was put and sufficiently mixed with a vacuum mixer ARV-310 (made by Sinky).

Thereafter, 10 parts by mass of YE5822 (B) was added and mixed well. This is put in a 100 mm × 100 mm × 30 mm mold and heated at 4.9 MPa (50 kg / cm ² ) in a vacuum electric heating press at room temperature under vacuum for 3 hours and at 50 ° C. for 3 hours to block the composite particles. Produced. The density of the block at this time was 10.2 g / cm ³ . This is cut into 1 cm square, and this is first coarsely pulverized with a cutter mill VM-20 type (manufactured by Hadano Sangyo Co., Ltd.), screened with a pin mill M-4 type (manufactured by Nara Machinery Co., Ltd.) at a screen of 0.5 mm and a rotational speed of 2800 rpm. The mixture was then pulverized, and then sieved with a circular vibrating sieve KG-400 type (manufactured by Nishimura Machinery Co., Ltd.) with an opening of 212 μm to prepare filler composite particles-1.

  The particle size distribution of the filler composite particle-1 was determined by using a laser diffraction / scattering particle size distribution analyzer (LMS-30 manufactured by Seishin Enterprise Co., Ltd.), using isopropyl alcohol as a dispersion medium for measurement, adjusting the optimal point of the scattering intensity, and stirring. And measured under ultrasonic dispersion. As a result of measuring the particle diameter, the average particle diameter was 191 μm and there was no peak particle diameter below 30 μm (see FIG. 5).

  Moreover, the density of the composite particles was carried out by the following method.

Density known (1.17 × 10 ³ kg / m ³ ) epoxy resin, 68 parts by mass of JER-828 (Japan Epoxy Resin), 300 parts by mass of filler composite particles, vacuum mixer ARV-310 (Sinky) Then, 32 parts by mass of JER Cure ST-12 (manufactured by Japan Epoxy Resin) as a cross-linking agent was similarly mixed in a vacuum mixer ARV-310, and this was mixed into a 100 mm × 100 mm × 10 mm mold. It was cured by heating in a vacuum electric heat press at a pressure of 9.8 MPa (100 kg / cm ² ) at room temperature for 4 hours and at 60 ° C. for 3 hours. Then, it cut out to 20x20x10mm and produced the test piece. The density of the test piece was measured by the following density measurement method to determine the filler composite particle density.

(Preparation of filler composite particle-2)
Surface treatment was performed on tungsten using methylmethoxysilane (A-1630, manufactured by Momentive Performance Materials) in the same manner as in the preparation of the filler composite particles-1. As a result of the infrared spectrum in the diffuse reflection method, since the peak specific to the silanol group observed in the vicinity of 3750 cm ⁻¹ disappeared, it was judged that the silicon oxide surface was surface-treated with the silane coupling agent.

  Filler composite particles-2 were prepared in the same manner as filler composite particles-1 using the surface-treated tungsten. The average particle diameter was 60 μm, and the peak of 30 μm or less was about 20 vol% (see FIG. 6).

(Preparation of filler composite particle-3)
Coupling agent used for the surface treatment was 3-massacryloxypropyltrimethoxysilane (A-174, manufactured by Momentive Performance Materials) 2 parts by mass and methylmethoxysilane (A-1630, manufactured by Momentive Performance Materials) 98 masses. The treatment was performed in the same manner as in Example 1 except that a part of the mixture was used. As a result of the infrared spectrum obtained by the diffuse reflection method, it was confirmed that a peak specific to the silanol group observed in the vicinity of 3750 cm −1 disappeared.

  Filler composite particles-3 were prepared using the surface-treated tungsten in the same manner as filler composite particles-1. The average particle diameter was 185 μm, and no peak of 30 μm or less could be confirmed (see FIG. 7).

(Preparation of filler composite particle-4)
Comparative filler composite particles -4 were similarly produced using tungsten particles without surface treatment. The recovery was 70%, the average particle size was 43 μm, and the volume fraction of the peak of 30 μm or less was 50% (see FIG. 8). The recovery rate is obtained after preparing the composite particles after putting the prepared composite particle block, coarsely pulverizing with a cutter mill, main pulverizing with a pin mill, and sieving with a free sieve of 212 μm. The mass of the composite particles divided by the mass of the composite particle block charged.

(Preparation of filler composite particle-5)
In the preparation of the filler composite particles-4, comparative filler composite particles-5 were similarly prepared except that the conditions during pulverization were changed to a pin mill (M-4) rotation speed of 1000 rpm and a screen of 0.5 mm. The recovery rate was 55%, the average particle size was 60 μm, and the peak of 30 μm or less was 40 vol% (see FIG. 9).

(Preparation of filler composite particle-6)
The filler composite particle-5 of the comparison was sieved with an opening of 50 μm to prepare the filler composite particle-6 of the present invention. The recovery rate was 52%, the average particle size was 155 μm, and no peak of 30 μm or less was observed (see FIG. 10).

  The above results are summarized in Table 1.

Example 2
(Production of backing block)
Epoxy resin, JER-828 (manufactured by Japan Epoxy Resin) 68 parts by mass of Composite Particle-1 150 parts by mass and ferrite 140 parts by mass were sufficiently mixed with a vacuum mixer ARV-310 (Sinky Corporation). Thereafter, as a cross-linking agent, 32 parts by mass of jER Cure ST-12 (manufactured by Japan Epoxy Resin) was similarly mixed with a vacuum mixer ARV-310 to prepare a compound. The compound is placed in a 100 mm × 100 mm × 10 mm mold and heated in a vacuum electric heat press at a pressure of 9.8 MPa (100 kg / cm ² ) at room temperature for 4 hours and at 60 ° C. for 3 hours to form a backing block-1. Formed. A test piece of 20 mm × 20 mm × 2 mm was cut out from this block as a test piece, and the following evaluation was performed.

(density)
The density was measured using an electronic hydrometer SD-200L (manufactured by Alpha Mirage) in accordance with the density measurement method of Method A (underwater substitution method) described in JIS-K711212.

(Acoustic characteristics)
The ultrasonic sound velocity was measured at 25 ° C. using a sing-around sound velocity measuring device manufactured by Ultrasonic Industry Co., Ltd. according to JIS Z2353-2003, and the acoustic impedance was derived according to the following equation.
Acoustic impedance (Z: Mrayls) = density (ρ: × 10 ³ kg / m ³ ) × sound velocity (C: × 10 ³ m / sec)
In addition, ultrasonic attenuation is in accordance with JIS Z2354-1992, filling a water tank with water at 25 ° C., and generating ultrasonic waves of 1 MHz in water with an ultrasonic pulser / receiver JPR-10C (manufactured by Japan Probe Co., Ltd.). The amplitude was measured before and after passing through the sheet.

  Similarly, as shown in Table 2, test backing sheets-1 to 11 were produced from the backing block and evaluated.

Example 3
(Preparation and evaluation of ultrasonic probe)
As shown in FIG. 1, a backing layer, a flexible substrate, a piezoelectric layer, an acoustic matching layer-1, and an acoustic matching layer-2 were laminated in this order. The piezoelectric material is PZT 3203HD (manufactured by CTS Electro Component Inc.) having a thickness of 0.15 mm, and the acoustic matching layer-1 is a thickness obtained by mixing 1200 parts by mass of ferrite with 100 parts by mass of the matching epoxy resin. As the 0.06 mm object and the acoustic matching layer-2, an epoxy resin alone having a thickness of 0.05 mm was used. These were laminated and each element was diced with a dicer at a pitch of 0.16 mm as shown in FIG. The situation after dicing was confirmed with a microscope.

  Table 2 shows the results of trial manufacture and evaluation of an ultrasonic probe using the test backing sheets -1 to 11 produced from the backing block as the backing layer.

  It can be seen that any of the test backing sheets produced from the backing block using the composite particles of the present invention does not cause any element peeling and is extremely excellent in yield. Using these images, an image of a living body was observed with the image display device having the configuration shown in FIGS. As a result, a clear image could be obtained.

(Yield)
The frequency of occurrence of element collapse and element peeling when dicing into 192 elements was confirmed with a microscope and calculated by the following formula.

Yield = Nominal number of elements / 192 × 100
The evaluation results are summarized in Table 2.

  As is apparent from the results shown in Table 2, it can be seen that the ultrasonic probe using the backing material of the present invention is superior in acoustic characteristics and yield compared to the comparative example.

DESCRIPTION OF SYMBOLS 1 Ultrasonic probe 2 Electrode 3 Flexible substrate 4 Backing layer 5 Piezoelectric material 6 Acoustic matching layer-1
7 Acoustic matching layer-2
DESCRIPTION OF SYMBOLS 8 Acoustic lens 1a Ultrasonic medical image diagnostic apparatus main body 2a Ultrasonic probe 3a Cable 4a Ultrasonic probe folder 11a Operation input part 12a Transmission part 13a Reception part 14a Signal processing part 15a Image processing part 16a Display part 17a Control part 18a Voltage control means 19a Storage unit 30a Vibrating unit H Subject

Claims (6)

  An ultrasonic probe backing material that is provided behind an ultrasonic transducer constituting an ultrasonic probe and attenuates ultrasonic waves radiated backward from the ultrasonic transducer, wherein the backing material is Containing a base material and a filler mixture, as the filler mixture, containing filler composite particles comprising at least an elastomer and a filler, and having an average particle size of the filler composite particles in the range of 50 to 200 μm, A backing material for an ultrasound probe, wherein the content of fine particles having a particle size of 30 μm or less among the composite particles is 20 vol% or less.   The backing material for an ultrasonic probe according to claim 1, wherein the filler composite particles contain a silane coupling agent or a reaction product thereof. Density of the filler composite particles, an ultrasonic probe for backing according to claim 1 or claim 2, characterized in that in the range of ^{5.0 × 10 3 ~15 × 10 3} kg / m 3 Wood.   The ultrasonic probe according to any one of claims 1 to 3, wherein the filler contained in the filler composite particles is subjected to a surface treatment with the coupling agent in advance. Backing material.   An ultrasonic probe using the backing material for an ultrasonic probe according to any one of claims 1 to 4.   An ultrasonic medical image diagnostic apparatus comprising an ultrasonic probe using the backing material for an ultrasonic probe according to any one of claims 1 to 4.

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