JP2010138339A - Thiourea group-containing organic polymer, organic piezoelectric material containing compound containing urea group or thiourea group, and ultrasonic wave probe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new material high in piezoelectric property and excellent in heat resistance, and to provide an ultrasonic wave probe using the same. <P>SOLUTION: The organic piezoelectric material contains a compound represented by general formula (1), wherein, X<SB>1</SB>and X<SB>2</SB>represent carbon or nitrogen atom, Y<SB>1</SB>and Y<SB>2</SB>represent hydrogen atom or a substituent, n1 and n2 represent an integer of 0-4, R<SB>1</SB>, R<SB>2</SB>, R<SB>3</SB>and R<SB>4</SB>represent hydrogen atom or a substituent, Q<SB>1</SB>and Q<SB>2</SB>represent oxygen or sulfur atom, W<SB>1</SB>represents single bond or oxygen atom, m represents an integer of 0 or above, and p represents an integer of 5 or above. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a thiourea group-containing polymer compound, an organic piezoelectric material, and an ultrasonic probe, and more particularly, an organic piezoelectric material including a urea group or a compound containing a thiourea group, and an ultrasonic probe using the same. About.

  Conventionally, acoustic devices such as microphones and speaker diaphragms, various thermal sensors, pressure sensors, measuring devices such as infrared detectors, ultrasonic probe, vibration sensors that detect mutations such as genes and proteins with high sensitivity, etc. Organic piezoelectric materials having piezoelectricity and pyroelectricity that can be used to convert heat and mechanical stimulation into electrical energy are known.

As the pyroelectric material, a so-called inorganic material in which a crystal, a single crystal such as LiNbO ₃ , LiTaO ₃ , KNbO ₃ , a thin film such as ZnO or AlN, or a sintered body such as Pb (Zr, Ti) O ₃ is polarized. Piezoelectric materials are widely used. However, these inorganic piezoelectric materials have characteristics such as high elastic stiffness, high mechanical loss coefficient, high density and high dielectric constant.

  Meanwhile, organic piezoelectric materials such as polyvinylidene fluoride (hereinafter abbreviated as “PVDF”) and polycyanovinylidene (hereinafter abbreviated as “PVDCN”) have also been developed (for example, see Patent Document 1). This organic piezoelectric material is excellent in processability such as thin film and large area, can be made in any shape and form, and has features such as low elastic modulus and low dielectric constant. When considering use, it has a feature that enables highly sensitive detection.

  Organic piezoelectric materials have low heat resistance and lose their pyroelectric properties at high temperatures, and their physical properties such as elastic stiffness are greatly reduced, so there is a limit to the usable temperature range.

  In contrast to such limitations, polyurea resin compositions composed of urea bonds have a large dipole moment of urea bonds and are excellent in temperature characteristics as resins, and thus various studies have been made as organic piezoelectric materials.

  For example, there is a so-called vapor deposition polymerization method in which a polyisocyanate film is formed by simultaneously evaporating a diisocyanate compound such as 4,4′-diphenylmethane diisocyanate (MDI) and a diamine compound such as 4,4′-diaminodiphenylmethane (MDA). It is disclosed (for example, see Patent Documents 2 and 3). However, since the polyurea resin composition prepared by the vapor deposition polymerization method described in these documents has a non-uniform molecular weight of the oligomer or high molecular weight product to be produced, when the molecular weight is increased while performing polarization treatment, In this state, the polyurea resin composition is formed. For this reason, the dipole moment of the urea bond cannot be fully utilized, and further improvement has been demanded as an organic piezoelectric material.

There is a report using a ferroelectric liquid crystal compound as a piezoelectric material (see, for example, Patent Document 4). However, in the previous reports, the types of polarization groups are limited, spontaneous polarization and piezoelectricity are low, and film formation is performed. The properties are not sufficient, and a material satisfying the performance required as a piezoelectric material has not yet been found.
JP-A-6-216422 JP-A-2-284485 Japanese Patent Laid-Open No. 5-31399 JP 7-115230 A

  The present invention has been made in view of the above problems and circumstances, and an object thereof is to provide a novel material having high piezoelectricity and excellent heat resistance as an organic piezoelectric material, and an ultrasonic probe using the same. It is to provide.

  The object of the present invention is achieved by the following constitution.

  1. An organic piezoelectric material comprising a compound represented by the following general formula (1):

(Wherein, _{X 1} and _{X 2} .Y ₁ and _{Y 2} represents a carbon atom or a nitrogen atom represents a hydrogen atom or a substituent, _{.R 1, R} 2 are n1 and n2 represents an integer of 0 to 4, R ₃ and R ₄ represent a hydrogen atom or a substituent, Q ₁ and Q ₂ represent an oxygen atom or a sulfur atom, W ₁ represents a single bond or an oxygen atom, m represents an integer of 0 or more, and p represents Represents an integer of 5 or more.)
2. _2. The organic piezoelectric material as described in 1 above, wherein Q ₁ and Q ₂ in the general formula (1) are sulfur atoms.

3. 3. The organic piezoelectric material as described in 1 or 2 above, wherein W ₁ in the general formula (1) is an oxygen atom, and m is 4 or more.

  4). An ultrasonic probe including an ultrasonic transmission transducer and an ultrasonic reception transducer, wherein the ultrasonic transducer using the organic piezoelectric material according to any one of the above items 1 to 3 is ultrasonicated. An ultrasonic probe comprising a receiving transducer.

  5. A compound represented by the following general formula (2).

(Wherein, .Y ₁ and _{Y 2 X 1} and _{X 2} represents a carbon atom or a nitrogen atom represents a substituent, _.R 1 is n1 and n2 represents an integer of _{0~4, R 2,} R ₃ and R ₄ represents a hydrogen atom or a substituent, W ₁ represents a single bond or an oxygen atom, m represents an integer of 0 or more, and p represents an integer of 5 or more.)
6). 6. The compound according to 5 above, wherein W ₁ in the general formula (2) is an oxygen atom, and m is 4 or more.

  According to the present invention, a novel material having high piezoelectricity and excellent heat resistance as an organic piezoelectric material and an ultrasonic probe using the same can be provided.

  Next, the best mode for carrying out the present invention will be described, but the present invention is not limited thereto.

  In the present invention, by using the compound represented by the general formula (1) for an organic piezoelectric material, not only high orientation and excellent piezoelectricity but also good film formability and thermal stability Therefore, it can be effectively used as a versatile organic piezoelectric material.

(Compound represented by the general formula (1))
In general formula (1), _{X 1} and _{X 2} represents a carbon atom or a nitrogen atom. X ₁ and X ₂ are preferably carbon atoms.

Y ₁ and Y ₂ represent a hydrogen atom or a substituent. Specific examples of the substituent represented by Y ₁ and Y ₂ include an alkyl group having 1 to 25 carbon atoms (methyl group, ethyl group, propyl group, isopropyl group, t-butyl group, pentyl group, hexyl group, octyl group). Group, decyl group, dodecyl group, octadecyl group, etc.), halogenated alkyl group (trifluoromethyl group, perfluorooctyl group, etc.), cycloalkyl group (cyclohexyl group, cyclopentyl group, etc.), alkynyl group (propargyl group, etc.), Glycidyl group, acrylate group, methacrylate group, aromatic group (phenyl group, etc.), heterocyclic group (pyridyl group, thiazolyl group, oxazolyl group, imidazolyl group, furyl group, pyrrolyl group, pyrazinyl group, pyrimidinyl group, pyridazinyl group, piperidinyl group Group, pyrazolyl group, tetrazolyl group, etc.), halogen atom (chlorine atom, odor) Atoms, iodine atoms, fluorine atoms, etc.), alkoxy groups (methoxy group, ethoxy group, propyloxy group, pentyloxy group, hexyloxy group, octyloxy group, decyloxy group, dodecyloxy group, octadecyloxy group, cyclopentyloxy group, hexyloxy Group, cyclohexyloxy group, etc.), aryloxy group (phenoxy group etc.), alkoxycarbonyl group (methyloxycarbonyl group, ethyloxycarbonyl group, butyloxycarbonyl group etc.), aryloxycarbonyl group (phenyloxycarbonyl group etc.), Sulfonamide groups (methanesulfonamide groups, ethanesulfonamide groups, butanesulfonamide groups, hexanesulfonamide groups, cyclohexanesulfonamide groups, benzenesulfonamide groups, etc.), sulfamoyl groups (amino Sulfonyl group, methylaminosulfonyl group, dimethylaminosulfonyl group, butylaminosulfonyl group, hexylaminosulfonyl group, cyclohexylaminosulfonyl group, phenylaminosulfonyl group, 2-pyridylaminosulfonyl group, etc., urethane group (methylureido group, ethylureido) Group, pentylureido group, cyclohexylureido group, phenylureido group, 2-pyridylureido group, etc.), acyl group (acetyl group, propionyl group, butanoyl group, hexanoyl group, cyclohexanoyl group, benzoyl group, pyridinoyl group, etc.), Carbamoyl group (aminocarbonyl group, methylaminocarbonyl group, dimethylaminocarbonyl group, propylaminocarbonyl group, pentylaminocarbonyl group, cyclohexylaminocarbonyl group, Phenylaminocarbonyl group, 2-pyridylaminocarbonyl group, etc.), amide group (acetamide group, propionamide group, butanamide group, hexaneamide group, benzamide group etc.), sulfonyl group (methylsulfonyl group, ethylsulfonyl group, butylsulfonyl group, Cyclohexylsulfonyl group, phenylsulfonyl group, 2-pyridylsulfonyl group, etc.), amino group (amino group, ethylamino group, dimethylamino group, butylamino group, cyclopentylamino group, anilino group, 2-pyridylamino group, etc.), cyano group Nitro group, sulfo group, carboxyl group, hydroxyl group, oxamoyl group and the like.

Further, these groups may be further substituted with these groups. Y ₁ and Y ₂ may form a condensed ring structure with the ring substituted by Y ₁ and Y ₂ . Y ₁ and Y ₂ are preferably an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a hydroxy group, and a halogen atom, and more preferably an alkyl group having 1 to 4 carbon atoms and 4 carbon atoms. ˜18 alkoxy groups, hydroxy groups, and halogen atoms.

n1 and n2 represent an integer of 0 to 4, and when n1 and n2 are 2 to 4, the substituents represented by Y ₁ and Y ₂ may be the same or different.

R ₁ , R ₂ , R ₃ and R ₄ represent a hydrogen atom or a substituent. Specific examples of the substituent represented by R ₁ , R ₂ , R ₃ and R ₄ include alkyl groups having 1 to 25 carbon atoms (methyl group, ethyl group, propyl group, isopropyl group, t-butyl group, n-butyl group, pentyl group, hexyl group, cyclohexyl group, etc.), cycloalkyl group (cyclohexyl group, cyclopentyl group, etc.), and aromatic group (phenyl group, naphthyl group, etc.).

The substituent represented by R ₁ , R ₂ , R ₃ and R ₄ is preferably a hydrogen atom or a methyl group, an ethyl group, an n-butyl group, an alkoxy group having 4 to 20 carbon atoms, and a phenyl group, and more Preferred are a hydrogen atom, a methyl group, an ethyl group, a butyroxy group, a hexyloxy group, an octyloxy group, a decyloxy group, and a dodecyloxy group.

Q ₁ and Q ₂ represent an oxygen atom or a sulfur atom. Q ₁ and Q ₂ are preferably sulfur atoms.

m represents an integer of 0 or more. m is preferably 0 to 20, and more preferably 0 to 12. when m is 0, among the _{Y 1} and _{Y 2,} it is preferable that at least one is an alkoxy group having 4 to 20 carbon atoms, a plurality of _{Y 1} and _{Y 2} is an alkoxy group having 4 to 20 carbon atoms More preferably. When m is 4 or more, Y ₁ and Y ₂ are preferably a hydroxy group, an alkyl group, or a halogen atom.

  p represents an integer greater than or equal to 5, Preferably it is an integer of 5-5000, More preferably, it is an integer of 5-2000, More preferably, it is an integer of 5-1000.

  Although the specific example of a compound represented by General formula (1) below is given, this invention is not limited to these.

  The compound represented by the general formula (1) can be synthesized by a known method. For example, it can be synthesized by referring to the method described in the 5th edition, Experimental Science Course (Maruzen, 2005), 26, Polymer Chemistry, pages 123-140, JP-A No. 2002-265553.

(Compound represented by the general formula (2))
In the general formula (2), _{X 1} and _{X 2} represents a carbon atom or a nitrogen atom. Y ₁ and _{Y 2} represents a substituent, n1 and n2 represent an integer of 0-4. R ₁ , R ₂ , R ₃ and R ₄ represent a hydrogen atom or a substituent. W ₁ represents a single bond or an oxygen atom. m represents an integer of 0 or more. p represents an integer of 5 or more. In the general formula (2), X ₁ and X ₂ , Y ₁ and Y ₂ , n1 and n2, R ₁ , R ₂ , R ₃ and R ₄ , W ₁ , m, and p are those in the general formula (1). Is the same.

(Organic piezoelectric material)
The organic piezoelectric material of the present invention forms an organic piezoelectric film by forming a film containing the compound represented by the general formula (1) or by subjecting the film to further polarization treatment. Can do.

  In the organic piezoelectric film, when stress is applied to the piezoelectric film, charges of opposite signs appear in proportion to both ends of the piezoelectric film, that is, a phenomenon called electric polarization occurs, and conversely, the organic piezoelectric material is transmitted through the organic piezoelectric material. It has the property (piezoelectric performance) that a distortion proportional to the occurrence of the electric field (applying an electric field) is generated. In particular, in the organic piezoelectric film made of the organic piezoelectric material of the present invention, a large piezoelectric effect is generated by polarization due to orientation freezing of the dipole moment of the polymer main chain or side chain.

  On the other hand, when energy (heat) is applied to the piezoelectric film, the magnitude of spontaneous polarization in the piezoelectric film changes accordingly. At this time, the surface charge existing on the surface of the piezoelectric film so as to neutralize the spontaneous polarization cannot respond to the energy change as quickly as the spontaneous polarization. There is a charge corresponding to the change in spontaneous polarization. The generation of electricity associated with this energy change is called pyroelectricity. In particular, in the organic piezoelectric film made of the organic piezoelectric material of the present invention, due to the freezing of the orientation of the dipole moment of the main chain or side chain of the polymer. Great pyroelectric performance occurs due to polarization.

(Method of forming organic piezoelectric film)
The organic piezoelectric film is preferably formed by coating. Examples of the coating method include spin coating, solvent casting, melt casting, melt press, roll coating, flow coating, printing, dip coating, and bar coating.

  In the present invention, it is preferable to apply or form a film in the temperature range in which the compound represented by the general formula (1) exhibits a liquid crystal phase, and the formed film may be further subjected to polarization treatment described later.

  When the compound represented by the general formula (1) is formed on the organic piezoelectric film, an arbitrary polymer compound may be further mixed to improve the film forming property. Specifically, a thermoplastic resin, thermosetting resin or photocurable resin having a number average molecular weight of 1500 or more is used as the non-liquid crystal polymer compound.

  Any thermoplastic resin having a number average molecular weight of 1500 or more, preferably 1500 to 100,000 can be used without particular limitation. If the number average molecular weight of the thermoplastic resin is less than 1500, the glass transition temperature is too low, and the mechanical stability of the organic piezoelectric film may be lowered.

  Specific examples of the thermoplastic resin suitably used in the present invention include polyvinyl chloride, polyvinyl bromide, polyvinyl fluoride, vinyl chloride-vinyl acetate copolymer, vinyl chloride-ethylene copolymer, vinyl chloride-propylene. Copolymer, vinyl chloride-vinylidene chloride copolymer, vinyl chloride-butadiene copolymer, vinyl chloride-acrylic acid ester copolymer, vinyl chloride-acrylonitrile copolymer, vinyl chloride-styrene-acrylonitrile terpolymer , Vinyl chloride-vinylidene chloride-vinyl acetate copolymer, polyvinylidene chloride, polytetrafluoroethylene, polytetrafluorochloroethylene, polyvinylidene fluoride, and other halogenated vinyl polymers or copolymers; polyvinyl alcohol, polyallyl alcohol, Polyvinyl ether, polyallyl A Polymers or copolymers of unsaturated alcohols or ethers such as ruthenium; Polymers or copolymers of unsaturated carboxylic acids such as acrylic acid or methacrylic acid; Polyvinyl esters such as polyvinyl acetate, Polyallyl such as polyphthalic acid Polymers or copolymers of unsaturated residues in alcohol residues such as esters; acid residues or acid residues such as polymers of polyacrylates, polymethacrylates, maleates or fumarates Or polymers having unsaturated bonds in the alcohol residue; polymers or copolymers of acrylonitrile or methacrylonitrile; unsaturated nitriles such as polymers or copolymers of polycyanide vinylidene, malononitrile or fumaronitrile Polymer or copolymer; polystyrene Polymers of aromatic vinyl compounds such as poly-α-methylstyrene, poly-p-methylstyrene, styrene-α-methylstyrene copolymer, styrene-p-methylstyrene copolymer, polyvinylbenzene, and polyhalogenated styrene Or copolymer; polymer or copolymer of a heterocyclic compound such as polyvinyl pyridine, poly-N-vinyl pyrrolidine, poly-N-vinyl pyrrolidone; polyester condensate such as polycarbonate, nylon 6, nylon 6, 6, etc. Polyamide condensates; polymers or copolymers containing maleic anhydride, fumaric anhydride and imidized products thereof; polyamideimide, polyetherimide, polyimide, polyphenylene oxide, polyphenylene sulfide, polysulfone, polyethersulfone, polyarylate, etc. Heat resistant organic Etc. The. Of these, polycarbonate, polystyrene, polyacrylate, polymethacrylate, nylon and the like are preferably used.

  As a thermosetting resin, various things including what is marketed, such as an epoxy adhesive and an acrylic adhesive, can be used. As the photocurable resin, various resins including those that are commercially available such as an adhesive that is cured by visible light, UV light, electron beam, or the like can be used. These non-liquid crystalline polymer substances may be appropriately selected from the viewpoint of the manufacturing method of the organic piezoelectric film and the required durability.

  Specific examples of the heat or photo-curable resin suitably used in the present invention include, for example, epoxy adhesives, acrylic adhesives, unsaturated polyester adhesives, polyurethane adhesives, hot melt adhesives, elastomers A mold adhesive can be mentioned.

  As an example of the epoxy adhesive, a bisphenol A type is preferable as the main agent. A main agent in which the bisphenol A portion is a bisphenol compound as shown below can also be used.

  Examples of polyurethane adhesives include methylene bis (p-phenylene diisocyanate), tolylene diisocyanate, hexamethylene diisocyanate, 1-chlorophenyl diisocyanate, 1,5-naphthylene diisocyanate, thiodipropyl diisocyanate, ethylbenzene-α as isocyanate components. -2-di-isocyanate, 4,4,4-triphenylmethane triisocyanate, etc., and the components that react with them include ethylene glycol, propylene glycol, triethylene glycol, tetraethylene glycol, glycerol, hexanetriol, xylylene Rangeol, lauric acid monoglyceride, stearic acid monoglyceride, oleic acid monoglyceride, polyethylene glycol, polyp Propylene glycol, polyesters, polyamides, and the like.

  The amount of the non-liquid crystalline polymer substance is 2 to 40% by mass, preferably 2 to 20% by mass with respect to the compound represented by the general formula (1). When the amount of the non-liquid crystalline polymer substance is less than 2% by mass, the film formability of the liquid crystal layer may be deteriorated and the mechanical strength may be insufficient. On the other hand, if it exceeds 40 mass%, unnecessary light scattering may occur, and the performance of the organic piezoelectric film may be deteriorated.

  Further, the compound represented by the general formula (1) may be used by mixing with another ferroelectric polymer. Specifically, polyvinylidene fluoride (PVDF), vinylidene fluoride / ethylene trifluoride copolymer P (VDF / TrFE), vinylidene fluoride / tetrafluoroethylene copolymer P (VDF / TeFE), cyanide To vinylidene / vinyl acetate copolymer P (VDCN / VA), vinyl fluoride / ethylene trifluoride copolymer P (VF / TrFE), and vinyl fluoride / ethylene trifluoride copolymer P (VF / TrFE) Copolymers added with vinylidene fluoride, tetrafluoride ethylene, hexafluoroacetone, hexafluoropropylene, etc. as the third component, amide polymers such as nylon 7 or nylon 11, aliphatic polyurea, aliphatic polyurethane, etc. Can be used.

(Polarization treatment)
As a polarization processing method in the polarization processing according to the present invention, various conventionally known methods can be applied. For example, in the case of the corona discharge treatment method, the corona discharge treatment can be performed using a commercially available high-voltage power source and an electrode device.

  Since the discharge conditions vary depending on the equipment and processing environment, it is preferable to select the conditions as appropriate. The applied voltage is preferably 0.5 to 2.0 MV / m.

  As the electrodes, needle-like electrodes, linear electrodes (wire electrodes), and mesh-like electrodes that have been conventionally used are preferable, but the invention is not limited thereto.

  In addition, since heating is performed during corona discharge, it is necessary to install a heater via an insulator under the electrode in contact with the substrate manufactured according to the present invention.

  In the present invention, when the corona discharge treatment is performed as the polarization treatment in the state where the solvent of the coating solution remains, it is sufficient to remove the volatile components of the solvent in order to avoid the danger of flammable explosion. It is necessary for safety to carry out with ventilation.

(substrate)
As the substrate, the selection of the substrate differs depending on the use and usage of the organic piezoelectric film according to the present invention. It may be a plastic plate or film such as polyimide, polyamide, polyimide amide, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polymethyl methacrylate (PMMA), polycarbonate resin, cycloolefin polymer, or the surface of these materials. May be covered with aluminum, gold, copper, magnesium, silicon or the like. Alternatively, a single crystal plate or film of aluminum, gold, copper, magnesium, silicon simple substance, or rare earth halide may be used.

  Further, it may be formed on a multilayer piezoelectric element. As a method of using a multilayer in which piezoelectric elements are stacked, there is a method of superposing an organic piezoelectric film according to the present invention on a ceramic piezoelectric element via an electrode. PZT is used as the ceramic piezoelectric element, but in recent years, one containing no lead has been recommended.

PZT is preferably within the range of the formula Pb (Zr _1-X Ti _X ) O ₃ (0.47 ≦ X ≦ 1). As deleading, natural or artificial quartz, lithium niobate (LiNbO ₃ ), potassium niobium tantalate [K (Ta, Nb) O ₃ ], barium titanate (BaTiO ₃ ), lithium tantalate (LiTaO ₃ ), or strontium titanate (SrTiO ₃ ). The composition of various ceramic materials can be appropriately selected in terms of use performance.

(Ultrasonic transducer)
The ultrasonic transducer according to the present invention is characterized by using an organic piezoelectric film formed using the organic piezoelectric material of the present invention. The ultrasonic transducer is preferably an ultrasonic receiving transducer used in an ultrasonic medical diagnostic imaging device probe including an ultrasonic transmitting transducer and an ultrasonic transmitting transducer. .

  In general, an ultrasonic transducer is configured by arranging a pair of electrodes with a layer (or film) (also referred to as “piezoelectric film” or “piezoelectric layer”) made of a film-like piezoelectric material interposed therebetween. Then, an ultrasonic probe is configured by, for example, one-dimensionally arranging a plurality of transducers.

  Then, a predetermined number of transducers in the major axis direction in which a plurality of transducers are arranged is set as the aperture, and the plurality of transducers belonging to the aperture are driven to focus the ultrasonic beam on the measurement site in the subject. And has a function of receiving reflected echoes of ultrasonic waves emitted from the subject by a plurality of transducers belonging to the aperture and converting them into electrical signals.

  Hereinafter, each of the ultrasonic wave receiving transducer and the ultrasonic wave transmitting transducer according to the present invention will be described in detail.

<Ultrasound receiving transducer>
An ultrasonic receiving transducer according to the present invention is a transducer used in a probe for an ultrasonic medical image diagnostic apparatus, and is formed using the organic piezoelectric material of the present invention as a piezoelectric material constituting the transducer. An organic piezoelectric film is used.

The organic piezoelectric material or the organic piezoelectric film used for the ultrasonic receiving vibrator preferably has a relative dielectric constant of 10 to 50 at the thickness resonance frequency. The relative dielectric constant is adjusted by adjusting the number, composition, degree of polymerization, etc. of the polar functional groups such as the substituent R, CF ₂ group, and CN group of the compound constituting the organic piezoelectric material, and the polarization treatment described above. Can be done by.

<Transmitter for ultrasonic transmission>
The ultrasonic transmission vibrator according to the present invention is preferably made of a piezoelectric material having an appropriate relative dielectric constant in relation to the reception vibrator. Moreover, it is preferable to use a piezoelectric material excellent in heat resistance and voltage resistance.

  Various known organic piezoelectric materials and inorganic piezoelectric materials can be used as the ultrasonic transmitting vibrator constituent material.

  As the organic piezoelectric material, a polymer material similar to the above-described organic piezoelectric material for constituting an ultrasonic receiving vibrator can be used.

As an inorganic material, quartz, lithium niobate (LiNbO ₃ ), potassium niobate tantalate [K (Ta, Nb) O ₃ ], barium titanate (BaTiO ₃ ), lithium tantalate (LiTaO ₃ ), or titanate Lead zirconate (PZT), strontium titanate (SrTiO ₃ ), barium strontium titanate (BST), or the like can be used. PZT is preferably Pb (Zr _1-n Ti _n ) O ₃ (0.47 ≦ n ≦ 1).

(electrode)
The piezoelectric (body) vibrator according to the present invention is manufactured by forming electrodes on both surfaces or one surface of a piezoelectric film (layer) and polarizing the piezoelectric film. The electrode is formed using an electrode material mainly composed of gold (Au), platinum (Pt), silver (Ag), palladium (Pd), copper (Cu), nickel (Ni), tin (Sn), or the like. .

  In forming the electrodes, first, 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 metal mainly composed of the above metal elements and those A metal material made of the above alloy, and further, if necessary, a part of insulating material is formed to a thickness of 1 to 10 μm by sputtering or other suitable methods. In addition to sputtering, these electrodes can be formed by screen printing, dipping, or thermal spraying using a conductive paste in which a fine metal powder and low-melting glass are mixed.

  Furthermore, a predetermined voltage is supplied between the electrodes formed on both surfaces of the piezoelectric film to polarize the piezoelectric film, thereby obtaining a piezoelectric element.

(Ultrasonic probe)
The ultrasonic probe of the present invention is a probe for an ultrasonic diagnostic imaging apparatus including an ultrasonic transmission transducer and an ultrasonic reception transducer, and the reception transducer according to the present invention. The ultrasonic receiving vibrator is used.

  In the present invention, both transmission and reception of ultrasonic waves may be performed by a single transducer, but more preferably, the transducer is 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 of 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 image diagnostic apparatus and biological frequency collection from a practical frequency band, the film thickness is preferably 40 to 150 μm.

  Note that 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.

(Ultrasonic medical diagnostic imaging equipment)
The above-mentioned ultrasonic probe of the present invention can be used for various types of ultrasonic diagnostic apparatuses. For example, it can be suitably used in an ultrasonic medical image diagnostic apparatus as shown in FIG.

  FIG. 1 is a conceptual diagram showing a configuration of a main part of an ultrasonic medical image diagnostic apparatus according to an embodiment of the present invention. This ultrasonic medical diagnostic imaging apparatus transmits an ultrasonic wave to a subject such as a patient and receives an ultrasonic wave reflected from the subject as an echo signal. Probe). In addition, 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 piezoelectric vibrator of the ultrasonic probe, and transmission / reception of the transmission / reception circuit A transmission / reception control circuit for performing control.

  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 that controls and displays the monitor with the ultrasonic image data converted by the image data conversion circuit, and a control circuit that controls the entire ultrasonic medical image diagnostic 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 vibrator of the ultrasonic probe to transmit an ultrasonic wave to the subject, and the reflected wave caused by acoustic impedance mismatch inside the subject is detected by the ultrasonic probe. Receive at.

  The transmission / reception circuit corresponds to “means for generating an electrical signal”, and the image data conversion circuit corresponds to “image processing means”.

  According to the ultrasonic diagnostic apparatus as described above, taking advantage of the characteristics of an ultrasonic probe that is excellent in piezoelectric characteristics and heat resistance, and suitable for high frequency and wide band, image quality and its reproduction and stability are compared with the conventional technology. An ultrasonic image with improved properties can be obtained.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated, this invention is not limited to these.

  In addition, the physical property value of the polymer obtained in the Example was measured with the following method. The average molecular weight measurement uses GPC, the obtained unsaturated monomer polymer is dissolved in DMF, and a gel perme using Waters GPC system (column: Shodex LF-804, Showa Denko KK) as a detector. Measured by association chromatography. A dimethylformamide (hereinafter referred to as DMF) containing LiBr and 0.1M was used as a solvent, and the solvent flow rate was 0.8 ml / min. A sample was prepared by dissolving about 20 mg of a polymer sample to be analyzed in 4 ml of DMF containing LiBr and 0.1 M, and 80 μl was injected into the column. The column temperature was set to 40 ° C. An RI (differential refractive index) detector was used as the detector. The molecular weight of the polymer was expressed in terms of polystyrene.

  Synthesis Example 1: Synthesis of Compound 2

  In a 300 ml flask, 9.6 g of 2-hexyloxy-1,4-diisocyanatobenzene and 50 ml of dimethylformamide were placed and cooled in an ice water bath. When the solution reached 5 ° C, 7.7 g of 2-hexyloxy-p-phenylenediamine was added and stirred at 5 ° C for 15 minutes. Furthermore, after stirring at room temperature for 3 hours, the mixture was poured into a mixed solvent of 100 ml of water and 50 ml of methanol for purification. The obtained white crystals were dried under reduced pressure to obtain 16.4 g (yield 95%) of Compound 2. The weight average molecular weight Mw by GPC measurement was 28,000, the weight average molecular weight Mw / number average molecular weight Mn = 2.8.

  Synthesis Example 2: Synthesis of Compound 27

  Into a 300 ml flask, 9.6 g of 1,4-dithioisocyanatobenzene and 80 ml of dimethylformamide were placed and cooled in an ice water bath. When the solution reached 5 ° C., 10.5 g of 5- (3-aminohexyloxy) -2-aminopyridine was added and stirred at 5 ° C. for 30 minutes. The mixture was further stirred at room temperature for 5 hours, and then poured into 100 ml of methanol for purification. The obtained white crystals were dried under reduced pressure to obtain 19.2 g of Compound 27 (yield 96%). The weight average molecular weight Mw by GPC measurement was 22,000, weight average molecular weight Mw / number average molecular weight Mn = 2.5.

  Synthesis Example 3: Synthesis of Compound 31

  Into a 300 ml flask, 9.6 g of 1,4-dithioisocyanatobenzene and 100 ml of dimethylformamide were placed and cooled in an ice water bath. When the solution reached 5 ° C., 11.8 g of 4- (8-aminooctyloxy) -1-aminobenzene was added and stirred at 5 ° C. for 30 minutes. The mixture was further stirred at room temperature for 3 hours, and then poured into 100 ml of methanol for purification. The obtained white crystals were dried under reduced pressure to obtain 20.7 g (yield 98%) of compound 31. The weight average molecular weight Mw by GPC measurement was 22,000, weight average molecular weight Mw / number average molecular weight Mn = 2.0.

  Synthesis Example 4: Synthesis of Compound 42

  A 300 ml flask was charged with 10.5 g of 2-fluoro-1,4-dithioisocyanatobenzene and 80 ml of dimethylformamide and cooled in an ice-water bath. When the solution reached 5 ° C., 15.5 g of 4- (12-aminododecyloxy) -1-amino-2-fluorobenzene was added and stirred at 5 ° C. for 30 minutes. The mixture was further stirred at room temperature for 4 hours, and then poured into 100 ml of methanol for purification. The obtained white crystals were dried under reduced pressure to obtain 25.2 g (yield 97%) of Compound 42. The weight average molecular weight Mw by GPC measurement was 21,000, weight average molecular weight Mw / number average molecular weight Mn = 2.2.

Example 1
(Production of organic piezoelectric film)
After the compound represented by the general formula (1) was dissolved in dimethylformamide, a cast film was formed on a glass plate so as to have a thickness of about 100 μm, and dried at 100 ° C. under reduced pressure for 12 hours. This film was peeled from the glass plate and then pressed to a thickness of about 40 μm to produce films corresponding to organic piezoelectric films-1 to 11. For the films corresponding to the organic piezoelectric films-12, 13, and 14, when the compound represented by the general formula (1) is dissolved in dimethylformamide, polystyrene or PVDF is dissolved together, and the film is cast as described above. It produced by the press process after film | membrane.

  A film corresponding to the organic piezoelectric films-1 to 14 is fixed on a hot plate, a tungsten needle is placed 1.5 cm away from the top of the organic piezoelectric film, and a voltage of 4.0 kV is applied thereto. Organic piezoelectric films -1 to 14 were prepared by performing a polarization treatment by corona discharge. The temperature of the organic piezoelectric film was kept at 120 ° C. during the corona discharge treatment.

  Similarly, comparative organic piezoelectric films -A to C were prepared using Comparative-A, Comparative-B, and Comparative-C shown below instead of the compound represented by the general formula (1).

(Evaluation of organic piezoelectric film)
With respect to the organic piezoelectric films -1 to 14 and the comparative organic piezoelectric films-A to C obtained above, the piezoelectric e characteristics were evaluated while being heated to room temperature and 100 ° C. by a resonance method. The results are shown in Table 1. The piezoelectric e characteristic is shown as a relative value with respect to 100% of the value measured for the comparative organic piezoelectric film-C at room temperature. As is clear from the results shown in Table 1, it can be seen that the piezoelectric e characteristics of the organic piezoelectric film formed from the compound according to the present invention are superior to those of the comparative example and the orientation of the polarization group is high.

Example 2
Fabrication and evaluation of ultrasonic probe (fabrication of transmission pressure transducer)
Component raw materials CaCO ₃ , La ₂ O ₃ , Bi ₂ O ₃ and TiO ₂ , and subcomponent raw materials MnO are prepared, and for the component raw materials, the final composition of the components is (Ca _{0. 97} La _{0.0 3} . ) Bi ₄ . Weighed to be ₀₁ Ti ₄ O ₁₅ . Next, pure water was added, mixed for 8 hours in a ball mill containing zirconia media in pure water, and sufficiently dried to obtain a mixed powder. The obtained mixed powder was temporarily molded and calcined in air at 800 ° C. for 2 hours to prepare a calcined product. Next, pure water was added to the obtained calcined material, finely pulverized in a ball mill containing zirconia media in pure water, and dried to prepare a piezoelectric ceramic raw material powder. In the fine pulverization, the piezoelectric ceramic raw material powder having a particle diameter of 100 nm was obtained by changing the pulverization time and the pulverization conditions. 6% by mass of pure water as a binder is added to each piezoelectric ceramic raw material powder having a different particle diameter, press-molded to form a plate-shaped temporary molded body having a thickness of 100 μm, and this plate-shaped temporary molded body is vacuum-packed and then 235 MPa. It shape | molded by the press with the pressure of. Next, the molded body was fired. The final sintered body had a thickness of 20 μm. The firing temperature was 1100 ° C. An electric field of 1.5 × Ec (MV / m) or more was applied for 1 minute to perform polarization treatment.

(Manufacture of receiving vibrator)
After an aluminum electrode was attached to the surface of the organic piezoelectric film-7 produced in Example 1 by vapor deposition, an electric field of 100 MV / m was used using a high voltage power supply device HARB-20R60 (manufactured by Matsusada Precision Co., Ltd.). The temperature was raised to 200 ° C. at a rate of 5 ° C./min while being applied, and held at 200 ° C. for 15 minutes, and then slowly cooled to room temperature while applying a voltage to perform poling treatment. A laminated receiving vibrator was prepared by laminating an organic piezoelectric film-7 subjected to polarization treatment and a polyester film having a thickness of 50 μm with an epoxy adhesive.

(Production of ultrasonic probe)
Next, in accordance with an ordinary method, a receiving transducer was laminated on the above-described transmitting transducer, and a backing layer and an acoustic matching layer were installed to produce an ultrasonic probe. As a comparative example, a probe similar to the above-described ultrasonic probe was manufactured using the comparative organic piezoelectric film-A instead of the receiving transducer.

(Evaluation of ultrasonic probe)
Next, the above two types of ultrasonic probes were evaluated by measuring the reception sensitivity and the dielectric breakdown strength.

Incidentally, the reception sensitivity is originating the fundamental frequency _{f 1} of 5 MHz, to determine the received relative sensitivity of 20MHz as 15 MHz, 4 harmonics as received second harmonic wave _{f 2} as 10 MHz, 3 harmonic. For the relative sensitivity of reception, a sound intensity measurement system Model 805 (1 to 50 MHz) manufactured by Sonora Medical System, Inc. (2021 Miller Drive Longmont, Colorado (0501 USA)) was used.

  For the measurement of the dielectric breakdown strength, the load power P was multiplied by 5 and the test was performed for 10 hours, and then the load power was returned to the reference to evaluate the relative reception sensitivity. The sensitivity was evaluated as good when the decrease in sensitivity was within 1% before the load test, more than 1% and less than 10%, and 10% or more as bad.

  In the above evaluation, the ultrasonic probe including the receiving pressure transducer according to the present invention has a relative reception sensitivity that is about 1.3 times that of the comparative example, and has a good dielectric breakdown strength. I confirmed that there was. That is, it was confirmed that the ultrasonic probe according to the present invention can be suitably used for the probe used in the ultrasonic medical image diagnostic apparatus as shown in FIG.

It is a conceptual diagram which shows the structure of the principal part of the ultrasonic medical image diagnostic apparatus of embodiment of this invention.

Explanation of symbols

1 Receiving vibrator (membrane)
2 Support 3 Transmitter vibrator (membrane)
4 Backing layer 5 Electrode 6 Acoustic lens

Claims (6)

An organic piezoelectric material comprising a compound represented by the following general formula (1):

(Wherein, _{X 1} and _{X 2} .Y ₁ and _{Y 2} represents a carbon atom or a nitrogen atom represents a hydrogen atom or a substituent, _{.R 1, R} 2 are n1 and n2 represents an integer of 0 to 4, R ₃ and R ₄ represent a hydrogen atom or a substituent, Q ₁ and Q ₂ represent an oxygen atom or a sulfur atom, W ₁ represents a single bond or an oxygen atom, m represents an integer of 0 or more, and p represents Represents an integer of 5 or more.) The organic piezoelectric material according to claim 1, wherein Q ₁ and Q ₂ in the general formula (1) are sulfur atoms. The organic piezoelectric material according to claim 1, wherein W ₁ in the general formula (1) is an oxygen atom, and m is 4 or more. An ultrasonic probe comprising an ultrasonic transmission transducer and an ultrasonic reception transducer, wherein the ultrasonic transducer using the organic piezoelectric material according to claim 1 is supersonic. An ultrasonic probe comprising a transducer for receiving a sound wave. A compound represented by the following general formula (2).

(Wherein, .Y ₁ and _{Y 2 X 1} and _{X 2} represents a carbon atom or a nitrogen atom represents a substituent, _.R 1 is n1 and n2 represents an integer of _{0~4, R 2,} R ₃ and R ₄ represents a hydrogen atom or a substituent, W ₁ represents a single bond or an oxygen atom, m represents an integer of 0 or more, and p represents an integer of 5 or more.) The compound according to claim 5, wherein W ₁ in the general formula (2) is an oxygen atom, and m is 4 or more.

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