JP2010165771A - Organic piezoelectric material, ultrasonic vibrator and ultrasonic probe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic piezoelectric material giving an ultrasonic vibrator and an ultrasonic probe having high piezoelectric characteristics and superior in reception sensitivity: and to provide the ultrasonic vibrator and the ultrasonic probe using the organic piezoelectric material. <P>SOLUTION: The organic piezoelectric material contains a compound represented by general formula (1): R1-A1-(L1-A1)n-R2 or a polymer having the residue of the compound represented by formula (1) in a side chain via R1 or R2. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an ultrasonic probe that transmits and receives ultrasonic waves to perform ultrasonic inspection, an ultrasonic transducer used in the ultrasonic probe, and an organic piezoelectric material.

As a piezoelectric body used for a sensor such as an ultrasonic probe, an inorganic piezoelectric body and an organic piezoelectric body are known. As an inorganic piezoelectric material using an inorganic piezoelectric material, for example, a single crystal such as quartz, 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 used. Polarized inorganic piezoelectric materials are known. These inorganic piezoelectric materials have properties such as high elastic stiffness, high mechanical loss coefficient, high density and high dielectric constant.

  As an organic piezoelectric material using an organic piezoelectric material, for example, as described in JP-A-2008-171935, a vinylidene fluoride polymer or copolymer, a vinylidene cyanide polymer or copolymer was used. Organic piezoelectric materials are known. Examples of organic piezoelectric materials other than the polyvinylidene fluoride-based organic piezoelectric material comprising a polyurea film obtained by vapor deposition polymerization described in JP-A-2006-225565 and -NHCONH- described in JP-A-2006-16352 An organic piezoelectric material using a liquid crystal substance having a partial structure such as is known. In addition, organic piezoelectric material in which inorganic piezoelectric material fine particles are dispersed and contained in a matrix of organic polymer piezoelectric material (see Patent Document 1), non-fluorinated resin such as polyester and polyurea, and fluorine-based polymer such as a polymer of vinylidene fluoride. An organic piezoelectric material containing polymer fine particles (see Patent Document 2) is known.

  Organic piezoelectric materials are relatively superior to inorganic piezoelectric materials in terms of workability such as thinning and large area, and can be made in any shape and form, with low elastic modulus and low dielectric constant. Since it has low characteristics, it has characteristics such as wide application range and high versatility when used as a sensor.

  On the other hand, in recent years, harmonic imaging that forms an image of the internal state in the subject not by the frequency (fundamental frequency) component of the ultrasound transmitted from the ultrasound probe into the subject but by its harmonic frequency component ( (Harmonic Imaging) technology is being researched and developed.

  In this harmonic imaging technique, (1) the side lobe level is smaller than the fundamental frequency component level, the S / N ratio (signal to noise ratio) is improved, and the contrast resolution is improved. Increasing the beam width narrows and the lateral resolution improves. (3) Multiple reflections are suppressed because the sound pressure is small and the fluctuation of the sound pressure is small at a short distance, and (4) It has various advantages such as the attenuation beyond the focal point is the same as that of the fundamental wave, and the depth speed can be increased as compared with the case of using the high frequency as the fundamental wave, thereby enabling highly accurate diagnosis.

  The organic piezoelectric body is suitable as a piezoelectric body used for a piezoelectric material in the above harmonic imaging technology that requires high frequency characteristics and broadband characteristics. Further, the acoustic impedance of the organic piezoelectric body as described above has a feature that it is close to that of a living body, and has an advantage that it is easy to perform acoustic matching when the subject is a living body.

  However, when the element having the organic piezoelectric material as described above functions as an ultrasonic vibrator, it is relatively excellent in broadband characteristics compared to the element having an inorganic piezoelectric material, but the reception sensitivity is still insufficient. There was a problem.

JP 2008-47693 A JP 2008-36202 A

  The present invention has been made in view of the above problems and circumstances, and the problem to be solved is an organic piezoelectric material that provides an ultrasonic transducer and an ultrasonic probe that have high piezoelectric characteristics and excellent reception sensitivity, and uses the same. It is to provide an ultrasonic transducer and an ultrasonic probe.

  The above-described problems of the present invention are solved by the following means.

  1. Containing a polymer compound and a polymer represented by the following general formula (1) or a polymer having a residue of a compound represented by the following general formula (1) in a side chain via R1 or R2. Organic piezoelectric material characterized by

General formula (1) R1-A1- (L1-A1) n-R2
(In the formula, A1 represents —NHCONH—, —NHCOO—, or —NHCO—. R1 and R2 each independently represents an aromatic group substituted with an unsubstituted aromatic group, an alkyl group, or an alkoxy group, or Represents a cycloalkyl group substituted with an alkyl group or an alkoxy group, L1 represents a divalent linking group, and n represents an integer of 0 to 100.)
2. 2. The organic piezoelectric material as described in 1 above, wherein R1 and R2 in the general formula (1) are aromatic groups having an alkoxy group as a substituent.

  3. 3. The organic piezoelectric material as described in 1 or 2 above, wherein the polymer compound is a polymer of polystyrene, polyurea, polythiourea or vinylidene fluoride or a copolymer thereof.

  4). Content of the compound represented by the said General formula (1) is 10 mass%-200 mass% with respect to the said high molecular compound, The organic of any one of said 1-3 characterized by the above-mentioned. Piezoelectric material.

  5. The organic piezoelectric material has a residue of the polymer compound and the compound represented by the general formula (1) or the compound represented by the general formula (1) in a side chain via R1 or R2. 5. The organic piezoelectric material according to any one of 1 to 4, wherein the organic piezoelectric material is produced by applying a coating solution containing a polymer on a substrate and drying the coating solution.

  6). 6. An ultrasonic transducer comprising the organic piezoelectric material according to any one of 1 to 5 and an electrode.

  7). An ultrasonic probe comprising the ultrasonic transducer described in 6 above.

  By the above means of the present invention, an organic piezoelectric material that provides an ultrasonic transducer and an ultrasonic probe having high piezoelectric characteristics and excellent reception sensitivity, and an ultrasonic transducer and an ultrasonic probe using the same can be provided.

It is a schematic cross section of an example of an ultrasonic transducer of the present invention. It is a schematic cross section of an example of an ultrasonic probe of the present invention. It is a conceptual diagram which shows the structure of the principal part of the ultrasonic image detection apparatus in which the ultrasonic probe of this invention is used.

  The present invention relates to an organic piezoelectric material, wherein a polymer compound and a compound represented by the following general formula (1) or a residue of the compound represented by the following general formula (1) are bonded via R1 or R2. It contains a polymer having in a side chain. In the present invention, an organic piezoelectric material having excellent piezoelectric characteristics can be obtained when the organic piezoelectric material contains a polymer compound and the above compound or polymer.

(Compound represented by the general formula (1))
In general formula (1), R1 and R2 each independently represents an unsubstituted aromatic group, an aromatic group substituted with an alkyl group or an alkoxy group, or a cycloalkyl group substituted with an alkyl group or an alkoxy group. .

  Examples of the aromatic group in R1 or R2 include a phenyl group, a naphthyl group, and an anthranyl group. Examples of the cycloalkyl group include a cyclohexyl group and a cyclopentyl group.

  Examples of the alkyl group that is a substituent of the aromatic group and the cycloalkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a tert-butyl group, a pentyl group, a hexyl group, an octyl group, a decyl group, and an octadecyl group. And a cyclohexyl group. Among these, an alkyl group having 5 to 20 carbon atoms is preferable, and an alkyl group having 6 to 15 carbon atoms is more preferable.

  Examples of the alkoxy group include methoxy group, ethoxy group, propyloxy group, pentyloxy group, cyclopentyloxy group, hexyloxy group, octyloxy group, decyloxy group, octadecyloxy group, cyclohexyloxy group and the like. Among these, an alkoxy group having 5 to 20 carbon atoms is preferable, and an alkoxy group having 6 to 15 carbon atoms is more preferable.

  R1 and R2 are preferably an aromatic group or a cycloalkyl group substituted with an alkoxy group, and particularly preferably an aromatic group substituted with an alkoxy group.

  A1 represents —NHCONH—, —NHCOO—, or —NHCO—, and is particularly preferably —NHCONH—.

  n represents an integer of 0 to 100. Preferably it is 0-80, More preferably, it is 0-50.

  L1 represents a divalent linking group. Examples of the divalent linking group include an alkylene group, an alkyleneoxy group, an arylene group, and an aralkylene group. Examples of the alkylene group include a methylene group, an ethylene group, an n-propylene group, and an n-butylene group. Examples of the alkyleneoxy group include an ethyleneoxy group, a propyleneoxy group, an octyleneoxy group, and a polyethyleneoxy group. Examples of the arylene group include a phenylene group, a naphthylene group, and a biphenylene group. Examples of aralkylene groups include benzylene groups and phenethylene groups. These linking groups may form a divalent linking group by a combination of a plurality of linking groups.

  L1 is preferably a linking group represented by the following general formula (2).

Formula (2) -Ar-L2-
In the general formula (2), Ar represents an arylene group, and examples of the arylene group include a phenylene group, a naphthylene group, and a biphenylene group.

  L2 represents a divalent linking group or a simple bond, and examples of the divalent linking group include the divalent linking groups exemplified in L1 of the general formula (1).

  As described above, in the present invention, preferred embodiments are the following embodiments.

  2. The organic piezoelectric material according to item 1, wherein n in the general formula (1) is 0. 2. The organic piezoelectric material according to the means 1, wherein n in the general formula (1) is 1 or more and L1 is the general formula (2).

(Polymer)
The polymer which has the residue of the compound represented by the general formula (1) according to the present invention in the side chain via R1 or R2 has a polymerizable group, and the above-mentioned generality via R1 or R2 It is obtained by polymerizing a compound having a residue of the compound represented by the formula (1). As a compound having a polymerizable group and used for preparing a compound having a polymerizable group and having a residue of the compound represented by the general formula (1) through R1 or R2, an acrylic acid derivative is used. , Methacrylic acid derivatives, cinnamic acid derivatives, compounds having double bonds such as allyl groups and vinyl groups.

  These compounds are bonded to the residue of the compound represented by the general formula (1) via R1 or R2, and the bonded compound is used with light, a polymerization initiator, a catalyst, an acid, a base, or the like. By polymerizing by this, the polymer according to the present invention is obtained. As the compound having a polymerizable group, a compound having an acryloyl group, a methacryloyl group or an allyl group is preferable, and an acrylic acid derivative or a methacrylic acid derivative having an acryloyl group or a methacryloyl group is preferable.

  Examples of the polymerization catalyst include benzoin compounds such as benzoin, benzoin methyl ether, benzoin ethyl ether, and benzoin isopropyl ether, carbonyl compounds such as benzyl, benzophenone, acetophenone, and Michler's ketone, azobisisobutyronitrile, azodibenzoyl, and the like. Azo compounds, peroxides such as benzoyl peroxide, mixtures of α-diketones and tertiary amines, or polymerization by irradiation may be performed.

  The polymerization temperature may be any temperature as long as it is a polymerization temperature, but is preferably −50 to 250 ° C., and more preferably −50 to 200 ° C. Polymerization may be performed by solution polymerization, vapor deposition polymerization or solvent-free polymerization, but solution polymerization or polymerization without solvent is preferred. The solvent used for the polymerization is preferably a solvent in which the reaction substrate and the target compound are well dissolved. Aliphatic hydrocarbons such as cyclohexane, pentane and hexane, aromatic hydrocarbons such as benzene, toluene and chlorobenzene, THF (tetrahydrofuran) May be a solvent such as ethers such as diethyl ether and ethylene glycol diethyl ether, ketones such as acetone, methyl ethyl ketone and 4-methyl-2-pentanone, and esters such as methyl propionate, ethyl acetate and butyl acetate. These may be used in combination.

  The polymer obtained as described above may be isolated and purified, or may be applied using the reaction solution as it is to form a film. A method of isolation and purification by reprecipitation is preferred. For reprecipitation purification, any means may be used, but a method in which the reaction solution is dropped into a poor solvent to precipitate or a method in which a poor solvent is added to the reaction solution to precipitate is preferable. As used herein, the poor solvent may be any solvent as long as the polymer of the compound represented by the general formula (1) is not dissolved therein, but may be an aliphatic hydrocarbon such as cyclohexane, pentane, hexane or the like, benzene Aromatic hydrocarbons such as toluene and chlorobenzene, ethers such as diethyl ether and ethylene glycol diethyl ether, esters such as methyl propionate, ethyl acetate and butyl acetate, and alcohols such as methanol, ethanol and propanol Can do.

  The molecular weight (mass average molecular weight) of the polymer is preferably from 5,000 to 100,000, particularly preferably from 40,000 to 100,000. The mass average molecular weight of the polymer is a value calculated by gel permeation chromatography (GPC) in the following manner.

  The measurement conditions are as follows.

Solvent: 30 mM LiBr in N-methylpyrrolidone Device: HLC-8220GPC (manufactured by Tosoh Corporation)
Column: TSKgel SuperAWM-H x 2 (manufactured by Tosoh Corporation)
Column temperature: 40 ° C
Sample concentration: 1.0 g / L
Injection volume: 40 μl
Flow rate: 0.5 ml / min
Calibration curve: Standard polystyrene: PS-1 (manufactured by Polymer Laboratories) Mw = 580 to 2,560,000 calibration curves with 9 samples are used.

  The compound represented by the general formula (1) can be synthesized by a known method.

  For example, Japanese Patent Laid-Open No. 2006-16352, Chemische Berichte, 34, 1901, 1945, J. Am. Chem. Soc, 125, 1924, 1704; Chem. Soc, 1927, 440, Chem. Eur. J. et al. 1999, 5, no. 3, 1070-1083, J. MoI. Am. Chem. Soc. It can be synthesized with reference to the method described in 2005, 127, 2565-2571, etc.

  The polymerizable compound used for the preparation of a polymer having a compound represented by the general formula (1) or a residue of the compound represented by the following general formula (1) in the side chain through R1 or R2 below. Although the specific example is given, this invention is not limited to this.

1-78: 1-51 polymer (mass average molecular weight 55000, molecular weight distribution 1.6)
1-79: 1-55 polymer (mass average molecular weight 57000, molecular weight distribution 1.6)
1-80: 1-62 polymer (mass average molecular weight 57000, molecular weight distribution 1.6)
(Polymer compound)
The polymer compound is not particularly limited. For example, polyvinyl chloride, polyethylene, chlorinated polyethylene, polypropylene, ethylene-vinyl acetate copolymer, polymethyl methacrylate, polyvinylidene fluoride, polyisoprene, polystyrene, styrene-butadiene. -Acrylonitrile copolymer, styrene-acrylonitrile copolymer, acrylic rubber, acrylonitrile-butadiene rubber, styrene-butadiene rubber, butadiene rubber, natural rubber, isoprene rubber, chloroprene rubber, polyvinyl alcohol, polyvinyl butyral, polyurethane, polyurea, polythiourea Etc.

  Among these, in particular, polystyrene, polyurethane, polyurea, polythiourea, polyvinylidene fluoride, or a copolymer thereof is preferably used in terms of piezoelectric properties. The mass average molecular weight of the polymer material is preferably 10,000 to 1,000,000, more preferably 10,000 to 500,000, and particularly preferably 100,000 to 300,000.

(Organic piezoelectric material)
The organic piezoelectric material of the present invention includes a polymer compound and a compound represented by the general formula (1) or a residue of the compound represented by the general formula (1) in a side chain via R1 or R2. An organic piezoelectric film containing a polymer having the same.

  The organic piezoelectric film is subjected to polarization treatment and used for an ultrasonic transducer.

  The organic piezoelectric material may be subjected to stretching treatment and annealing treatment, and these treatments may be performed in combination.

  The content of the polymer having the compound represented by the general formula (1) or the residue of the compound represented by the general formula (1) in the side chain through R1 or R2 is 10 mass%-200 mass% is preferable, More preferably, it is 50 mass%-200 mass%.

  In the case of the above polymer, the polymer material may be mixed with the precursor before polymerization with the polymer compound and then polymerized, or the polymer may be mixed with the polymer material. good. As a method of polymerizing after mixing, the above-described polymerization method can be used.

(Method of forming organic piezoelectric film)
The formation of the organic piezoelectric film has a polymer compound and the compound represented by the general formula (1) or the residue of the compound represented by the general formula (1) in the side chain via R1 or R2. A method of applying a coating solution containing a polymer on a substrate and drying it is preferably used. Examples of the coating method include spin coating, solvent casting, melt casting, roll coating, flow coating, printing, dip coating, and bar coating. Further, a method of using a coating solution, forming a film, drying, and then molding by hot pressing may be applied in combination.

  Cooling of the film after film formation may be performed by cooling the film at room temperature or quenching, but is preferably rapid cooling. Any method may be used for the rapid cooling method, and cooling may be performed by immersing a molded film in ice water or liquid nitrogen.

  As the substrate, a plastic plate such as a glass plate, polyimide, polyamide, polyimide amide, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polymethyl methacrylate (PMMA), polycarbonate resin, or cycloolefin polymer may be used. it can.

  Examples of the solvent used in the coating solution include methylene chloride, dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, and methyl ethyl ketone. As drying temperature, it can carry out at the temperature below the glass transition temperature of a high molecular compound, for example, 20 to 100 degreeC, and also you may dry under reduced pressure.

  In the present invention, a method of subjecting the formed film to the polarization treatment described later is preferable. The reason why the organic piezoelectric material of the present invention is excellent in piezoelectric characteristics is not clear, but in the polymer compound, the NHCO portion of the compound having the specific structure of the present invention is particularly easily oriented in a certain direction. Therefore, when used as a film-like organic piezoelectric material, the orientation of the NHCO portion in a certain direction is maintained in the film, and therefore it is presumed that high piezoelectric characteristics are exhibited.

(Polarization treatment)
As a method of polarization treatment, a conventionally known DC voltage application treatment, AC voltage application treatment, or corona discharge treatment method can be applied. For example, in the case of the corona discharge treatment method, the corona discharge treatment can be performed by using a commercially available device comprising a high voltage power source and electrodes.

  Since the discharge conditions vary depending on the equipment and processing environment, the conditions may be selected as appropriate. The voltage of the high voltage power source is −1 to −20 kV, the current is 1 to 80 mA, the interelectrode distance is 1 to 10 cm, The applied voltage is preferably 0.5 to 2.0 MV / m.

  Conventionally used needle electrodes, linear electrodes (wire electrodes), and mesh electrodes can be used as the electrodes used for the polarization treatment. The polarization treatment may be performed before attaching the electrode described below that the ultrasonic transducer has, or after attaching the electrode, the polarization treatment may be performed using the electrode.

  Various known methods can be employed as the stretching treatment. In the stretching treatment, the organic piezoelectric film having a predetermined shape can be stretched uniaxially or biaxially to the extent that the organic piezoelectric film is not broken. The draw ratio can be 2 to 10 times, preferably 2 to 6 times. For example, a solution obtained by dissolving the compound of the present invention in a solvent is cast on a substrate such as a glass plate, and the solvent is dried at room temperature to obtain a film having a desired thickness. The method of extending | stretching to the length of a magnification is mentioned.

  The annealing treatment is a heat treatment, and examples thereof include a method of heating at 100 ° C. to 200 ° C. As the annealing treatment, it is preferable to heat-treat the film-like organic piezoelectric body, and the film of the organic piezoelectric body may be heated together with the base material supporting the film, or only the film (film-like) is heated in the atmosphere. You may heat with.

  Examples of the heating time include a method of heating at the above temperature for 1 minute to 60 minutes.

(Ultrasonic transducer)
The ultrasonic vibrator of the present invention is obtained by attaching an electrode to the organic piezoelectric material of the present invention, but an embodiment having an organic piezoelectric material between a pair of opposed electrodes is preferable. When the organic piezoelectric material of the present invention is used in an ultrasonic vibrator, it is preferably used after being polarized in the state of the formed film.

(electrode)
Materials used for the electrodes attached to the ultrasonic transducer include gold (Au), platinum (Pt), silver (Ag), palladium (Pd), copper (Cu), aluminum (Al), nickel (Ni) And tin (Sn).

  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 composed of a metal to be used and an alloy thereof, and further forming a part of an 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.

  Furthermore, a predetermined voltage can be supplied between the electrodes formed on both surfaces of the piezoelectric material film to polarize the piezoelectric material film.

  The ultrasonic transducer is preferably used with a substrate when used in an ultrasonic probe.

  The substrate 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, The surface of these materials may be covered with aluminum, gold, copper, magnesium, silicon or the like.

  A single crystal plate or film of aluminum, gold, copper, magnesium, silicon simple substance, or rare earth halide may also be used.

  The ultrasonic transducer according to the present invention is used as an ultrasonic transducer for reception or as an ultrasonic transducer for transmission when used in an ultrasonic probe, and particularly used as an ultrasonic transducer for reception. Is a preferred embodiment.

  The ultrasonic transducer according to the present invention will be described with reference to FIG.

  In the ultrasonic vibrator 10, electrodes 2 are arranged on both sides of the piezoelectric material 1.

  The electrode 2 may be disposed over the entire surface of the piezoelectric material 1 as necessary, or may be disposed on a part of the organic piezoelectric material 1.

(Ultrasonic probe)
The ultrasonic probe of the present invention comprises the ultrasonic transducer of the present invention. The ultrasonic probe preferably includes a transmission ultrasonic transducer and a reception ultrasonic transducer as the ultrasonic transducer.

  The ultrasonic probe of the present invention requires at least one of the ultrasonic transducer for transmission and the ultrasonic transducer for reception to be the ultrasonic transducer of the present invention. The child is preferably the ultrasonic transducer of the present invention.

  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 ultrasonic probe. preferable.

  When an ultrasonic transducer other than the ultrasonic transducer of the present invention is used, it may be a conventionally known ceramic inorganic piezoelectric material or an organic piezoelectric material.

  The arrangement of the transducer for transmission and the transducer for reception may be either an arrangement in which the transducers are arranged vertically or an arrangement in which the transducers are arranged in parallel. The thickness of the transmitting vibrator and the receiving vibrator when stacked is preferably 40 to 150 μm.

  The ultrasonic probe of the present invention preferably includes a backing layer, an acoustic matching layer, an acoustic lens, and the like as necessary. FIG. 2 shows an example of a preferred embodiment of the ultrasonic probe of the present invention.

  The ultrasonic probe 20 has a transmission ultrasonic transducer 12 in which an electrode 2 is attached to a transmission piezoelectric material 5 on a backing layer 6, and has a substrate 7 on the transmission ultrasonic transducer 12. The receiving ultrasonic transducer 13 having the electrode 2 attached to the receiving organic piezoelectric material 11 is provided on the substrate 7, and the acoustic matching layer 8 and the acoustic lens 9 are further provided thereon.

  The ultrasonic probe of the present invention can be used in various types of ultrasonic diagnostic apparatuses. For example, it can be suitably used in an ultrasonic image detection apparatus as shown in FIG. FIG. 3 is a conceptual diagram showing a configuration of a main part of the ultrasonic image detection apparatus.

  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 electric signal is applied to each ultrasonic transducer of the ultrasonic probe to transmit an ultrasonic wave to the subject, and the reflected wave generated by the mismatch of acoustic impedance inside the subject is detected by the ultrasonic probe. Receive at.

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

Example 1
(Production of organic piezoelectric material 1 and ultrasonic transducer 1)
Polystyrene (Aldrich, mass average molecular weight 45,000) was dissolved in methylene chloride, and 50% by mass of Exemplified Compound 1-1 with respect to polystyrene was dissolved in methylene chloride and mixed with the polystyrene solution. It apply | coated on the base material so that the film thickness after drying might be set to 50 micrometers, it dried, and the film | membrane containing exemplary compound 1-1 and polystyrene was obtained. The obtained film was hot pressed under conditions of 130 ° C. and 5 MPa, and then rapidly cooled with ice water to produce a film having a thickness of 40 μm.

  Next, after attaching an aluminum electrode to the surface of the produced film by vapor deposition, a high voltage power supply device HARB-20R60 (manufactured by Matsusada Precision Co., Ltd.) was used and an electric field of 100 MV / m was applied at 120 ° C. The organic piezoelectric material 1 is an organic piezoelectric film 1 that is an organic piezoelectric film that has been subjected to polarization treatment after being held at 120 ° C. for 15 minutes and then slowly cooled to room temperature while being applied with a voltage. A sound wave vibrator 1 was produced.

(Production of organic piezoelectric material 2 and ultrasonic transducer 2)
Polystyrene (Aldrich, mass average molecular weight 280,000) was dissolved in methylene chloride, and 70% by mass of Exemplified Compound 1-1 with respect to polystyrene was dissolved in methylene chloride and mixed with the polystyrene solution.

  It apply | coated so that the film thickness after drying might be set to 50 micrometers, it dried, and the film | membrane containing exemplary compound 1-1 and polystyrene was obtained. The obtained film was hot pressed under conditions of 130 ° C. and 5 MPa, and then rapidly cooled with ice water to produce a film having a thickness of 40 μm.

  Next, after attaching an aluminum electrode to the surface of the produced film by vapor deposition, a high voltage power supply device HARB-20R60 (manufactured by Matsusada Precision Co., Ltd.) was used and an electric field of 100 MV / m was applied at 120 ° C. The organic piezoelectric material 2 is an organic piezoelectric material 2 that is an organic piezoelectric film that has been subjected to polarization treatment after being held at 120 ° C. for 15 minutes and then slowly cooled to room temperature while being applied with a voltage. A sound wave vibrator 2 was produced.

(Production of organic piezoelectric material 3 and ultrasonic transducer 3)
Polyurea-1 (having the following repeating units) is dissolved in 1,1,1,3,3,3-hexafluoroisopropanol (hereinafter referred to as HFIP), and 50% by mass of Exemplified Compound 1 with respect to polyurea-1 -1 was dissolved in methylene chloride and mixed with a solution containing polyurea-1.

  It apply | coated so that the film thickness after drying might be set to 50 micrometers, it dried, and the film | membrane containing exemplary compound 1-1 and polyurea-1 was obtained.

  The obtained film was hot pressed under the conditions of 120 ° C. and 5 MPa, and the pressed film was quenched with ice water to produce a film having a thickness of 40 μm.

  Next, after attaching an aluminum electrode to the surface of the produced film by vapor deposition, a high voltage power supply device HARB-20R60 (manufactured by Matsusada Precision Co., Ltd.) was used and an electric field of 100 MV / m was applied at 120 ° C. The organic piezoelectric material 3 is an organic piezoelectric material film 3 that is an organic piezoelectric film that has been subjected to polarization treatment by gradually cooling to room temperature while keeping the voltage applied for 15 minutes. A sound wave vibrator 3 was produced.

(Production of organic piezoelectric materials 4, 5, 6, 7 and ultrasonic transducers 4, 5, 6, 7)
Polythiourea-1 (having the following repeating units) is dissolved in DMF, 100% by mass of Exemplified Compound 1-1 is dissolved in methylene chloride with respect to polythiourea-1, and mixed with a solution containing polyurea-1. did. It apply | coated so that the film thickness after drying might be set to 40 micrometers, and it dried, and obtained the film | membrane containing exemplary compound 1-1 and polythiourea-1.

  Next, after attaching an aluminum electrode to the surface of the produced film by vapor deposition, a high voltage power supply device HARB-20R60 (manufactured by Matsusada Precision Co., Ltd.) was used and an electric field of 100 MV / m was applied at 120 ° C. The organic piezoelectric material 4 is an organic piezoelectric material 4 that is an organic piezoelectric film that has been subjected to polarization treatment by gradually cooling to room temperature while keeping the voltage applied for 15 minutes. A sound wave oscillator 4 was produced.

  Next, using the exemplified compounds 1-3 and 1-14 and the exemplified compound 1-42 instead of the exemplified compound 1-1 and performing the same operation in the amounts shown in Table 1, organic piezoelectric materials 5 and 6 7, Ultrasonic vibrators 5, 6, 7 were produced.

(Production of organic piezoelectric material 8 and ultrasonic vibrator 8)
A copolymer of vinylidene fluoride and ethylene trifluoride (copolymer ratio = 65: 35, hereinafter referred to as PVDF-TrFE) is dissolved in MEK, and 30% by mass of Exemplified Compound 1- 1% with respect to PVDF-TrFE 1 was dissolved in methylene chloride and mixed with a solution of PVDF-TrFE. It apply | coated so that the film thickness after drying might be set to 40 micrometers, and it dried, and obtained the film | membrane containing exemplary compound 1-1 and PVDF-TrFE.

  Next, the obtained film is stretched 4 times uniaxially, an aluminum electrode is attached to the stretched film surface by vapor deposition, polarization is performed in the same manner as the organic piezoelectric material 4, and an organic piezoelectric film that is an organic piezoelectric film is obtained. An ultrasonic vibrator 8 having the material 8 was produced.

(Production of organic piezoelectric material 9 and ultrasonic vibrator 9)
Exemplified compound 1-51, 2.0 g, was dissolved in 20 ml of degassed toluene, and 0.02 g of α, α'-azobisisobutyronitrile (hereinafter referred to as AIBN) was added under a nitrogen atmosphere.

  After stirring the reaction solution at 60 ° C. for 12 hours, the reaction solution was concentrated, dissolved in methylene chloride, and purified by reprecipitation with methanol. The obtained residue was dried under reduced pressure at 60 ° C. to obtain a polymer of Exemplified Compound 1-51 (Exemplified Compound 1-78). The polymer obtained at this time had a mass average molecular weight of 55,000 and a molecular weight distribution of 1.5. Using the obtained exemplary compound 1-78 and polyurea-1, the same operation as that of the organic piezoelectric material 3 described above was performed to produce an organic piezoelectric material 9.

(Production of organic piezoelectric materials 10 and 11 and ultrasonic transducers 10 and 11)
Exemplified Compound 1-55 (1.8 g) was dissolved in 20 ml of degassed toluene, and AIBN (0.02 g) was added under a nitrogen atmosphere. After stirring the reaction solution at 60 ° C. for 12 hours, the reaction solution was concentrated, dissolved in methylene chloride, and purified by reprecipitation with methanol. The obtained residue was dried under reduced pressure at 60 ° C. to obtain a polymer of Exemplified Compound 1-55 (Exemplified Compound 1-79). The polymer obtained at this time had a mass average molecular weight of 57,000 and a molecular weight distribution of 1.6.

  By using the obtained exemplary compound 1-79 and polythiourea-1, the same operation as that of the organic piezoelectric material 4 described above was performed, so that the organic piezoelectric material 10 and the ultrasonic vibrator 10 were produced.

  Next, instead of Example Compound 1-55, Example Compound 1-62 was used, and a polymer was obtained by the same operation. The polymer of Example Compound 1-62 had a mass average molecular weight of 57,000 and a molecular weight distribution of 1.6. An organic piezoelectric material 11 and an ultrasonic vibrator 11 were produced by performing the same operation as the organic piezoelectric material 4 on the obtained polymer using polythiourea-1.

(Production of organic piezoelectric materials 12 to 22 and ultrasonic transducers 12 to 22)
In the production of the organic piezoelectric material 4, the exemplified compounds to be used and the contents thereof are described in Table 1, and the others are the same as the organic piezoelectric material 4, and the organic piezoelectric materials 12 to 22 and the ultrasonic vibrators 12 to 22 are formed. Produced.

(Production of organic piezoelectric material comparison 1 and ultrasonic transducer comparison 1)
The polymer of Exemplified Compound 1-51 was dissolved in methylene chloride and applied and dried on a glass substrate so that the dry film thickness was 40 μm.

  Next, after peeling the produced film | membrane and attaching the aluminum electrode to the surface of the film | membrane by vapor deposition, the electric field of 100MV / m was applied using the high voltage power supply apparatus HARB-20R60 (made by Matsusada Precision Co., Ltd.). The organic piezoelectric film is a comparative organic piezoelectric film that is heated to 120 ° C. at a rate of 5 ° C./min, held at 120 ° C. for 15 minutes, and then slowly cooled to room temperature with the voltage applied, and subjected to polarization treatment. An ultrasonic vibrator comparison 1 having a piezoelectric material comparison 1 was produced.

(Production of organic piezoelectric material comparison 2 and ultrasonic transducer comparison 2)
The polymer of Exemplified Compound 1-62 was dissolved in methylene chloride, applied onto a glass substrate so as to have a dry film thickness of 40 μm, and dried.

  Next, after peeling the produced film | membrane and attaching the aluminum electrode to the surface of the film | membrane by vapor deposition, the electric field of 100MV / m was applied using the high voltage power supply apparatus HARB-20R60 (made by Matsusada Precision Co., Ltd.). The organic piezoelectric film is a comparative organic piezoelectric film that is heated to 120 ° C. at a rate of 5 ° C./min, held at 120 ° C. for 15 minutes, and then slowly cooled to room temperature with the voltage applied, and subjected to polarization treatment. An ultrasonic vibrator comparison 2 having a piezoelectric material comparison 2 was produced.

(Production of organic piezoelectric material comparison 3 and ultrasonic transducer comparison 3)
Polyurea-1 was dissolved in 1,1,1,3,3,3-hexafluoroisopropanol (hereinafter referred to as HFIP), applied so that the film thickness after drying was 50 μm, and dried.

  The obtained film was hot pressed under the conditions of 120 ° C. and 5 MPa, and the pressed film was quenched with ice water to produce a film having a thickness of 40 μm.

  Next, after attaching an aluminum electrode to the surface of the produced film by vapor deposition, a high voltage power supply device HARB-20R60 (manufactured by Matsusada Precision Co., Ltd.) was used and an electric field of 100 MV / m was applied at 120 ° C. Ultrasonic vibrator comparison 3 having organic piezoelectric material comparison 3 that has been subjected to polarization treatment after being gradually cooled to room temperature while being applied with a voltage after being held at 120 ° C. for 15 minutes. Produced.

(Production of organic piezoelectric material comparison 4 and ultrasonic transducer comparison 4)
In the production of the organic piezoelectric material 4, the exemplified compound used is changed to the compound (CaBi ₄ Ti ₄ O ₁₅ ) described in Example 1 of Japanese Patent Application Laid-Open No. 2008-47693, and the content is organic as described in Table 1. In the same manner as the piezoelectric material 4, an organic piezoelectric material comparison 4 and an ultrasonic vibrator comparison 4 were produced.

(Production of organic piezoelectric material comparison 5 and ultrasonic transducer comparison 5)
In the production of the organic piezoelectric material 4, the exemplified compound used is changed to the compound described in Example 1 of JP-A-2008-36202 (vinylidene fluoride-perfluoroalkyl vinyl ether), and the content is as shown in Table 1. The organic piezoelectric material comparison 5 and the ultrasonic vibrator comparison 5 were produced in the same manner as the organic piezoelectric material 4.

(Preparation of comparative organic piezoelectric material 6)
Exemplified Compound 1-1 was dissolved in methylene chloride and applied and dried on a glass substrate so that the dry film thickness was 40 μm. However, the film was very brittle and could not be peeled off, so the electrode could not be attached. It was.

(Evaluation)
For the ultrasonic vibrators 1 to 22 and comparisons 1 to 5, the piezoelectric constant e ₃₁ was measured at 25 ° C. by the resonance method, and used as an index of piezoelectric characteristics.

  For the measurement, Rheograph Solid (manufactured by Toyo Seiki Co., Ltd.) was used, and the evaluation results are shown in Table 1 as relative values when the ultrasonic transducer comparison 1 is set to 100.

  From Table 1, it can be seen that the organic piezoelectric material of the present invention is excellent in piezoelectric characteristics.

Example 2
(Preparation and evaluation of ultrasonic probe)
<Manufacture of piezoelectric material constituting the transducer for transmission>
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 _0.03 ) Weighed to be Bi _4.01 Ti ₄ O ₁₅ .

  Next, pure water was added, mixed in a ball mill containing zirconia media in pure water for 8 hours, 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 above 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.

<Production of laminated resonator for reception>
Receiving laminated vibrators 1 to 22 and comparisons 1 to 5 in which the ultrasonic vibrators 1 to 22 manufactured as described above, comparisons 1 to 5 and a polyester film having a thickness of 50 μm are bonded with an epoxy adhesive. Produced.

  Next, according to a conventional method, the receiving laminated vibrators 1 to 22 and the comparisons 1 to 5 are respectively laminated on the transmitting piezoelectric material, and a backing layer and an acoustic matching layer are installed, and ultrasonic probe is performed. Children 1 to 22 and comparisons 1 to 5 were produced.

Next, with respect to the ultrasonic probes 1 to 22 and the comparisons 1 to 5, the relative reception sensitivity is obtained as follows, and expressed as a relative value with the ultrasonic probe comparison 1 being 100, and evaluated by the following rank. It was used as an index of reception sensitivity. (○ and above are practically satisfactory levels)
◎: 130 or more ○: 120 or more and less than 130 Δ: 110 or more and less than 120 ×: less than 110 Note that the reception sensitivity is such that a fundamental frequency f _{1 of} 5 MHz is transmitted, and the received second harmonic f ₂ is 10 MHz, third harmonic. The reception sensitivity of 15 MHz as the wave and 20 MHz as the fourth harmonic was measured, and the relative sensitivity was obtained.

  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.

  From the results in Table 1, it can be seen that the ultrasonic transducer and the ultrasonic probe using the organic piezoelectric material of the present invention are excellent in receiving sensitivity.

DESCRIPTION OF SYMBOLS 1 Organic piezoelectric material 2 Electrode 5 Transmission piezoelectric material 6 Backing layer 7 Substrate 8 Acoustic matching layer 9 Acoustic lens 10 Ultrasonic transducer 11 Receiving organic piezoelectric material 12 Transmitting ultrasonic transducer 13 Receiving ultrasonic transducer 20 Super Acoustic probe

Claims (7)

Containing a polymer compound and a polymer represented by the following general formula (1) or a polymer having a residue of a compound represented by the following general formula (1) in a side chain via R1 or R2. Organic piezoelectric material characterized by
General formula (1) R1-A1- (L1-A1) n-R2
(In the formula, A1 represents —NHCONH—, —NHCOO—, or —NHCO—. R1 and R2 each independently represents an aromatic group substituted with an unsubstituted aromatic group, an alkyl group, or an alkoxy group, or Represents a cycloalkyl group substituted with an alkyl group or an alkoxy group, L1 represents a divalent linking group, and n represents an integer of 0 to 100.) 2. The organic piezoelectric material according to claim 1, wherein R1 and R2 in the general formula (1) are aromatic groups having an alkoxy group as a substituent. 3. The organic piezoelectric material according to claim 1, wherein the polymer compound is a polymer or copolymer of polystyrene, polyurea, polythiourea, or vinylidene fluoride. Content of the compound represented by the said General formula (1) is 10 mass%-200 mass% with respect to the said high molecular compound, The any one of Claims 1-3 characterized by the above-mentioned. Organic piezoelectric material. The organic piezoelectric material has a residue of the polymer compound and the compound represented by the general formula (1) or the compound represented by the general formula (1) in a side chain via R1 or R2. The organic piezoelectric material according to any one of claims 1 to 4, wherein the organic piezoelectric material is produced by applying a coating liquid containing a polymer on a base material and drying the coating liquid. An ultrasonic transducer comprising the organic piezoelectric material according to any one of claims 1 to 5 and an electrode. An ultrasonic probe comprising the ultrasonic transducer according to claim 6.

Images