WO2009128322A1

WO2009128322A1 - Sound damping member and method for producing sound damping member, ultrasonic probe, and ultrasonic diagnosis device

Info

Publication number: WO2009128322A1
Application number: PCT/JP2009/055502
Authority: WO
Inventors: 悟広瀬
Original assignee: コニカミノルタエムジー株式会社
Priority date: 2008-04-14
Filing date: 2009-03-19
Publication date: 2009-10-22
Also published as: JP5212468B2; JPWO2009128322A1

Abstract

A sound damping member (21) is equipped with a sound damper (211) made of a polymer material, and the polymer material of the sound damper (211) contains a plurality of metal fibrous conductors (212) that extend in one predetermined direction and function as a lead wire while adjusting the acoustic impedance. A method for producing the sound damping member (21) comprises a step of coating one major surface of a substrate on which a plurality of growth nucleus are formed with a resin in flowing state into which metal powder conductor is mixed, and a step of curing the resin after applying a magnetic field in the direction normal to the major surface. With such an arrangement, conductor wires are provided onto the sound damping member (21) while reducing irregularities of the sound damping material (21). Furthermore, an ultrasonic probe and an ultrasonic diagnosis device equipped with such a sound damping material (21) can be provided.

Description

Acoustic braking member, acoustic braking member manufacturing method, ultrasonic probe, and ultrasonic diagnostic apparatus

The present invention relates to an acoustic braking member used for an ultrasonic probe that transmits ultrasonic waves into a subject and a method for manufacturing the same. The present invention also relates to an ultrasonic probe using the acoustic braking member and an ultrasonic diagnostic apparatus including the ultrasonic probe.

Ultrasound generally refers to sound waves of 16000 Hz or higher, and can be examined non-destructively, harmlessly, and in real time, so that it is applied to various fields such as defect inspection and disease diagnosis. . For example, an ultrasound that scans the inside of the subject with ultrasound and images the internal state of the subject based on a reception signal generated from the reflected wave (echo) of the ultrasound coming from inside the subject. There is a diagnostic device. This ultrasonic diagnostic apparatus is smaller and less expensive for medical use than other medical imaging apparatuses, has no radiation exposure such as X-rays, is highly safe, and has a blood effect using the Doppler effect. It has various features such as the ability to display flow. For this reason, the ultrasonic diagnostic apparatus includes a circulatory system (eg, coronary artery of the heart), a digestive system (eg, gastrointestinal), an internal system (eg, liver, pancreas, and spleen), and a urinary system (eg, kidney and bladder). Widely used in obstetrics and gynecology.

In this ultrasonic diagnostic apparatus, an ultrasonic probe that transmits and receives an ultrasonic wave (ultrasonic signal) to a subject is used. This ultrasonic probe uses a piezoelectric phenomenon to generate an ultrasonic wave by mechanical vibration based on an electric signal transmitted, and to generate a reflected wave of the ultrasonic wave caused by an acoustic impedance mismatch inside the subject. A plurality of piezoelectric elements that receive and generate received electrical signals are provided, and the plurality of piezoelectric elements are, for example, two-dimensionally arranged in an array. A member called an acoustic braking member (acoustic load member, backing layer, damper layer, acoustic absorbing member) that absorbs ultrasonic waves is provided on one surface (back surface) of the plurality of piezoelectric elements. A wiring for transmitting and receiving electrical signals is connected to each of the plurality of piezoelectric elements.

For example, Patent Document 1 proposes a structure in which a hole structure is provided in an acoustic braking member to draw out wiring. However, in this acoustic braking member, when the number of elements in the plurality of piezoelectric elements is increased and the element pitch is reduced, naturally the arrangement pitch of the hole structure needs to be reduced accordingly. As a result, the aspect ratio of the hole structure becomes large and it becomes difficult to process the hole structure. This aspect ratio is the ratio of the depth and diameter (diameter or radius) in the axial direction in the hole structure, that is, the depth / diameter.

Also, for example, in Patent Document 2, a plurality of flexible printed circuit boards in which a plurality of linear wiring patterns are formed are stacked with a gap, and a resin that functions as an acoustic braking material is filled in the gap, and the resin is cured. An acoustic braking member formed by doing so has been proposed. However, in this acoustic braking member, the flexible printed circuit board exists in the acoustic braking member, the uniformity of the material in the acoustic braking member is lost, and the function of the acoustic braking member is degraded. Patent Document 2 also proposes an acoustic braking member in which a lead wire is embedded in a resin, which is formed by filling a plurality of lead wires arranged in two dimensions with a resin that functions as an acoustic braking material. Yes. However, in this acoustic braking member, uneven filling of the resin may occur, a gap is generated in the acoustic braking member, and the function of the acoustic braking member is degraded. In particular, when the size of the acoustic braking member is increased or the wiring pitch is reduced, it becomes difficult to fill the center portion with resin, and uneven filling of resin tends to occur.

Further, for example, in Patent Document 3, a predetermined number of piezoelectric vibrators are mounted at the same pitch along one end, and a plurality of signal lines are formed to draw out electrical wiring from signal electrodes provided on each piezoelectric vibrator. A two-dimensional array ultrasonic probe formed by inserting a plurality of printed circuit boards into a plurality of grooves formed in advance in a backing material at a predetermined pitch has been proposed. However, in this acoustic braking member (backing material), the printed circuit board exists in the acoustic braking member, the uniformity of the material in the acoustic braking member is lost, and the function of the acoustic braking member is degraded.

Further, for example, Patent Document 4 proposes a backing material made of a composite material including a carbon fiber fiber material in which metal powder is dispersed and arranged in one direction and a resin, and the fiber material is used as a lead wire. . However, in this acoustic braking member (backing material), while the fiber material functions as a lead wire, a metal powder, for example, a tungsten metal powder is used to adjust the acoustic impedance. For this reason, if the fiber material is increased in order to increase the wiring density, the amount of metal powder that can be mixed into the acoustic braking member (backing material) is limited, and the acoustic impedance may not be sufficiently adjusted. . Moreover, it becomes difficult to uniformly disperse the metal powder due to the presence of the fiber material, the uniformity of the material in the acoustic braking member is lost, and the function of the acoustic braking member is degraded.
US Pat. No. 5,267,221 JP 2000-166923 A JP 2001-309493 A JP 2007-134767 A

The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide an acoustic braking member having a conductor wire in the acoustic braking body while reducing unevenness in characteristics of the acoustic braking body, a method for manufacturing the acoustic braking member, and the acoustic To provide an ultrasonic probe and an ultrasonic diagnostic apparatus provided with a braking member.

The acoustic braking member according to the present invention includes an acoustic braking body made of a polymer material, and in the polymeric material of the acoustic braking body, the acoustic impedance is adjusted and a predetermined one direction that functions as a lead wire is provided. A plurality of metallic fibrous conductors extending in the direction. The acoustic braking member manufacturing method according to the present invention includes applying a fluid resin in which a metal powder conductor is mixed on the main surface of the substrate having a plurality of growth nuclei on one main surface. The resin of the fluid body is cured after applying a magnetic field in the normal direction of the main surface. According to this configuration, the conductor wire is provided in the acoustic braking body while the unevenness of characteristics in the acoustic braking body is reduced.

Further, the ultrasonic probe and the ultrasonic diagnostic apparatus according to the present invention include such an acoustic braking member. According to this configuration, there is provided an ultrasonic probe and an ultrasonic diagnostic apparatus that include an acoustic braking member including a conductor wire in the acoustic braking body while reducing unevenness in characteristics of the acoustic braking body.

The above and other objects, features and advantages of the present invention will become apparent from the following detailed description and the accompanying drawings.

It is a figure which shows the external appearance structure of the ultrasonic diagnosing device in embodiment of this invention. FIG. 2 is a block diagram showing an electrical configuration of the ultrasonic diagnostic apparatus shown in FIG. 1. It is a figure which shows the structure of the ultrasound probe in the ultrasound diagnosing device shown in FIG. FIG. 4 is a perspective view showing a configuration of an acoustic braking member in the ultrasonic probe shown in FIG. 3. It is a figure for demonstrating the manufacturing method of the acoustic braking member shown in FIG.

Hereinafter, an embodiment according to the present invention will be described with reference to the drawings. In addition, the structure which attached | subjected the same code | symbol in each figure shows that it is the same structure, The description is abbreviate | omitted. Further, in this specification, a reference symbol without a suffix is used when referring generically, and a reference symbol with a suffix is used when referring to an individual configuration.

FIG. 1 is a diagram illustrating an external configuration of an ultrasonic diagnostic apparatus according to an embodiment. FIG. 2 is a block diagram illustrating an electrical configuration of the ultrasonic diagnostic apparatus according to the embodiment. FIG. 3 is a diagram illustrating a configuration of an ultrasound probe in the ultrasound diagnostic apparatus according to the embodiment.

As shown in FIGS. 1 and 2, the ultrasonic diagnostic apparatus S transmits an ultrasonic wave (first ultrasonic signal) to a subject such as a living body (not shown) and reflects the ultrasonic wave reflected by the subject. The ultrasonic probe 2 that receives the reflected wave (echo, second ultrasonic signal) is connected to the ultrasonic probe 2 via the cable 3 and connected to the ultrasonic probe 2 via the cable 3. By transmitting an electrical signal transmission signal (transmission electrical signal), the ultrasound probe 2 transmits the first ultrasound signal to the subject, and the inside of the subject received by the ultrasound probe 2 An ultrasonic image that images the internal state of the subject as an ultrasound image based on a received signal (received electrical signal) of an electrical signal generated by the ultrasound probe 2 according to the second ultrasound signal coming from The diagnostic apparatus main body 1 is provided.

The ultrasonic diagnostic apparatus body 1 exchanges signals with the ultrasonic probe 2 as described above. For example, as shown in FIG. 2, an operation input unit 11, a transmission unit 12, and a reception unit are provided. 13, an image processing unit 14, a display unit 15, and a control unit 16.

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

The transmission unit 12 is a circuit that supplies a transmission signal of an electrical signal to the ultrasonic probe 2 via the cable 3 under the control of the control unit 16 and causes the ultrasonic probe 2 to generate a first ultrasonic signal. is there. The transmission unit 12 includes, for example, a high voltage pulse generator that generates a high voltage pulse. The receiving unit 13 is a circuit that receives a reception signal of an electrical signal from the ultrasound probe 2 via the cable 3 under the control of the control unit 16, and outputs the reception signal to the image processing unit 14. For example, the receiver 13 amplifies the received signal with a predetermined amplification factor set in advance to compensate for transmission loss (transmission loss) of the cable 3, and the received signal amplified by the amplifier is an analog signal. An analog-digital converter for converting from a digital signal to a digital signal is provided.

The image processing unit 14 is a circuit that generates an image (ultrasonic image) representing the internal state in the subject based on the received signal received by the receiving unit 13 under the control of the control unit 16.

The image processing unit 14 receives an ultrasonic signal having a frequency band substantially the same as the frequency band of the first ultrasonic signal as a second ultrasonic signal, and receives the received ultrasonic wave at the receiving unit 13. Based on the received reception signal, the image processing unit 14 Although it may be configured to generate an ultrasonic image, from the viewpoint of obtaining a higher-accuracy ultrasonic image, the image processing unit 14 receives a reception signal received by the receiving unit 13 using a harmonic imaging technique. The ultrasonic image of the subject may be generated based on the above.

The harmonic imaging technology is roughly classified into two methods, a filter method and a phase inversion method (pulse inversion method), as disclosed in, for example, Japanese Patent Application Laid-Open No. 2001-286472. There is a way. This filter method is a method in which a fundamental wave component and a harmonic component are separated by a harmonic detection filter, only the harmonic component is extracted, and an ultrasonic image is generated from the harmonic component. Further, this phase inversion method transmits first and second transmission signals whose phases are successively inverted in the same direction, and first and second reception signals corresponding to the first and second transmission signals are transmitted. In this method, a harmonic component is extracted by addition and an ultrasonic image is generated from the harmonic component. Although the fundamental wave components in the first and second received signals are inverted in phase, the second harmonic component of the harmonic, for example, is in phase, so by adding the first and second received signals This second harmonic component is extracted.

In the image processing unit 14, for example, a harmonic component is extracted from the received signal by a filter method, and an ultrasonic image of the subject is generated using a harmonic imaging technique based on the extracted harmonic component. Further, for example, the image processing unit 14 extracts a harmonic component from the received signal by the phase inversion method, and generates an ultrasonic image of the subject based on the extracted harmonic component using a harmonic imaging technique.

The display unit 15 is a device that displays an ultrasonic image of the subject generated by the image processing unit 14 under the control of the control unit 16. The display unit 15 is, for example, a display device such as a CRT display, LCD (liquid crystal display), organic EL display, or plasma display, or a printing device such as a printer.

The control unit 16 includes, for example, a microprocessor, a storage element, and peripheral circuits thereof, and the ultrasonic probe 2, the operation input unit 11, the transmission unit 12, the reception unit 13, the image processing unit 14, and a display. It is a circuit that performs overall control of the ultrasound diagnostic apparatus S by controlling the unit 15 according to the function.

The ultrasonic probe (ultrasonic probe) 2 is a device that transmits a first ultrasonic signal into a subject and receives a second ultrasonic signal coming from within the subject based on the first ultrasonic signal. . For example, as shown in FIG. 3A, the ultrasonic probe 2 includes a flat acoustic braking member 21, a piezoelectric portion 22 laminated on one main surface of the acoustic braking member 21, and the piezoelectric The acoustic matching layer 23 is laminated on the portion 22, and the acoustic lens 24 is laminated on the acoustic matching layer 23.

The acoustic braking member 21 is made of a material that absorbs ultrasonic waves (ultrasonic absorbing material), and absorbs ultrasonic waves radiated from the piezoelectric portion 22 toward the acoustic braking member 21. The acoustic braking member 21 preferably has a sufficient thickness with respect to the wavelength of the ultrasonic wave to be used in order to keep the acoustic characteristics of the piezoelectric portion 22 good by sufficiently attenuating the ultrasonic wave. The acoustic braking member 21 mechanically supports the piezoelectric unit 22 and acoustically applies braking so as to shorten the pulse waveform of the first ultrasonic signal. The acoustic braking member 21 is generally also called an acoustic load member, a backing layer, a damper layer, or an acoustic absorbing member. In the acoustic braking member 21, a plurality of fibrous conductors that are fibrous and are electrical conductors are embedded in a polymer material. The acoustic braking member 21 will be described in detail later.

The piezoelectric unit 22 includes a plurality of piezoelectric elements that are electrically connected to a plurality of fibrous conductors in the acoustic braking member 21 and convert electrical signals and ultrasonic signals to each other by using a piezoelectric phenomenon. Is done.

The piezoelectric unit 22 includes a plurality of piezoelectric elements that are two-dimensionally arranged in an array of m rows × n columns in two directions that are linearly independent in a plan view with a predetermined interval therebetween, for example, in two directions orthogonal to each other. Configured. m and n are positive integers, for example, m = n = 128. In this case, the number of piezoelectric elements is 128 × 128 = 16384, and accordingly, the number of conductor wires of the acoustic braking member 21 is 16384. The gap generated by the predetermined interval is preferably filled with an ultrasonic absorber from the viewpoint of reducing crosstalk between the plurality of piezoelectric elements. Each piezoelectric element includes an electrode on each of both opposing surfaces of a piezoelectric body made of a piezoelectric material. One electrode of each piezoelectric element is grounded, and the other electrode is electrically connected to one or more fibrous conductors of the acoustic braking member 21. The thickness of the piezoelectric body is appropriately set depending on, for example, the frequency of ultrasonic waves to be transmitted / received and the type of piezoelectric material. In each of the plurality of piezoelectric elements, a transmission signal of an electric signal input from the transmitter 12 via the cable 3 to the ultrasonic probe 2 is input via each of the plurality of fibrous conductors. . Each piezoelectric element converts this electric signal into an ultrasonic wave by using a piezoelectric phenomenon, generates an ultrasonic wave, and transmits the ultrasonic wave. Then, by applying the ultrasonic probe 2 to the subject, the ultrasonic waves generated by the piezoelectric elements of the piezoelectric unit 22 are transmitted into the subject as a first ultrasonic signal. On the other hand, each piezoelectric element of the piezoelectric unit 22 receives a second ultrasonic signal coming from within the subject based on the first ultrasonic signal, and electrically converts the received second ultrasonic signal by using a piezoelectric phenomenon. This signal is converted into a signal and output. This electrical signal is output from the electrodes of each piezoelectric element via each of the plurality of fibrous conductors. This electrical signal is output from the ultrasound probe 2 to the receiving unit 13 of the ultrasound diagnostic apparatus body 1 via the cable 3.

Here, as shown in FIG. 3B, the piezoelectric portion 22 includes a transmission piezoelectric portion 221 laminated on one main surface of the acoustic braking member 21 and an intermediate layer laminated on the transmission piezoelectric portion 221. The layer 222 and the receiving piezoelectric portion 223 stacked on the intermediate layer 222 may be provided. The transmission piezoelectric unit 221 includes an inorganic piezoelectric material, and converts a transmission electrical signal into a first ultrasonic signal by using a piezoelectric phenomenon. Examples of the inorganic piezoelectric material include so-called PZT, quartz, lithium niobate (LiNbO ₃ ), potassium tantalate niobate (K (Ta, Nb) O ₃ ), barium titanate (BaTiO ₃ ), lithium tantalate (LiTaO _3). And strontium titanate (SrTiO ₃ ). The intermediate layer (buffer layer) 222 is a member for laminating the transmission piezoelectric unit 221 and the reception piezoelectric unit 223. In the present embodiment, the intermediate layer 222 is a member that matches the acoustic impedances of the transmission piezoelectric unit 221 and the reception piezoelectric unit 223. The receiving piezoelectric unit 223 includes an organic piezoelectric material, and converts the second ultrasonic signal coming from within the subject based on the first ultrasonic signal into a received electric signal by using a piezoelectric phenomenon. is there. As the organic piezoelectric material, for example, a polymer of vinylidene fluoride can be used. Further, for example, a vinylidene fluoride (VDF) copolymer can be used as the organic piezoelectric material. This vinylidene fluoride copolymer is a copolymer (copolymer) of vinylidene fluoride and other monomers. Examples of the other monomers include ethylene trifluoride, tetrafluoroethylene, perfluoroalkyl vinyl ether ( PFA), perfluoroalkoxyethylene (PAE), perfluorohexaethylene, and the like can be used. In the vinylidene fluoride copolymer, the electromechanical coupling constant (piezoelectric effect) in the thickness direction varies depending on the copolymerization ratio. For example, an appropriate copolymerization ratio is adopted according to the specifications of the ultrasonic probe, etc. .

In such a configuration, the piezoelectric unit 22 is functionally separated into the transmitting piezoelectric unit 221 and the receiving piezoelectric unit 223, and the transmitting piezoelectric unit 221 is configured to include an inorganic piezoelectric material. Therefore, it is possible to increase the transmission power with a relatively simple structure. For this reason, the ultrasonic probe 2 including the piezoelectric unit 22 can transmit the first ultrasonic signal of the fundamental wave with a relatively large power, and obtain a higher harmonic component of the second ultrasonic signal. be able to. The receiving piezoelectric portion 223 is configured to include an organic piezoelectric material. Therefore, since the ultrasonic probe 2 including the piezoelectric portion 22 can make the frequency band wide with a relatively simple structure, it can receive the harmonic component included in the second ultrasonic signal. Is possible. For this reason, this ultrasonic probe 2 can receive suitably the high frequency component of a 2nd ultrasonic signal. In particular, since the ultrasonic probe 2 including the piezoelectric unit 22 having such a configuration can suitably receive the harmonic component of the second ultrasonic signal, an ultrasonic image is formed by the harmonic imaging technique described above. This is suitable for the ultrasonic diagnostic apparatus S.

Further, as shown in FIG. 3B, since the transmitting piezoelectric portion 221 and the receiving piezoelectric portion 223 are laminated, the piezoelectric portion 22 and the ultrasonic probe 2 can be reduced in size. . Further, as shown in FIG. 3B, a receiving piezoelectric portion 223 is disposed between the transmitting and receiving surfaces of the first and second ultrasonic signals (the surface of the acoustic lens 24) and the transmitting piezoelectric portion 221. Therefore, it is possible to reduce the reception noise and improve the SN ratio.

3A, the acoustic matching layer 23 is a member that matches the acoustic impedance of the piezoelectric portion 22 and the acoustic impedance of the subject. The acoustic matching layer 23 may be composed of a single layer or may be composed of a plurality of layers. For example, in the case where the reception frequency band is widened, the acoustic matching layer 23 is preferably composed of a plurality of layers. The acoustic lens 24 is a member that converges the ultrasonic wave transmitted toward the subject, and has, for example, a shape that bulges in an arc as shown in FIG. Note that the acoustic matching layer 23 and the acoustic lens 24 may be integrally formed.

In the ultrasonic diagnostic apparatus S having such a configuration, for example, when an instruction to start diagnosis is input from the operation input unit 11, a transmission signal of an electrical signal is generated by the transmission unit 12 under the control of the control unit 16. The generated electrical signal transmission signal is supplied to the ultrasonic probe 2 via the cable 3. The electric signal transmission signal is, for example, a voltage pulse repeated at a predetermined cycle. In the piezoelectric unit 22, when the electrical signal transmission signal is supplied, each of the plurality of piezoelectric elements expands and contracts in the thickness direction, and ultrasonically vibrates in accordance with the electrical signal transmission signal. Due to this ultrasonic vibration, the piezoelectric unit 22 radiates an ultrasonic wave (first ultrasonic signal) through the acoustic matching layer 23 and the acoustic lens 24. For example, when the ultrasonic probe 2 is in contact with the subject, the first ultrasonic signal is transmitted from the ultrasonic probe 2 to the subject.

Note that the ultrasound probe 2 may be used in contact with the surface of the subject, or may be used by being inserted into the subject, for example, being inserted into a body cavity of a living body. .

The first ultrasonic signal transmitted to the subject is reflected by one or a plurality of boundary surfaces having different acoustic impedances inside the subject, and becomes an ultrasonic reflected wave (second ultrasonic signal). The second ultrasonic signal includes not only the frequency (fundamental fundamental frequency) component of the transmitted first ultrasonic signal but also a harmonic frequency component that is an integral multiple of the fundamental frequency. For example, second harmonic components such as twice, three times, and four times the fundamental frequency, third harmonic components, fourth harmonic components, and the like are also included. This second ultrasonic signal is received by the ultrasonic probe 2. More specifically, the second ultrasonic signal is received by the piezoelectric unit 22 via the acoustic lens 24 and the acoustic matching layer 23, and mechanical vibration is converted into an electric signal by the piezoelectric unit 22 as a received signal. It is taken out. The extracted reception signal of the electrical signal is received from the ultrasonic probe 2 via the cable 3 by the receiving unit 13 of the ultrasonic diagnostic apparatus body 1. The reception unit 13 performs reception processing on the input reception signal, more specifically, for example, after amplification, converts the analog signal into a digital signal, and outputs the converted signal to the image processing unit 14.

Here, in the above description, the first ultrasonic signal is sequentially transmitted from each piezoelectric element of the piezoelectric unit 22 toward the subject, and the second ultrasonic signal reflected by the subject is received by the piezoelectric unit 22.

Then, under the control of the control unit 16, the image processing unit 14 generates an ultrasonic image of the subject based on the reception signal received by the reception unit 13 from the time from transmission to reception, the reception intensity, and the like, and the display unit 15 displays the ultrasonic image of the subject generated by the image processing unit 14 under the control of the control unit 16. Note that the image processing unit 14 may generate an ultrasonic image of the subject by the above-described harmonic imaging technique.

Next, the acoustic braking member 21 will be described in further detail.

FIG. 4 is a diagram illustrating a configuration of an acoustic braking member in the ultrasonic probe according to the embodiment. 4A is a side view of the acoustic braking member, and FIG. 4B is a perspective view of the acoustic braking member. FIG. 4A also shows the piezoelectric portion 22.

As shown in FIG. 4, the acoustic braking member 21 of the present embodiment includes an acoustic braking member 211 that is provided adjacent to the piezoelectric portion 22 and is made of a polymer material. The molecular material includes a plurality of fibrous conductors 212 extending in a predetermined direction.

The acoustic brake member 211 is made of a resin such as a thermosetting resin or an ultraviolet curable resin, and is a rectangular, layered or plate-like member in plan view. In the present embodiment, for example, a thermosetting epoxy resin or an ultraviolet curable epoxy resin having two or more epoxy groups in the molecule is used as the acoustic braking body 211. Further, for example, polyvinyl chloride, rubber or the like may be used for the acoustic braking body 211.

The fibrous conductor 212 has a function of adjusting acoustic impedance and functions as a lead wire. The predetermined direction is the same as the vibration direction of the piezoelectric portion 22 when the piezoelectric portion 22 is ultrasonically vibrated in a state where the acoustic braking member 21 and the piezoelectric portion 22 are laminated. The fibrous conductor 212 extends in the predetermined direction so as to penetrate the acoustic braking body 211. That is, one end of the fibrous conductor 212 is exposed on one main surface of the acoustic braking body 211, and the other end is exposed on the other main surface of the acoustic braking body 211. The fibrous conductor 212 is, for example, a metal fiber in the present embodiment, and more specifically, for example, a tungsten metal fiber made of tungsten (W). By using tungsten which is generally used for adjusting the acoustic impedance, it is possible to design relatively easily to sufficiently adjust the acoustic impedance. For example, the fibrous conductor 212 may be made of ferrite. In this embodiment, the number of fibrous conductors 212 is larger than the number of the plurality of piezoelectric elements in the piezoelectric portion 22. For example, the pitch of the growth nuclei described later in the fibrous conductor 212 is set so as to be equal to or less than half of the element pitch of the piezoelectric elements in the piezoelectric portion 22, whereby the number of fibrous conductors 212 is larger than the number of piezoelectric elements. There have also been many.

Since the fibrous conductor 212 having such a configuration penetrates the acoustic braking body 211, it can be electrically connected from one main surface of the acoustic braking body 211 to the other main surface. Therefore, the fibrous conductor 212 can function as a lead wire. For this reason, when the piezoelectric part 22 is laminated | stacked on one main surface of the acoustic braking body 211, it can electrically connect to the piezoelectric part 22 via the fibrous conductor 212 from the other main surface of the acoustic braking body 211. It becomes possible.

And the fibrous conductor 212 of such a structure becomes an acoustic scatterer and can enlarge the attenuation factor of an ultrasonic wave. Therefore, the fibrous conductor 21 can adjust the acoustic impedance of the acoustic braking member 21. The acoustic impedance of the acoustic braking member 21 is adjusted by the density of the fibrous conductor 212 and set to a predetermined value. The density of the fibrous conductor 212 is adjusted by the number and the wire diameter, and is set to a predetermined value. For example, the fibrous conductor 212 is adjusted so that its diameter is about 100 nm to several μm, and its density is adjusted so as to be several volume percent to about 10 volume percent with respect to the resin. That is, in this embodiment, the resin and the fibrous conductor 212 constitute a material that absorbs ultrasonic waves (ultrasonic absorber).

In the acoustic braking member 21 having such a configuration, only the plurality of fibrous conductors 212 are included in the acoustic braking body 211. Therefore, unlike the background art, there is no need to include a printed circuit board having a wiring pattern or a signal line in the acoustic braking body 211, and the material uniformity in the acoustic braking member 21 can be improved. The fibrous conductor 212 can be formed, for example, by mixing a powdered conductor in a fluidized resin and growing the powdered conductor in the fluidized resin. Therefore, there is no need to fill the resin, and the unevenness of the resin can be reduced. In the acoustic braking member 21 having such a configuration, the acoustic braking body 211 includes a plurality of fibrous conductors 212, and the plurality of fibrous conductors 212 function as lead wires penetrating the acoustic braking body 211. In addition, the function of adjusting the acoustic impedance of the acoustic braking body 211 is also exhibited. Therefore, even if the wiring density is increased, the acoustic impedance can be sufficiently adjusted, and the uniformity of the material of the acoustic braking member can be improved.

Further, in the acoustic braking member 21 having such a configuration, the acoustic braking member 21 and the piezoelectric portion 22 are stacked, and each of the plurality of piezoelectric elements in the piezoelectric portion 22 and the plurality of fibers in the acoustic braking member 21 are arranged. When the conductor 212 is electrically connected, since the number of the fibrous conductors 212 is larger than the number of the piezoelectric elements, it is possible to connect at least one fibrous conductor 212 to the piezoelectric element. The alignment of the element and the plurality of fibrous conductors 212 is not necessarily performed. For this reason, the piezoelectric part 22 can be assembled to the acoustic braking member 21 more easily, and productivity can be improved.

The acoustic braking member 21 having such a configuration is manufactured as follows, for example. FIG. 5 is a diagram for explaining a method of manufacturing the acoustic braking member.

For the production of the acoustic braking member 21, an acoustic braking member production apparatus 31 having the configuration shown in FIG. 5 is used. The acoustic braking member manufacturing apparatus 31 includes a pair of coils 311 (311a, 311b) arranged at a predetermined interval from each other and a pair of the

coils

311a, 311b to generate a magnetic field between the pair of

coils

311a, 311b. A power supply device 311c that supplies power to the

coils

311a and 311b, and a plurality of growth nuclei 3121 are formed on one main surface, and the one main surface and the magnetic field direction are orthogonal to each other between the pair of

coils

311a and 311b. And a resin supply member 313 for supplying a fluid resin in which a powdered conductor is mixed on one main surface of the substrate 312.

The coil 311 is configured, for example, by forming a coil winding conductor pattern on one main surface of a plate-like member. The growth nuclei 3121 formed on the substrate 312 serve as a growth base point when the fibrous conductor 212 is grown from the powder conductor by applying a magnetic field. The growth nucleus 3121 is, for example, a circular pattern (circular pad, circular dot) made of a magnetic material formed on a non-magnetic substrate 312. For example, the magnetic film formed on substantially the entire one main surface of the substrate. It is formed by etching. The wire diameter of the fibrous conductor 212 can be adjusted by adjusting the size of the growth nucleus 3121. The resin supply member 313 includes, for example, a cylindrical member having a slit-like discharge port that extends across the entire width of the substrate 312. The resin supply member 313 is preferably configured to move relative to the substrate 312 in order to apply the resin substantially uniformly on the one main surface of the substrate 312 over the entire surface. .

In the acoustic braking member manufacturing apparatus 31 having such a configuration, when power is supplied from the power supply device 311c to the pair of

coils

311a and 311b, between the pair of

coils

311a and 311b, the coil 311 is connected to the other coil 311b. For example, a magnetic field is generated in the direction of the coil 311b toward the coil 311a. For this reason, the acoustic braking member manufacturing apparatus 31 having such a configuration can apply a magnetic field in the normal direction of one main surface of the substrate 312.

In manufacturing the acoustic braking member 21, first, a fluid resin in which a metal powder conductor is mixed is prepared. For example, a fluid epoxy resin in which tungsten particles are dispersed substantially uniformly is prepared.

Next, as shown in FIG. 5, the resin mixed with the powder conductor is poured from the resin supply member 313 onto one main surface of the substrate 312, and the fluid resin mixed with the powder conductor becomes the substrate. On the one main surface of 312, a film is developed over substantially the entire surface, and one main surface of the substrate 312 is applied with this resin (application process).

Next, power is supplied to the pair of

coils

311a and 311b from the power supply device 311c, and a magnetic field is applied to the substrate 312 coated with the resin in the normal direction of the one main surface (application process).

When a magnetic field is applied, the powder conductors in the resin are arranged in a straight line along the magnetic field direction starting from the growth nucleus 3121, and the powder conductors are connected in a fibrous form. In addition, by subjecting the powder conductor to a surface treatment that covers the surface with a surface treatment agent having one or more halogen elements, the ease of movement of the powder conductor in the resin can be increased.

Next, after a predetermined time has elapsed since the magnetic field was applied, a flat lid member 315 for regulating the resin is placed on the resin, and the resin in a fluid state is cured (curing step). When the resin is a thermosetting resin, the resin is cured by applying heat. When the resin is an ultraviolet curable resin, the resin is cured by irradiating ultraviolet rays. As a result, the fibrous conductor connected in a fibrous form is held in the fibrous form, and a fibrous conductor 212 embedded in the acoustic braking body 211 is formed. Note that a frame body may be provided between the substrate 312 and the lid member 315 so that the fluid resin does not flow out.

Next, the acoustic braking body 211 including the fibrous conductor 212 is peeled off from the substrate 312 and peeled off from the lid member 315. Alternatively, the substrate 312 and the lid member 315 are removed from the acoustic braking body 211 including the fibrous conductor 212 (separation step). As a result, the acoustic braking member 21 including the acoustic braking body 211 including the fibrous conductor 212 is manufactured.

In addition, in order to confirm whether the fibrous conductor 212 has penetrated the acoustic braking body 211, the edge part of the acoustic braking body 211 may be cut | disconnected and the cross section may be exposed.

In the manufacturing method of the acoustic braking member 21 having such a configuration, the acoustic braking member 21 including the fibrous conductor 212 in the acoustic braking body 211 is manufactured through the application process, the application process, and the curing process. . Therefore, unlike the background art, there is no need to include a printed circuit board having a wiring pattern or a signal line in the acoustic braking body 211, and the material uniformity in the acoustic braking member 21 can be improved. Further, there is no need to fill the resin, and the unevenness of the resin can be reduced. And since the fibrous conductor fulfills not only the lead wire function but also the acoustic impedance adjustment function, even if the wiring density is increased, the acoustic impedance can be sufficiently adjusted, and the material of the acoustic braking member can be adjusted. The uniformity can be improved.

This specification discloses various modes of technology as described above, and the main technologies are summarized below.

An acoustic braking member according to one aspect is an acoustic braking member used for an ultrasonic probe that transmits ultrasonic waves into a subject, and includes an acoustic braking body formed of a polymer material, and the acoustic braking body The polymer material includes a plurality of metallic fibrous conductors that adjust acoustic impedance and extend in one predetermined direction that function as lead wires.

In the acoustic braking member having such a configuration, the acoustic braking body includes a plurality of fibrous conductors. Therefore, unlike the background art, it is not necessary to include a printed circuit board having a wiring pattern or a signal line in the acoustic braking body, and the uniformity of the material in the acoustic braking member can be improved. The fibrous conductor can be formed, for example, by mixing a powdered conductor with a fluidized resin and growing the powdered conductor in the fluidized resin. Therefore, there is no need to fill the resin, and the unevenness of the resin can be reduced. In the acoustic braking member having such a configuration, the acoustic braking body includes a plurality of fibrous conductors, and the plurality of fibrous conductors not only function as lead wires penetrating the acoustic braking body, but also the acoustic braking body. It also has the function of adjusting the acoustic impedance. Therefore, even if the wiring density is increased, the acoustic impedance can be sufficiently adjusted, and the uniformity of the material of the acoustic braking member can be improved.

In another aspect, in the above-described acoustic braking member, the metallic fibrous conductor is preferably made of tungsten.

According to this configuration, since the metallic fibrous conductor is made of tungsten, which is generally used for adjusting the acoustic impedance, it can be designed relatively easily to sufficiently adjust the acoustic impedance.

In another aspect, the acoustic braking member manufacturing method for manufacturing the above-described acoustic braking member includes a metal powder conductor on the main surface of the substrate on which a plurality of growth nuclei are formed on one main surface. An application step of applying a resin in a fluidized state, a step of applying a magnetic field in the normal direction of the main surface to the substrate on which the resin has been applied, and after applying the magnetic field, And a curing step for curing the resin.

In the method of manufacturing an acoustic braking member having such a configuration, an acoustic braking member including a fibrous conductor in an acoustic braking body can be manufactured through the application process, the application process, and the curing process. Therefore, unlike the background art, it is not necessary to include a printed circuit board having a wiring pattern or a signal line in the acoustic braking body, and the uniformity of the material in the acoustic braking member can be improved. Further, there is no need to fill the resin, and the unevenness of the resin can be reduced. Even if the wiring density is increased, the acoustic impedance can be sufficiently adjusted, and the material uniformity of the acoustic braking member can be improved.

An ultrasonic probe according to another aspect is provided adjacent to the piezoelectric unit including a plurality of piezoelectric elements for generating ultrasonic waves by using a piezoelectric phenomenon, and the piezoelectric unit. Any one of the above-described acoustic braking members is provided, and the number of the metallic fibrous conductors is larger than the number of the plurality of piezoelectric elements.

According to this configuration, when each of the plurality of piezoelectric elements in the piezoelectric portion and the plurality of fibrous conductors in the acoustic braking member are electrically connected, the number of the fibrous conductors is larger than the number of the piezoelectric elements. Since there are many, at least one fibrous conductor can be connected to the piezoelectric element, it is not always necessary to align the plurality of piezoelectric elements and the plurality of fibrous conductors. For this reason, a piezoelectric part can be assembled | attached to an acoustic braking member more easily, and productivity can be improved.

Further, an ultrasonic diagnostic device according to another aspect includes the above-described ultrasonic probe and an ultrasonic diagnostic device main body that transmits and receives signals between the ultrasonic probe. is there.

According to this configuration, an ultrasonic diagnostic apparatus using an ultrasonic probe provided with an acoustic braking member including a conductor wire in the acoustic braking body while reducing unevenness of the acoustic braking body is provided.

This application is based on Japanese Patent Application No. 2008-104739 filed on Apr. 14, 2008, the contents of which are included in this application.

In order to express the present invention, the present invention has been properly and fully described through the embodiments with reference to the drawings. However, those skilled in the art can easily change and / or improve the above-described embodiments. It should be recognized that this is possible. Therefore, unless the modifications or improvements implemented by those skilled in the art are at a level that departs from the scope of the claims recited in the claims, the modifications or improvements are not covered by the claims. To be construed as inclusive.

According to the present invention, it is possible to provide an acoustic braking member, an acoustic braking member manufacturing method, an ultrasonic probe ultrasonic wave using the acoustic braking member, and an ultrasonic diagnostic apparatus using the ultrasonic probe. it can.

Claims

An acoustic braking member used in an ultrasonic probe that transmits ultrasonic waves into a subject,
It has an acoustic braking body made of a polymer material,
An acoustic braking member, wherein the polymer material of the acoustic braking body includes a plurality of metallic fibrous conductors that adjust acoustic impedance and function as lead wires and extend in one predetermined direction.
The acoustic braking member according to claim 1, wherein the metallic fibrous conductor is made of tungsten.
An acoustic braking member manufacturing method for manufacturing the acoustic braking member according to claim 1,
On the main surface of the substrate having a plurality of growth nuclei formed on the main surface, an application step of applying a fluid resin in which a metal powder conductor is mixed;
An application step of applying a magnetic field in the normal direction of the main surface to the substrate coated with the resin;
A method of manufacturing an acoustic braking member, comprising: a curing step of curing the fluid resin after application of the magnetic field.
A piezoelectric unit including a plurality of piezoelectric elements for generating ultrasonic waves by utilizing a piezoelectric phenomenon;
The acoustic braking member according to claim 1 or 2 provided adjacent to the piezoelectric portion,
The number of the metallic fiber conductors is larger than the number of the plurality of piezoelectric elements.
The ultrasonic probe according to claim 4,
An ultrasonic diagnostic apparatus comprising: a main body that transmits and receives signals to and from the ultrasonic probe.