JP2011050538A - Ultrasonic probe and ultrasonic diagnostic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly reliable ultrasonic probe with excellent operability, and an ultrasonic diagnostic apparatus having the ultrasonic probe. <P>SOLUTION: The ultrasonic probe includes: a plurality of inorganic piezoelectric elements; an amplifier for amplifying the output of a plurality of organic piezoelectric elements; and a switching means for connecting a corresponding signal line to one of output terminals of the inorganic piezoelectric elements or the amplifier according to a switch control signal. The ultrasonic probe is configured to transmit drive signals for driving the inorganic piezoelectric elements and receiving signals from the inorganic piezoelectric elements or the amplifier via the signal line. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an ultrasonic probe and an ultrasonic diagnostic apparatus.

  An ultrasonic diagnostic apparatus is a medical imaging device that obtains a tomographic image of soft tissue in a living body in a minimally invasive manner from the body surface by an ultrasonic pulse reflection method. Compared to other medical imaging equipment, this ultrasound diagnostic device has features such as being smaller and cheaper, without exposure to X-rays, etc., being highly safe, and capable of blood flow imaging by applying the Doppler effect. Yes. Therefore, it is widely used in the circulatory system (cardiac coronary artery), digestive system (gastrointestinal), internal medicine system (liver, pancreas, spleen), urology system (kidney, bladder), and obstetrics and gynecology.

  Conventionally, such an ultrasonic diagnostic apparatus is called a harmonic imaging (HI) method in which a harmonic component generated by nonlinear propagation of ultrasonic waves is taken out, and an ultrasonic image is generated and displayed based on the harmonic component. Have been used.

  The harmonic imaging is a technique for detecting and imaging a harmonic component contained in an ultrasonic reception signal (for example, transmitting a 5 MHz ultrasonic wave and imaging with a 10 MHz harmonic wave). It was developed for the purpose of detecting sonic contrast agents more efficiently.

  The microbubbles have strong nonlinear scattering characteristics, and the scattered signal contains a higher harmonic component than that of the living tissue. Therefore, by detecting only this harmonic component, it is possible to visualize a minute blood flow (perfusion) that is normally buried in an echo from the surrounding tissue (fundamental wave).

  As a specific structure of an array-type ultrasonic probe used for harmonic imaging, an array-type ultrasound that separates the operation during transmission and reception of ultrasonic waves by separating the transmitting piezoelectric element and the receiving piezoelectric element. A probe has been proposed.

  It is desirable that the receiving piezoelectric element used in such an array type ultrasonic probe can receive a harmonic signal with high sensitivity. However, since the transmission / reception frequency of a piezoelectric element made of an inorganic piezoelectric element such as lead zirconate titanate depends on the thickness of the piezoelectric element, it is necessary to process the piezoelectric element more compactly as the received frequency becomes higher. It was difficult.

  In order to solve such a problem, a piezoelectric element for transmission and a sheet-like piezoelectric element for reception having a single layer or laminated structure of sheet-like piezoelectric ceramics are made into a single layer or laminated, and separate transmission and reception piezoelectric elements And a method of obtaining a highly sensitive ultrasonic probe by using a highly sensitive organic piezoelectric material for reception has been proposed (see Patent Documents 1, 2, and 3).

  On the other hand, a piezoelectric element made of such an organic material has high output impedance, so it is difficult to achieve impedance matching. Therefore, in Non-Patent Document 1, a configuration in which an amplifier is arranged near a piezoelectric element and a received signal of the piezoelectric element is amplified by the amplifier and then A / D converted to reduce parasitic capacitance and noise mixing. Is disclosed (see Non-Patent Document 1).

  Also, a method using a phased array type probe in which a plurality of transducers are arranged, and assigning odd-numbered transducers for transmitting and receiving fundamental wave components and assigning even-numbered transducers for receiving harmonic components. Is disclosed (for example, see Patent Documents 4 and 5).

JP 2008-188415 A International Publication No. 2007/145073 Pamphlet International Publication No. 2008/010509 Pamphlet JP 2004-620 A JP-A-8-182680 S. J Carey, C.I. M Gregory, M.M. P. Brewin, S.M. Ng, J .; V Hatfield, “PVdF Array Charactorization for High Frequency Ultrasonic Imaging” 2004 IEEE Ultrasonics and Frequency Control Joint Ace

  However, as in Patent Documents 4 and 5, separate piezoelectric elements are allocated for transmission and reception, and transmission and reception are separately performed between the transmission circuit and the reception circuit provided in the ultrasonic diagnostic apparatus body. If the wiring is performed, the number of wirings between the ultrasonic probe and the ultrasonic diagnostic apparatus main body is increased.

  Further, as in Patent Documents 1, 2, and 3, a piezoelectric element made of an inorganic material for wave transmission (hereinafter referred to as an inorganic piezoelectric element) is used for transmission, and a piezoelectric element made of an organic material (hereinafter referred to as an organic piezoelectric element). The number of wirings is also increased in the same manner when used for reception.

  When the amplifier is provided as in Non-Patent Document 1, it is desirable that the amplifier is disposed near the organic piezoelectric element of the ultrasonic probe. Therefore, the amplifier disposed in the ultrasonic probe and the ultrasonic diagnostic apparatus body It is necessary to wire separately from the wiring for transmission between the receiving circuit provided in.

  For this reason, the cable between the ultrasonic probe and the ultrasonic diagnostic apparatus main body becomes thick, and operability problems such as difficulty in pressing the ultrasonic probe against a desired part of the subject occur. Further, the possibility of cable breakage or the like increases, and reliability is impaired.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an ultrasonic probe and an ultrasonic diagnostic apparatus that have good operability and high reliability.

  In order to solve the above problems, the present invention has the following characteristics.

1. An ultrasonic probe that transmits and receives ultrasonic waves,
A plurality of inorganic piezoelectric elements made of an inorganic material;
A plurality of organic piezoelectric elements made of organic materials;
A plurality of amplifiers for amplifying reception signals generated by the respective organic piezoelectric elements that have received the ultrasonic waves;
It has switching means each provided with a connection part to a plurality of signal lines for connecting to the ultrasonic diagnostic apparatus body,
The switching means is
It has a function of switching and connecting a connection form for connecting the inorganic piezoelectric element and the connection part and a connection form for connecting the organic piezoelectric element and the connection part via the amplifier. Ultrasonic probe characterized by

2. When connecting to more inorganic piezoelectric elements than the plurality of signal lines,
Having a second switching means between the inorganic piezoelectric element and the switching means;
The second switching means includes
Switching between a connection mode for connecting a part of the plurality of inorganic piezoelectric elements and the switching unit and a connection mode for connecting the other part of the plurality of inorganic piezoelectric elements and the switching unit. 2. The ultrasonic probe according to 1 above, wherein the ultrasonic probe has a function of connecting to each other.

3. When connecting to more organic piezoelectric elements than the plurality of signal lines,
Having a third switching means between the organic piezoelectric element and the amplifier;
The third switching means includes
Switching connection between a connection form connecting a part of the plurality of organic piezoelectric elements and the amplifier and a connection form connecting another part of the plurality of organic piezoelectric elements and the amplifier 3. The ultrasonic probe according to 1 or 2 above, which has a function of

  4). 4. The ultrasonic probe according to any one of 1 to 3, wherein the inorganic piezoelectric element and the organic piezoelectric element are laminated.

5). The organic piezoelectric element is
5. The ultrasonic probe according to any one of 1 to 4 above, wherein the ultrasonic probe is formed using a vinylidene fluoride polymer or a vinylidene fluoride copolymer as a material.

6). In an ultrasonic diagnostic apparatus configured to transmit an ultrasonic wave inside a subject, receive a reflected wave, and visualize the inside of the subject,
The ultrasonic probe according to any one of 1 to 5,
Transmitting means for transmitting a drive signal for driving the inorganic piezoelectric element or the organic piezoelectric element via the signal line;
Receiving means for receiving the received signal via the signal line;
A control means for transmitting a switching control signal for switching a connection form of the switching means, and for controlling the switching means;
Have
The control means includes
An ultrasonic diagnostic apparatus, wherein the switching control signal is transmitted according to a setting to switch the connection of the switching means.

7). The control means includes
Applying a drive signal to the inorganic piezoelectric element and transmitting an ultrasonic wave toward the inside of the subject, the fundamental frequency of the drive signal included in the reflected wave reflected from the subject received by the inorganic piezoelectric element A first mode for controlling the inside of the subject to be imaged mainly with components;
After applying a drive signal to the inorganic piezoelectric element and transmitting an ultrasonic wave toward the inside of the subject, the switching means is switched, and the organic piezoelectric element receives and reflects from the subject amplified by the amplifier. A second mode for controlling the inside of the subject to be imaged mainly with a non-basic frequency component other than the fundamental frequency included in the reflected wave;
7. The ultrasonic diagnostic apparatus according to 6, wherein the ultrasonic diagnostic apparatus is configured to be settable.

  According to the present invention, since the ultrasonic probe is provided with the switching means for switching the plurality of inorganic piezoelectric elements and the amplifier for amplifying the outputs of the plurality of organic piezoelectric elements to connect to the signal line, the ultrasonic probe is provided. The number of wires connected to the diagnostic device can be reduced.

  Therefore, it is possible to provide an ultrasonic probe and an ultrasonic diagnostic apparatus that have good operability and high reliability.

It is a figure which shows the external appearance structure of the ultrasound diagnosing device in embodiment. It is a block diagram which shows the electrical structure of the ultrasonic diagnosing device in embodiment. It is a detailed circuit block diagram of an ultrasonic probe, a transmission processing unit, and a reception processing unit in the embodiment. It is sectional drawing of the head part of the ultrasonic probe in embodiment. It is a figure which shows each focus area | region set by the multistage focus method. It is a figure which illustrates typically until an ultrasonic wave is transmitted to the focus of each focus area | region, and is received. It is a time chart explaining the timing of transmission / reception. It is an example which comprised the switching means combining the single pole single throw analog switch. It is a block diagram which shows the electrical structure of the ultrasonic probe of 2nd Embodiment.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. However, the present invention is not limited to the embodiment. 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.

  FIG. 1 is a diagram illustrating an external configuration of an ultrasonic diagnostic apparatus according to an embodiment.

  The ultrasonic diagnostic apparatus 100 transmits ultrasonic waves (ultrasound signals) to a subject such as a living body (not shown) and reflects the reflected ultrasonic waves (echoes, ultrasonic signals) reflected by the received subject. The internal state in the subject is imaged as an ultrasound image and displayed on the monitor 10.

  The ultrasonic probe 2 transmits an ultrasonic wave (ultrasonic signal) to the subject and receives a reflected wave of the ultrasonic wave reflected by the subject. As shown in FIG. 1, the ultrasonic probe 2 is connected to an ultrasonic diagnostic apparatus main body 14 via a cable 15.

  The input unit 13 includes a switch, a keyboard, and the like. The input unit 13 inputs a command for instructing the user to start diagnosis, selects a first mode or a second mode described later, and inputs data such as personal information of a subject. It is provided to do.

  The monitor 10 is composed of a liquid crystal panel or the like, and displays an imaged ultrasonic image.

  FIG. 2 is a block diagram showing an electrical configuration of the ultrasonic diagnostic apparatus according to the present embodiment. FIG. 3 is a detailed circuit block diagram of the ultrasonic probe, transmission processing unit, and reception processing unit in the embodiment. FIG. 4 is a cross-sectional view of the head portion of the ultrasonic probe in the embodiment.

  First, the configuration of the ultrasonic probe 2 will be described with reference to FIGS. 2, 3, and 4.

  As shown in FIG. 3, a plurality of inorganic piezoelectric elements 50 a to 50 u arranged in an array for mutual conversion between an electric signal and an acoustic signal are arranged at the tip of the ultrasound probe 2. A plurality of organic piezoelectric elements 51a to 51u arranged are stacked. The inorganic piezoelectric elements 50a to 50u are piezoelectric elements made of an inorganic material, and the organic piezoelectric elements 51a to 51u are piezoelectric elements made of an organic material. In the following description, it is assumed that one piezoelectric element constitutes one channel. The number of inorganic piezoelectric elements 50 and organic piezoelectric elements 51 is assumed to be 21, and an example in which the number is distinguished by a to u will be described. However, the number of elements is not particularly limited, and the number of elements of about 20 to 200 is used. It is done.

  In FIG. 2, the inorganic piezoelectric element array 50 composed of a plurality of inorganic piezoelectric elements 50 a to 50 u and the organic piezoelectric element array 51 composed of a plurality of organic piezoelectric elements 51 a to 51 u are illustrated as one block.

  Since the organic piezoelectric elements 51a to 51u have a very high impedance of several KΩ, they are easily affected by noise. Therefore, the organic piezoelectric elements 51a to 51u are connected to the amplifiers 52a to 52u, respectively. The amplifiers 52a to 52u are electric signals (hereinafter referred to as reception signals) generated by the organic piezoelectric elements 51a to 51u that have received ultrasonic waves. Amplify). The received signals can be transmitted to the ultrasonic diagnostic apparatus main body 14 with high S / N by amplifying the received signals by the amplifiers 52a to 52u and outputting them with low impedance.

  As the amplifiers 52a to 52u, general-purpose amplifiers having high input impedance such as operational amplifiers using FETs (field effect transistors) in the first stage can be used.

  Signal lines 56a to 56u for connecting to the ultrasonic diagnostic apparatus main body 14 are connected to the connection portions 58a to 58u of the switching means 53, respectively.

  The switches 53a to 53u of the switching means 53 are connected in a direct connection between the inorganic piezoelectric elements 50a to 50u and the connection portions 58a to 58u in accordance with a switching control signal transmitted by the switching control signal line 57. The piezoelectric element 51a-51u and the connection part 58a-58u are switched and connected to the connection form which connects via amplifier 52a-52u.

  The single-pole double-throw switches 53a to 53u shown in FIG. 3 can be combined with a single-pole / single-throw analog switch or the like, and can be equivalently configured as switches having the same function by being appropriately turned on or off by a switching control signal. it can.

  FIG. 8 shows an example in which the switching means 53 is configured by using four single-pole single-throw analog switches 110a and 111a.

  FIG. 8 shows a circuit for one channel corresponding to the switch 53a. The analog switches 110a and 111a are connected to switching control signal lines 57a and 57b, respectively, and are turned on and off according to the transmitted switching control signal.

  In the state of FIG. 8, the analog switch 110a is on, the analog switch 111a is off, and the inorganic piezoelectric element 50a and the connecting portion 58a are directly connected. When the analog switch 110a is turned off and the analog switch 111a is turned on by the switching control signal, the organic piezoelectric element 51a and the connection portion 58a can be connected via the amplifier 52a.

  Since the wiring between the organic piezoelectric elements 51a to 51u and the amplifiers 52a to 52u is high impedance, it is desirable to make the wiring length as short as possible so as not to be affected by external noise using a coaxial cable or a shielded wire.

  In FIG. 2, the amplifiers 52 a to 52 u are illustrated as blocks of the amplifier 52, and the switches 53 a to 53 u are illustrated as blocks of the switching unit 53.

  The signal lines 56 a to 56 u and the switching control signal line 57 are connected to the connector 54, and are connected to the connector 16 of the ultrasonic diagnostic apparatus main body 14 via the cable 15. As described above, since the corresponding signal lines 56a to 56u are connected to any one of the output terminals of the inorganic piezoelectric elements 50a to 50u or the amplifiers 52a to 52u by the switching means 53, the number of wires by the cable 15 is reduced. be able to. Thereby, since the cable 15 can be made thin, the operability and reliability of the ultrasonic probe 2 can be improved.

  Next, the configuration of the ultrasonic probe 2 of the second embodiment shown in FIG. 9 will be described.

  The present embodiment can be applied to a case where more inorganic piezoelectric elements or organic piezoelectric elements are connected than the signal line 56. In this embodiment, as an example, the case where the inorganic piezoelectric element array 50 composed of 42 inorganic piezoelectric elements is connected to the 21 signal lines 56, the organic piezoelectric element array 51 composed of 42 organic piezoelectric elements, and 21 The case where the signal line 56 is connected via the amplifier 52 will be described.

  FIG. 9 shows a state in which an inorganic piezoelectric element array 50 composed of 42 inorganic piezoelectric elements is divided into blocks 50A and 50B each composed of 21 inorganic piezoelectric elements and connected to the second switching means 120. Yes.

  The second switching means 120 has the same configuration as the switching means 53, and includes a connection configuration for connecting the 21 inorganic piezoelectric elements of the block 50A and the switching means 53, and the 21 inorganic piezoelectric elements of the block 50B and the switching means. 53, and the connection form for connecting to 53 is switched. The second switching unit 120 switches between the two connection modes according to a switching control signal transmitted through the switching control signal line 57A.

  In this way, since more inorganic piezoelectric elements than the signal lines can be driven in a time division manner, a high-resolution image can be obtained using many inorganic piezoelectric elements. Also in this case, since the cable 15 can be made thinner, the operability and reliability of the ultrasonic probe 2 can be improved.

  FIG. 9 shows a state in which an organic piezoelectric element array 51 composed of 42 organic piezoelectric elements is divided into blocks 51A and 51B each composed of 21 organic piezoelectric elements and connected to the third switching means 121. Show.

  The third switching unit 121 has the same configuration as the switching unit 53, a connection configuration in which the organic piezoelectric element 21 of the block 51 </ b> A and the switching unit 53 are connected via the amplifier 52 of 21, and the 21 of the block 51 </ b> B. The connection mode in which the organic piezoelectric element and the switching means 53 are connected through the amplifier 52 is switched and connected. The third switching means 121 switches between the two connection modes according to a switching control signal transmitted through the switching control signal line 57B.

  In this way, since received signals can be received in a time-sharing manner from more organic piezoelectric elements than the signal lines, a high resolution image can be obtained using many organic piezoelectric elements. Also in this case, since the cable 15 can be made thinner, the operability and reliability of the ultrasonic probe 2 can be improved. Further, since the received signal can be amplified with a smaller number of amplifiers 52 than the organic piezoelectric elements, the ultrasonic probe 2 can be reduced in size and power consumption can be reduced.

  Next, the configuration of the head portion of the ultrasonic probe will be described with reference to FIG.

  In the following description, description will be made based on the coordinate axes indicated by X, Y, and Z in the drawing. The X direction is the elevation direction (the dicing direction), and the Z-axis positive direction is the direction in which ultrasonic waves are transmitted. The Z-axis direction is the stacking direction.

  The head portion of the ultrasonic probe shown in FIG. 4 includes a fourth electrode 75, an inorganic piezoelectric film 62, a third electrode 74, an intermediate layer 73, a second electrode 70, an organic piezoelectric film 63, a first electrode on a backing material 65. One electrode 69, a matching layer 66, and an acoustic lens 67 are laminated in this order. The matching layer 66 to the fourth electrode 75 are diced in the X direction to form a plurality of inorganic piezoelectric elements 50a to 50u and organic piezoelectric elements 51a to 51u.

  Hereinafter, each component will be described in the order in which they are stacked.

(Inorganic piezoelectric element array)
The inorganic piezoelectric element array 50 includes inorganic piezoelectric elements 50a to 50 each having a third electrode 74 and a fourth electrode 75 on both surfaces of the inorganic piezoelectric film 62 made of an inorganic material such as lead zirconate titanate, which face each other in the thickness direction. 50u. The thickness of the inorganic piezoelectric film 62 is about 320 μm.

  The third electrodes 74a to 74u of the inorganic piezoelectric elements 50a to 50u are connected to the terminals of the switches 53a to 53u via connectors (not shown), and the fourth electrodes 75a to 75u are grounded.

  When a drive signal is applied to the third electrodes 74a to 74u, the inorganic piezoelectric elements 50a to 50u vibrate, and an ultrasonic wave is transmitted from the inorganic piezoelectric element array 50 in the positive Z-axis direction.

  Further, when the inorganic piezoelectric element array 50 receives and vibrates the reflected ultrasonic wave reflected by the subject, an electrical signal (hereinafter referred to as a received signal) is generated in the third electrodes 74a to 74u according to the reflected wave. .

  The third electrode 74 and the fourth electrode 75 are formed by vapor deposition or photolithography on both surfaces of the inorganic piezoelectric element array 50 using a metal material such as gold, silver, or aluminum.

(Middle layer)
The intermediate layer 73 vibrates the organic piezoelectric element array 51 so that the inorganic piezoelectric element array 50 does not resonate and vibrate when the organic piezoelectric element array 51 receives and vibrates the reflected ultrasonic wave reflected by the subject. Is provided to absorb.

  Such an intermediate layer 73 can be formed by molding a resin material. Examples of the resin material used for the intermediate layer 73 include polyvinyl butyral, polyolefin, polyacrylate, polyimide, polyamide, polyester, polysulfone, epoxy, and oxetane.

  The thickness of the intermediate layer 73 is selected depending on the required sensitivity and frequency characteristics, and is, for example, about 180 to 190 μm.

  Note that the intermediate layer 73 may be omitted depending on the sensitivity and frequency characteristics to be obtained.

(Organic piezoelectric element array)
The organic piezoelectric element array 51 includes a plurality of organic piezoelectric elements 51a to 51u having first electrodes 69a to 69u and second electrodes 70a to 70u on both surfaces of an organic piezoelectric film 63 made of an organic material facing in the thickness direction. It is composed of

  As an organic material used for the organic piezoelectric film 63, for example, a polymer of vinylidene fluoride can be used. Further, for example, a vinylidene fluoride (VDF) copolymer can be used for the organic piezoelectric film 63. This vinylidene fluoride copolymer is a copolymer (copolymer) of vinylidene fluoride and other monomers. Examples of other monomers include ethylene trifluoride (TrFE) and tetrafluoroethylene (TeFE). Perfluoroalkyl vinyl ether (PFA), perfluoroalkoxyethylene (PAE), perfluorohexaethylene, and the like can be used.

  In general, a piezoelectric element made of a piezoelectric material such as lead zirconate titanate can receive only an ultrasonic wave having a frequency band about twice the frequency of the fundamental wave. For example, ultrasonic waves in a frequency band of about 3 to 5 times the frequency can be transmitted and received, which is suitable for widening the reception frequency band.

  The thickness t of the organic piezoelectric film 63 is appropriately set depending on the frequency of the ultrasonic wave to be received, the type of the organic piezoelectric material, and the like.

  Such an organic piezoelectric film 63 is cast from a solution of an organic piezoelectric material to form a film having a predetermined thickness, heated to be crystallized, and then molded into a sheet having a predetermined size. Make it.

  A first electrode 69 and a second electrode 70 are formed on both surfaces of the organic piezoelectric film 63 facing each other in the thickness direction (Z-axis direction).

  The first electrodes 69a to 69u of the organic piezoelectric elements 51a to 51u are respectively connected to the terminals of the switches 53a to 53u via connectors not shown, and the second electrodes 70a to 70u are grounded.

  When a drive signal is applied to the first electrodes 69a to 69u, the organic piezoelectric elements 51a to 51u vibrate, and ultrasonic waves are transmitted from the organic piezoelectric element array 51 in the positive direction of the Z axis.

  Further, when the organic piezoelectric element array 51 receives and vibrates the reflected wave of the ultrasonic wave reflected by the subject, an electrical signal is generated in the first electrodes 69a to 69u according to the reflected wave.

(Matching layer)
The matching layer 66 has an acoustic impedance intermediate between the acoustic impedance of the human body, which is one of the subjects, and the organic piezoelectric element array 51, and matches the acoustic impedance. The matching layer 66 can be formed by molding a resin material, for example.

  The material used for the matching layer 66 is preferably a material having an acoustic impedance of about 1.7 to 1.8 and a sound speed of 1300 m / sec to 2200 m / sec, which is close to that of the human body. For example, polymethylpentene can be used.

(Acoustic lens)
The acoustic lens 67 converges the ultrasonic wave transmitted from the inorganic piezoelectric element array 50 to a predetermined distance.

  Thus, since the inorganic piezoelectric element array 50 and the organic piezoelectric element array 51 are laminated, the ultrasonic probe 2 can be reduced in size.

  The explanation of the ultrasonic probe 2 has been described above.

  Next, the electrical configuration of the ultrasonic diagnostic apparatus main body 14 will be described with reference to FIGS.

  The signal lines 56a to 56u of the ultrasonic probe 2 are connected to the transmission processing unit 1 and the reception processing unit 3 through the connector 54, the cable 15, and the connector 16 as shown in FIGS. The switching control signal line 57 is connected to the control unit 99 as shown in FIGS. 2 and 3 via the connector 54, the cable 15, and the connector 16. The transmission processing unit 1 is a transmission unit of the present invention, and the reception processing unit 3 is a reception unit of the present invention.

  The control unit 99 includes a CPU 98 (central processing unit), a storage unit 96, and the like, reads a program stored in the storage unit 96 into the RAM 97, and controls each unit of the ultrasound diagnostic apparatus 100 according to the program. The storage unit 96 includes a RAM (Random Access Memory), a ROM (Read Only Memory), and the like.

  The control unit 99 sets the mode (first mode and second mode) input from the input unit 13 by the operator in the transmission processing unit 1 and the reception processing unit 3.

  When transmitting ultrasonic waves, the control unit 99 causes the switches 53a to 53u to connect the signal lines 56a to 56u to the inorganic piezoelectric elements 50a to 50u, respectively.

  The controller 99 switches the switches 53a to 53u so that the signal lines 56a to 56u are connected to the inorganic piezoelectric elements 50a to 50u in both the first mode and the second mode.

The transmission processing unit 1 is a drive subjected to delay processing so as to form an ultrasonic wave in a beam shape at a timing corresponding to the mode set by the control unit 99 and to converge at an arbitrary depth to form a focal point. A signal is applied to each channel of the ultrasonic probe 2 via the signal lines 56a to 56u. The transmission processing unit 1 applies the drive signal having the fundamental frequency f _{0 in} both the first mode and the second mode.

  The ultrasonic wave generated by the ultrasonic probe 2 is transmitted to the subject, propagates inside the subject, is reflected by a discontinuous surface of the acoustic impedance in the middle thereof, and is echoed to the ultrasonic probe 2 as an echo. Come back.

  After transmitting the ultrasonic wave toward the subject, the echoes returned to the ultrasonic probe 2 are the inorganic piezoelectric elements 50a to 50u and the organic piezoelectric elements 51a to 51u arranged on the ultrasonic probe 2. Is mechanically vibrated to generate a weak received signal.

  When receiving the ultrasonic wave, the control unit 99 switches the switches 53a to 53u according to the set mode so that the signal lines 56a to 56u are the inorganic piezoelectric elements 50a to 50u or the organic piezoelectric elements 51a to 51u or the amplifiers 52a to 52a. 52u is connected.

  In the first mode, the control unit 99 causes the signal lines 56a to 56u to connect to the inorganic piezoelectric elements 50a to 50u as they are even when the switches 53a to 53u receive signals, and in the second mode, the switches 53a to 53u Switch so that lines 56a-56u connect to amplifiers 52a-52u.

  The signals of the signal lines 56a to 56u at the time of ultrasonic reception are taken into the reception processing unit 3, amplified by the preamplifiers 42a to 42u, and then subjected to the reception beam former 41 subjected to the same delay processing as at the time of transmission. The addition unit 43 adds the values.

In the first mode, the received signal has a fundamental band pass filter whose pass band is set to a predetermined band centered on the fundamental frequency f ₀ in order to mainly extract a fundamental wave component from the received signal. (BPF) 4 is sent to the B-mode processing unit 6.

Further, in the second mode, the pass band through a predetermined harmonic bandpass filter that is set in the band (BPF) 5 around the example three times the frequency of the fundamental frequency f _0, B-mode It is sent to the processing unit 6.

In the second mode, non-fundamental wave components other than the fundamental frequency f ₀ generated by so-called non-linearity of propagation are used, in which the ultrasonic waves included in the echo are 'propagated' while distorting the inside of the subject (living body). . Among the non-fundamental component, twice the second harmonic component of the fundamental frequency f _0, but a like three times the third harmonic component can be used for image formation for diagnosis, in the embodiment In the following description, it is assumed that a third harmonic component having a triple frequency 3f ₀ is used.

The B mode processing unit 6 generates a normal B mode image based on the component of the fundamental frequency f ₀ from the fundamental band pass filter 4 in the first mode, and for harmonics in the second mode. An image is generated based on a 3f ₀ component that is three times the fundamental frequency from the band-pass filter 5. These images are reconstructed by a digital scan converter (DSC) 9, converted into a video signal, and displayed on the monitor 10.

  Next, the multistage focus method will be described with reference to FIGS. 5, 6, and 7.

  FIG. 5 is a diagram illustrating an example of each focus region set by the multistage focus method, and FIG. 6 is a diagram schematically illustrating the process of transmitting and receiving ultrasonic waves to the focus of each focus region. FIG. 7 is a time chart for explaining an example of the transmission timing.

  In the present embodiment, a case will be described in which images of four focus areas E1, E2, E3, and E4 that are equally spaced in the depth direction of the living body (subject) shown in FIG. 5 are obtained.

  The transmission processing unit 1 forms ultrasonic waves in the form of a beam, and sequentially applies drive signals that have been subjected to delay processing so as to form focal points in the focus regions E1, E2, E3, and E4, to the inorganic piezoelectric elements 50a to 50u. The focus of the focus area E1 is F1, the focus of the focus area E2 is F2, the focus of the focus area E3 is F3, and the focus of the focus area E4 is F4. In the example of FIG. A focal point is formed on the central axis of 50u. The ultrasonic beam transmitted from the inorganic piezoelectric elements 50a to 50u is spread again after being converged at the position of each focal point as shown in FIG.

  FIGS. 6B to 6E schematically illustrate the maximum time from when an ultrasonic wave is transmitted to each focal point until a harmonic generated near the focal point is received in the second mode. It shows. Harmonics are generated only in the focus area near the focal position. Since the generated harmonics have a higher attenuation factor than the fundamental wave, they do not travel and reflect deeper areas. Therefore, the maximum time is the time until the fundamental wave of the transmitted ultrasonic wave travels to the deeper boundary of each focus region, and the harmonic generated at the boundary returns to the ultrasonic probe 2.

  FIG. 6E shows a case where the wave is transmitted to the deepest focal point F4, where t is the maximum time until a harmonic generated near the deeper boundary of the focus region E4 is received. FIG. 6D shows a case where waves are transmitted to the focal point F3. When the focus areas are equally spaced, the maximum time required to receive harmonics generated near the deeper boundary of the focus area E3 is 3 /. 4t.

  Similarly, FIG. 6C shows a case where the wave is transmitted to the focal point F2, and FIG. 6B shows a case where the wave is transmitted to the focal point F1, and the harmonics generated near the deeper boundary of the focus region E2. Is 2/4 × t, and the maximum time until a harmonic generated near the deeper boundary of the focus area E1 is 1/4 × t.

  FIG. 7 is a time chart for explaining the transmission timing. The horizontal axis in FIG. 7 is a time axis and shows timing pulses generated by the transmission processing unit 1. A drive signal is transmitted to the inorganic piezoelectric elements 50a to 50u at the rising edge of the timing pulse for each period t, and an ultrasonic wave is transmitted. T is a period for forming one screen.

  The transmission processing unit 1 applies drive signals to the inorganic piezoelectric elements 50a to 50u at the transmission timing shown in FIG.

  First, the transmission / reception timing in the first mode will be described.

  The controller 99 connects the switches 53a to 53u so that the signal lines 56a to 56u are connected to the inorganic piezoelectric elements 50a to 50u, and then the ultrasonic wave is converged to the closest focus F1 at the rising edge of the timing pulse of F1. Send a wave. During the period in which the reflected wave from the focus area E1 indicated by E1 in FIG. 7 is received, the signal received by the inorganic piezoelectric elements 50a to 50u is caused to be subjected to the same delay processing as that at the time of wave transmission. Similarly, ultrasonic waves are transmitted so as to converge to the focal points F2, F3, and F4 at the rising edges of the timing pulses of F2, F3, and F4.

  As described above, the signals received by the inorganic piezoelectric elements 50a to 50u during the periods E1, E2, E3, and E4 are added by the reception processing unit 3 through the same delay processing as that at the time of transmission, so that the bandpass filter for harmonics is used. 5, only the harmonic component is sent to the B-mode processing unit 6 to generate an image.

  Next, transmission / reception timing in the second mode will be described.

  The controller 99 connects the switches 53a to 53u so that the signal lines 56a to 56u are connected to the inorganic piezoelectric elements 50a to 50u, and then the ultrasonic wave is converged to the closest focus F1 at the rising edge of the timing pulse of F1. Send a wave. After about 1 μS after transmission, the control unit 99 switches the switches 53a to 53u so that the signal lines 56a to 56u are connected to the amplifiers 52a to 52u, and the signals received by the organic piezoelectric elements 51a to 51u during the period E1. The reception processing unit 3 is caused to perform the same delay processing as that during transmission.

  Next, the control unit 99 switches the switches 53a to 53u so that the signal lines 56a to 56u are connected to the inorganic piezoelectric elements 50a to 50u, and then converges to the focal point F2 at the rising edge of the timing pulse of F2. Send ultrasonic waves. After about 1 μS after transmission, the control unit 99 switches the switches 53a to 53u so that the signal lines 56a to 56u are connected to the amplifiers 52a to 52u, and the signals received by the organic piezoelectric elements 51a to 51u during the period E2. The reception processing unit 3 is caused to perform the same delay processing as that during transmission. Similarly, ultrasonic waves are transmitted from the inorganic piezoelectric elements 50a to 50u so as to converge to the focal points F3 and F4 at the rising edges of the timing pulses of F3 and F4, respectively, and during the period of E3 and E4, the reception processing unit 3 performs the amplifier 52a. Control to process ~ 52u output.

  In this way, the signals received by the organic piezoelectric elements 51a to 51u during the periods E1, E2, E3, and E4 are added by the reception processing unit 3 through the same delay processing as that at the time of transmission, and the harmonic band-pass type Through the filter 5, only the harmonic component is sent to the B-mode processing unit 6 to generate an image.

  In the present embodiment, the example in which the first mode and the second mode are switched when the operator performs a mode switching operation with the input unit 13 has been described. However, for example, every time one section is scanned once. Alternatively, it may be switched automatically every time transmission / reception is performed once.

  As described above, according to the present invention, it is possible to provide an ultrasonic probe having good operability and high reliability, and an ultrasonic diagnostic apparatus having the ultrasonic probe.

DESCRIPTION OF SYMBOLS 1 Transmission processing part 2 Ultrasonic probe 3 Reception processing part 4 Bandpass filter for fundamental waves 5 Bandpass filter for harmonics 6 B mode processing part 9 Digital scan converter 10 Display part 13 Input part 14 Ultrasonic diagnostic apparatus Body 15 Cable 50 Inorganic piezoelectric element array 50a to 50u Inorganic piezoelectric element 51 Organic piezoelectric element array 51a to 51u Organic piezoelectric element 52 Amplifier 53 Switching means 53a to 53u Switch 56 Signal line 57 Switching control signal line 69 First electrode 70 Second electrode 74 3rd electrode 75 4th electrode 96 Memory | storage part 98 CPU
99 Control Unit 100 Ultrasound Diagnostic Device 120 Second Switching Unit 121 Third Switching Unit

Claims (7)

An ultrasonic probe that transmits and receives ultrasonic waves,
A plurality of inorganic piezoelectric elements made of an inorganic material;
A plurality of organic piezoelectric elements made of organic materials;
A plurality of amplifiers for amplifying reception signals generated by the respective organic piezoelectric elements that have received the ultrasonic waves;
It has switching means each provided with a connection part to a plurality of signal lines for connecting to the ultrasonic diagnostic apparatus body,
The switching means is
It has a function of switching and connecting a connection form for connecting the inorganic piezoelectric element and the connection part and a connection form for connecting the organic piezoelectric element and the connection part via the amplifier. Ultrasonic probe characterized by When connecting to more inorganic piezoelectric elements than the plurality of signal lines,
Having a second switching means between the inorganic piezoelectric element and the switching means;
The second switching means includes
Switching between a connection mode for connecting a part of the plurality of inorganic piezoelectric elements and the switching unit and a connection mode for connecting the other part of the plurality of inorganic piezoelectric elements and the switching unit. The ultrasonic probe according to claim 1, wherein the ultrasonic probe has a function of connecting with each other. When connecting to more organic piezoelectric elements than the plurality of signal lines,
Having a third switching means between the organic piezoelectric element and the amplifier;
The third switching means includes
Switching connection between a connection form connecting a part of the plurality of organic piezoelectric elements and the amplifier and a connection form connecting another part of the plurality of organic piezoelectric elements and the amplifier The ultrasonic probe according to claim 1, wherein the ultrasonic probe has a function of:   The ultrasonic probe according to any one of claims 1 to 3, wherein the inorganic piezoelectric element and the organic piezoelectric element are laminated. The organic piezoelectric element is
The ultrasonic probe according to any one of claims 1 to 4, wherein the ultrasonic probe is formed by using a vinylidene fluoride polymer or a vinylidene fluoride copolymer as a material. In an ultrasonic diagnostic apparatus configured to transmit an ultrasonic wave inside a subject, receive a reflected wave, and visualize the inside of the subject,
The ultrasonic probe according to any one of claims 1 to 5,
Transmitting means for transmitting a drive signal for driving the inorganic piezoelectric element or the organic piezoelectric element via the signal line;
Receiving means for receiving the received signal via the signal line;
A control means for transmitting a switching control signal for switching a connection form of the switching means, and for controlling the switching means;
Have
The control means includes
An ultrasonic diagnostic apparatus, wherein the switching control signal is transmitted according to a setting to switch the connection of the switching means. The control means includes
Applying a drive signal to the inorganic piezoelectric element and transmitting an ultrasonic wave toward the inside of the subject, the fundamental frequency of the drive signal included in the reflected wave reflected from the subject received by the inorganic piezoelectric element A first mode for controlling the inside of the subject to be imaged mainly with components;
After applying a drive signal to the inorganic piezoelectric element and transmitting an ultrasonic wave toward the inside of the subject, the switching means is switched, and the organic piezoelectric element receives and reflects from the subject amplified by the amplifier. A second mode for controlling the inside of the subject to be imaged mainly with a non-basic frequency component other than the fundamental frequency included in the reflected wave;
The ultrasonic diagnostic apparatus according to claim 6, wherein the ultrasonic diagnostic apparatus is configured to be settable.

Images