JP2014226498A - Ultrasonic probe and ultrasonograph - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultrasonic probe and ultrasonograph capable of improving an S/N ratio in a reception when using an aperture synthesis.SOLUTION: The ultrasonic probe includes first piezoelectric vibrator groups 21, second piezoelectric vibrator groups 22, and switches 31. The first piezoelectric vibrator groups 21 are directly connected to a control unit for controlling transmission/reception of ultrasonic waves respectively. The second piezoelectric vibrator groups 22 are disposed between the first piezoelectric vibrator groups and connected in parallel to one of adjacent first piezoelectric vibrator groups 21 and the other of the adjacent first piezoelectric vibrator groups 21 at prescribed timing. The switches change over the connection destinations of the parallel connection of the second piezoelectric vibrator groups 22 at the prescribed timing.

Description

  Embodiments described herein relate generally to an ultrasonic probe and an ultrasonic diagnostic apparatus.

  Conventionally, in an ultrasonic diagnostic apparatus, the ultrasonic diagnostic apparatus is a device that can display the state of movement of an inspection object in real time, for example, by a simple operation of simply applying an ultrasonic probe from the body surface. It plays an important role in today's medicine. Here, the ultrasonic diagnostic apparatus transmits an ultrasonic wave from the ultrasonic probe into the subject, receives a reflected wave caused by an acoustic impedance mismatch inside the subject, and generates a reception signal. . In order to transmit and receive such ultrasonic waves, the ultrasonic probe includes a plurality of piezoelectric vibrators in the scanning direction. These piezoelectric vibrators are piezoelectrically polarized in a direction in which ultrasonic waves are transmitted and received. The piezoelectric vibrators vibrate based on transmission signals to generate ultrasonic waves, receive reflected waves, and generate reception signals.

  In such an ultrasonic probe, a large number of piezoelectric vibrators are arranged in one direction (scanning direction) at a constant pitch, and the ultrasonic wave is controlled by controlling the drive timing or reception delay of each piezoelectric vibrator. The beam is deflected or the depth of focus is changed. These piezoelectric vibrators may be arranged in a curved manner on the scanning surface, or each piezoelectric vibrator may be formed by arranging a plurality of micro vibrators in parallel.

  Here, in an ultrasonic probe provided with such a piezoelectric vibrator (arrayed piezoelectric vibrator), when transmitting a main lobe by synthesizing a wavefront from a plurality of piezoelectric vibrators, it is between adjacent piezoelectric vibrators. In some cases, a grading lobe is generated in which the wavefront is synthesized with a shift of one wavelength. The grading lobe forms a beam in a direction different from the main lobe in the originally intended direction, causing artifacts. Such a grading lobe can be suppressed by narrowing the pitch at which the piezoelectric vibrators are arranged, but in such a case, the aperture width becomes small and the resolution has a certain limit.

  Therefore, an aperture synthesis method is known as a technique for increasing resolution with a large aperture while suppressing grading lobes with a limited number of piezoelectric vibrators. The aperture synthesis method is a technique of obtaining a virtual large aperture by switching a piezoelectric vibrator driven by transmission / reception of ultrasonic waves and synthesizing a plurality of reception signals. However, in the above-described conventional technique, when the aperture synthesis method is used, the S / N during reception sometimes decreases.

JP 2000-300553 A JP 2003-235840 A

  The problem to be solved by the present invention is to provide an ultrasonic probe and an ultrasonic diagnostic apparatus that can improve the S / N during reception when the aperture synthesis method is used.

  The ultrasonic probe according to the embodiment includes a first piezoelectric vibrator group, a second piezoelectric vibrator group, and a switching unit. The first piezoelectric vibrator group is directly connected to a control unit that controls transmission and reception of ultrasonic waves. The second piezoelectric vibrator group is disposed between the first piezoelectric vibrators, and at a predetermined timing with respect to one adjacent first piezoelectric vibrator and the other first piezoelectric vibrator. Connected in parallel. The switching means switches the connection destination of the second piezoelectric vibrator group in parallel connection at the predetermined timing.

FIG. 1 is a diagram for explaining the overall configuration of the ultrasonic diagnostic apparatus according to the first embodiment. FIG. 2 is a diagram for explaining suppression of grading lobes. FIG. 3 is a diagram for explaining a conventional example of the aperture synthesis method. FIG. 4 is a diagram for explaining a conventional example of the aperture synthesis method. FIG. 5 is a diagram illustrating an example of the configuration of the ultrasonic probe according to the first embodiment. FIG. 6 is a diagram illustrating an example of transmission / reception of ultrasonic waves during aperture synthesis by the ultrasonic probe according to the first embodiment.

(First embodiment)
Details of the ultrasonic probe and the ultrasonic diagnostic apparatus according to the present application will be described below. First, the configuration of the ultrasonic diagnostic apparatus according to the first embodiment will be described. FIG. 1 is a diagram for explaining a configuration of an ultrasonic diagnostic apparatus 100 according to the first embodiment. As shown in FIG. 1, the ultrasonic diagnostic apparatus 100 according to the first embodiment includes an ultrasonic probe 1, a monitor 2, an input apparatus 3, and an apparatus main body 10.

  The ultrasonic probe 1 includes a plurality of piezoelectric vibrators, and the plurality of piezoelectric vibrators generate ultrasonic waves based on a drive signal supplied from a transmission / reception unit 11 included in the apparatus main body 10 described later. The ultrasonic probe 1 receives the reflected wave from the subject P and converts it into an electrical signal. The ultrasonic probe 1 includes a matching layer provided on the piezoelectric vibrator, a backing material that prevents propagation of ultrasonic waves from the piezoelectric vibrator to the rear, and the like. The ultrasonic probe 1 is detachably connected to the apparatus main body 10.

  For example, when ultrasonic waves are transmitted from the ultrasonic probe 1 to the subject P, the transmitted ultrasonic waves are reflected one after another on the discontinuous surface of the acoustic impedance in the body tissue of the subject P, and are reflected as reflected wave signals. Received by a plurality of piezoelectric vibrators of the acoustic probe 1. The amplitude of the received reflected wave signal depends on the difference in acoustic impedance at the discontinuous surface where the ultrasonic wave is reflected. Note that the reflected wave signal when the transmitted ultrasonic pulse is reflected on the moving blood flow or the surface of the heart wall depends on the velocity component of the moving body in the ultrasonic transmission direction due to the Doppler effect. And undergoes a frequency shift.

  Here, the ultrasonic probe 1 according to the first embodiment is configured to be able to improve the S / N during reception when the aperture synthesis method is used. Details will be described later. The ultrasound probe 1 according to the first embodiment may be an ultrasound probe that scans the subject P in two dimensions with ultrasound, or the subject P can be scanned in three dimensions. An ultrasonic probe may be used.

  The monitor 2 displays a GUI (Graphical User Interface) for an operator of the ultrasonic diagnostic apparatus 100 to input various setting requests using the input apparatus 3, and displays an ultrasonic image generated in the apparatus main body 10. Or display.

  The input device 3 includes a trackball, a switch, a dial, a touch command screen, and the like. The input device 3 receives various setting requests from an operator of the ultrasonic diagnostic apparatus 100 and transfers the received various setting requests to the apparatus main body 10. For example, the input device 3 receives various setting requests for controlling the ultrasonic probe 1 and transfers the request to the control unit 17.

  The apparatus main body 10 is an apparatus that controls transmission / reception of ultrasonic waves by the ultrasonic probe 1 and generates an ultrasonic image based on reflected waves received by the ultrasonic probe 1. As shown in FIG. 1, the apparatus body 10 includes a transmission / reception unit 11, a B-mode processing unit 12, a Doppler processing unit 13, an image generation unit 14, an image memory 15, an internal storage unit 16, and a control unit 17. And have.

  The transmission / reception unit 11 includes a trigger generation circuit, a delay circuit, a pulsar circuit, and the like, and supplies a drive signal to the ultrasonic probe 1. The pulsar circuit repeatedly generates rate pulses for forming transmission ultrasonic waves at a predetermined rate frequency. The delay circuit also sets the delay time for each piezoelectric vibrator necessary for determining the transmission directivity by focusing the ultrasonic wave generated from the ultrasonic probe 1 into a beam shape, and for each rate pulse generated by the pulser circuit. Give to. The trigger generation circuit applies a drive signal (drive pulse) to the ultrasonic probe 1 at a timing based on the rate pulse. In other words, the delay circuit arbitrarily adjusts the transmission direction from the piezoelectric vibrator surface by changing the delay time given to each rate pulse.

  The transmission / reception unit 11 has a function capable of instantaneously changing the transmission frequency, the transmission drive voltage, and the like in order to execute a predetermined scan sequence based on an instruction from the control unit 17 described later. In particular, the change of the transmission drive voltage is realized by a linear amplifier type transmission circuit capable of instantaneously switching its value or a mechanism for electrically switching a plurality of power supply units.

  The transmission / reception unit 11 includes an amplifier circuit, an A / D converter, an adder, and the like, and performs various processes on the reflected wave signal received by the ultrasonic probe 1 to generate reflected wave data. The amplifier circuit amplifies the reflected wave signal for each channel and performs gain correction processing. The A / D converter performs A / D conversion on the gain-corrected reflected wave signal and gives a delay time necessary for determining reception directivity to the digital data. The adder performs an addition process of the reflected wave signal processed by the A / D converter to generate reflected wave data. By the addition processing of the adder, the reflection component from the direction corresponding to the reception directivity of the reflected wave signal is emphasized.

  As described above, the transmission / reception unit 11 controls transmission directivity and reception directivity in ultrasonic transmission / reception. Here, the transmission / reception unit 11 according to the present embodiment performs aperture synthesis processing for switching the piezoelectric vibrator to be driven for each transmission rate and adding signals. The details of switching of the piezoelectric vibrator by the transmission / reception unit 11 will be described later.

  The B-mode processing unit 12 receives the reflected wave data from the transmission / reception unit 11 and performs logarithmic amplification, envelope detection processing, and the like to generate data (B-mode data) in which the signal intensity is expressed by brightness. . Here, the B-mode processing unit 12 can change the frequency band to be visualized by changing the detection frequency. Further, the B-mode processing unit 12 can perform detection processing with two detection frequencies in parallel on one reflected wave data.

  The Doppler processing unit 13 performs frequency analysis on velocity information from the reflected wave data received from the transmission / reception unit 11, extracts blood flow, tissue, and contrast agent echo components due to the Doppler effect, and mobile body information such as average velocity, dispersion, and power. Is generated for multiple points (Doppler data).

  Note that the B-mode processing unit 12 and the Doppler processing unit 13 according to the present embodiment can process both two-dimensional reflected wave data and three-dimensional reflected wave data. That is, the B-mode processing unit 12 according to the present embodiment can generate three-dimensional B-mode data from the three-dimensional reflected wave data. In addition, the Doppler processing unit 13 according to the present embodiment can generate three-dimensional Doppler data from the three-dimensional reflected wave data.

  The image generation unit 14 generates an ultrasound image from the data generated by the B mode processing unit 12 and the Doppler processing unit 13. That is, the image generation unit 14 generates a B-mode image in which the intensity of the reflected wave is represented by luminance from the B-mode data generated by the B-mode processing unit 12. Specifically, the image generation unit 14 generates a two-dimensional or three-dimensional B-mode image from the two-dimensional B-mode data or the three-dimensional B-mode data generated by the B-mode processing unit 12.

  In addition, the image generation unit 14 generates a color Doppler image as an average velocity image, a dispersed image, a power image, or a combination image representing moving body information from the Doppler data generated by the Doppler processing unit 13. Specifically, the image generation unit 14 generates a two-dimensional or three-dimensional color Doppler image from the two-dimensional Doppler data or the three-dimensional Doppler data generated by the Doppler processing unit 13.

  The image generation unit 14 can also generate various images for displaying the generated three-dimensional data on the monitor 2. Specifically, the image generation unit 14 can generate an MPR image and a rendering image from three-dimensional data.

  The image memory 15 is a memory that stores the ultrasonic image generated by the image generation unit 14. The image memory 15 can also store data generated by the B-mode processing unit 12 and the Doppler processing unit 13.

  The internal storage unit 16 stores a control program for performing ultrasonic transmission / reception, image processing and display processing, diagnostic information (for example, patient ID, doctor's findings, etc.), various data such as a diagnostic protocol and various body marks. To do. The internal storage unit 16 is also used for storing images stored in the image memory 15 as necessary.

  The control unit 17 is a control processor (CPU: Central Processing Unit) that realizes a function as an information processing apparatus (computer), and controls the entire processing of the ultrasonic diagnostic apparatus 100. Specifically, the control unit 17 is based on various setting requests input from the operator via the input device 3 and various control programs and various data read from the internal storage unit 16. The processing of the processing unit 12, the Doppler processing unit 13, and the image generation unit 14 is controlled. The control unit 17 also includes an ultrasonic image stored in the image memory 15, various images stored in the internal storage unit 16, a GUI for performing processing by the image generation unit 14, a processing result of the image generation unit 14, and the like. Is displayed on the monitor 2.

  The overall configuration of the ultrasonic diagnostic apparatus 100 according to the first embodiment has been described above. With this configuration, the ultrasonic diagnostic apparatus 100 according to the first embodiment improves the S / N during reception when the aperture synthesis method is used by the configuration of the ultrasonic probe 1 described in detail below. Configured to allow that.

  Here, first, the case where the S / N at the time of reception when the aperture synthesis method is used in the prior art will be described. As described above, in the conventional technique, the aperture synthesis method is used to improve the resolution while suppressing the grading lobe in the ultrasonic probe including the array type piezoelectric vibrator. FIG. 2 is a diagram for explaining suppression of grading lobes. Here, in FIG. 2, (A) in FIG. 2 shows the generation of grading lobes, and (B) in FIG. 2 shows the suppression of grading lobes. Note that FIG. 2 shows ultrasonic waves transmitted from the piezoelectric vibrator 20 when the ultrasonic probe is viewed from the side.

  For example, in the array-type piezoelectric vibrator 20, as shown in the left diagram of FIG. 2A, a wavefront is generated from each of the piezoelectric vibrators 20, and those wavefronts are combined to form a main lobe. Is formed. At this time, in the array type piezoelectric vibrator 20, the main lobe can have directivity by providing a delay time for each piezoelectric vibrator 20. Thus, in the array type piezoelectric vibrator 20, wavefronts of the same wavelength are combined to form a main lobe, and a beam is transmitted in a desired direction.

  However, in the array type piezoelectric vibrator 20, as shown in the right diagram of FIG. 2A, there may be a grading lobe in which the wave fronts of the adjacent piezoelectric vibrators 20 are shifted by one wavelength. . As shown in the diagram on the right side of FIG. 2A, this grading lobe has a wavelength of “dsin θ” when the pitch of adjacent piezoelectric vibrators 20 (interval between the piezoelectric vibrators) is “d”. It is emitted in the direction of “nλ” which is an integral multiple of “λ”.

Such a grading lobe is emitted in a different direction from the main lobe and causes artifacts, so it is required to suppress it. Therefore, as a condition for suppressing such a grading lobe, for example, an equation shown in FIG. 2B is known. That is, as shown in FIG. 2B, in order not to generate a grading lobe within the main lobe scanning angle “θ _M ”, the element pitch (pitch (interval) between piezoelectric vibrators) “d” is An ultrasonic probe with a narrow pitch is designed so that “d <λ / (1 + sin θ _M )”.

  Here, if the pitch between the piezoelectric vibrators is designed to be narrow, if the number of the piezoelectric vibrators is constant, the opening width becomes narrow, and a certain limit occurs in the resolution. Therefore, in order to improve the resolution while suppressing the grading lobe, an aperture synthesis method is used in which the piezoelectric vibrator to be driven is switched for each transmission rate, and each data is stored and added. 3 and 4 are diagrams for explaining a conventional example of the aperture synthesis method. 3B and 3C show a state in which a plurality of piezoelectric vibrators are arranged.

  For example, in the conventional aperture synthesis method, as shown in FIG. 3A, by switching the piezoelectric vibrator 20 using the switch 30, the plurality of piezoelectric vibrators 20 are divided into left and right halves, and two or more Are combined to obtain a high resolution beam. As an example, as shown in the upper diagram of FIG. 3B, in the aperture synthesis method, at the first transmission “T: transmission”, all the piezoelectric vibrators 20 are driven to transmit ultrasonic waves. Then, at the time of reception “R: reception”, the left half piezoelectric vibrator 20 is driven to receive the reflected wave. As shown in the lower diagram of FIG. 3B, in the aperture synthesis method, at the second transmission “T”, all the piezoelectric vibrators 20 are driven again to transmit ultrasonic waves. When receiving “R”, the right half piezoelectric vibrator 20 is driven to receive the reflected wave. In the aperture synthesis method, the reflected waves received at the first time and the second time are synthesized (complex addition).

  Also, for example, in the conventional aperture synthesis method, as shown in FIG. 3C, even during transmission “T”, the driving element is divided into the left and right halves, and the ultrasonic wave is transmitted four times. The data and the data of the reflected wave at the time of four receptions are synthesized.

  Further, in the conventional aperture synthesis method, as shown in FIG. 4, by switching the piezoelectric vibrator 20 using the switch 30, the timing for driving the plurality of piezoelectric vibrators 20 for each vibrator is switched. Two or more beams are combined to obtain a high resolution beam. As an example, as shown in FIG. 4A, in the aperture synthesis method, at the first transmission “T”, all the piezoelectric vibrators 20 are driven to transmit ultrasonic waves and receive “R”. ”, The piezoelectric vibrator 20 is driven every other vibrator to receive the reflected wave. As shown in FIG. 4B, in the aperture synthesis method, at the second transmission “T”, all the piezoelectric vibrators 20 are driven again to transmit ultrasonic waves and receive “R”. Sometimes the reflected wave is received by driving the piezoelectric vibrator 20 that was not driven at the first time. In the aperture synthesis method, the reflected waves received at the first time and the second time are synthesized.

  As described above, in the conventional aperture synthesis method, the driving of a plurality of piezoelectric vibrators is switched ON / OFF. However, in the case of such an aperture synthesis method, about half of the piezoelectric vibrators do not receive the reflected wave at one ultrasonic transmission rate. That is, when such an aperture synthesis method is used, the S / N during reception at a single transmission rate is reduced. Therefore, the ultrasonic diagnostic apparatus 100 according to the first embodiment improves the S / N during reception when the aperture synthesis method is used.

  FIG. 5 is a diagram illustrating an example of the configuration of the ultrasonic probe 1 according to the first embodiment. As shown in FIG. 5, the ultrasonic probe 1 according to the first embodiment includes a first piezoelectric vibrator 21, a second piezoelectric vibrator 22, and a switch 31.

  Each of the first piezoelectric vibrators 21 is directly connected to a control unit that controls transmission and reception of ultrasonic waves. Specifically, the first piezoelectric vibrator 21 is directly connected to the transmitting / receiving unit 11 as shown in FIG. That is, in the first piezoelectric vibrator 21, transmission / reception of ultrasonic waves is directly controlled by the transmission / reception unit 11.

  The second piezoelectric vibrator 22 is disposed between the first piezoelectric vibrators 21 and has a predetermined relationship with respect to one adjacent first piezoelectric vibrator 21 and the other first piezoelectric vibrator 21. Connected in parallel at timing. Specifically, as shown in FIG. 5, the second piezoelectric vibrator 22 is connected directly to the transmitting / receiving unit 11 and connected in parallel with the adjacent first piezoelectric vibrator 21 by the switch 31. Selected.

  The switch 31 switches the connection destination of the second piezoelectric vibrator 22 group in parallel connection at a predetermined timing. Specifically, the switch 31 connects the first piezoelectric vibrator 21 adjacent to the connection destination of the second piezoelectric vibrator 22 disposed between the first piezoelectric vibrators 21 for each transmission rate of ultrasonic waves. Switch alternately with.

  For example, in the upper diagram of FIG. 5, the second piezoelectric vibrator 22 shown third from the left is connected in parallel with the first piezoelectric vibrator 21 arranged on the right side of the drawing at the first transmission rate. It is controlled so that That is, the switch 31 switches the connection destination as shown in the upper diagram of FIG. The second piezoelectric vibrator 22 shown third from the left is, as shown in the lower figure of FIG. 5, with the first piezoelectric vibrator 21 arranged on the left side of the drawing at the second transmission rate. It is controlled to be connected in parallel. That is, the switch 31 switches the connection destination as shown in the lower diagram of FIG.

  In the ultrasonic probe 1 according to the first embodiment, as shown in FIG. 5, the first piezoelectric vibrators 21 and the second piezoelectric vibrators 22 are alternately arranged, and the second piezoelectric element 21 is switched by the switch 31. The connection destination of the parallel connection of the vibrator is switched. Here, the switch 31 is configured by, for example, a high-voltage switch made of a semiconductor. For example, the switch 31 is a toggle switch as shown in FIG.

  Here, switching of the connection destination of the parallel connection by the switch 31 is executed by the transmission / reception unit 11. That is, when the transmission / reception unit 11 controls transmission / reception of ultrasonic waves by aperture synthesis, the transmission / reception unit 11 controls the switch 31 for each transmission rate to switch the connection destination of the second piezoelectric vibrators 22 in parallel.

  FIG. 6 is a diagram illustrating an example of transmission / reception of ultrasonic waves during aperture synthesis by the ultrasonic probe 1 according to the first embodiment. FIG. 6 shows an example of ultrasonic transmission / reception when the left end is the second piezoelectric vibrator 22 and the right end is the first piezoelectric vibrator 21 in the array type piezoelectric vibrator.

  For example, as shown in FIG. 6A, the ultrasonic probe 1 transmits all ultrasonic waves by driving all piezoelectric vibrators at the first transmission “T”, and at the reception “R”, The two piezoelectric vibrators 22 are connected in parallel with the first piezoelectric vibrator 21 on the right side of the drawing to receive the reflected wave (upper state in FIG. 5). Then, as shown in FIG. 6B, at the time of the second transmission “T”, the ultrasonic probe 1 drives all the piezoelectric vibrators again to transmit ultrasonic waves, and at the time of reception “R”. Then, the second piezoelectric vibrator 22 is connected in parallel with the first piezoelectric vibrator 21 on the left side in the drawing to receive the reflected wave (lower state in FIG. 5).

  Thereby, in the ultrasonic probe 1 according to the first embodiment, as shown by the downward triangle in FIG. 5, the first probe on the right side in the drawing is compared with the case where only the first piezoelectric vibrator 21 is driven. When connected in parallel with one piezoelectric vibrator 21, the center position of the piezoelectric vibrator shifts to the left by a half vibrator. On the other hand, when the first piezoelectric vibrator 21 on the left side in the drawing is connected in parallel, the center position of the piezoelectric vibrator is half the vibrator as compared with the case where only the first piezoelectric vibrator 21 is driven. Shift right.

  This is because the first piezoelectric vibrator 21 and the second piezoelectric vibrator 22 connected in parallel effectively function as one vibrator, and the ultrasonic diagnostic apparatus 100 according to the first embodiment. In the aperture synthesis method, the first and second reflected waves shifted by one piezoelectric vibrator are synthesized. In FIG. 6, the ultrasonic waves are transmitted by driving all the piezoelectric vibrators at the time of transmission, but this is wired so that the second piezoelectric vibrator 22 is further directly connected to the transmission / reception unit 11. Can be executed.

  As described above, in the ultrasonic probe 1 according to the first embodiment, almost all piezoelectric vibrators are driven in transmission / reception of ultrasonic waves for each transmission rate. Accordingly, high sensitivity can be maintained even during reception in aperture synthesis, and S / N during reception can be improved. At this time, since the phase of the grading lobe is inverted by shifting the transmission / reception beam by one piezoelectric vibrator, the grading lobe can be effectively suppressed by the addition process.

  Here, as described above, in the ultrasonic probe 1 according to the first embodiment, the first piezoelectric vibrator 21 and the second piezoelectric vibrator 22 connected in parallel are effectively used as one vibrator. Function. That is, since the effective width of the piezoelectric vibrator is twice that of the normal state, the directivity (element factor) of one piezoelectric vibrator is narrowed, and the sensitivity at the time of beam deflection is relatively lowered. Luminance unevenness may occur. Therefore, in the ultrasonic diagnostic apparatus 100 according to the first embodiment, it is possible to reduce luminance unevenness by performing gain correction for each raster. In addition, it is also possible to suppress luminance unevenness by making the pitch of the piezoelectric vibrators sufficiently fine.

  As described above, according to the first embodiment, the first piezoelectric vibrator 21 group is directly connected to the transmission / reception unit 11 that controls transmission / reception of ultrasonic waves. The second piezoelectric vibrator 22 group is disposed between the first piezoelectric vibrators 21, and is predetermined with respect to the adjacent one first piezoelectric vibrator 21 and the other first piezoelectric vibrator 21. Are connected in parallel. The switch 31 switches the connection destination of the second piezoelectric vibrator 22 group in parallel connection at a predetermined timing. Therefore, the ultrasonic probe 1 according to the first embodiment can perform aperture synthesis by driving almost all piezoelectric vibrators in transmission / reception of ultrasonic waves for each transmission rate. It is possible to improve the S / N during reception.

  Further, for example, in the case of the prior art in which the piezoelectric vibrators shown in FIG. 3 are divided into halves on the left and right sides, in the mounting of the switch circuit, between the piezoelectric vibrators at positions separated by a half distance of the piezoelectric vibrator array. It is necessary to connect in parallel, the wiring is complicated, the wiring length becomes long, or in some cases, it can not be mounted in the probe gripping part, it may be mounted in the connector part with the device body . In such a case, there is a problem that the number of core wires of the cable increases, the cable becomes thicker and costs increase. However, since the ultrasonic probe 1 according to the first embodiment only requires wiring between adjacent piezoelectric vibrators, the wiring length is short, and the ultrasonic probe 1 can be mounted in the probe holding portion.

  Further, for example, in the case of the prior art in which every other piezoelectric vibrator is driven as shown in FIG. 4, signal leakage (cross coupling) may occur. In other words, since the load impedance in the piezoelectric vibrator differs greatly between when it is connected to the transmitter / receiver and when it is not connected, cross coupling may occur when the load impedance is high (not driven). is there. For example, as shown in FIG. 4, when the piezoelectric vibrators in the ON state and the piezoelectric vibrators in the OFF state are alternately arranged, the cross between the piezoelectric vibrators in the ON state via the piezoelectric vibrators in the OFF state. Coupling occurs. However, the ultrasonic probe 1 according to the first embodiment can suppress cross coupling by driving almost all of the piezoelectric vibrators.

  Further, according to the first embodiment, the switch 31 is a toggle switch. Therefore, the ultrasonic probe 1 according to the first embodiment can be easily configured without using a complicated switch as a crosspoint switch or the like.

  In addition, since the toggle switch is used as the switch 31, the ultrasonic probe 1 according to the first embodiment can control switching with simpler control than when a multiplexer or the like is used, for example.

(Second Embodiment)
Although the first embodiment has been described so far, the present invention may be implemented in various different forms other than the first embodiment described above.

  In the first embodiment described above, an example in which aperture synthesis is performed has been described. However, the ultrasonic diagnostic apparatus 100 according to the present application can be controlled not to perform aperture synthesis in accordance with the frequency of ultrasonic waves transmitted and received.

  In such a case, the switch 31 moves the second piezoelectric vibrator 22 group between the adjacent first piezoelectric vibrators 21 when the ultrasonic frequency controlled by the transmission / reception unit 11 falls below a predetermined frequency. Maintain in parallel with either one of them. That is, the transmission / reception unit 11 does not perform switching control of the switch 31 for each transmission rate when the frequency of ultrasonic waves to be transmitted / received is low, and the first piezoelectric vibrator 22 adjacent to one of the first piezoelectric vibrators 22 is not used. It is maintained in a state of being connected in parallel with the piezoelectric vibrator 21.

  Here, since the intensity of the grading lobe depends on the frequency of the ultrasonic wave, the influence of the grading lobe may not be a problem at a low frequency. Therefore, in such a case, the ultrasonic diagnostic apparatus 100 is in a state in which the second piezoelectric vibrator 22 is connected in parallel to one of the adjacent first piezoelectric vibrators 21 without performing aperture synthesis. To maintain. Note that the low frequency and the pitch of the piezoelectric vibrator, in which the influence of the grading lobe described above is not a problem, are set in advance.

  That is, the transmission / reception unit 11 is based on information on the pitch between the piezoelectric vibrators of the ultrasonic probe 1 currently connected (a pitch twice as high as that of the parallel connection) and the frequency of the ultrasonic wave transmitted / received at the present time. Whether or not to control the switch 31 is determined. And the transmission / reception part 11 performs switching control of the switch 31 based on the determination result.

  Further, in the above-described first embodiment, the case where the total number of the first piezoelectric vibrator 21 and the second piezoelectric vibrator 22 is an even number has been described. However, the embodiment is not limited to this. For example, the total number may be an odd number.

  As described above, according to the first embodiment and the second embodiment, the ultrasonic probe and the ultrasonic diagnostic apparatus of this embodiment improve the S / N at the time of reception when the aperture synthesis method is used. Make it possible.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 Ultrasonic probe 10 Apparatus main body 11 Transmission / reception part 17 Control part 21 1st piezoelectric vibrator 22 2nd piezoelectric vibrator 31 Switch 100 Ultrasonic diagnostic apparatus

Claims (4)

A first piezoelectric vibrator group directly connected to a control unit that controls transmission and reception of ultrasonic waves;
A second piezoelectric vibration disposed between the first piezoelectric vibrators and connected in parallel at a predetermined timing to one adjacent first piezoelectric vibrator and the other first piezoelectric vibrator. A group of children,
Switching means for switching a connection destination of parallel connection of the second piezoelectric vibrator group at the predetermined timing;
An ultrasonic probe comprising:   When the frequency of the ultrasonic wave controlled by the control unit falls below a predetermined frequency, the switching unit moves the second piezoelectric vibrator group to one of the adjacent first piezoelectric vibrators. The ultrasonic probe according to claim 1, wherein the ultrasonic probe is maintained in a parallel connection state.   The ultrasonic probe according to claim 1, wherein the switching unit is a toggle switch. The ultrasonic probe according to any one of claims 1 to 3,
An ultrasonic diagnostic apparatus comprising: a switching control unit that controls the switching unit for each transmission rate to switch a connection destination of parallel connection of the second piezoelectric vibrator group.

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