JP2001286467A - Ultrasonic diagnostic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform the three-dimensional sector scanning in a small number of delay circuits even with a probe having two-dimensionally arrayed vibrators. SOLUTION: Plural ring vibrators are selected in a concentric circle for the two-dimensionally arrayed vibrators 20, and elements constituting one ring vibrator are connected to a delay circuit so that the same delay time is given to each element. The pattern of selecting the ring vibrators 20 in a concentric circle, including the position of the center, is changed according to the position of the transmission focal point and the direction of the received beam. The direction dynamic focus for slanting the received beam toward the vibrator surface moves the ring vibrators continuously according to the position of the receiving focal point.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic diagnostic apparatus, and more particularly, to an ultrasonic probe incorporating a two-dimensionally arrayed transducer.
The present invention relates to an ultrasonic diagnostic apparatus capable of forming a three-dimensional image of the inside of a subject using a two-dimensional probe (hereinafter, referred to as a two-dimensional probe).

[0002]

2. Description of the Related Art Ultrasonic diagnostic apparatuses which use an ultrasonic probe (hereinafter referred to as a one-dimensional probe) in which a plurality of transducers are arranged in an array form are still in use today. Recently,
As the recognition of the usefulness of three-dimensional image diagnosis in other modalities, for example, the field of X-ray CT apparatus and MRI apparatus, the apparatus for displaying the inside of a subject with a three-dimensional image in the field of ultrasonic image diagnosis and providing the diagnosis is also provided. Are being researched and developed. An ultrasonic beam scanning method for obtaining a three-dimensional image in an ultrasonic diagnostic apparatus includes moving a one-dimensional probe manually or mechanically on a body surface of a subject in a direction intersecting a scanning direction of the ultrasonic beam. There are two methods: one is to make the probe two-dimensional and the other is to electronically three-dimensionally scan the inside of the subject with an ultrasonic beam. It is difficult to manually or mechanically move the probe while making contact with the body surface, and the latter is promising.

A two-dimensional probe has a structure in which an elongated rod-shaped transducer element of a conventional one-dimensional array probe is divided into a plurality of elements in a longitudinal direction. This two-dimensional probe is used for actual medical diagnosis. In this case, the number of transducers is required to be about 64 × 64. In this case, the number of transducers is as large as 4,096. When three-dimensional measurement of the inside of the subject is performed by the two-dimensional probe using a sector scan method, 4,09
Drive all six transducers. Therefore, it is necessary to provide delay circuits for all of the 4,096 transducers. For this reason, the device becomes large and the device becomes expensive. For this purpose, a method has been proposed in which 4,096 transducers are thinned out and transmitted and received by 256 transducers.

Further, in order to reduce the number of delay circuits (synonymous with the number of channels of the phasing circuit), the transducers of the two-dimensional probe are formed into a plurality of transducer groups in a concentric manner. It has been proposed to transmit and receive ultrasonic waves by giving the same delay time to each group. This is called a Fresnel ring bundling method and is effective for a linear scan method.

[0005]

A sector scan type probe which is often used for examination of the heart transmits and receives an ultrasonic beam from between the ribs of a living body to the heart.
The transmitting and receiving area of the probe cannot be increased. Also, the size of the transducer element of the two-dimensional probe is naturally smaller than that of the one-dimensional probe in which the transducers are arranged in an array.

Therefore, if the transducers are thinned and used to reduce the number of delay circuits, the sensitivity of the probe is lowered,
The S / N of the obtained signal is reduced, and the image quality is also reduced. Therefore, the number of delay circuits cannot be simply reduced.

The present invention has been made in view of the above, and a first object of the present invention is to enable a sector scan in which an image with a good S / N can be obtained using a two-dimensional probe even if the number of delay circuits is small. It is to provide a simple ultrasonic diagnostic apparatus.

It is a second object of the present invention to provide an ultrasonic diagnostic apparatus capable of performing a three-dimensional sector scan of a subject using a two-dimensional probe.

A third object of the present invention is to provide an ultrasonic diagnostic apparatus which can scan a subject at high speed in a three-dimensional sector using a two-dimensional probe.

[0010]

According to the present invention, there is provided an ultrasonic probe in which a plurality of ultrasonic transducers for transmitting and receiving ultrasonic waves are two-dimensionally arranged. A plurality of transducer element groups are selected from the transducers in a concentric ring shape, ultrasonic waves to be transmitted and received are formed by giving different delay times to the respective element groups, an ultrasonic image is formed from the received signals, and a display device is provided. In an ultrasonic diagnostic apparatus for displaying an image to
Means for changing the transmission / reception direction of the ultrasonic wave for each transmission / reception cycle, means for changing the selection pattern of the ultrasonic transducer element group according to the beam direction of the transmission / reception, and ultrasonic transducer selection for each transducer element Means for providing a delay time according to the pattern.

According to another aspect of the present invention, there is provided an ultrasonic probe in which a plurality of ultrasonic transducers for transmitting and receiving ultrasonic waves are two-dimensionally arranged. A plurality of transducer element groups are selected in a ring shape, an ultrasonic beam for transmission and reception is formed by giving a different delay time to each element group, an ultrasonic image is formed from the received signal, and an image is displayed on a display device. In ultrasonic diagnostic equipment, at the time of transmission and reception,
The center of the concentric ring is defined by the point at which the perpendicular line from the focus point of the transmitting or receiving wave positioned on the ultrasonic beam line in the direction inclined to the transducer array plane to the array transducer plane intersects the array transducer plane. Means for selecting the concentric ring-shaped transducer group at the time of transmission / reception, and means for moving a selected center of the ring-shaped transducer group together with movement of a reception focus point on the ultrasonic beam line. It is characterized by.

According to another aspect of the present invention, there is provided an ultrasonic probe in which a plurality of ultrasonic transducers for transmitting and receiving ultrasonic waves are arranged two-dimensionally, and concentric with the ultrasonic transducer. A plurality of transducer element groups are selected in a ring shape, ultrasonic waves for transmission and reception are formed by giving different delay times to the respective element groups, an ultrasonic image is formed from the received signal, and an ultrasonic image is displayed on a display device. A means for setting the transmission / reception direction of the ultrasonic wave at a predetermined position on the arrayed transducer surface in a three-dimensional direction in the ultrasonic diagnostic apparatus; Means for selecting the concentric ring-shaped vibrator group at the time of transmission / reception with a point at which a perpendicular line from the focus point of the transmitting or receiving wave positioned to the arrayed oscillator surface intersects with the arrayed oscillator surface located at the center of the concentric ring And the ultrasonic beam It is characterized by comprising a means for moving the selected center of the ring-shaped transducer groups with the movement of the reception focus point on in.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 8 is a block diagram showing an overall configuration of an ultrasonic diagnostic apparatus for implementing the present invention. In the drawing, reference numeral 10 denotes a two-dimensional probe having M and N, that is, M × N two-dimensional array transducers 20 in each of two orthogonal directions. And a switching circuit unit 30 for switching and selecting the two-dimensional arrayed transducers 20 for each transmission / reception cycle of the ultrasonic beam is accommodated in the case. Reference numeral 40 denotes a switch control unit, and the switching circuit 3
A signal for selecting an oscillator is supplied to 0.

Reference numeral 50 denotes a transmission / reception separation circuit for changing a signal passing direction between transmission and reception, and reference numeral 60 denotes a transmission wave for supplying a drive signal to an ultrasonic transducer for transmitting an ultrasonic wave into a subject. The circuit includes a conventionally known pulse generation circuit, an amplification circuit, and a transmission delay circuit. Reference numeral 70 denotes a wave receiving and phasing unit, which receives a signal obtained by converting a reflected wave (echo) reflected in the object by an ultrasonic wave emitted into the object into an electric signal (echo signal) by an ultrasonic vibrator. And forming and outputting an ultrasonic beam signal as received from a predetermined direction,
This also includes a conventionally known delay circuit and an addition circuit. Reference numeral 80 denotes a signal processing unit which performs logarithmic conversion processing, filter processing, γ correction, and the like as pre-processing for imaging the echo signal output from the reception phasing unit 70.

Reference numeral 90 denotes a signal output from the signal processing unit 80 for each scan of the ultrasonic beam, which is digitized as necessary, input and stored to form image data, and output according to the scan of the image display device. That is, a scan converter that performs scan conversion between ultrasonic scanning and display scanning,
Conventionally, in this field, it is well known as a digital scan converter (DSC).

A display device 100 converts the image data output from the digital scan converter 90 into a luminance signal by D / A conversion and displays the image as an image, and usually has a CRT monitor. Reference numeral 200 denotes a central processing unit (CPU) that directly or indirectly controls each of the above-described components and performs transmission and reception of ultrasonic waves and image display.

Next, the operation of the above-described apparatus will be briefly described. The two-dimensional probe 10 is brought into contact with the body surface of the subject to be examined, and after inputting scan parameters such as a transmission focus depth from an operation panel (not shown), an ultrasonic scan start command is input. Then, the CPU 200 controls each unit and starts an ultrasonic scan. First, the CPU 20
0 outputs to the switch control unit 40 and the wave transmitting unit 60 a vibrator selection instruction in the first transmission, a drive pulse output instruction, and an instruction to set a delay time corresponding to the transmission focus depth. When these commands are executed, a driving pulse is supplied from the transmitting unit 60 to the two-dimensional probe 10 via the transmitting delay circuit. The switching circuit 30 in the two-dimensional probe 10 connects the transmission delay circuit and the driving pulse input line of the vibrator so as to form a concentric ring-shaped vibrator group to be described later according to a command from the CPU 200. When a driving pulse is input, the vibrator vibrates at a predetermined frequency and sequentially transmits ultrasonic waves into the subject.

The ultrasonic wave transmitted into the subject is partially reflected on the surface of the tissue or organ in the living body where the acoustic impedance is different, and is reflected toward the probe 10 as an echo. In order to receive this echo, CPU 200 controls the receiving system. First, at the same time as the end of the transmission, the switching circuit 30 is switched to select the oscillator for reception and the reception and transmission unit. The selection of the transducer for reception also forms a concentric ring-shaped transducer group as in the case of the transmission, and details thereof will be described later. Along with the selection of the transducer switching, the control of the reception delay time for the wave receiving and transmitting unit 70 is performed.

As a result, echoes generated as the ultrasonic wave propagates from a shallow portion to a deep portion in the subject are received, and the echo signals output from the respective reception delay circuits are added to the addition circuit of the reception and transmission section 70. And output as an echo signal of the received beam to the signal processing unit 80. The signal processing unit 80 performs the above-described processing on the input echo signal and outputs the processed signal to the DSC 90. The DSC 90 stores the input signal in the memory, and reads out and outputs the stored content to the display device 100 in accordance with the display synchronization signal.
When the above operation is completed, the CPU 200 changes the transmission / reception direction of the ultrasonic wave and sequentially changes the transmission / reception direction of the ultrasonic wave in the second, third, and so on, and repeats the above operation.

In the repetition of transmission and reception, the ultrasonic beam is changed in many directions so that a predetermined position on the arrayed transducer surface is always set as the base point so as to be the vertex of the cone. As a result, the ultrasonic beam performs a three-dimensional sector scan inside the subject.

Next, a detailed description will be given of a transducer selection state in transmitting and receiving an ultrasonic wave according to the present invention. FIG. 3 is a schematic diagram of forming a transmitting and receiving ultrasonic beam at the center of the two-dimensional array transducer 20 built in the two-dimensional probe 10. FIG.
(a) and the concentric circles shown in FIG. 3 (b) indicate that the concentric vibrators are selected as a group. That is, the same delay time is given to the vibrator group existing in the region sandwiched between the concentric circles, with each concentric circle as a boundary. In FIG. 3A, the fan-shaped straight line group is a point F (focus point) at which an ultrasonic wave radiated from each ring-shaped vibrator group selected in a ring shape.
And a state where the ultrasonic wave reflected from the point F is directed to each ring-shaped vibrator group. Note that FIG.
In (b), the number of two-dimensional array transducers is shown as 7 × 7 = 49 in the orthogonal X and Y directions.
An array of about 64 × 64 = 4,096 elements is formed in both lateral directions, and the element group selected in a ring shape draws many finer concentric circles. The distance from the point F to each of the vibrators forming one ring is slightly different between the distance to the vibrator located on the inner periphery of the ring and the distance to the vibrator located on the outer periphery of the ring. Occurs. Therefore, in order to give the same delay time to the vibrator positioned on the inner circumference of the ring and the vibrator positioned on the outer circumference of the ring, it is preferable to limit the difference between the diameters of the inner circumference and the outer circumference of the ring. Will be obtained.

If the difference between the inner and outer diameters of the ring is large, the problem of the phase of the ultrasonic wave will be highlighted. That is, since the input / output lines of the plurality of vibrators forming the ring-shaped vibrator are bundled (common connection) by the switching circuit, if the ring width of the ring-shaped vibrator is large, the transmission focus becomes weak, Further, a cancellation phenomenon of the received echo occurs. That is, the phasing accuracy is reduced. In particular, when an echo from the inside of the subject returns to the transducer surface in an oblique direction at the time of receiving a wave, there is a phase difference between the received echoes in the ring inner peripheral transducer and the ring outer peripheral transducer. If the ring width is such that the echoes are out of phase, the outputs of those vibrators are bundled and added, causing a reduction in the echo signal. In order to reduce the influence, the width of the ring is preferably set to at least 1/4 wavelength or less, more preferably about 1/8 wavelength of the echo signal.

Next, a case where the ultrasonic beam is oscillated in an oblique direction with respect to the transducer surface will be described. The example of FIG. 4 shows a selected state of the element group when the ultrasonic beam is swung obliquely with respect to the arrayed transducer plane. The concentric circles shown in FIGS. 4A and 4B indicate that the transducers on the concentric circles are selected as a group. With the concentric circles as boundaries, the same delay time is given to the vibrator group existing in the region sandwiched between the concentric circles. In the example shown in FIG. 3, the center ring is located in the plane of the arrayed transducers. However, when the angle formed by the ultrasonic beam with the plane of the transducer becomes large, the center of the ring is arranged as shown in FIG. The ring-shaped vibrator group is selected so as to protrude from the end face of the plane or from within the arrayed vibrator plane.

The maximum delay time is given to the vibrator group located at the position of the perpendicular line from the focus point F to the plane of the two-dimensional array of vibrators, and the vibrator group located on the outer periphery is sequentially given a delay time shorter than the maximum delay time When the delay time corresponding to the distance between the focus point F and the arrayed transducer plane is controlled for each transducer group, an ultrasonic beam can be formed in a direction perpendicular to the transducer plane. Therefore, the linear scan can be executed by moving the ultrasonic beam in each transmission / reception cycle of the ultrasonic wave, and the concentric transducer selection state is changed to two.
By sequentially moving in two directions of the X direction and the Y direction on the plane of the two-dimensional array transducer, the ultrasonic beam can be two-dimensionally scanned,
Thus, a three-dimensional linear scan can be performed inside the subject.

When comparing FIG. 3 (b) and FIG. 4 (b), the number of concentric circles becomes different, so that the number of phasing circuits (the number of channels) for setting or controlling the delay time is set. Need the same number as the maximum number of concentric circles.

Next, the transmission / reception principle of the sector scan in this embodiment will be described. Typically, a sector scan looks like a fan bone with multiple beams spread out. FIG. 1 shows a case where an ultrasonic beam is formed in the direction of the center line of the fan, that is, FIG. The transmission of the ultrasonic beam is performed by the two-dimensional array transducer 20 as shown in FIG.
A predetermined delay time is given to each element group on each concentric circle so that a predetermined point on a straight line BL1 passing through the vibrator at the center of the concentric circle and perpendicular to the two-dimensional array vibrator plane becomes a focus point Ft. Transmits sound waves. Then, ultrasonic waves are sequentially emitted from the transducer groups so as to reach the focus point Ft in the same phase. Then, if there is a tissue having a different acoustic impedance during the propagation of the ultrasonic wave in the body, a part of the ultrasonic wave is reflected and returns as a reflected wave (echo) toward the probe. This echo is received by a plurality of concentric transducer groups as shown in FIG. Upon receiving this,
With the selected state of the ring-shaped vibrator fixed, the output signal (echo signal) of each vibrator group is sequentially received from the shallow position to the deep position on the straight line BL1 located at the center of the fan by the wave receiving phasing unit 70. The delay time is dynamically changed so as to move the focus point Fr. At the time of this reception, the delay time is controlled so that the reception focus point Fr is moved on the straight line BL1 in the direction of increasing the depth. Also, as mentioned above,
Naturally, it is necessary to oscillate the ultrasonic beam in a sector shape in order to perform a sector scan. In the present invention, this ultrasonic beam is inclined with respect to the transducer array plane by moving a concentric selection pattern as described below.

The transmission and reception when the beam is deflected from the center of the fan will be described with reference to FIG. As shown in FIG. 2A, a delay time is given to each transducer group so that ultrasonic waves reach the transmission focus point Ft at a position shifted from the center of the arrayed transducers simultaneously (in the same phase). Is the same as described above, but at this time, the selection of the concentric vibrator group is different from the above. That is, in this case, as shown in FIG. 2A, a concentric oscillator group is defined as a center of a concentric circle at a position where a perpendicular L drawn from the transmission focus point Ft to the arrayed oscillator surface intersects the arrayed oscillator surface. select. At this time, depending on the position of the focus point Ft, a perpendicular line from the focus point Ft to the arrayed transducer surface may deviate from the arrayed transducer as indicated by L1. Thereby, the ultrasonic waves radiated from the respective transducer groups simultaneously reach the transmission focus point Ft at the same time.

The reception of the echo generated by this transmission is shown in FIG.
This is performed as shown in FIG. The direction of the reception beam is set as a straight line BL2 connecting the reception focus point Fr and the center of the two-dimensional array transducer 20 so as to be inclined toward the array transducer plane,
The reception focus point Fr on this reception beam line BL2
Move dynamically. Now, assuming a reception focus point Fr at the position of FIG. 2B, the selection of the concentric vibrator group formed to receive the echo reflected from the reception focus point Fr depends on the reception focus point Fr. The process is performed centering on a point where a perpendicular line L1 descended from Fr to the vibrator plane intersects the vibrator plane. As the transmitted ultrasonic wave travels through the subject, the reception focus point changes to the reception beam line B.
L2 moves in a deep direction, but the receiving beam line BL
2 is inclined with respect to the arrayed oscillator plane, the point at which the perpendicular line from the reception focus point Fr to the arrayed oscillator plane intersects the oscillator plane moves rightward in the figure on the oscillator plane, and the perpendicular line Also moves like L3. As the wave receiving focus point Fr moves, the selection of the concentric ring-shaped vibrator group also moves. As described above, by moving the reception focus point Fr, one reception beam in the oblique direction of the sector scan is formed. The sector scan can be performed by changing the direction of the reception beam by a predetermined angle in each transmission / reception cycle. If the ultrasonic scanning is performed with the center direction of the fan and the inclination direction set to a number of directions within the solid angle of the top of the cone, the subject can be three-dimensionally sector-scanned. .

When three-dimensionally scanning the inside of a subject using a two-dimensional probe, the number of ultrasonic beams becomes very large in order to obtain a three-dimensional image that can be used for diagnosis. Therefore, a long measurement time is required to obtain one three-dimensional image. Next, a measure adopted by the present invention to shorten the measurement time will be described. FIG. 5 is a block diagram showing the connection between the vibrator and the reception phasing unit according to the present invention. In the drawings, the configuration for only one row of vibrators is shown,
Actually, it is two-dimensionally configured.

In FIG. 5, reference numeral 20 denotes the above-described two-dimensionally arranged vibrator in which M × N vibrators are arranged in two orthogonal directions, and 30-1 and 30-2 denote switching circuits and vibrators. A device for turning on / off the connection with the phasing circuit in the receiving phasing unit and switching the connection destination. Reference numerals 70-1 and 70-2 denote a receiving phasing unit A and a receiving phasing unit B. An echo signal from the inside of the subject received by the N transducers is input, and each of them forms and outputs an ultrasonic beam signal in a predetermined direction.

Here, the switching circuits 30-1 and 30
-2 is a two-dimensional arrayed oscillator 2 such that each forms a single ring-shaped oscillator group with respect to the two-dimensionally arrayed oscillator 20.
0 is selectively connected to the wave receiving phasing units A and B. The centers of the two selected multiple ring oscillator groups are separated by a small distance. Therefore, the wave receiving phasing units A70-1 and B70
-2, there are a number of transducers commonly connected to both. The two phasing units, the receiving phasing unit A70-1 and the receiving phasing unit B70-2, have respective circuits so that each forms an ultrasonic beam in a slightly different direction from the other. The delay time is set and controlled. Here, the reception phasing unit A70-1 and the reception phasing B70-2 are no. 1 to
No. It has Z (Z channels) delay circuits up to Z. Z is a number equal to the maximum number of concentric circles from which the two-dimensional array transducer is selected.

Each of the switching circuits 30-1 and 30-2 has a switching element SW as shown in FIG.
1n and SW2n are provided in a matrix of M × Z, and each of the M × N two-dimensional array vibrators is connected to the 1 to Z channels of the phasing circuit A or the 1 to 1 channels of the phasing circuit B.
It can be connected to any of the Z-channel phasing circuits.

The wave phasing unit A70-1 and the wave phasing unit B7
8 is supplied with a control signal from the control unit 200 shown in FIG. 8, thereby setting or controlling the delay time of each channel.
A control signal is input to 30-2 from the switch control unit 40 based on a control signal from the control unit 200, and the vibrator is selectively connected concentrically to the wave receiving phasing unit. Here, the control pattern of the delay time and the selection pattern of the vibrator are stored in a ROM (Read Only M) built in the control unit 200 in advance.
memory) is set by the data stored in the memory.

FIG. 6 is an explanatory diagram of the receiving operation by the configuration shown in FIG. FIG. 6 shows a portion having a certain diameter or less extracted from each of the two ring-shaped vibrators.
That is, the ring-shaped vibrator TR1 forming the reception focus Fr1 and the ring-shaped vibrator Tr2 forming the reception focus Fr2 are selected close to each other, and the ring-shaped vibrator T
The output of R1 is output to the reception phasing unit A70-1, and the output of the ring-shaped vibrator TR2 is output to the reception phasing unit B70-2. The dynamic movement of the reception focus Fr1 and Fr2 is the same as that described with reference to FIG.

This embodiment is based on the well-known technical idea that if a plurality of reception beams are obtained by one transmission, the time for ultrasonic scanning can be reduced.
The problem caused by selectively forming a multiple ring transducer group for a two-dimensional array transducer and performing sector scan is solved as follows. In order to obtain a plurality of reception beams by one transmission, two ring-shaped transducer groups are selectively formed as described above. At this time, transducers included in both rings are selected. All the oscillator groups forming one ring are commonly connected because they are all given the same delay time,
If there is at least one oscillator commonly included in the two rings, all the oscillator groups forming the two rings are commonly connected via the commonly selected oscillator.

FIG. 7 shows a circuit configuration for preventing this. FIG. 7 is a simplified diagram for explaining connection of a vibrator commonly selected for two rings. Now ring A201
Assuming that the vibrator elements 101 and 102 are located at positions as shown in FIG.
2 and the vibrator element 102 is included only in the ring B. Therefore, the output of the vibrator element 101 is output to, for example, both the wave phasing units A70-1 and B70-2, and the output of the vibrator element 102 is received by the wave phasing unit B70-2.
Must be output only to FIG. 7A shows a circuit configuration for connecting the vibrator for output and the phasing circuit. In FIG. 7A, 301a, 302a, 303
a, 304a are electronic switches, 301b, 302b, 3
03b and 304b are diodes, and the ON / OFF signal of the electronic switch is supplied from the CPU 200.

As shown in FIG. 7B, at a certain time during reception, ultrasonic waves are received by two ring-shaped vibrators and two reception beams are formed. A signal for closing the electronic switches 301a and 302a connected to the output lines of the transducer element 101 included in both rings is output to each switch, and the transducer element 1 included only in the ring B202 is output.
A signal for closing the electronic switch 303a connected to the output line No. 02 is output. As a result, the transducer element 101
Are input from the circuit of the electronic switch 301a and the diode 301b to the wave phasing unit A701, and from the circuit of the electronic switch 302a and the diode 302b to the wave phasing unit B702. On the other hand, the echo signal from the transducer element 102 is transmitted to the electronic switch 303a and the diode 3
03b is input to the wave receiving phasing unit B702.

Although the present invention has been described with reference to the typical embodiments, the present invention is not limited to the above embodiments and can be variously modified without departing from the gist. For example, in the case where the number of the two-dimensionally arranged transducers is M × N, instead of using all the transducers, as shown in FIG. 9, predetermined elements are thinned out and selected from all the transducers. May be selected and driven. By performing this thinning, the number of switches can be reduced. In the description of the above embodiment, the widths of the rings are equal, but the present invention is not limited to this. One more
Although the embodiment in which two reception beams are obtained for each transmission has been described above, it is needless to say that the number of reception beams can be further increased.

[0039]

As described above, according to the present invention, a plurality of ring-shaped vibrators are formed on a two-dimensional array of transducers, and the same delay time is given to each ring-shaped vibrator. Since transmission and reception are performed, a sector scan can be performed with a small number of phasing circuits, and since all the transducers contribute to transmission and reception, an image with good S / N can be obtained.
According to the present invention, a three-dimensional sector scan can be performed using a two-dimensional probe. Further, since a plurality of receiving beams are obtained for one transmission, three-dimensional sector scanning can be performed at high speed.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an operation of transmitting and receiving an ultrasonic wave in the direction of the center line of a fan according to an embodiment of the present invention.

FIG. 2 is an operation explanatory diagram for transmitting and receiving ultrasonic waves in a direction deviating from the center of the fan according to the embodiment of the present invention.

FIG. 3 is a diagram showing a selected state of a ring-shaped vibrator when transmitting and receiving ultrasonic waves in the direction of the center line of a fan according to an embodiment of the present invention.

FIG. 4 is a diagram showing a selected state of a ring-shaped vibrator when transmitting and receiving ultrasonic waves in a direction deviated from a center line direction of a fan according to an embodiment of the present invention.

FIG. 5 is a diagram illustrating a configuration of a main part of an apparatus according to an embodiment that obtains reception beams in a plurality of directions by one reception.

FIG. 6 is a view for explaining a receiving operation in the configuration shown in FIG. 5;

FIG. 7 is a diagram for explaining connection between the oscillator and the wave receiving phasing unit when an oscillator commonly included in two ring oscillators occurs in FIG. 6;

FIG. 8 is a block diagram showing an overall configuration of an ultrasonic diagnostic apparatus according to one embodiment of the present invention.

FIG. 9 is a diagram illustrating a selected state of a vibrator according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Two-dimensional probe 20 ... Two-dimensional array oscillator 30 ... Switching circuit 40 ... Switch control part 70 ... Receiving phasing part Ft ... Transmission focus point Fr ... Receiving focus point

Claims (3)

[Claims] A plurality of ultrasonic transducers for transmitting and receiving ultrasonic waves have an ultrasonic probe arranged two-dimensionally, and a plurality of transducer element groups are concentrically formed in a ring shape from the ultrasonic transducers. Selecting, giving a different delay time to each element group, forming an ultrasonic beam for transmission and reception, forming an ultrasonic image from a received signal, and displaying an image on a display device in an ultrasonic diagnostic apparatus,
Means for changing the transmission / reception direction of the ultrasonic wave for each transmission / reception cycle, means for changing the selection pattern of the ultrasonic transducer element group according to the beam direction of the transmission / reception, and ultrasonic transducer selection for each transducer element Means for giving a delay time according to a pattern. 2. An ultrasonic probe in which a plurality of ultrasonic transducers for transmitting and receiving ultrasonic waves are two-dimensionally arranged, and a plurality of transducer element groups arranged in a concentric ring shape from the ultrasonic transducer. Selecting, giving a different delay time to each element group, forming an ultrasonic beam for transmission and reception, forming an ultrasonic image from a received signal, and displaying an image on a display device in an ultrasonic diagnostic apparatus,
At the time of transmission / reception, a point at which a perpendicular drawn from the focus point of the transmitting or receiving wave positioned on the ultrasonic beam line in the direction inclined with respect to the transducer array plane to the array transducer plane intersects with the array transducer plane is concentric. Means for selecting the concentric ring-shaped vibrator group at the time of transmission and reception as a center of a ring, and means for moving the selected center of the ring-shaped vibrator group along with movement of a reception focus point on the ultrasonic beam line. An ultrasonic diagnostic apparatus, comprising: 3. An ultrasonic probe in which a plurality of ultrasonic transducers for transmitting and receiving ultrasonic waves are two-dimensionally arranged, and a plurality of transducer element groups arranged in a concentric ring shape from the ultrasonic transducer. Selecting, giving a different delay time to each element group, forming an ultrasonic beam for transmission and reception, forming an ultrasonic image from a received signal, and displaying an image on a display device in an ultrasonic diagnostic apparatus,
Means for setting the transmission / reception direction of the ultrasonic wave at a predetermined position on the arrayed transducer surface and setting it in a three-dimensional direction; Or a means for selecting the concentric ring-shaped vibrator group at the time of transmission / reception with the point at which a perpendicular line from the focus point of the received wave to the arrayed transducer surface intersects the arrayed transducer surface as the center of the concentric ring, and the ultrasonic wave Means for moving the selected center of the ring-shaped vibrator group together with the movement of the reception focus point on the beam line.