JP2003325507A - Ultrasonic probe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance the quality of an ultrasonic image by increasing transmission power per a single transmission part in an ultrasonic probe provided with a sparse array type oscillator. <P>SOLUTION: On an element array 14, a plurality of receiving elements 52 are set dispersedly, and a plurality of transmission element connectors 54 are set dispersedly. Each connector 54 is obtained by electrically connecting two elements 56, and its connecting direction is constituted irregularly as the whole of the element array 14. It is possible that on the element array 14, the number of elements to be connected is increased about a center part than a peripheral part, then an apodization may be performed. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic probe, and more particularly to an element array in which a plurality of elements are two-dimensionally arranged.

[0002]

2. Description of the Related Art A two-dimensional array transducer has an element array (vibration element array) in which a plurality of piezoelectric elements are arranged in a matrix. This two-dimensional array transducer is used when electronically two-dimensionally scanning an ultrasonic beam to form a three-dimensional data acquisition area. The element array is, for example, 256
It is composed of × 256 square-shaped elements (piezoelectric elements), that is, an extremely large number of elements. Therefore, the connection of the signal line to each element is extremely complicated in combination with the miniaturized structure, which increases the manufacturing cost. Also, on the ultrasonic diagnostic apparatus side, it is necessary to provide a transmission circuit, a reception circuit, etc. for each element, which complicates the apparatus configuration.

Therefore, a so-called sparse array type oscillator has been proposed as a two-dimensional array oscillator in which the number of elements is greatly reduced while realizing the electronic two-dimensional scanning of the ultrasonic beam similarly to the above. This sparse array type oscillator, for a plurality of elements arranged in a matrix,
A plurality of effective elements that are actually made to function by transmitting and receiving ultrasonic waves are set dispersively, and the other elements are set as ineffective elements. Note that some invalid elements are physically excluded. In addition, a plurality of effective elements may be configured as a reception (dedicated) element or a transmission (dedicated) element, or a plurality of effective elements may be configured as a transmission / reception (combined) element.

[0004]

In the conventional sparse array type oscillator, a single element constitutes a transmitting element and a receiving element (or a transmitting / receiving element). Here, regarding reception, in order to improve directivity and enhance spatial resolution, it is generally desirable to configure the receiving element with a single element, but particularly regarding transmission, if transmission is performed with a single element, , Sound power is not enough.
On the other hand, if the element area is uniformly increased, the directivity of each element is reduced, and as a result, the side lobe is increased, which causes a problem of deterioration in image quality of an ultrasonic image. on the other hand,
When the transmission voltage of the transmission signal is increased, heat generation of the element is increased and deterioration of the element is accelerated.

The present invention has been made in view of the above conventional problems, and an object thereof is to provide an ultrasonic probe having a sparse array type transducer capable of enhancing the image quality of an ultrasonic image. .

[0006]

(1) In order to achieve the above object, the present invention includes an element array in which a plurality of elements are two-dimensionally arranged, and the element array is dispersed on the element array. At least one of a transmission element connection body and a transmission / reception element connection body is included in the plurality of element connection bodies, the plurality of element connection bodies being electrically connected to each other. It is characterized by being included.

According to the above construction, since it is possible to transmit ultrasonic waves by utilizing the element connected body, it is possible to increase the acoustic power at the time of transmission. Here, the element connection body is formed by electrically connecting (connecting) a plurality of elements that are adjacent to each other. For example, after the element array is configured, electrical connection (installation of common electrodes, signal lines) is performed. Common connection). Therefore, the element assembly can be easily configured without going through a complicated manufacturing process. It is desirable that all of the plurality of element connection bodies are transmission element connection bodies,
All of them may be a transmission / reception element connection body, or may be a mixture of a transmission element connection body and a transmission / reception element connection body.

Preferably, the element array further includes a plurality of receiving elements each including a single element. According to this configuration, since the element array includes the receiving element formed of a single element, the spatial resolution at the time of reception can be improved in combination with the increase of the acoustic power at the time of transmission. It is desirable to receive the ultrasonic wave only by the receiving element, but it may be performed by both the receiving element and the transmitting / receiving element.

Preferably, each element other than the plurality of element coupling bodies and the plurality of receiving elements in the element array is an ineffective element. The invalid element may function as a dummy element, and each invalid element may be electrically short-circuited to a common ground, for example.

Preferably, the element array as a whole is
The connection patterns of the element connection bodies are not uniform. If the connection pattern has directionality or regularity, the side lobes are inevitably emphasized, but the above configuration can alleviate such a problem. The concept of the connection pattern includes the number of connections, the direction of connection, the form of connection, and the like, and particularly preferably, the connection direction has diversity.

Preferably, each element connecting body is formed by electrically connecting two adjacent elements, and the connecting directions of the element connecting bodies are not uniform in the entire element array.

(2) Further, in order to achieve the above object,
The present invention includes an element array formed by arranging a plurality of elements two-dimensionally, the element array includes a plurality of transmission element units dispersively arranged on the element array, and the plurality of transmission element units are , A single transmission element, and a plurality of transmission element coupling bodies electrically connecting a plurality of elements in an adjacent relationship, according to the position of each transmission element unit on the element array, It is characterized in that the number of transmitting elements constituting each transmitting element is changed.

According to the above configuration, each transmitting element section is composed of a single transmitting element and a transmitting element connected body. Since the number of transmitting elements forming a transmission unit is changed on the element array, acoustic weighting (apodization) during transmission can be performed on the element array surface. This eliminates the need for a circuit or control for performing electrical weighting (although it may be used in combination), and further reduces the side lobe by such weighting to improve the quality of the ultrasonic image. can do.

Desirably, the number of transmitting elements forming each of the transmitting element sections is increased from the peripheral portion to the central portion of the element array.

(3) Further, in order to achieve the above object,
The present invention includes an element array formed by arranging a plurality of elements in a two-dimensional array, the element array including a plurality of transmission / reception element units dispersively arranged on the element array, and the plurality of transmission / reception element units are , A single transmission / reception element, and a plurality of transmission / reception element connection bodies that electrically connect a plurality of elements that are adjacent to each other, according to the position of each transmission / reception element section on the element array, It is characterized in that the number of transmission / reception elements constituting each transmission / reception element section is changed.

According to the above construction, each transmission / reception element section is composed of the transmission / reception element and the transmission / reception element connection body which are composed of a single element, and acoustic weighting can be performed similarly to the above.

Preferably, the number of transmitting / receiving elements forming each of the transmitting / receiving element sections is increased from the peripheral portion to the central portion of the element array.

Preferably, the element array further includes a plurality of receiving elements each including a single element.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a conceptual diagram showing the overall configuration of an ultrasonic diagnostic apparatus having an ultrasonic probe according to the present invention.

This ultrasonic diagnostic apparatus includes an ultrasonic probe 10
The ultrasonic probe 10 is composed of
Is connected to the apparatus main body 12 by a cable 11.

In the ultrasonic probe 10, the element array 1
Reference numeral 4 denotes a plurality of elements 16 formed by cutting a piezoelectric plate made of a known piezoelectric material such as PZT in a matrix. The plurality of elements 16 are composed of an effective element that functions as a transmission element, a reception element or a transmission / reception element, and an invalid element other than that. Incidentally, the ineffective element may be subjected to a short-circuit treatment or the like between both electrodes on the upper and lower surfaces thereof.
In the present embodiment, the transmission / reception element (combined element) is not provided, but of course such an element can be included.

The element configuration of the element array 14 (excluding invalid elements) is as follows: 1) a configuration including a plurality of receiving elements and a plurality of transmitting elements (this embodiment), 2) a plurality of receiving elements and a plurality of transmitting / receiving elements. Configuration of elements, 3) Configuration of multiple transmission / reception elements and multiple transmission elements, 4) Configuration of multiple reception elements, multiple transmission elements and multiple transmission / reception elements, 5) Configuration of multiple transmission / reception elements, Can be raised. In each of those configurations, the receiving element may be a single element, and other than that, an element connection body may be adopted.

In the configuration example shown in FIG. 1, a common ground electrode 18 is provided on the upper surface side of the element array 14, and an individual electrode 20 is formed on the lower surface side of the element array 14 corresponding to each element. . In the present embodiment, the leads 32,
In addition to the effective elements (transmitting element and receiving element) to which 36 is connected, the individual electrodes 20 are also provided for the ineffective elements, but of course such individual electrodes can be omitted. However, in order to further simplify the manufacturing process, it is desirable that the individual electrode 20 is provided for each element 16 and the connection of the signal line is omitted to form a substantially ineffective element.

A backing 30 is provided on the lower surface side of the element array 14. The backing 30 is for absorbing unnecessary ultrasonic waves emitted rearward. In this configuration example, a lead 36 is embedded inside the backing 30 for each receiving element, and a lead 32 is embedded for each transmitting element. A signal line 38 for a reception signal is connected to the lead 36 via an electrode (not shown), while for the lead 32,
A transmission element connection body, which will be described later, is used as one unit, and a signal line 34 for a transmission signal is connected via an electrode (not shown).

That is, in the configuration example shown in FIG. 1, a plurality of receiving elements made up of a single element are dispersedly set on the element array 14, and signal lines are individually provided to the respective receiving elements. 38 is connected. On the element array 14, a plurality of transmission element connected bodies functioning as transmission units are dispersedly set, and the signal line 34 is individually connected to each transmission element connected body.

In the configuration example shown in FIG. 1, the two leads 32 drawn out from each transmitting element that constitutes the transmitting element coupling body.
By commonly connecting one signal line 34 to
Although these transmitting elements are electrically connected, of course, as a method for such an electrical connection, a method such as providing a common electrode can be used in addition to the method shown in the drawing. If a large element corresponding to the transmission element coupling body is configured in the manufacturing process from the beginning, the manufacturing of the element array 14 becomes complicated and the manufacturing cost increases, but according to the present embodiment, it is easy to perform wiring or formation of a common electrode. The transmission element connected body can be configured by the method. The receiving element and transmitting element coupling body as described above will be specifically described later with reference to FIG.

Incidentally, a first matching layer 22 and a second matching layer 24 are provided on the upper surface side of the element array 14. The first matching layer 22 includes a plurality of matching elements 26 divided for each element 16, and similarly, the second matching layer 24 also has a plurality of matching elements 28 divided for each element 16.
It is composed by. Of course, the ultrasonic probe 10
1 is an example, and various structures other than this can be adopted.

Explaining the apparatus main body 12, the transmitting section 40 is provided for each of the above-described linked transmitting elements.
Each transmission unit 40 supplies a common transmission pulse to the transmission element assembly, and the plurality of transmission units 40 as a whole function as a transmission beam former that forms an ultrasonic beam in a specific direction. A control unit 46 controls the transmission timing and the like in the transmission unit 40.

On the other hand, a receiving section 42 is provided for each receiving element. Each reception unit 42 is configured by an amplifier, an A / D converter, a delay device, and the like, and the adder 48 performs phasing addition on the reception signal output from the reception unit 42 to thereby obtain a reception beam. Is formed.
That is, the plurality of receivers 42 and the adder 48 collectively form a receive beamformer. The received signal output from the adder 48 is input to the image processing unit 49, where, for example, an ultrasonic three-dimensional image is formed, and the image data is output to the display unit 50.

In FIG. 1, the ground signal line connected to the ground electrode 18 is not shown.

FIG. 2 shows the ultrasonic probe 10 shown in FIG.
An array pattern of the receiving elements 52 and the transmitting element connected bodies 54 in FIG. As described above, the element array 14 is composed of a large number of elements 16 arranged in a two-dimensional matrix, and the plurality of receiving elements 52 are arranged on the element array 14 due to the above-mentioned wiring relationship.
Are set in a distributed manner, and a plurality of transmission element connection bodies 54 are
Are distributed. Of course, it is also possible to dispersively set the transmission / reception element connection body instead of or together with them.

In the example shown in FIG. 2, each transmitting element connection body 54
Indicates that two elements (transmission elements) 56 are electrically connected to each other, and specifically, two elements 56 that are adjacent to each other in any of vertical, horizontal, and diagonal directions are connected. In the figure, the direction of the connection is virtually shown by a thick straight line.

As shown in FIG. 2, in the entire element array 14, the connecting directions of the transmitting element connecting bodies 54 are set to be non-uniform, that is, the transmitting element connecting bodies 54 have a total of four directions in the vertical and horizontal directions. One of the directions is randomly selected from the above.

FIG. 3 shows a comparative example corresponding to the conventional example. In this comparative example, the receiving element 52 is composed of a single element and the transmitting element 56 is composed of a single element. ing. In comparison with this comparative example, according to the configuration example shown in FIG. 2, at the time of transmission, a plurality of transmission elements 56 are connected to form a transmission element connection body 54, and thus such a transmission unit unit is used. Therefore, there is an advantage that the radiation area for transmission can be increased and thereby the transmission power can be increased. Further, at the time of reception, since the receiving element 52 is formed by a single element, there is an advantage that the spatial resolution can be improved as compared with the case where the receiving element is formed by the element connected body. Therefore, the image quality of the three-dimensional ultrasonic image can be improved as compared with the comparative example shown in FIG.
By the way, since the configuration example shown in FIG. 2 has the sparse array type described above, it is possible to reduce the number of signal lines and the scale of the transmission / reception circuit. It has the advantage of being configurable.

FIG. 5 shows a structural example according to another embodiment. In the example shown in FIG. 5, as in the configuration example shown in FIG. 2, a plurality of receiving elements 52 are set dispersively on the element array 14, but in one of them,
Transmitters composed of n elements 16 are set in a distributed manner. Here, n is an integer of 1 or more, that is, each transmitting unit is a single element 16 or two or more elements 1.
6 is connected. In the figure, the transmission element configured as a single element is shown as a transmission element 58, and the transmission element formed by two or more elements 16 is shown as a transmission element connection body 54. .

As shown in FIG. 5, the number of elements forming the transmitting section is larger in the central portion of the element array 14 than in the peripheral portion.

That is, in the peripheral portion, the number of transmitting elements 58 made up of a single element 16 is set more,
On the other hand, from the peripheral part to the central part, elements such as a transmission element connection 54A in which two elements are connected, a transmission element connection 54B in which three elements are connected, a transmission element connection 54C in which four elements are connected, and the like. Setting conditions for increasing the number are defined. Therefore, the element array 1
When viewing the whole of No. 4, the transmission area in the central portion is larger than that in the peripheral portion, which makes it possible to perform so-called apodization, that is, weighting.

Conventionally, apodization may be performed by an electric method such as delicate adjustment of the transmission voltage level, but according to the present embodiment, the ultrasonic radiation area is switched stepwise, that is, physically. There is an advantage that the apodization similar to the conventional method can be performed by using the weighting method. Incidentally, with respect to the transmission element connection body 54A in which two elements are connected, the connection directions of the element array 14 as a whole are not uniform, and similarly to this,
The pattern of three connections of the transmission element connection body 54B in which three elements are connected is also irregular. further,
Also for the transmission element connection body 54C in which four elements are connected, various connection patterns may be adopted as necessary.

A comparative example is shown in FIG.
In this comparative example, the connecting directions of the transmitting element connected bodies 54 are aligned in a fixed direction. In this case, it can be pointed out that the side lobe is enhanced in a specific direction,
As can be understood from the comparison with this comparative example, the side lobes can be suppressed by making the connection directions and the connection modes uneven.

FIGS. 6 and 7 show FIGS. 2 and 3, respectively.
Simulation results are shown when the configuration shown in FIG.

The horizontal axis of the characteristic diagrams shown in FIGS. 6 and 7 is the azimuth angle, which corresponds to the deflection angle of the ultrasonic beam. The vertical axis represents the relative sound pressure in dB with respect to the sound pressure of the main beam at a deflection angle of 0 degree.

FIG. 6 shows a beam profile when the main beam is set to a deflection angle of 0 degree, and FIG. 7 shows a beam profile when the deflection angle is 30 degrees. In each figure, the bold lines show the characteristics of the case where the above-mentioned two elements are connected (connected) to form the transmission element connection body 54 (see FIG. 2), and the thin lines show such connection. 4 shows the profile of the comparative example shown in FIG.

As shown in the drawings, according to the present embodiment, first, when the azimuth of the main beam is 0 degree, the sensitivity can be improved by about 6 dB as compared with the comparative example, and the deflection angle is 30. In the case of the degree, the sensitivity can be improved by about 2 dB.
Further, as is clear from each figure, it is possible to obtain a certain suppression effect also on the side lobes. Of course, FIG.
7 and FIG. 7 are simulation results, which have some different characteristics in an actual ultrasonic probe, but in any case, by adopting the above configuration,
It is possible to obtain the effect that the image quality of the ultrasonic image can be further improved as compared with the conventional sparse array type transducer.

In the above embodiment, a plurality of transmitting elements that are adjacent to each other are connected to form a transmitting element connected body. However, a plurality of transmitting and receiving elements that are adjacent to each other are connected to form a transmitting / receiving element connected body. You can also

[0046]

As described above, according to the present invention,
When using the sparse array type transducer, the image quality of the ultrasonic image can be improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing an overall configuration of an ultrasonic diagnostic apparatus including an ultrasonic probe according to the present invention.

FIG. 2 is a diagram showing an array pattern of a connected array of receiving elements and transmitting elements.

FIG. 3 is a diagram showing an array pattern of receiving elements and transmitting elements in a comparative example.

FIG. 4 is a diagram showing an array pattern of a connected array of receiving elements and transmitting elements in a comparative example.

FIG. 5 is a diagram for explaining apodization by changing the number of connections.

FIG. 6 is a diagram showing a simulation result when the deflection angle is 0 degree.

FIG. 7 is a diagram showing a simulation result in the case of a deflection angle of 30 degrees.

[Explanation of symbols]

10 ultrasonic probe, 12 device body, 14 element array, 16 element, 30 backing, 32, 36 lead, 34, 38 signal line, 40 transmitter, 42 receiver,
46 control unit, 48 addition unit, 49 image processing unit, 50
Display section.

Continued front page    F term (reference) 2G047 CA01 DB02 EA07 GA02 GB17                       GB21 GB23 GB28                 4C301 EE07 EE15 GA02 GA03 GB10                       GB19 GB20 GB22                 4C601 EE04 EE12 GA01 GA02 GA03                       GB01 GB03 GB06 GB19 GB20                       GB24 GB26                 5D019 AA21 BB19 FF03                 5J083 AA02 AB17 AC15 AC29 CA03                       CA13 DC05

Claims (10)

[Claims] 1. An element array comprising a plurality of elements arranged two-dimensionally, wherein the element array is arranged dispersively on the element array and electrically connects a plurality of elements that are adjacent to each other. An ultrasonic probe, comprising: a plurality of element coupling bodies, wherein at least one of a transmission element coupling body and a transmission / reception element coupling body is included in the plurality of element coupling bodies. 2. The ultrasonic probe according to claim 1, wherein the element array further includes a plurality of receiving elements each including a single element. 3. The ultrasonic probe according to claim 2, wherein each element other than the plurality of element coupling bodies and the plurality of receiving elements in the element array is an ineffective element. Tentacles. 4. The ultrasonic probe according to claim 1, wherein, in the entire element array, connection patterns of the element connection bodies are not uniform. 5. The ultrasonic probe according to claim 1, wherein each element connection body is formed by electrically connecting two adjacent elements, and the element connection as a whole is performed by connecting each element. An ultrasonic probe characterized in that the directions of body connections are not uniform. 6. An element array including a plurality of elements arranged two-dimensionally, wherein the element array includes a plurality of transmission element units arranged dispersively on the element array, and the plurality of transmission element units. Is composed of a single transmission element and a plurality of transmission element connection bodies each of which electrically connects a plurality of elements that are adjacent to each other. According to the position of each transmission element section on the element array, An ultrasonic probe characterized in that the number of transmitting elements constituting each transmitting element section is changed. 7. The ultrasonic probe according to claim 6, wherein the number of transmitting elements forming each of the transmitting element sections is increased from the peripheral portion to the central portion of the element array. Probe. 8. An element array formed by arranging a plurality of elements two-dimensionally, wherein the element array includes a plurality of transmission / reception element units dispersively arranged on the element array, and the plurality of transmission / reception element units. Is composed of a single transmission / reception element and a plurality of transmission / reception element connection bodies each of which electrically connects a plurality of adjacent transmission / reception elements. According to the position of each transmission / reception element section on the element array, An ultrasonic probe characterized in that the number of transmission / reception elements constituting each transmission / reception element section is changed. 9. The ultrasonic probe according to claim 8, wherein the number of transmission / reception elements forming each of the transmission / reception element sections is increased from the peripheral portion to the central portion of the element array. Probe. 10. The ultrasonic probe according to claim 6 or 8, wherein the element array further includes a plurality of receiving elements each including a single element.