JP3908595B2 - Ultrasonic probe - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ultrasonic probe including an array transducer including a plurality of vibration elements.
[0002]
[Prior art and problems]
As shown in FIG. 7, the electronic scanning ultrasonic probe generally has an array transducer 202 bonded on a backing layer 200 and a matching layer 204 bonded on the array transducer 202. Have a configuration. The array vibrator 202 has a configuration in which a plurality of vibration elements (piezoelectric elements) 206 are arranged one-dimensionally or two-dimensionally, and a groove 208 between the vibration elements 206 is filled with a filler 208. On the other hand, the matching layer 204 has a configuration in which a plurality of matching elements 214 are arranged. In the matching layer 204, a plurality of grooves 212 having the same pattern as the pattern of the grooves 210 are formed between adjacent matching elements 214. These grooves 212 are filled with the same filler as that described above. A ground electrode 220 is provided between the array transducer 202 and the matching layer 204. Further, in the backing layer 200, there are leads and contact members for transmitting a drive voltage to each vibration element 206 and taking out an echo signal, which are omitted in the drawing.
[0003]
Each vibration element 206 generates mechanical vibration when a driving voltage is applied, and transmits ultrasonic waves. Each vibration element 206 transmits an ultrasonic wave to a subject positioned on the upper side in the drawing mainly by longitudinally vibrating along the stacking direction (Z direction).
[0004]
Here, in order to prevent acoustic crosstalk between the vibration elements 206, a filler 208 having an extremely small acoustic impedance compared to the vibration element 206 is used. Note that there is a general correlation between acoustic impedance and rigidity, and materials with low acoustic impedance are usually low in rigidity and soft. Therefore, each vibration element 206 fixed on the backing layer 200 vibrates in the lateral direction as indicated by a one-dot chain line or a wavy line in FIG. Due to such energy loss due to unnecessary vibration, for example, it is not possible to transmit an ultrasonic wave with a planned acoustic power, or a frequency characteristic is deteriorated, and an ultrasonic wave having a predetermined band cannot be transmitted. Happens. These problems are the same at the time of reception of ultrasonic waves, causing a decrease in the performance of the ultrasonic probe.
[0005]
On the other hand, in order to suppress this lateral vibration, for example, instead of the matching layer 204 in FIG. 7, an integrated plate-like matching layer in which no groove is formed can be used. Since the ultrasonic wave spreads in the matching layer, the opening of each vibration element 206 becomes wide, and it becomes difficult to transmit the ultrasonic wave with an appropriate spread. As a result, it is difficult to widen the scanning angle of the ultrasonic beam in electronic scanning, and the viewing angle in ultrasonic measurement becomes narrow.
[0006]
The present invention has been made in view of the above problems, and an object of the present invention is to provide an ultrasonic probe that enables good mechanical vibration of each vibration element.
[0007]
[Means for Solving the Problems]
The present invention provides a backing layer, an array vibrator provided on the backing layer and having a plurality of vibrator elements in which first grooves are formed between the vibrator elements, and an alignment element provided on the array vibrator. A matching layer having a plurality of matching elements each having a second groove formed therebetween, each first groove is filled with a first filler, and each second groove is filled with the first groove. The present invention relates to an ultrasonic probe characterized by being filled with a second filler for suppressing unnecessary vibrations having a composition different from that of the filler .
[0008]
Here, by using a filler having a characteristic of suppressing unnecessary vibration of the vibration element as the second filler, unnecessary vibration of each vibration element is suppressed.
[0009]
In the present invention, each of the second grooves is a non-through groove, said multiple between elements mutually in matching element, that is connected portion continuous to the two adjacent matching elements are formed. In a preferred aspect of the present invention, the connecting portion is formed below the second groove. Alternatively, the connecting portion is formed above the second groove. By providing this connecting portion, the effect of suppressing unnecessary vibration can be increased. However, it is desirable to provide the connecting portion within a range where the problem of acoustic crosstalk can be ignored.
[0010]
In order to achieve the above object, the present invention provides an array having a backing layer and a plurality of vibrating elements provided on the backing layer and having a first groove formed between the vibrating elements and two-dimensionally arranged. An oscillator and a matching layer provided on the array oscillator and having a plurality of matching elements arranged two-dimensionally, and the matching layer is provided between every two matching elements adjacent in the row direction. And a plurality of second grooves formed between two matching elements adjacent to each other in the column direction, and formed at each lattice point portion surrounded by the corners of the four matching elements. The first groove is filled with a first filler, and the second groove has a composition different from that of the first filler for suppressing unnecessary vibration. The second filler is filled.
[0011]
In a preferred aspect of the present invention, the acoustic impedance of the second filler is larger than the acoustic impedance of the first filler.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
A preferred embodiment of the present invention will be described with reference to the drawings. 1 is a cross section of a principal portion of the ultrasonic probe is schematically illustrated. The ultrasonic probe mainly includes a backing layer 12, an array transducer 14, a ground electrode 22, and a matching layer 16.
[0013]
The array transducer 14 is a 2D array transducer that can electronically scan ultrasonic waves two-dimensionally, and includes a plurality of transducer elements 18 and a first filler 20.
[0014]
The plurality of vibration elements 18 are two-dimensionally arranged in the Y direction and the X direction orthogonal to the Y direction. In the figure, five vibration elements 18 are arranged in the Y direction. However, an actual array transducer is assumed to have a number of vibration elements 18 arranged in the Y direction and the X direction according to the application. Composed. Each vibration element 18 is a small prismatic piezoelectric element, and electrode films 18a and 18b are formed on the upper side and the lower side, respectively. A single ground electrode 22 is joined above the plurality of vibration elements 18, and is connected to the electrode film 18 a of each vibration element 18.
[0015]
Each vibration element 18 is formed at a predetermined interval from each other. In other words, the first grooves 24 penetrating the array transducer 14 in the Z direction are formed between the adjacent vibration elements 18, and the plurality of first grooves 24 are formed by the plurality of vibration elements 18. It runs in a grid pattern.
[0016]
Each first groove 24 is filled with the first filler 20. The first filler 20 has a composition in which a large number of filler materials are added to a synthetic resin such as silicone rubber or urethane rubber. Here, in this embodiment, for example, a hollow bubble (microbubble) having a polymer film as an outer shell is employed as the filler material. The acoustic impedance of the first filler 20 is extremely smaller than the acoustic impedance of the vibration element 18. Thereby, acoustic crosstalk between the vibration elements 18 is prevented. Moreover, since the 1st filler 20 contains many bubbles, its rigidity is low and it is soft.
[0017]
The backing layer 12 is a rectangular parallelepiped member, for example, and is formed of a highly rigid synthetic resin. The backing layer 12 is formed of a material that absorbs ultrasonic waves emitted downward from the array transducer 14. An array transducer 14 is bonded above the backing layer 12. The backing layer 12 has a lead, a contact member, and the like for transmitting a drive signal to each of the vibration elements 18 and extracting an echo signal, which are omitted in the drawing.
[0018]
The matching layer 16 is bonded to the upper surface of the array transducer 14. The matching layer 16 includes a plurality of matching elements 26 corresponding to the plurality of vibration elements 18. The matching layer 16 is formed with a plurality of second grooves 30 corresponding to the plurality of first grooves 24, and each second groove 30 is filled with a second filler 28.
[0019]
These matching elements 26 perform acoustic impedance matching between the subject (living body) and the vibration element 18, efficiently transmit ultrasonic waves into the subject, and transmit reflected waves from the subject to the vibration element. It is made of a material that efficiently transmits to 18. The matching element 26 of the present embodiment has a composition in which an additive such as silica is added to an epoxy resin, for example.
[0020]
The second filler 28 has a composition different from that of the first filler 20 described above. Specifically, the second filler 28 is a filler that is higher in rigidity (or harder) than the first filler 20 and has a larger acoustic impedance than the first filler 20. As the second filler, for example, a synthetic resin such as silicone rubber or urethane rubber to which a filler agent such as a bubble is not added is used.
[0021]
Further, the second filler 28 uses a material having an acoustic impedance smaller than that of the matching element 26. Incidentally, at this time, the second filler 28 is less rigid (or softer) than the matching element 26. That is, the composition of each of the first filler 20, the second filler 28, and the matching element 26 is adjusted so that, for example, the following relationship is established.
[0022]
[Expression 1]
0 <Za <Zb <Zc (1)
0 <Ga <Gb <Gc (2)
Here, Za, Zb, and Zc represent the acoustic impedances of the first filler 20, the second filler 28, and the matching element 26, respectively, and Ga, Gb, and Gc represent the first filler 20 and the second filler, respectively. The stiffness of the agent 28 and the matching element 26 is shown.
[0023]
Next, a description will be given vibration mode vibrating element 18 at ultrasonic transmitter having the above-described ultrasonic probe.
[0024]
As described above, the lower side of each vibration element 18 is fixed to the highly rigid backing layer 12. Therefore, when a driving signal is applied, each vibration element 18 generates mechanical vibrations in a state where the lower side is fixed and performs longitudinal vibrations. Thereby, each vibration element 18 transmits an ultrasonic wave upward.
[0025]
This can be evaluated by obtaining the electrical impedance in the equivalent circuit of the array transducer. For example, in the conventional array transducer 202 shown in FIG. 7, since the rigidity of the surrounding filler 208 is low (acoustic impedance is small), unnecessary fluctuations exist as shown by the wavy line in FIG. On the other hand, in this embodiment (FIG. 1), since the second groove 30 is filled with the second filler 28 having high rigidity (high acoustic impedance), the movement of the vibration element 18 (lateral vibration in FIG. 8). ) Is sufficiently suppressed by the second filler 28 via the electrode film 18a, the ground electrode 22 and the matching element 26. As a result, unnecessary fluctuations do not occur as shown by the solid line in the figure.
[0026]
Further, when evaluating the directivity angle characteristics of the array transducer, the conventional array transducer 202 has a large angle formed from the front of the array transducer 202 as shown by the broken line in FIG. As a result, the gain suddenly drops and the directivity becomes narrower. Therefore, a wide scan angle of the ultrasonic beam cannot be taken. On the other hand, the array transducer 14 of the present embodiment has a gain at each directivity angle larger than that of the conventional one, as indicated by a solid line in the figure. Therefore, the scanning angle of the ultrasonic beam can be widened, and the viewing angle can be widened.
[0027]
Next, an ultrasonic probe according to an embodiment of the present invention will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the structure same as the structure shown by FIG. 1, and the description is abbreviate | omitted.
[0028]
The matching layer 34 bonded above the array transducer 14 includes a plurality of matching elements 26, a connecting portion 38, and a second filler 42. The connecting portion 38 is provided between adjacent matching elements 26 and is connected to and connected to two adjacent matching elements 26.
[0029]
Here, the width (thickness) of the connecting portion 38 in the Z direction is smaller than the thickness of the matching element 26 in the Z direction. In the present embodiment, the connecting portion 38 is connected to the lower side of each matching element 26, and a second groove 40 as a non-penetrating groove having an opening upward is formed above the connecting portion 38. . The second groove 40 is filled with, for example, a second filler 42 having the same composition as the second filler 28 in the above embodiment.
[0030]
In the matching layer 34 in this embodiment, in addition to the composition of the second filler 42 with respect to the first filler 20, for example, by adjusting the dimensions of the connecting portion 38 such as the thickness of the connecting portion 38, each vibration element 18. The vibration mode can be controlled well. Also in this form, the same effect as the configuration of the above embodiment can be obtained.
[0031]
Furthermore, an ultrasonic probe in another embodiment will be described with reference to FIG. In the present embodiment, the configuration other than the matching layer is basically the same as the configuration of FIG. 3 described above. In addition, the matching layer 44 of the embodiment includes a plurality of matching elements 26, a coupling portion 38, and a second filler 42, and each of these components itself is each component in the matching layer 34 of FIG. It has the same configuration as the element.
[0032]
However, the connecting portion 38 is connected to the upper side of each matching element 26 when connecting to two adjacent matching elements 26. In the present embodiment, the connecting portion 38 and each matching element 26 are integrally formed, and a second groove 46 is formed below the connecting portion 38 as a non-penetrating groove having an opening below. The second groove 46 is filled with the second filler 42. Also in this embodiment, the same effect as in the above embodiment can be obtained.
[0033]
An ultrasonic probe in still another embodiment will be described. Here, in this embodiment, the configuration other than the matching layer shown in FIG. 1 is basically the same. Here, FIG. 5 partially shows the matching layer 50 of the present embodiment as viewed from above. The matching layer 50 includes a plurality of matching elements 26, a plurality of second fillers 54, and a plurality of connecting portions 58. For convenience, the second filler 54 is given the same pattern as the hatching of the second filler 42 in the above embodiment.
[0034]
The plurality of matching elements 26 are two-dimensionally arranged in the Y direction (row direction) and the X direction (column direction) in the same pattern as the arrangement pattern of the plurality of vibration elements (not shown) arranged below. .
[0035]
A second groove 56 is formed between each matching element 26. Here, each second groove 56 in the present embodiment is classified into one of two grooves described later, that is, an inter-row groove 56a and an inter-column groove 56b.
[0036]
As shown in the drawing, each inter-row groove 56 a is a groove formed between the matching elements 26 arranged in the row direction, and is formed for each of the two adjacent matching elements 26. In the figure, the opening of each inter-row groove 56a having a rectangular shape is shown. On the other hand, each inter-row groove 56b is a groove formed between the matching elements 26 arranged in the column direction, and is formed for each of the two adjacent matching elements 26. In the figure, the opening of each inter-row groove 56b having a rectangular shape is shown.
[0037]
Here, the plurality of inter-row grooves 56a are arranged in the X direction via the connecting portions 58 to be described later between the grooves 56a, and are separated from each other and independent. The inter-row grooves 56b are also arranged in the Y direction via the connecting portions 58 between the respective grooves 56b. Each inter-row groove 56a and each inter-column groove 56b is filled with a second filler 54 having the same composition as the second filler 28 shown in FIG. These inter-row grooves 56a and inter-column grooves 56b can be formed by laser processing or the like.
[0038]
Further, the connecting portion 58 is formed for each lattice point portion A surrounded by the corner portions 60 of the four matching elements 26, and is continuous with the corner portions 60 of the four elements 26. Each connecting portion 58 connects two sets of matching elements 26 that are diagonally adjacent to each other.
[0039]
FIG. 6 shows a part of a cross section indicated by BB ′ in FIG. As shown in the figure, each inter-row groove 56b passes through the matching layer 50 in the Z direction, and is filled with the second filler 54 as described above. Each connecting portion 58 is a columnar member formed along the Z direction from above to below the matching layer 50. Two adjacent second fillers 54 are partitioned by a connecting portion 58.
[0040]
The inter-row grooves 56 a, the second filler 54, and the connecting portion 58 have the same arrangement form as the inter-row grooves 56 b, the second filler 54, and the connecting portion 58.
[0041]
In the matching layer in the present embodiment, in addition to the composition of the second filler 54 with respect to the first filler 20, for example, by adjusting the dimensions of the connecting portion 58 such as the cross-sectional area of the connecting portion 58, The vibration mode can be controlled well. Also in this form, the same effect as the main part in the above-described embodiment can be obtained.
[0042]
In the above embodiments, the case where the present invention is applied to an ultrasonic probe including a 2D array transducer has been described as an example. However, the present invention is not limited to this. For example, a 1D array transducer or 1.5D array is used. If the ultrasonic probe includes an array transducer including a plurality of transducer elements such as a transducer, the present invention can be applied as in the case of the above embodiment, and the same effects as described above can be obtained.
[0043]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the ultrasonic probe which enabled the favorable mechanical vibration of each vibration element can be provided.
[Brief description of the drawings]
1 is a diagram cross section of the principal portion of the ultrasonic probe is schematically illustrated.
FIG. 2 is a diagram showing various characteristics of both the array transducer of the present embodiment and a conventional array transducer.
FIG. 3 is a view schematically showing a cross section of a main part in the ultrasonic probe according to the embodiment of the present invention .
FIG. 4 is a view schematically showing a cross section of a main part of an ultrasonic probe according to another embodiment.
FIG. 5 is a view of a main part in still another embodiment as viewed from above.
6 is a view schematically showing a cross section of BB ′ in the main part of FIG. 5;
FIG. 7 is a diagram schematically showing a cross section of a main part of a conventional ultrasonic probe.
FIG. 8 is a diagram schematically showing a transverse vibration mode of a vibration element included in an array transducer of a conventional ultrasonic probe.
[Explanation of symbols]
12 backing layer, 14 array transducer, 16 matching layer, 18 vibrating element, 20 first filler, 22 ground electrode, 24 first groove, 26 matching element, 28 second filler, 30 second groove.

Claims (5)

Backing layer,
An array vibrator having a plurality of vibration elements provided on the backing layer and having a first groove formed between the vibration elements;
A matching layer provided on the array transducer and having a plurality of matching elements each having a second groove formed between the matching elements;
Including
Each first groove is filled with a first filler,
Each of the second grooves is filled with a second filler for suppressing unnecessary vibrations having a composition different from that of the first filler .
Each of the second grooves is a non-through groove,
Between the elements of the plurality of matching elements, a connecting portion connected to two adjacent matching elements is formed,
An ultrasonic probe characterized in that lateral vibration of each vibration element is suppressed on the living body side by a second filler and a connecting portion . The ultrasonic probe according to claim 1 ,
The ultrasonic probe according to claim 1, wherein the connecting portion is formed below the second groove. The ultrasonic probe according to claim 1 ,
The ultrasonic probe according to claim 1, wherein the connecting portion is formed above the second groove. Backing layer,
An array vibrator having a plurality of vibration elements provided on the backing layer and having a first groove formed between the vibration elements and two-dimensionally arranged;
A matching layer provided on the array transducer and having a plurality of matching elements arranged two-dimensionally;
Including
The matching layer is
A plurality of second grooves formed between two matching elements adjacent in the row direction and between two matching elements adjacent in the column direction;
A connecting portion formed for each lattice point region surrounded by the corners of the four matching elements, and connected to the corners of the four matching elements;
Have
Each first groove is filled with a first filler,
Each of the second grooves is filled with a second filler for suppressing unnecessary vibrations having a composition different from that of the first filler .
An ultrasonic probe characterized in that lateral vibration of each vibration element is suppressed on the living body side by a second filler and a connecting portion . The ultrasonic probe according to claim 1 or 4 ,
The ultrasonic probe according to claim 1, wherein an acoustic impedance of the second filler is larger than an acoustic impedance of the first filler.

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