JPH0161062B2 - - Google Patents

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to an ultrasonic detector used in an ultrasonic diagnostic device that emits ultrasonic waves into a living body and detects reflected signals from the living body for medical diagnosis. It concerns tentacles.

[Technical background of the invention]

BACKGROUND ART Ultrasonic diagnostic devices emit ultrasonic waves one after another into a certain cross-section inside a living body, and detect reflected signals from within the living body to obtain a tomographic image of the living body, which is then used for medical diagnosis. At this time, the cross section through which the ultrasonic waves are emitted is limited by the structure of the ultrasonic probe. For example, the phased array transducer of the ultrasonic probe shown in Fig. 1 is composed of an array of minute short fence-like transducers, and each of these minute transducers 1 is excited while giving an appropriate delay time to each other. Although the ultrasonic beam can be scanned in a fan shape within the cross section in the arrangement direction of the array, it is not possible to scan the ultrasonic beam in any other direction. If this ultrasonic probe is rotated around its central axis, the scanning section of the ultrasonic beam will naturally also rotate within the living body, but it is unclear whether the position of the probe will not shift with this method.
Furthermore, it is difficult to accurately grasp the extent of the rotation angle. This also applies to the mechanical scanning type ultrasound probe shown in FIG. In this case, as the ultrasound probe 2 mechanically rotates around the central axis 3, the ultrasound beam is scanned within this rotation plane, but the ultrasound beam is scanned in other directions. I can't.

Generally, in ultrasound diagnosis, diagnosis is made by observing the morphology of in-vivo tissue, but in order to more accurately understand this morphology, it is necessary to
It is desired to observe cross sections simultaneously. In particular, when diagnosing cardiac function, two orthogonal
Simultaneous cross-sectional observation is absolutely necessary to improve the measurement accuracy of cardiac volume and cardiac output. Although there are restrictions due to the structure of the ultrasound probe as described above, there is a strong demand for an ultrasound diagnostic apparatus that can simultaneously observe two orthogonal cross sections from the same point.

[Problems with background technology]

As an ultrasonic probe that meets the above-mentioned demand, there is one in which two phased array transducers 4 and 5 are arranged so that their arrangement directions are perpendicular to each other, as shown in FIG. However, in this case, the centers of scanning of the ultrasound beams by the two transducers 4 and 5 do not match, and the size of the probe is twice as large as the normal one, and the width of the beam is narrow. It has two major drawbacks: it is inconvenient to obtain a tomographic image of the heart between the two.

As a means to solve these drawbacks, there is an ultrasonic probe shown in FIG. 4. In this probe, array electrodes are formed by cutting into the front and back sides of a piece of piezoelectric ceramic so that the array directions are perpendicular to each other, and lead lines X ₁ to X _o and Y ₁ to _{Y o} are formed from each of the array electrodes.
is being taken out. Now, one set of leader lines
Connect X ₁ to X _o in common to the ground side, and connect the other lead wire sets Y ₁ to _{Y o} to independent pulsers.
By applying voltage pulses with an appropriate phase difference, the ultrasonic beam can be scanned in a fan shape within the XZ plane. On the other hand, on the other hand, the set of lead wires from Y ₁ to Y _o is shared and connected to the ground side, and the lead wires from X ₁ to _{X o} are each connected to an independent pulser, and voltage pulses are applied with an appropriate phase difference. By doing this, the ultrasonic beam can be scanned in a fan shape in the YZ plane.

In order to enable such scanning, the micro piezoelectric vibrators under each array electrode must be not only electrically isolated from other adjacent vibrators, but also completely acoustically isolated. It is absolutely necessary that this is done. Therefore, as shown in FIG. 4, the piezoelectric ceramic is cut halfway through its thickness. Incidentally, in order to achieve complete acoustic separation, it is desirable to completely cut into the piezoelectric ceramic, but until then the electrodes are separated into a huge number of squares, making it difficult to pull out the electrodes.

The ultrasound probe shown in FIG. 4 has two major drawbacks. One is that the above-mentioned acoustic isolation is insufficient, and the other is manufacturing difficulties. That is, to cut into piezoelectric ceramic as shown in Fig. 4, first cut the piezoelectric ceramic in one direction, for example, in the Y direction, halfway through its thickness, then glue it to the batting material.
Furthermore, the difficult task of cutting halfway through the thickness in the X direction is required. In addition, although it is desirable to cut as deep as possible for acoustic separation, it is not possible to cut sufficiently deep because this work is necessary.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and has a structure that is easy to manufacture, can achieve sufficient acoustic separation between arrayed transducers, and can simultaneously observe two orthogonal cross sections from the same point. The purpose is to provide an ultrasonic probe.

[Summary of the invention]

In order to achieve the above object, the present invention comprises a piezoelectric ceramic, an acoustic backing material and a matching layer,
In ultrasonic probes that emit and receive ultrasonic waves,
an acoustic backing material, a first conductive adhesive layer provided on the surface of the acoustic backing material, a piezoelectric ceramic laminated on the first conductive adhesive layer, and a piezoelectric ceramic layer provided on the surface of the piezoelectric ceramic. The second conductive adhesive layer has a thickness that is approximately 1/4 of the wavelength of the ultrasonic wave, and the acoustic backing material passes through the first conductive adhesive layer from the surface of the piezoelectric ceramic. a group of short fence-like vibrators formed by cuts that reach , and the first conductive adhesive that penetrates the piezoelectric ceramic from the surface of the second conductive adhesive layer in a direction approximately perpendicular to the cuts. It is characterized by having a group of minute short fence-like vibrators formed in a direction approximately perpendicular to the group of short fence-like vibrators by cuts that reach the layer.

[Embodiments of the invention]

An important point in the present invention is that the acoustic impedance of the conductive adhesive, which is formed by mixing a large amount of metal powder such as silver powder into epoxy resin, is 4 to 5×.
Because it has a value of 10 ⁶ Kg/m ² ·sec, we focused on the fact that it can be used not only for its electrical properties but also as an acoustic material. Usually, an ultrasonic transducer that emits ultrasonic waves to a living body is installed on a backing material that has an appropriate acoustic impedance, and the acoustic impedance of the living body (approximately 1.5 × 10 ⁶
In order to match the acoustic impedance of the piezoelectric ceramic (approximately 35×10 ⁶ Kg/m ²・sec) with the acoustic impedance ^of the piezoelectric ceramic (approximately 4 to 6×10 ⁶ Kg/m 2
The acoustic matching layer has an acoustic impedance of m ² sec) and is formed on a piezoelectric ceramic with a thickness that is approximately 1/4 of the wavelength λ of the emitted ultrasonic wave. The conductive adhesive layer has an acoustic impedance suitable for this acoustic matching layer. In addition, many of the rubber materials containing fillers used as backing materials for ultrasonic probes currently on the market are 4 to 5 × 10 ⁶
Since it has a value of Kg/m ² sec, a layer of conductive adhesive material with a thickness roughly equal to or less than the ultrasonic wavelength λ is inserted between this backing material and the piezoelectric ceramic. However, the performance regarding ultrasonic emission and detection will not deteriorate.

An embodiment of the present invention focusing on the above points will be described with reference to FIGS. 5A and 5B.

FIG. 5A is a perspective view showing one manufacturing process of the ultrasonic probe according to the present invention. A first conductive adhesive layer 8 is laminated on the surface of the backing material 7, and a piezoelectric ceramic 9 is further laminated on the surface.
This piezoelectric ceramic 9 is cut into minute short fence-like vibrators using a cutting machine or the like, and the depth of the cut 10 is such that it penetrates the first conductive adhesive layer 8 and reaches the backing material 7. There is. In this way, by cutting until the backing material 7 is reached, the electrodes of each short fence-shaped vibrator are separated.
Lead lines Y ₁ to _Yo are attached to the separated electrodes, respectively.

FIG. 5B is a perspective view showing the manufacturing process of the completed ultrasonic probe of the present invention. Piezoelectric ceramic 9
A second conductive adhesive layer 11 is further laminated on the surface. Since this second conductive adhesive layer 11 also serves as an acoustic matching layer, its thickness is set to approximately 1/4 of the wavelength λ of the ultrasonic wave to be excited.
This second conductive adhesive layer 11 is cut into minute short fence-like vibrators in a direction perpendicular to the direction of the notches 10 in FIG. 5A. At this time, the depth of the second cut 12 is such that it penetrates the piezoelectric ceramic 9 and cuts halfway into the first conductive adhesive layer 8 . The electrodes of the second conductive adhesive layer 11 cut into short fence shapes are connected with lead lines X ₁ to X _o , respectively.
is installed.

As described above, according to the present invention, one set of lead wires X ₁ to _{X o} is connected to a common ground side, and the other set of lead wires Y ₁ to _{Y o} are each connected to an independent pulser, By applying voltage pulses with an appropriate phase difference, the ultrasonic beam can be scanned in a fan shape within the XZ plane. On the other hand, Y ₁ ~
Make the set of lead wires of Y _o common to the ground side,
The ultrasonic beam can be scanned fan-shaped in the YZ plane by making the lead lines X ₁ to X _o tangent to each independent pulser and applying a voltage pulse with an appropriate phase difference. In this way, two orthogonal cross sections can be observed simultaneously from the same point. This is similar to the conventional example shown in FIG. 4, but the present invention significantly improves the two drawbacks of the conventional example.

That is, regarding acoustic separation, since the piezoelectric ceramic 9 is completely cut in two orthogonal directions to form a square shape, complete acoustic separation is achieved. Regarding the manufacturing process, a piezoelectric ceramic 9 is laminated on the surface of the backing material 7 via a first conductive adhesive layer 8, first cut into short fence shapes, and a second layer is layered on the surface of the piezoelectric ceramic 9. Since the conductive adhesive layer 11 is laminated and cut into short fence shapes in a direction perpendicular to the cutting direction, the work is much easier than in the conventional example.

The configuration of the present invention shown in Figure 5 shows the basic configuration, and when actually used as an ultrasonic probe, an insulating protective film or silicone rubber etc. should be formed on these surfaces. It is used by adding an acoustic lens and covering it with a case to which a cable is connected.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to provide an ultrasonic probe that is easy to manufacture, has a structure that allows sufficient acoustic separation between arrayed transducers, and can simultaneously observe two orthogonal cross sections from the same point. .

In this way, being able to simultaneously observe two orthogonal cross-sections using ultrasound is particularly important for diagnosis of circulatory organs such as the heart, and the present invention has great clinical value.

[Brief explanation of drawings]

1 to 4 are perspective views of a conventional ultrasonic probe, and FIGS. 5A and 5B are perspective views showing the structure of an ultrasonic probe according to an embodiment of the present invention in the order of steps. 7... Backing material, 8... First conductive adhesive layer, 9... Piezoelectric ceramic, 10... Notch, 11... Second conductive adhesive layer, 12... Notch.

Claims (1)

[Claims] 1. An ultrasonic probe that is composed of a piezoelectric ceramic, an acoustic backing material, and a matching layer and that emits and receives ultrasonic waves, which includes an acoustic backing material and a first conductive adhesive layer provided on the surface of the acoustic backing material. , a piezoelectric ceramic laminated on the first conductive adhesive layer, and a second conductive adhesive having a thickness that is approximately 1/4 of the wavelength of the ultrasonic wave provided on the surface of the piezoelectric ceramic. a short fence-like vibrator group formed by a cut from the surface of the piezoelectric ceramic, penetrating the first conductive adhesive layer and reaching the acoustic backing material;
A cut that penetrates the piezoelectric ceramic from the surface of the conductive adhesive layer in a direction approximately perpendicular to the cut and reaches the first conductive adhesive layer in a direction approximately perpendicular to the short fence-like vibrator group. An ultrasonic probe characterized by having a group of minute short fence-like transducers formed.