JPS6133923Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an ultrasonic probe used in an ultrasonic diagnostic apparatus.

FIG. 1 shows the appearance of a transducer array section of an ultrasonic probe (hereinafter simply referred to as a probe). In FIG. 1, reference numeral 1 denotes an ultrasonic vibrating fine element (hereinafter simply referred to as a vibrating fine element), which is one of small pieces obtained by cutting a plate-shaped ultrasonic vibrator member into thin arrays. This ultrasonic transducer is made of PZT (lead zirconate titanate), for example.
It is composed of materials of the same type. 2 is a packing material which has the effect of absorbing the ultrasonic beam directed toward the back side of the transducer array. In what is shown in FIG. 1, the large plate-shaped ultrasonic transducer described above is adhered to a packing material 2 and then cut into individual vibrating microelements 1.

FIG. 2 is an external view showing the structure of a general probe. That is, a matching layer and an acoustic lens are arranged on the front side of the one shown in FIG. 1 (the B side shown in FIG. 2). In FIG. 2, reference numeral 1 denotes a vibrating micro-element, and 2 a packing material, which are the same as those in FIG. 1 and will not be explained again. 3 is a first matching layer provided in front of the array of vibrating micro elements 1; for example,
It is made of a rigid material such as glass. 4 is a second matching layer made of, for example, a polymer film;
It is provided on the front surface of the first matching layer 3 described above. These first matching layer 3 and second matching layer 4 match the acoustic impedance between the object (not shown) from which the ultrasonic beam is emitted and the array of vibrating microelements, and also It has the effect of improving the transmission efficiency of the transmitted ultrasonic waves and obtaining an ultrasonic beam with good damping, and the first matching layer 3 has a thickness of 1/4λ.
Also called layers. If the acoustic impedance of the vibrating micro-element is Zp, the acoustic impedance of the object is Zw, the acoustic impedance of the first matching layer 3 is Z ₁ , and the acoustic impedance of the second matching layer 4 is Z ₂ , then Z ₁
and Z ₂ are generally selected to values that satisfy equations (1) and (2) shown below.

Z ₁ =√ _p・₂ ...(1) Z ₂ =√ ₁・_w ...(2) If the subject is a human body, the first material that satisfies equations (1) and (2) is As the matching layer 3, glass or the like is used, and as the second matching layer 4, a polymer film or the like is used. Reference numeral 5 denotes an acoustic lens which not only improves the focusing (directivity) of the ultrasonic beam emitted from the array of vibrating micro elements 1, but also has the effect of serving as a matching layer. This acoustic lens 5 is provided in front of the second matching layer 4.

FIG. 3 shows a cross-sectional view of such a conventional probe taken along plane A shown in FIG. 2. Elements numbered 1 to 5 in FIG. 3 are the same as the elements described in FIG. 2, and therefore, their explanation will be omitted. As is clear from FIG. 3, the structure of the conventional probe is that the first matching layer 3 and the second matching layer 4 are simply pasted on the front surface of the array of vibrating microelements 1. , adjacent vibrating microelements 1 are acoustically coupled via the matching layer, causing crosstalk, which worsens the directivity of the transmitted ultrasound beam and also has an adverse effect on the waveform (damping) of the transmitted ultrasound beam. give. In particular, since the first matching layer 3 is made of a rigid body such as glass, the mutual interference of the ultrasonic beams through the first matching layer is large. Therefore, it causes blurring of images obtained by ultrasonic diagnostic equipment.

FIG. 4 is a diagram showing an example of a probe for explaining the present invention, and is a sectional view corresponding to the case where the probe is cut along plane A shown in FIG. The configuration of the probe in FIG. 4 is very similar to that shown in FIGS. 2 and 3, except that the first matching layer is cut.
That is, the key point of the configuration shown in FIG. 4 is that the first matching layer is cut in correspondence with the vibrating micro-element 1. In FIG. 4, reference numeral 3a indicates a cutting section where the first matching layer is cut corresponding to each vibrating fine element 1;
Reference numeral 1 denotes the first matching layer described above, which corresponds to the first matching layer 3 in FIG. 3, and is made of the same material. In FIG. 4, the rest of the configuration is the same as that in FIG. 3, so a re-explanation thereof will be omitted.

In this way, in FIG. 4, the first matching layer 31 is cut at the cutting part 3a so as to correspond to each vibrating fine element 1, so each first matching layer 31 is acoustically insulated, and each vibrating fine element 1 is Each ultrasonic beam emitted from the element 1 is emitted to the front (B in FIG. 2) without interfering with each other, and the directivity is not impaired. However, in a probe configured as shown in FIG. 4, the vibrating micro-element is usually very small, so the individual ultrasonic waves emitted from it are non-directional.

On the other hand, in a linear scanning type ultrasonic diagnostic apparatus that emits an ultrasonic beam in a direction substantially perpendicular to the surface of a probe, the emitted ultrasonic beam is required to have sharp directivity.

The present invention aims to provide a probe capable of outputting a highly directional ultrasonic beam suitable for linear scanning type ultrasonic diagnostic equipment while improving the drawbacks of the conventional means as described above. .

FIG. 5 is a diagram showing an example of the probe according to the present invention, and is a sectional view corresponding to the case where the probe is cut along plane A in FIG. In FIG. 5, the first matching layer is not cut to correspond to one vibrating fine element, but is cut to correspond to a plurality of vibrating fine elements. That is, in FIG. 5, the first matching layer 32 is cut at the cutting portion 3b so as to correspond to five vibrating microelements. This first
The matching layer 32 corresponds to the first matching layer 3 in FIG. 3 and is made of exactly the same material. The probe shown in Fig. 5 has five vibrating microelements electrically connected in parallel (acoustically insulated).
This is to simultaneously drive several vibrating microelements. Therefore, an ultrasonic beam with sharp directivity can be obtained from the probe shown in FIG. Furthermore, in the probe of FIG. 4, the first matching layer 31 is connected to one of the vibrating micro elements
Since it was cut to match the pitch of each individual piece, it had the disadvantage of being easily broken (the first matching layer was made of glass). However, according to FIG. 5 of the present invention, the first matching layer 32
Since the cutting pitch is large, there is little risk of cracking.

In addition, although FIG. 5 shows an example in which only the first matching layer is cut, as shown in FIG. 6, the second matching layer is cut so as to correspond to the first matching layer. It may be cut at the cutting part 4a.

As described above, according to the present invention, by cutting the matching layer arranged on the front surface so as to correspond to a plurality of vibrating microelements, the ultrasonic beams emitted from the probe can interfere with each other. Therefore, it is possible to obtain an ultrasonic beam with sharp directivity and without damaging the waveform (damping) of the ultrasonic wave, and the effect is extremely large.

[Brief explanation of the drawing]

Figure 1 is an external view of the transducer array section of the probe, Figure 2 is an external view of the structure of a typical probe, Figure 3 is a cross-sectional view of a conventional probe, and Figure 4. 5 and 6 are cross-sectional views showing one embodiment of the probe according to the present invention. 1... vibrating micro element, 2... packing material, 3,
31, 32...first matching layer, 4...second matching layer, 5...acoustic lens, 3a, 3b, 4a...cutting section.

Claims (1)

[Claims for Utility Model Registration] (1) An ultrasonic wave comprising an array of ultrasonic vibrating microelements bonded to a packing material and a first matching layer provided in front of the array of ultrasonic vibrating microelements. An ultrasonic probe, characterized in that the first matching layer is cut for each of the plurality of ultrasonic vibrating microelements. (2) The ultrasonic probe according to claim 1 of the utility model registration claim, characterized in that a second matching layer made of one or more layers is provided in front of the cut first matching layer. . (3) The ultrasonic probe according to claim 1, wherein glass is used as a constituent material of the first matching layer.