JPS60199435A - Ultrasonic probe - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention 1] The present invention relates to an ultrasonic probe installed in an ultrasonic diagnostic apparatus.

[Technical background of the invention and its issues] In recent years, in order to expand the characteristics of ultrasound emitted from an ultrasound probe to a high frequency band and improve the acoustic matching with the subject, the use of ultrasound transducers has been developed. A multilayer matching layer is now formed in front of the transmitting and receiving wave surface.

By the way, for example, a sector scanning type ultrasonic probe or a Luya scanning type ultrasonic probe, as shown in Fig. 1,
Air 2 is filled between a plurality of elements 18 obtained by cutting an ultrasonic transducer into strips. This is to prevent deterioration of directivity characteristics per element. In order to prevent the phenomenon of element collapse caused by the air gap between each element 18 of the ultrasonic transducer that reduces the reinforcing relationship between the elements, a matching layer 3 of an optimal thickness is placed on each element 1a.
After laminating and fixing the elements, a transfer 14 was further attached thereon to strengthen the reinforcing relationship between the elements.

However, as described above, since the multilayer matching layer 3 is laminated on each element 1a of the ultrasonic transducer, the height of the element 1a becomes higher than the width of the element 1a, and the element tends to fall down. ing. However, since the reinforcing transfer film 4 is located in front of the wave transmitting/receiving surface of the ultrasonic transducer, it is required to reduce its thickness in order to minimize acoustic deterioration J3. Therefore, it is very difficult to control the thickness of the transfer film 4.

Therefore, from the standpoint of eliminating the above-mentioned disadvantages, it is conceivable to fill the air gap between each element of the ultrasonic transducer with a different substance. According to this, element collapse does not occur, and since there is no need to attach a transfer film that has an adverse acoustic effect to the front surface of the wave transmitting/receiving surface of the ultrasonic transducer, acoustic deterioration does not occur.

However, the characteristics of the substance filling the air gap will actually deteriorate the directional characteristics of the ultrasonic waves.For example, the acoustic impedance Z = 3 (x 105
dyn -5ec/cm3) (7) When filled with epoxy resin, its directional characteristics become sharper than when a transfer film is attached with an air gap (see Fig. 1). Figure 4 shows the directivity characteristics of both, and 11 indicates the acoustic impedance Z = 3 (x 10S
dyn -5ec/cm') is the directional characteristic of an ultrasonic probe filled with epoxy resin, and 10 shows the directional characteristic of a conventional ultrasonic probe 11-b with an air gap and a transfer film attached. It is. On the other hand, on the platform where the ultrasonic beam is deflected by controlling the phase of each element 18 of the ultrasonic transducer, the sound pressure is lower than when the ultrasonic beam is not deflected (
Ru.

This tendency is more pronounced as the directional characteristics of the element become sharper.

Therefore, as described above, the ultra-B wave beam filled with the epoxy resin, which has sharp directivity characteristics, has a narrow viewing angle at which an image can be formed when, for example, sector scanning is performed. This is because the directivity characteristics are sharp, so when the beam is deflected, the sound pressure deteriorates significantly compared to when it is not deflected.

[Object of the Invention] The present invention has been made based on the above-mentioned circumstances, and provides a highly reliable ultrasonic beam with good directivity characteristics, no acoustic deterioration, and no element collapse. The purpose is to

[Summary of the Invention] The advantage of the present invention, which achieves the objective of the invention, is that a plurality of elements in an ultrasonic transducer are spaced apart (in an ultrasonic probe arranged in a J-shaped arrangement, the above-mentioned famous water = 3-elements). acoustic impedance Z=2 (xloS d
yn-Sec/Cm") is characterized by filling with the following substances:

Embodiments of the Invention] Examples of the present invention will be described below with reference to the drawings.

FIG. 2 is a sectional view showing an embodiment of the ultrasonic probe according to the present invention. In FIG. 2, reference numeral 21a denotes piezoelectric ceramic elements obtained by cutting rectangular piezoelectric ceramic into strips, and the piezoelectric ceramic elements 21a are arranged in parallel on the backing material 20 with a predetermined distance from each other. Reference numeral 23 denotes a matching layer which is fixed as an FI layer on each of the piezoelectric ceramic elements 21a. 22 is a silicone resin (Silicone RT V 3) filled in the gaps between each piezoelectric ceramic element 218 and the matching layer 23 laminated thereon.
87) J: another filling substance, the filling substance 22
is the acoustic impedance Z - approximately 1 (×105d111n
-SeC/Cm').

The ultrasonic probe constructed as described above obtained the directivity characteristics shown in FIG. In other words, in Figure 5, the frontage width is 0.
．． 2111111 and a piezoelectric ceramic element having a frequency of 5 M l-I Z is shown.

In order to compare with the conventional ultrasonic probe, etc. described above, the directional characteristics obtained by the conventional ultrasonic probe, etc. under the same conditions as described above are shown in FIG. 5 by dotted lines.

Therefore, the dimension indicated by 10 indicates the directivity in the conventional bubble structure, and the dimension indicated by 11 indicates the epoxy resin as the filling material (acoustic impedance 7; approximately 3 (x 10S).
dyn-5ec/cm3)) is shown by 12 (the solid line shows the directivity of the probe structure of one embodiment of the present invention).

According to this, it can be seen that the directivity characteristics of the device 12 of the present invention are slightly better than those of the conventional type. Further, it can be seen that the type 11 in which the filling material is an epoxy resin has worse directivity characteristics than both the type 12 of the present invention and the conventional type 10.

From the above experimental results, it was found that by filling the air gap between each piezoelectric ceramic element with a material having an acoustic impedance of around 1 (x 105 dyn sec/cm') as in the above example, the directivity characteristics can be improved. is good 4 [
It turns out that However, each ff city ceramic element 21a
Since the filling material 22 is filled in the void gap between the two, the element does not fall down.

Furthermore, since there is no transfer film in front of the ultrasonic wave transmitting/receiving surface, there is no possibility of acoustic deterioration.

It goes without saying that the present invention is not limited to the above-mentioned embodiments, and includes modifications of the gods within the scope of the gist of the present invention.

For example, the filler material embedded in the air gap between each piezoelectric ceramic element has an acoustic impedance of 2=1 (x 10
S dyn -5ec /aII13) It is acceptable as long as the directional characteristics are better than the conventional type probe, rather than the constant 8 real probe. As a result of repeated experiments, the range is acoustic impedance 7-2 (x 10 S d
It was found that it is sufficient if it is less than yn-sec/am3).

In addition, transcription l with less acoustic deterioration! 24 or a transfer film 24 with a thickness that is acoustically negligible, as shown in FIG. It may also be an attached structure. Even if J is added to this, a more reliable ultrasonic probe can be obtained.

[Effect of the invention 1 As explained above, the present invention has a structure in which a filling material having a specific acoustic impedance is embedded in the air gap between each element in an ultrasonic lifter, so that the directivity is good and acoustic deterioration is prevented. It is possible to provide a highly reliable ultrasonic probe that does not cause leakage and is free from the risk of element collapse.

[Brief explanation of the drawing]

Fig. 1 shows an example of a conventional ultrasonic blower;
FIG. 2 shows an embodiment of the ultrasonic probe according to the present invention (
3 is a sectional view showing another embodiment according to the present invention, FIG. 4 is a graph showing experimental results of directivity characteristics of a conventional ultrasonic probe, and FIG. 5 is a cross-sectional view showing another embodiment according to the present invention. The experimental results of the directional characteristics of the d3 ultra-combined wave probe and the conventional ones are compared and shown in Figure 7-7. element), 22...Filling substance (substance). Agent: Patent attorney Noriyuki Chika (and 1 other person) 8-

Claims (1)

[Claims] (1) In an ultrasonic probe in which a plurality of elements in an ultrasonic transducer are arranged at intervals, the acoustic impedance between the elements is Z = 2 (x i QS d
An ultrasonic probe characterized in that it is filled with the following substance: yn-sea/am'). (a) The ultrasonic probe according to claim 1, wherein the substance is a silicone resin.