JPS60119927A - 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 fa+ Technical Field of the Invention The present invention relates to an ultrasonic probe used in an ultrasonic diagnostic device, and in particular to an ultrasonic probe that reduces multiple reflections occurring within the ultrasonic probe. Regarding the probe.

(bl Background of the technology) There are two types of sector-scanning ultrasound probes used in ultrasound diagnostic equipment: mechanical and electronic.In electronic sector probes, the transducer is Since the structure is in close contact with the probe, multiple reflections hardly occur inside the probe, but it is necessary to maintain high precision in the variable delay circuit required to form the ultrasonic beam. There was a problem that it was difficult to make an ultrasonic probe.

On the other hand, in mechanical sector probes, rotation.

Alternatively, sector scanning can be performed using the swing mechanism, so a high-precision variable delay circuit as described above is not required.
Although it is easy to construct a high-frequency ultrasound probe, clear ultrasound tomographic images cannot be obtained due to multiple reflections that occur between the ultrasound transducer and the probe housing. There has been a demand for a mechanical sector probe that does not have multiple reflections and can handle high frequencies like electronic sector probes.

(C) Conventional technology and problems The tip of a conventional mechanical sector probe is shown in Figure 1, and consists of an ultrasonic transducer (1) and a plastic housing (2). Since the distance between the ultrasonic transducer and the housing is large, multiple reflections occur between the ultrasonic transducer and the housing, and as shown in (a) in Fig. 2, the true signal ■ has a negative There was a problem that the reflected signals were generated one after another, deteriorating the ultrasonic tomographic image. Part (B) of this figure shows the desirable convergence characteristics of the above-mentioned multiple reflections, which is the object of the present invention.

Further, attenuation of ultrasonic signals due to liquid paraffin existing between the ultrasonic transducer 1 and the housing 2 also poses a problem that cannot be ignored, especially when the frequency becomes high.

fd+ Purpose of the Invention In view of the above-mentioned conventional drawbacks, the present invention minimizes the distance between the ultrasonic transducer and the housing (plastic) of the probe, and minimizes the distance between the ultrasonic transducer and the housing. The purpose of this invention is to provide a method for quickly converging multiple reflections occurring between

According to the present invention, an ultrasonic probe having a mechanism for rotating or swinging an ultrasonic transducer is brought into close contact with a subject of the ultrasonic transducer. The piezoelectric element plates constituting the ultrasonic transducer are arranged concentrically in accordance with the internal curvature of the casing, and the piezoelectric element in the center is protruded outward to provide an ultrasonic transducer with a convex structure. In addition to obtaining ultrasonic images with less influence from multiple reflections, the aperture of the central piezoelectric element becomes smaller, which has the effect of obtaining ultrasonic reflection images with a thin ultrasonic beam even at short distances.

(fl Embodiments of the Invention First, to summarize the gist of the present invention, the present invention divides a piezoelectric element plate of an ultrasonic transducer into concentric circles, and forms a convex structure in which the piezoelectric element in the center protrudes outward. , which is placed close to the plastic housing of the ultrasonic probe so that it can rotate or swing.

Embodiments of the present invention will be described in detail below with reference to the drawings.

Fig. 3 shows an ultrasonic transducer used in an ultrasonic probe to which the present invention is applied, Fig. 4 shows its transmitting/receiving circuit, and Figs. It is a figure explaining the effect.

In FIG. 3, (11 is a cross-sectional view of an ultrasonic transducer embodying the present invention, and (2) is a cross-sectional view of the ultrasonic transducer according to the present invention.
It is a figure showing a top view. And L2 is the same as that explained in FIG. 1 ζ.

Drawing (1) shows the convex structure of the ultrasonic transducer of the present invention, and drawing (2) shows its concentric structure.
shown respectively.

The piezoelectric element plates labeled &J, Niguchi, and C in this figure are mounted independently from each other, and transmission and reception are performed by the transmission and reception circuit shown in FIG. 4.

In FIG. 4, ζ, I, B and C are the same as those explained in FIG. 3, and the delay circuit (DDLI) 3.

(RDLI) 5 gives a delay corresponding to the length of A shown in FIG. 3(1), and the delay 1
1 old-product CD111.2) 4, (RDL2) 6 is the delay corresponding to the length of B 5. It is something that can be achieved.

The respective delay times are A/C, B when the speed of sound is −〇.
/C.

O3C7 is a timing circuit that creates a transmission timing in several Kllz, (DVI to DV3) 8 is an ultrasonic drive circuit, (PAI to PA3 > 9 is a preamplifier, and 10 is a This is an adder that combines the received signals from each piezoelectric element plate.

Now, when the transmission timing signal is output from the transmission timing circuit (O5C) 7, the delay determined by the delay circuit (DDLI) 3 is adopted for the ultrasonic transducer (A), and the ultrasonic drive circuit (DVl) 8 is driven, and the delay determined by the delay circuit (DDL2) 4 is taken for (b), and the ultrasonic drive circuit (DV2) 8
is driven, and the ultrasonic drive circuit (DV3) 8 is driven without delay for (c), resulting in 41 ports of the ultrasonic transducer.

Each of the piezoelectric element plates (c) operates so as to send out an ultrasonic beam to the subject at the same timing.

In the same way, the ultrasound reflected signals from the subject are each amplified by the preamplifiers (P^1 to PA3) 9, and the output of the ultrasound transducer (A) is sent to the delay circuit (R).
OLE) 5, the output of (b) is delayed by the delay circuit (RDl2) 6, and the output of (c) is directly input to the adder 10. As a result, in the adder 10, the same Since the timing C is added t'J and a composite output signal is obtained, the same result as the transmission/reception signal by the conventional ultrasonic transducer, which is not cited, can be obtained.

Next, the features of the present invention will be specifically explained with reference to FIGS. 5 and 6. Fig. 5 shows a cross-sectional view of the ultrasonic transducer according to this embodiment, and Fig. 6 shows the ultrasonic beam radius and diagnostic depth according to the aperture of the ultrasonic transducer. Example of the relationship [Reference: Motoyoshi Okushima [Ultrasonic Medicine J Vol, 2].

No. 3 (1975)), ■ indicates 5.
The case of 86+++i diameter is shown, and the case of 13++++ diameter is shown.

The embodiment shown in FIG. 5 is 3.5 MIIZ, φ131
1II (d) ultrasonic transducer, φ5.8
Divide into two by 6mff1 (d"), φ5.86++m
(d') side ratio l1ll (Figure [) ■ Reference I! ! ′
The ultrasound transducer output of φ5.86m++ (d') was passed through a delay circuit, and
．． By combining the ultrasonic transducer output of the 86 mm to φ13 dragon part, the long distance It (■
(see ).

In this way, as is clear from the example in Fig. 6, φ5
．． Using an ultrasonic transducer with an aperture of 86m+, it becomes possible to view ultrasonic tomographic images with a narrow ultrasonic beam width up to short distances, widening the diagnostic range. The split structure is not disadvantageous.

In this example, four original effects of the present invention will be explained.

Now, R: the maximum radius of the motion trajectory of the ultrasonic transducer (crane).

g: Maximum gap between the ultrasonic transducer of φ13 dragon (d) and the circular orbit with radius R.

g'': Maximum gap (,,) between the ultrasonic transducer of φ5.86 dragon (d') and the circular orbit of radius R.

The results of calculating the relationship between R', g, and g' are shown below.

The gap between the ultrasonic transducer blade and the case (the gap required for rotating or swinging the ultrasonic transducer) is 0.51111. Even if the thickness of the housing is 0°51, the distance from the ultrasonic transducer to the subject is g-1.5ms for R=14+m - B2.
6 mm, and 1 at g' -0.31 mm,
31. vsm, and with a diameter of φ5.86mm, φ1
It can be seen that it can be made 21 times the diameter of 31110, and has a sufficient effect.

On the other hand, by increasing R, the value of g can be decreased, but in this case, the shape of the tip of the ultrasound probe (i.e., the part that touches the subject) becomes thicker, making it difficult to connect with the body surface. Problems arise in terms of contact, rib influence, etc.

Furthermore, since the aforementioned multiple reflections mainly become a problem at short distances due to their attenuation characteristics, the gap g" created between the ultrasonic transducer and the housing for viewing ultrasonic tomographic images with a side ratio of F411.
The value of is the most important, and from this point of view, the effects of the present invention are sufficient.

In addition, the delay circuits DDLI, 2 and R explained in FIG.
It goes without saying that by changing Dl, 1.2 from a fixed value to a variable value delay circuit, it is possible to perform a large scale make-up.

(gl) As explained in detail below, the ultrasonic probe of the present invention has a piezoelectric element plate of an ultrasonic transducer divided into concentric circles, a piezoelectric element in the center and an outer The convex structure shown in Figure 1 is designed to be close to the plastic housing of the ultrasound probe so that it can be rotated or oscillated, so that the divided piezoelectric element of the ultrasound transducer and the object under test can be easily moved. It is possible to narrow the gap between the plastic casing and the plastic casing, which allows multiple reflected waves to be quickly converged, and to obtain clear ultrasonic tomographic images. a small diameter ultrasonic transducer,
Since it can be used as an overall large-diameter ultrasound transducer, it has the effect of being able to obtain ultrasound tomographic images of the body with a narrow ultrasound beam from long distances to remote areas. be.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the tip of a conventional mechanical sector probe, and Fig. 2 is a diagram illustrating the intensity of multiple reflections in the conventional method.
FIG. 3 is a diagram showing an ultrasonic transducer used in an ultrasound probe to which the present invention is applied, FIG. 4 is a diagram showing its transmission/reception circuit, and FIG. 5. FIG. 6 is a diagram explaining the effect. In the drawings, l is an ultrasound transducer. 2 is a plus deck housing, 3.4 is a delay circuit DDLI,
DDL2.5.6 is a delay circuit RD1.1. RDL2.
7 is a transmission timing circuit (O3C), 8 is an ultrasonic drive circuit (DVl-+1V3), 9 is a preamplifier (FAI-PA3'), 10 is an adder, A, B, C are each divided piezoelectric element board. . Cicada 1 Figure ■ ■ ■ ■ ■ ■ ■ Kudzu 2 Figure 3 Man 4 Figure %5 Figure

Claims (1)

[Claims] Ultrasonic 1 - In an ultrasonic probe having a mechanism for rotating or swinging the transducer, the ultrasonic transducer as described in "-" is adapted to the internal curvature of the casing of the ultrasonic probe that is brought into close contact with the subject. An ultrasonic probe comprising an ultrasonic transducer in which piezoelectric element plates are arranged concentrically and the piezoelectric element in the center is protruded outward to form a convex structure.