JP3358907B2 - Array type ultrasonic probe - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an array type ultrasonic probe having an acoustic lens (hereinafter referred to as an array type probe), and particularly to an array type probe in which unnecessary ultrasonic waves are shielded. About.

[0002]

2. Description of the Related Art An array type probe is used, for example, in a medical ultrasonic diagnostic apparatus as a transmitting / receiving section of ultrasonic waves. For example, strip-shaped piezoelectric elements having a small width are arranged in the width direction (long axis direction), and linear or sector driving is performed in the same direction. In such a device, an acoustic lens is generally provided in the length direction (short axis direction) of the piezoelectric element to increase the resolution.

[0003]

2. Description of the Related Art FIG. 2 is a view of an array type probe for explaining a conventional example of this kind, wherein FIG. 2 (a) is a front sectional view and FIG. 2 (b) is a side sectional view. The array type probe has a P on the backing material 1.
Strip-shaped piezoelectric elements 2 made of ZT (lead zirconate titanate) or the like are arranged in the long axis direction. Electrodes are provided on both main surfaces, and a filler is embedded between the grooves (not shown). And
On the front surface of the piezoelectric element 2, a two-layer acoustic matching layer 3 (ab) for matching acoustic impedance with an object to be detected (a living body or the like) and improving ultrasonic wave propagation efficiency is provided. Furthermore, it is formed by attaching the acoustic lens 4 in the short axis direction. However, when the sound speed is slower than the detected object, the sound is convex, and when faster, the sound is concave (not shown).

[0004] The acoustic lens 4 is basically when bonded to match the length L _a of the curvature portion (lens portion) 4a to L _b of the piezoelectric element 2 (FIG. 3), the smallest thickness t Thus, the propagation loss of the ultrasonic wave can be minimized. However, if the center (AA ′, BB ′) of the acoustic lens 4 and the piezoelectric element 2 deviates from the manufacturing point such as an error or positioning, (fourth)
FIG.), The substantial radiation area S of the ultrasonic wave is reduced, and the convergence direction U is inclined from the center line, so that the specification cannot be achieved. Therefore, for example, larger than L _a of the lens portion 4a of the length L _b of the piezoelectric element 2. Then, a flat portion 4b is interposed at both ends, and a holding leg 4c is further provided (FIG. 2B). In this way, even if the center of the acoustic lens 4 deviates from that of the piezoelectric element 2 due to L _a <L _b , the ultrasonic wave is surely converged on the center line of the acoustic lens 4. Further, the holding leg 4c prevents the acoustic lens 4 from being detached or displaced by a pressing force or the like during use. In addition,
When the lens section 4a is made larger than the piezoelectric element 2 with the same curvature (FIG. 5), the thickness t becomes larger. Also,
When the centers of the two are shifted, the convergence direction of the ultrasonic wave is inclined from the center as in the case described above.

In such a device, each piezoelectric element 2 has
A high-voltage pulse P is applied through a delay circuit (not shown),
Sector drive is performed in the long axis direction. In the short-axis direction, the resolution can be increased by converging the ultrasonic waves by the acoustic lens 4. Note that reference numeral 5 in FIG.
Is a base, 6 is a flexible substrate, 7 is a fixing resin,
FIG. 8 is a case. Also, lead wires for commonly connecting the front sides of the piezoelectric elements 2 are omitted.

[0006]

Problems with the prior art However, with the above configuration, as described above, the acoustic lens 4 has a disadvantage in terms of manufacturing.
The lens section 4a is smaller than the length of the piezoelectric element 2. Therefore, the ultrasonic waves from the central region of the piezoelectric element 2 pass through the lens portion 4a and converge. However, it has been found that ultrasonic waves radiated from both ends of the piezoelectric element 2 have had an adverse effect with the recent increase in accuracy. That is, the ultrasonic waves from both ends pass straight through the flat portion 4b of the acoustic lens 4, are reflected by an interface region such as a diseased part in the same region, and are received. As a result, there is a problem that the reflected wave in the original convergence region becomes a noise component, disturbs an image, and lowers diagnostic accuracy.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide an ultrasonic probe which eliminates unnecessary ultrasonic waves from both ends of an acoustic lens and obtains a good image.

[0008]

The basic solution of the present invention is to provide an ultrasonic shield at both ends of an acoustic lens having a curvature portion set shorter than the length of a piezoelectric element. Hereinafter, an embodiment of the present invention will be described.

[0009]

FIG. 1 is a side sectional view of an ultrasonic probe illustrating an embodiment of the present invention. The same parts as those in the prior art are given the same numbers, and the description is simplified. In the array type probe, as described above, the piezoelectric elements 2 are arranged on the backing material 1 in the long axis direction, two acoustic matching layers 3 (ab) are provided, and the convex acoustic lens 4 is connected to the short axis. It is formed by attaching in the direction. The acoustic lens 4 has a length L of the lens portion 4a.
the _a smaller than L _b of the piezoelectric element 2, the flat portions 4 on both ends
The holding legs 4c are provided with the interposition of the b. The flat portion 4b is provided with, for example, a copper foil as a reflecting material, which functions as the ultrasonic shield 9.

With such a configuration, the ultrasonic waves radiated from both ends of the piezoelectric element 2 are reflected by the ultrasonic shield 9 and are not radiated to the object to be detected. Since the reflected waves from both ends are reflected from the vicinity of the surface of the piezoelectric element 2, they are clearly distinguished from the reflected waves from the object to be detected, and the resolution is not affected by image processing or the like. Therefore, only signals transmitted and received from the central region of the piezoelectric element 2 via the lens unit 4b can be processed, so that noise components can be reduced, images can be improved, and diagnostic accuracy can be improved. Further, incidentally, by setting the length L _a of the lens portion freely it can control the substantial opening area, thereby improving the steel production.

[0011]

[Others] In the above embodiment, the ultrasonic shield 9 has achieved its function as a reflector, but it may be a sound absorber having a large attenuation of the ultrasonic wave. Further, the ultrasonic shield 9 is applied on the flat portion 4b of the acoustic lens 4. However, the ultrasonic shield 9 may be placed on the lower side or embedded in the flat portion, and further, for example, a leg including the lens portion 4a and the flat portion 4b. The portion 4c may be integrally joined as a separate body. Although the flat portions 4b are interposed at both ends of the lens portion 4c, the flat portions 4b are not necessarily literally flat, but may be curved or rough. In addition, although described as the sector drive, a linear drive may be used. In short, an acoustic lens is attached in the short axis direction of an array type in which piezoelectric elements (including divisions) are arranged, and a substantial radiation area and A lens whose both ends are shielded other than the lens portion 4a belongs to the technical scope of the present invention. Although the acoustic lens has a convex shape, it is needless to say that the acoustic lens may have a concave shape in relation to the speed of sound as described above.

[0012]

According to the present invention, since the ultrasonic shields are provided at both ends of the acoustic lens having the curvature portion set shorter than the length of the piezoelectric element, unnecessary ultrasonic waves from both ends of the lens portion are eliminated. It is possible to provide an ultrasonic probe which eliminates and obtains a good image.

[Brief description of the drawings]

FIG. 1 is a side sectional view of an ultrasonic probe explaining one embodiment of the present invention.

FIG. 2 is a view of an ultrasonic probe for explaining a conventional example, wherein FIG. 2 (a) is a front sectional view and FIG. 2 (b) is a side sectional view.

FIG. 3 is a partial side sectional view of an ultrasonic probe explaining a conventional example.

FIG. 4 is a partial side sectional view of an ultrasonic probe explaining a conventional example.

FIG. 5 is a partial side sectional view of an ultrasonic probe explaining a conventional example.

[Explanation of symbols]

1 backing material, 2 piezoelectric element, 3 acoustic matching layer, 4
Acoustic lens, 5 bases, 6 flexible, 7 fixing resin, 8 cases, 9 ultrasonic shield.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) H04R 17/00 332 A61B 8/00 G01N 29/24 502

Claims (1)

(57) [Claims] 1. A side-by-side plurality of piezoelectric elements in the width direction, the pressure <br/> conductive flat and leg on both sides has a shorter curvature portion than the length of the piezoelectric element in the longitudinal direction of the element An ultrasonic lens having an acoustic lens having a portion on the piezoelectric element group, wherein an ultrasonic shield is provided on flat portions on both end sides of the acoustic lens. Tentacles.