JPH07274296A - Array type ultrasonic probe - Google Patents

Abstract

PURPOSE:To obtain an excellent diagnostic image by providing an electric shield together with an ultrasonic shield between piezoelectric elements so as to enhance the independence of each piezoelectric element. CONSTITUTION:The ultrasonic probe is formed by arranging a reference potential electrode 3a and a signal electrode 3b on a packing member 1 and providing an acoustic matching layer 5 to a front side. A lamination plate 8 having a rubber-based elastic body 7 is provided between piezoelectric elements 2 on both major sides of a metallic foil 6. The metallic foil 6 is connected in common and led out by a lead wire 6. In this case, the metallic foil 6 acts as an electric shield and the rubber-based elastic body 7 acts as an acoustic shield. Through the structure above, the rubber-based elastic body 7 prevents acoustic coupling and the metallic foil 6 prevents electric coupling by the capacitance between the signal electrodes. Since the piezoelectric elements are isolated acoustically and electrically, the independence is enhanced. In the case of sector drive, the directivity of each piezoelectric element 2 is improved so as to ensure wide-angle transmission and reception.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an application field of an array type ultrasonic probe (arrangement type probe) in which a plurality of piezoelectric elements are arranged, and in particular, each piezoelectric element is electrically shielded. An array type transducer.

[0002]

BACKGROUND OF THE INVENTION Array type probes are useful as a transmitting / receiving unit of an ultrasonic diagnostic apparatus for medical purposes. For example, strip-shaped piezoelectric elements are arranged in the width direction (major axis direction),
Electronic scanning such as sector or linear scanning is performed in the same direction. In recent years, it has been desired to increase the independence between adjacent piezoelectric elements and obtain a good diagnostic image.

[0003]

2. Description of the Related Art FIG. 4 is a sectional view of an ultrasonic probe for explaining a conventional example of this type. The ultrasonic probe is formed by arranging strip-shaped piezoelectric elements 2 made of PZT (lead zirconate titanate) on a backing material 1 in the width direction. Electrodes 3 (ab) are provided on both main surfaces of the piezoelectric element 2, and a reinforcing filler 4 is embedded between the piezoelectric elements 2. The front electrode 3a is a reference potential electrode, and the rear electrode is a signal electrode 3b. Further, the filler 4 prevents acoustic coupling between the piezoelectric elements 2,
Urethane resin or the like is selected. Then, the acoustic impedance matching with the living body is measured on the front surface of the piezoelectric element 2,
The acoustic matching layer 5 that improves the propagation efficiency of ultrasonic waves is provided.
Further, from each piezoelectric element 2, a lead wire (not shown), which is connected to the signal electrode 3b on the rear surface, is connected to the lead wire 6 made of a flexible substrate or the like and the electrode 3a on the front surface in common.

In such a device, as shown in FIG. 5, for example, a delay circuit is connected to each piezoelectric element 2 to apply a high-voltage pulse P for ultrasonic wave generation, and a delay time φ of the delay circuit 4 is further applied. Sector driving is performed by sequentially controlling ₍₁ to ₅₎ . In this figure, the delay time φ ₁ is the shortest and φ ₅
An example in which the ultrasonic waves are sequentially lengthened up to is shown in FIG. That is, the ultrasonic waves are driven in a fan shape in the long axis direction of the ultrasonic probe to be transmitted, and the reflected waves from the living body are received.

[0005]

However, in the above-mentioned structure, although the acoustic coupling between the adjacent piezoelectric elements 2 is made sparse by the filling material 4, the coupling is not sufficiently lost. That is, even if there is no acoustic coupling, the interelectrode capacitance C ₀ exists between the signal electrodes 3b of each piezoelectric element 2. Then, normally, a high-voltage pulse of about 10 to 200 V is applied to each piezoelectric element 2. Therefore, the interelectrode capacitance C ₀ causes electrical coupling between the piezoelectric elements 2 and also drives the adjacent piezoelectric elements. Along with this, there is a problem that ultrasonic waves are generated and interfere with each other to impair their independence. In particular, in the case of sector drive, delay drive of each piezoelectric element 2 is impaired and its directional characteristics (omnidirectionality) is impaired, so wide-angle transmission / reception cannot be performed.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an array type probe which enhances the independence between piezoelectric elements and obtains a good diagnostic image.

[0007]

The present invention is, for example, a Doppler type transmission,
Focusing on a split-type ultrasonic probe that electrically shields reception, the basic idea is to increase the independence between each piezoelectric element by providing an ultrasonic shield along with an ultrasonic shield between the piezoelectric elements. As a solution. An embodiment of the present invention will be described below.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram of an ultrasonic probe for explaining one embodiment of the present invention. FIG. 1 (a) is a sectional view and FIG. 1 (b) is a plan view. The same parts as those in the previous conventional example are given the same numbers and their explanations are omitted. The ultrasonic probe has the reference potential electrode 3a and the signal electrode 3 on the backing material 1 as described above.
b piezoelectric elements 2 are arranged, and an acoustic matching layer 5 is provided on the front surface thereof.
Is provided. In this embodiment, the laminated plate 8 having the rubber-based elastic bodies 7 on both main surfaces of the metal foil 6 is provided between the piezoelectric elements 2. However, the metal foil 6 is commonly connected,
It is led out by the lead wire 6. The metal foil 6 acts as an electrical shield and the rubber elastic body acts as an acoustic shield.

With this structure, the rubber elastic body 7 can prevent acoustic coupling, and the metal foil 6 can prevent electrical coupling due to capacitance between the signal electrodes. Therefore, the piezoelectric elements 2 can be separated acoustically and electrically, so that their independence can be enhanced. Therefore, when the sector drive is performed, the directivity of each piezoelectric element 2 can be improved and wide-angle transmission / reception can be performed.

[0010]

[Other Matters] In the above embodiment, the metal foil 6 as the metal shield body is simply interposed between the piezoelectric elements 2 and commonly connected. However, as shown in FIG. 2, for example, as shown in FIG. It may be connected to the potential electrode 3a and led out individually. In this case, the reference potential of each piezoelectric element 2 is independent, which is advantageous in that the independence of each piezoelectric element 2 is further improved. Although the laminated body 8 is interposed between the piezoelectric elements, for example, as shown in FIG. 3, after the insulating resin 9 as the acoustic shield is applied on the wall surface between the piezoelectric elements, the conductive paint 10 and the like are applied. May be embedded. Further, a shield line may be formed between the signal electrodes 3b of each piezoelectric element 2 by printing or the like. Further, although the piezoelectric elements 2 are arranged in the width direction, they can be applied to, for example, an annular shape in which they are arranged concentrically.

[00011]

According to the present invention, an electric shield is provided between the piezoelectric elements together with an ultrasonic shield to enhance the independence between the piezoelectric elements. Can be provided.

[Brief description of drawings]

FIG. 1 is a diagram of an ultrasonic probe for explaining an embodiment of the present invention, in which FIG. 1 (a) is a sectional view and FIG. 1 (b) is a plan view.

FIG. 2 is a sectional view of an ultrasonic probe for explaining another embodiment of the present invention.

FIG. 3 is a sectional view of an ultrasonic probe for explaining another embodiment of the present invention.

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

FIG. 5 is a schematic ultrasonic probe diagram for explaining sector drive of a conventional example.

[Explanation of symbols]

1 backing material, 2 piezoelectric element, 3 electrode, 4 filler, 5 acoustic matching layer, 6 metal foil, 7 rubber type elastic body,
8 laminated body, 9 insulating resin, 10 conductive paint.

Claims (1)

[Claims] 1. An array type ultrasonic probe having a plurality of piezoelectric elements, which has a reference potential electrode and a signal electrode on both main surfaces, and the reference potential electrode surface is arranged as an ultrasonic wave transmitting / receiving surface. In the ultrasonic probe, the electric shield is provided between the plurality of piezoelectric elements together with the acoustic shield.