JPS5830658A - Ultrasonic probe and manufacture therefor - Google Patents

Abstract

PURPOSE:To suppress sufficiently subsidiary peak values and provide acute directivity in the range from short distance to long distance by forming the vibrating face of a vibrator in the shape of a rotating face with two circular arc leaves and arranging an imaginary ring shaped sound source behind the vibrator. CONSTITUTION:An ultrasonic probe is formed by laminating successively an ultrasonic vibrator 12 and an acoustic matching layer 16 on an acoustic packing material 10. The surface shape of those members, the acoustic packing material 10, vibrator 2 and matching layer 16 is a rotating face formed by rotating two circular arcs with respect to the center axis X-X' and those two circular arcs used as a reference face of this rotating face does not cross the axis X-X'. Since the vibrating face of the vibrator 12 is formed on the rotating face of the two circular arcs, it is possible to provide an imaginary ring focus with an imaginary ring sound source arranged behind the vibrator 12 without using an acoustic lens.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ultrasonic probe and a method of manufacturing the same, particularly an ultrasonic probe that is used in an ultrasonic diagnostic apparatus and transmits and receives diagnostic ultrasonic waves to a subject, and the manufacturing method thereof. Concerning improvements in methods.

2. Description of the Related Art Currently, in the medical field, ultrasonic diagnostic apparatuses are used that display images of the inside of a living body using ultrasonic waves. In this device, the ultrasonic probe used to transmit and receive ultrasonic waves to and from a subject such as a living body has a wide field of view and within the entire field of view in order to reliably diagnose diseased tissue. It is required to have high resolution.

However, while conventional probes have a fixed focus and have high resolution near the focus and can obtain clear images, they cannot obtain sufficiently clear images at distances near and far from the focus. There was a drawback that there was no For this reason,
Research has been carried out on ultrasonic probes that can obtain clear images with high resolution regardless of distance, from short to long distances. A ring-shaped ultrasonic probe is known as a result of such research. This ring-shaped probe has the sharpest directivity from the immediate vicinity to the farthest distance. However, the first sub-maximum of this probe, which indicates unnecessary sensitivity in directions other than the target direction, is as large as 116 dB, and the on-axis sensitivity, which indicates sensitivity at far distances, rapidly decreases in inverse proportion to the square of the distance. It has two drawbacks. In order to eliminate these drawbacks, a virtual ring-shaped ultrasonic probe shown in FIG. 1 was developed.

The probe has a structure in which a flat ultrasonic transducer 12 is laminated on an acoustic backing material 10, and an acoustic lens 14 is further laminated on this vibrator 12. As shown in Figure 12, the center is 0.
, 0'' are rotated about the central axis X-X'.

This acoustic lens 14 applies a virtual ring focus to the ultrasonic waves transmitted and received from the transducer 12, and the apparent sound source of the ultrasonic waves is placed behind the transducer in a ring shape with a diameter of oo'. (Hereinafter, this apparent ring-shaped sound source will be referred to as a virtual ring sound source.) The drop is compensated for, and the apparent upper sound source forms a wide ring sound source with diameter OO′, which sufficiently suppresses the submaximum.However, this virtual ring-shaped probe is flat. Because it is necessary to stack acoustic lenses 14 of different thicknesses on the vibrating surface of the vibrator 12, multiple reflections of ultrasonic waves occur within the acoustic lenses 14, and as a result, the received echoes are substantially reduced. There is a drawback that the pulse width is long, which causes deterioration in the distance resolution of ultrasonic diagnostic images.

The present invention was made in view of the above-mentioned problems in the prior art.
The purpose is to provide an ultrasound probe that has sharp directivity from short to long distances while sufficiently suppressing sub-maximum, and does not cause deterioration of the distance resolution of ultrasound diagnostic images. be.

To achieve the above object, the present invention provides an ultrasonic probe that transmits and receives ultrasonic waves toward a subject from an ultrasonic transducer laminated on an acoustic backing material, in which the vibration surface of the ultrasonic transducer is It is characterized in that it is formed in the shape of a rotating surface with two circular arcs, and that the virtual ring sound source of the ultrasonic waves is arranged behind the vibrator.

Further, in the above-mentioned ultrasonic probe, a polymer piezoelectric film is generally used as the ultrasonic transducer. Here, since the polarization of the polymer piezoelectric film is removed when heat is applied, there is a problem with the manufacturing method.

Therefore, in order to solve the above problems, the method of the present invention involves thermal compression molding of a polymer piezoelectric film so that the vibration surface has a rotating surface shape of two circular arcs, and an ultrasonic virtual ring sound source is arranged behind it. An ultrasonic probe is manufactured by forming an ultrasonic transducer, then performing a polarization operation on this ultrasonic transducer, and laminating the ultrasonic transducer on a pre-formed acoustic backing material. It is characterized by

Next, preferred embodiments of the present invention will be described based on the drawings.

Note that the imperial palaces corresponding to each of the above-mentioned members are given the same reference numerals, and explanations thereof will be omitted.

In view of the fact that the drawbacks of the conventional probe shown in Fig. 1 are caused by the use of an acoustic lens, the ultrasonic probe of the present invention forms the vibration surface of the ultrasonic transducer itself into a rotating surface of two circular arcs. By doing so, a virtual ring sound source is placed behind the transducer without using an acoustic lens, and the distance resolution of the ultrasound diagnostic image obtained through the probe is improved.

FIG. 3 is an explanatory diagram showing the cross-sectional structure of such an ultrasonic probe, in which an ultrasonic transducer 12 is placed on an acoustic backing material lo.
and an acoustic matching layer 16 are sequentially laminated. Each of these members, that is, the acoustic backing material 10
The shapes of the surfaces of the vibrator 12 and the matching layer 16 each consist of a rotating surface formed by rotating two circular arcs about the central axis x-x'. A shape that does not intersect with the central axis x-x' is used.

In this embodiment, the acoustic backing material 1o is made of silicone rubber containing tungsten powder, the vibrator 12 is made of a polymer piezoelectric film, and the acoustic matching layer 16 is made of polyester. The above polymer piezoelectric film is, for example, a piezoelectric film obtained by polarizing polyvinylidene fluoride, polyvinyl fluoride, copolymers containing these as main components, or a mixture of these and ferroelectric ceramic powder. means the body.

The present invention consists of the above configuration, and its operation will be explained next.

In the ultrasonic probe of the present invention, the vibration surface of the vibrator 12 is formed as a rotating surface of two circular arcs, so unlike the conventional probe shown in FIG. 1, there is no need to use an acoustic lens. Virtual ring focus can be performed by arranging a virtual ring sound source behind the vibrator 12.

Therefore, when performing ultrasonic diagnosis by bringing the acoustic matching layer 16 of the probe into contact with a subject such as a living body, the transducer 12
Ultrasonic waves can be transmitted and received from the object to the subject without causing multiple reflections within the acoustic lens, and as a result,
The ultrasonic diagnostic image of the subject obtained through this probe has extremely high distance resolution.

Furthermore, in this embodiment, an acoustic matching layer 16 is laminated on the surface of the transducer 12 to ensure matching with the object, thereby suppressing the reflection of ultrasound generated at the interface between the probe and the object. be able to. Therefore, the sensitivity of this probe is improved, and the ultrasonic diagnostic image of the subject obtained through this probe can also have higher distance resolution. Note that this acoustic matching layer 16 does not need to be formed integrally with the probe as in this embodiment, and may not need to be used depending on the type of subject or the part to be inspected.

In addition, in order to improve the adhesion at the interface between the probe and the subject, for example, it is applied to the opening of the rotating surface of the probe, that is, the opening of the acoustic matching layer 16.

As shown in FIG. 4, a filler 18 having a flat contact portion may be filled. This filler 18 can be formed using, for example, low impedance polyester.

Next, a method for manufacturing an ultrasonic probe according to the present invention will be explained.

For example, when manufacturing a probe as shown in FIG. 3, there is a problem in that the polymer piezoelectric film commonly used as the material for the ultrasonic transducer 12 loses its polarization when exposed to heat. Therefore, in the method of the present invention, first, an acoustic backing material 10. The ultrasonic transducer 12 and the acoustic matching layer 16 are preheated and compression molded [2], and then the transducer 12 is polarized, and the acoustic backing material 10, the transducer I2,
A probe is formed by laminating the acoustic matching layers 16 in this order.

Here, since the polarization operation of the vibrator 12 can be carried out after the vibrator 12 is thermally compression molded, each of the above-mentioned members 1
0.12.16 may be sequentially bonded together, then polarization operation may be performed on the vibrator 12.

As described above, according to one aspect of the present invention, the vibration surface of the ultrasonic transducer is formed in the shape of a rotating surface of two circular arcs.

It is possible to obtain an ultrasonic probe that performs virtual ring focusing without using an acoustic lens. As a result, it has a sharp directivity from short to long distances, while sufficiently suppressing sub-maximum like the conventional virtual rectangular/gu-shaped ultrasonic probe. This eliminates the need for multiple reflections in the acoustic lens, prevents a decrease in distance resolution caused by multiple reflections within the acoustic lens, and allows extremely clear ultrasound diagnostic images to be obtained.

In addition, a polymer piezoelectric film is thermally compression molded to form an ultrasonic transducer whose vibrating surface has the shape of a rotating surface with two circular arcs, and then this transducer is polarized to form an ultrasonic probe. In particular, it is possible to prevent the polarization characteristics of the transducer from being affected by heat, thereby efficiently producing ultrasonic waves that have the above effects.
A probe can be manufactured.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the cross-sectional structure of a conventional ultrasound probe, FIG. 2 is an explanatory diagram of its virtual ring sound source, and FIG. 3 is a cross-sectional diagram of an embodiment of the ultrasound probe according to the present invention. FIG. 4 is an explanatory diagram showing another embodiment of the present invention. Corresponding members in each figure are designated by the same reference numerals, and 10 is an acoustic backing material, 12 is an ultrasonic transducer, and 16 is an acoustic matching layer. Applicant Aloka Co., Ltd. 1st grade 2nd grade 3rd grade 4th grade

Claims (1)

[Claims] (1) In an ultrasonic probe/probe that transmits and receives ultrasonic waves toward a subject from an ultrasonic transducer laminated on an acoustic banking material, the vibration surface of the ultrasonic transducer is An ultrasonic probe characterized in that it is formed in the shape of a rotating surface of two circular arcs, and the above-mentioned virtual ring sound source of ultrasonic waves is arranged behind the transducer. (2. Claims (11) An ultrasonic probe characterized in that an ultrasonic transducer is laminated on the surface of an acoustic backing material formed in the shape of a rotating surface of 5 arcs and 2 leaves. 〇(3) In the probe according to any one of claims (1) and: f2), an acoustic matching layer whose surface is formed into two circular arcs is laminated on the vibration surface of the ultrasonic transducer. 7
An ultrasonic probe characterized by: (4) A polymeric piezoelectric film is thermally compression molded to form an ultrasonic vibrator whose vibrating surface has a rotating surface shape of two circular arcs and a virtual ring sound source of ultrasonic waves arranged behind it. A method for manufacturing an ultrasonic probe, comprising subjecting the ultrasonic transducer to a polarization operation and laminating the ultrasonic transducer on a pre-formed acoustic backing material.