JPH06245931A - Ultrasonic probe - Google Patents

Abstract

PURPOSE:To constitute an ultrasonic probe so that a focal length has plural points with regard to not only in the longitudinal direction of the ultrasonic probe, but also in the thickness direction, and resolution of an image can be improved enough. CONSTITUTION:The ultrasonic probe is constituted of a vibrator 1, a matching layer 2, an acoustic lens 3, etc. This acoustic lens 3 has plural curvatures, therefore, an ultrasonic beam generated from the vibrator 1 passes through the matching layer 2, and when it is radiated to the outside from the acoustic lens 3, its refractive index becomes different by a passing position, and the ultrasonic beam is converged in plural points.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic probe for use in ultrasonic diagnostic equipment, ultrasonic flaw detectors, fish finder and the like.

[0002]

2. Description of the Related Art Ultrasonic diagnostic equipment as medical equipment, ultrasonic flaw detectors for detecting scratches and defects in an object to be inspected, fish finder for detecting a school of fish, etc., use ultrasonic waves for inspection and exploration. An ultrasonic probe is used to do this.

For example, the ultrasonic diagnostic apparatus is composed of an ultrasonic probe and an ultrasonic diagnostic apparatus main body. As shown in FIG. Ultrasonic echoes reflected and returned from 42 are received by the ultrasonic probe 41 and sent to the ultrasonic diagnostic apparatus body (not shown) to obtain a tomographic image of the subject 42 for diagnosis.

By the way, each ultrasonic beam from the ultrasonic probe 41 is focused on a desired depth position of the subject 42 to enhance the resolution and obtain a clear image. That is, in order to enhance the directivity of the ultrasonic beam emitted from the ultrasonic probe and improve the resolution, the ultrasonic beam is three-dimensionally focused at a predetermined depth position in the subject. To focus the ultrasonic beam, an acoustic lens is used on the ultrasonic beam emitting surface of the ultrasonic probe, or the wavefront is generated by driving the individual transducers arranged in an array with a predetermined delay time. Have been performed.

The main components of a conventional ultrasonic probe are
As shown in FIG. 3, a rectangular transducer 31 for transmitting and receiving ultrasonic waves and a matching layer 32 for acoustic impedance matching are provided.
And an acoustic lens 33 and the like. X direction is
The Y direction corresponds to the longitudinal direction of the ultrasonic probe 41, and the Y direction corresponds to the thickness direction of the ultrasonic probe 41. The oscillators 31 are arranged in an array in the X direction, and a plurality of oscillators are used to form one ultrasonic beam. By giving a delay time to each transducer 31, the ultrasonic beam can be focused in the X direction at the point of f ₂ , and the acoustic lens 33 can focus the ultrasonic beam in the Y direction at the point of f _1. it can.

[0006]

By the way, in order to increase the overall resolution of the tomographic image of the subject, the focal length of the ultrasonic beam is changed from a near position to a distant position on the body surface,
It is necessary to collect reflected echo data. However, although the focal length f ₂ of the ultrasonic beam in the X direction can be arbitrarily changed by adjusting the delay time given to each transducer 31, the focal length f _{1 in the} Y direction is equal to that of the acoustic lens. Since the curvature is fixed, it is concentrated on one point and cannot be changed.

Therefore, in the longitudinal direction of the ultrasonic probe, the resolution can be improved by changing the focal length and sufficiently focusing the ultrasonic beam. However, in the thickness direction of the ultrasonic probe, the resolution is increased at a desired depth. Because the sound beam cannot be focused sufficiently,
The image could not be obtained with sufficient resolution because it could not cover from near to far from the body surface.

The present invention was devised to solve the above-mentioned problems, and an object thereof is to provide a plurality of focal lengths in the thickness direction of an ultrasonic probe to obtain an image with sufficient resolution. There is.

[0009]

In order to achieve the above object, the ultrasonic probe of the present invention has at least two kinds of transducers arranged in an array and at least two in a direction perpendicular to the arrangement direction of the transducers. And an acoustic lens that is arranged on the ultrasonic wave emission side of the transducer.

[0010]

When an exciting pulse is applied to the vibrator of the ultrasonic probe of the present invention, the vibrator emits an ultrasonic beam. The exit side of the ultrasonic beam has at least two kinds of curvatures. Since the acoustic lens is arranged, the ultrasonic beam is refracted according to each curvature, and the ultrasonic beam is focused at a plurality of points without being focused at only one place.

[0011]

An embodiment of the present invention will be described below with reference to FIG. FIG. 1A is a view of the ultrasonic probe as seen from the ultrasonic wave emission side, and rectangular transducers 1 are arranged in an array inside the ultrasonic probe. Further, FIG. 1B shows a cross-sectional view taken along the line AA of the ultrasonic probe of FIG.

The ultrasonic probe of the present invention includes a transducer 1 for transmitting and receiving an ultrasonic beam as shown in FIG. 1 (b).
And a matching layer 2 for matching acoustic impedance
And an acoustic lens 3 for focusing the ultrasonic beam in the thickness direction of the ultrasonic probe. The acoustic lens 3 has different upper and lower curvatures with a central portion as a boundary, an upper curvature is small, and a lower curvature is large.

When an excitation pulse is applied to the vibrator 1 to irradiate the inside of the subject with the ultrasonic beam, the vibrator 1
The ultrasonic beam is generated from the ultrasonic wave, passes through the matching layer 2, reaches the acoustic lens 3, and is propagated to the outside. At this time, the acoustic lens 3 refracts the ultrasonic beam,
Focus at a fixed point outside.

However, since the acoustic lens 3 has different curvatures from the center to the upper side and the lower side, FIG.
As shown in, the ultrasonic beam passing through the upper half of the acoustic lens 3 is focused at a short distance, and the ultrasonic beam passing through the lower half of the acoustic lens 3 is focused at a long distance, which has a plurality of focal points. Becomes

According to this structure, a plurality of focal points can be obtained at the same time by emitting the ultrasonic beam once, and a sufficient resolution can be obtained from a portion near the body surface of the subject to a portion far from the body surface. Further, the ultrasonic beam having a larger curvature forms a focal point at a distant position, and the smaller curvature of the acoustic lens 3 causes an ultrasonic beam to form a near focal point. Therefore, these are combined. If so, it is possible to form a focal point at an arbitrary point.

FIG. 2 shows another embodiment, in which the central portion 21 of the acoustic lens 3 has a large curvature, the constant portions 22 and 23 on both sides thereof have a medium curvature, and the upper and lower end portions 24 and 25 have the same curvature. It has a small curvature. This large curvature portion 21 is
It is formed vertically symmetrically from the center, and the lengths of 22 and 23 are equal, and they are vertically symmetrically formed from the center. Further, the lengths of 24 and 25 are also equal to each other and are vertically symmetrical from the center.

By doing so, the portion 21 having a large curvature is
The focal point F ₁ due to, the focal point F ₂ due to the curved portions 22 and 23, and the focal point F ₃ due to the small curvature portions 24 and 25 are aligned on the center line of the acoustic lens 3 and deviated in the vertical direction. In addition, since there are three types of focus, it is possible to cover a region close to the body surface of the subject and a region far from the body surface of the subject.

Further, not limited to the above embodiment, the curvature of the curved surface of the acoustic lens may be partially finely changed to form a large number of focal points. In addition, it can be applied to other types of probes such as convex type and sector type used for ultrasonic diagnostic equipment, and it can also be used for other measuring instruments such as ultrasonic flaw detectors and fish finder using ultrasonic waves. Therefore, the resolution can be improved.

[0019]

As described above, according to the ultrasonic probe of the present invention, the curvature of the acoustic lens is partially changed to have a plurality of focal points in the thickness direction of the ultrasonic probe. It is possible to uniformly increase the resolution of an image from a portion close to the surface of the subject or the inspection object to a portion far from the surface.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of an ultrasonic probe of the present invention.

FIG. 2 is a diagram showing another embodiment of the ultrasonic probe of the present invention.

FIG. 3 is a main configuration diagram of a conventional ultrasonic probe.

FIG. 4 is a diagram showing a relationship between an ultrasonic probe and a subject.

Claims (1)

[Claims] 1. A transducer arranged in an array, and an acoustic wave having at least two kinds of curvatures in a direction perpendicular to the arrangement direction of the transducer and arranged on the ultrasonic wave emission side of the transducer. An ultrasonic probe having a lens.