JPH0779817B2 - Ultrasonic imaging device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an ultrasonic imaging apparatus or a metal flaw detection apparatus for performing endoscopic observation of an inner wall surface of a body cavity or an inner surface of a metal tube using ultrasonic waves. The present invention relates to a suitable ultrasonic imaging device.

[Conventional technology]

The conventional endoscopes are roughly classified into an optical endoscope for optically observing and an ultrasonic endoscope for utilizing ultrasonic waves. The former is suitable for observing the surface inside the body cavity, but when observing a tube filled with an opaque liquid, such as an artery, it is necessary to inject physiological saline so that the liquid (blood) does not hinder the observation. There is. On the other hand, an ultrasonic endoscope reproduces a tomographic image by the pulse reflection method as shown in, for example, Japanese Patent Laid-Open No. 56-156142, and even if an optically opaque liquid or the like is present, A tomographic image can be observed.

[Problems to be solved by the invention]

However, since the above-mentioned ultrasonic endoscope displays a tomographic image, the inner wall of the body cavity displays a tomographic image, and thus is suitable for observing the inside of the inner wall of the body cavity.
It is not suitable for observing the state of the inner wall surface. For example, when examining an aneurysm or valvular lesion from inside a blood vessel, it may be more effective to observe the state of the inner wall surface of the blood vessel rather than the cross-sectional image. The same applies to the inspection of metal pipes filled with opaque liquid (inspection of oxidation and cracks on the inner wall surface).

However, the conventional ultrasonic endoscope does not image the interface between the medium (liquid in the tube) and the object, but images the cross section of the object. In particular, the probe has a shape suitable for capturing a tomographic image (B-mode image), and effective observation cannot be performed in the above case.

Then, the objective of this invention is providing the ultrasonic imaging device which uses the probe of the ultrasonic endoscope suitable for observation of the inner wall surface of a tubular target object.

[Means for solving problems]

The ultrasonic probe in the ultrasonic imaging apparatus of the present invention uses a transducer having a concave and convex shape in one direction and a convex and concave shape in the other direction, that is, a saddle-shaped transmitting / receiving surface. The radius of curvature of this concave surface changes sequentially along the direction of the convex surface, so that the focal length of the ultrasonic beam continuously changes from a short distance to a long distance.

[Action]

According to such an ultrasonic probe, since the focal length changes along the direction of the convex surface, the detection signals of the reflected waves sequentially obtained by one transmission and reception are discriminated according to time and displayed to display from the line-shaped reflection point. The signal of can be displayed. Moreover, the shape of the unidirectional convex surface allows the focus to be focused on a wider range than the length of the vibrator, and by rotating the vibrator inside the inspection target, the unevenness of a wide range on the inner wall surface of the inspection target can be obtained. The status can be displayed.

〔Example〕

1 (a), (b) and (c) show a vibrator used in a probe according to an embodiment of the present invention. The wave transmitting / receiving surface of this oscillator has a concave shape in one direction, but the radius of curvature of the concave surface continuously changes from R ′ to R ″ as shown in FIG. 1 (c). As shown in FIG. 1A or 1B, the focal length F of the ultrasonic beam continuously changes from F ′ to F ″. Further, as shown in FIG. 1 (b), the wave transmitting / receiving surface of the vibrator is formed to be convex in the other direction, and as a result, as shown in FIG. 1 (a), it is formed in a saddle shape as a whole. .

In this way, the ultrasonic beam can be focused in a wide range. Therefore, the resolution in the azimuth direction is improved.

The ultrasonic transducer is formed by connecting a plurality of strip-shaped transducers to each other with an adhesive at predetermined intervals on a support formed in the saddle shape, in the short side direction. They can be installed side by side to form a saddle type. Further, it is also possible to form a saddle shape with a flexible material in which a plurality of vibrators cut in a columnar shape are bonded at a predetermined interval to each other and bonded to each other by organic bonding in a plane shape.

The ultrasonic probe is composed of a piezoelectric organic polymer material, single crystal lithium niobate, lead zirconate titanate (PZT),
The piezoelectric material may be made of lead titanate (PbTiO ₃ ) or other inorganic material.

FIG. 2 shows a conventional, general ultrasonic endoscopic device (for example, actual open 60).
-86310) is shown. The ultrasonic probe 1 is attached to the rotary shaft, and the motor 3 is connected to the flexible wire 2.
Is driven to rotate. At this time, the ultrasonic beam is provided in the direction orthogonal to the rotation axis. The ultrasonic transducer 1 is connected to the electric drive circuit 4 and emits ultrasonic pulses by applying high-voltage impulses. A part of the echo reflected from the test object is displayed on the monitor 6 whose image is reproduced by the receiving circuit 5. As an image reproducing method, ultrasonic waves are transmitted and then echoes that are diffusely reflected are sequentially received, and the intensity of the sound is converted to luminance on the raster, and the propagation time is replaced with the distance for display. This raster displays circularly in synchronism with rotation.

Next, FIG. 3 shows an ultrasonic endoscopic apparatus using the probe according to the present invention. The ultrasonic probe 1 is attached so as to be inclined with respect to the rotating shaft, and is rotationally driven by the motor 3 connected to the flexible wire 2. At this time, the ultrasonic beam changes the depth of focus in the direction of the rotation axis to provide a focus on the surface of the object. The ultrasonic probe 1 is connected to the electric drive circuit 4 and emits ultrasonic pulses by applying high-voltage impulses. A part of the echoes diffusely reflected from the unevenness of the surface of the object to be inspected are reproduced by the receiving circuit 5 and displayed on the monitor 6. As an image reproducing method, ultrasonic waves are transmitted and then echoes that are diffusely reflected are sequentially received, and the intensity of the sound is converted to luminance on the raster, and the propagation time is replaced with the distance for display. This raster is displayed in a fan shape or a circular shape in synchronization with the rotation.

FIG. 4 is a cross-sectional view and display example when the ultrasonic probe according to the present invention is attached to an endoscope and observed from the inside of the pipe 8. In the ultrasonic probe 1, the ultrasonic beam 7 has a pipe 8
The ultrasonic pulse is attached so as to be obliquely incident on the surface of the pipe, and the ultrasonic pulse is transmitted so as to focus at a wide range of different depths at a time, thereby providing a continuous ultrasonic beam. Therefore, the lateral resolution can be improved over a wide range of the pipe surface. The pipe surface has irregularities 9 due to oxidation or cracks, and the irregularities cause irregular reflection of ultrasonic pulses.
An image of a part of the irregularly reflected echo is reproduced by the receiving circuit and displayed on the monitor 6. At this time, as is well known, the propagation time of the ultrasonic wave varies depending on the size of the unevenness, the type of medium that fills the space in which the ultrasonic wave propagates, and the like. When such a propagation time difference exists, the displayed image may be distorted. However, if a reflected echo is detected by the receiving circuit, even if the displayed image is distorted, the distorted image is displayed in FIG. As shown in the portion 10 shown, the presence of the convex portion 9 can be known by being clearly distinguished from the surrounding portions. In addition, observation of an aneurysm or a valvular disorder of the heart from within a blood vessel can be similarly performed.

〔The invention's effect〕

With the ultrasonic imaging apparatus of the present invention, the operation of the ultrasonic probe is simplified, and the inner wall surface can be observed in places where the optical endoscope cannot be used. Also, the imaging speed can be improved.

[Brief description of drawings]

FIG. 1 shows the structure of the probe according to the present invention. FIG. 2 is a schematic view of a conventional ultrasonic endoscopic device. FIG. 3 is a schematic view of an ultrasonic endoscopic apparatus using the ultrasonic probe according to the present invention. FIG. 4 is a cross-sectional view and a display example when the ultrasonic probe according to the present invention is inserted into a pipe.

Claims (6)

[Claims] 1. An ultrasonic probe that transmits and receives ultrasonic pulses, and a beam of the ultrasonic pulse is spread from the ultrasonic probe in a predetermined direction at a predetermined angle so that the beam is substantially aligned with the predetermined direction. Driving means for converging the beam in an orthogonal direction and transmitting the beam to an inspection target, rotating means for rotating the ultrasonic probe about an axis parallel to the predetermined direction, and the ultrasonic probe. A receiving circuit that performs a process of converting the intensity of the reflected signal of the ultrasonic pulse reflected by the inspection target and converting the propagation time of the ultrasonic pulse into a distance, the brightness and the distance. Is displayed as a raster, and the position of the raster is changed on the display surface of the display unit in synchronization with the rotation, and an ultrasonic imaging apparatus for obtaining a reflected image of an inspection target. 2. The driving means changes the focal length of a beam of the ultrasonic pulse in accordance with the distance from the ultrasonic probe to the inspection target. The ultrasonic imaging device according to the item. 3. The ultrasonic imaging apparatus according to claim 1, wherein each of the plurality of rasters is displayed so as to converge on one point on the display surface. 4. The ultrasonic probe has a plurality of strip-shaped ultrasonic transducers, and the ultrasonic transducers are sequentially arranged while changing the curvature of the concave surface in the predetermined direction. The ultrasonic imaging apparatus according to claim 1. 5. The ultrasonic probe has a plurality of pillar-shaped ultrasonic transducers, and the ultrasonic transducers are sequentially arranged while changing the curvature of the concave surface in the predetermined direction. The ultrasonic imaging apparatus according to claim 1. 6. An ultrasonic imaging apparatus for transmitting and receiving ultrasonic pulses from an ultrasonic probe to obtain a reflection image of an object to be inspected, wherein the ultrasonic probe has a concave surface in a predetermined direction of its ultrasonic radiation surface. And a convex surface in a direction substantially orthogonal to the concave surface, and the ultrasonic wave emitting surface has a saddle shape, and the curvature of the concave surface is equal to the predetermined value. The ultrasonic imaging apparatus is characterized in that the focal length of the beam of the ultrasonic pulse is changed by sequentially changing the direction along a direction substantially orthogonal to the direction.