JPS63302362A - Ultrasonic image sensing apparatus - Google Patents

Abstract

PURPOSE:To improve resolution by a construction wherein a body to be inspected is scanned by ultrasonic beams perpendicular to each other. CONSTITUTION:Ultrasonic beams generated from blindlike electrodes 1a and 1b are emitted to a body 2 to be inspected through the intermediary of a liquid L, and the ultrasonic beams reflected by the body 2 are made to enter blindlike electrodes 1c and 1d corresponding thereto respectively. The ultrasonic waves of the electrodes 1a and 1b are perpendicular to each other, and a phase difference appears between the reflected ultrasonic beams when the body 2 to be inspected has an elastic anisotropy due to a flaw or the like. Signals S01 and S02 outputted from the electrodes 1c and 1d are inputted to a detecting circuit 3. Then the circuit 3 extracts a certain signal component from the signals S01 and S02 according to a gate signal 4a and outputs a signal 3a. This signal 3a is subjected to A/D conversion 5 and stored 11 through a computer 7. A series of informations which are stored 11 are processed by the computer 7, and an acoustic image thus obtained is displayed in a display device 8 or recorded in a printer 9.

Description

Detailed Description of the Invention (Industrial Application Field) This invention scans an object with a plurality of ultrasonic beams to obtain an acoustic image two-dimensionally showing the surface of the object and the state of its vicinity. The present invention relates to a MU wave imaging device.

(Conventional technology) Recently, there has been a great deal of interest in non-destructive testing technology.
Among these, ultrasonic technology is attracting attention as a powerful means of displaying the internal state of even optically opaque substances.

In ultrasonic technology, it is known that a transducer capable of transmitting and receiving Lamb waves can be constructed by equipping a thin plate-shaped piezoelectric material with a wave-shaped electrode. Such a transducer functions as an in-liquid ultra-RF transducer by being placed at an interface with a liquid and driven.

Conventionally, as this type of ultrasonic device, for example, the patent application No. 58
There was one disclosed in No.-22978.

FIG. 2 shows such an ultrasonic device. That is, on one plane -F of the piezoelectric plate 1, there is an arc-shaped transducer T. and T. ut is arranged in such a way that one circle is divided into two. Transducers T in and T. ut
strikes a pair of interdigital electrodes Ea, Eb; Ec, Ed arranged concentrically. The transducer T in functions as an electrode for transmitting an ultrasound beam,
Transducer T. ut functions as an electrode that receives reflected waves of the ultrasound beam.

In order to function as an ultrasonic device, the piezoelectric plate 1 is placed so as to be immersed in a liquid L (for example, pure water) with the side on which the transducer T in is placed facing down, as shown in FIG. be done. Historically, the subject 2 is placed at a position in the liquid that opposes the piezoelectric plate 1 .

A signal S1 in the radio frequency range, which is determined by the piezoelectric plate 1 and the period of the electrodes, is applied to the transducer T in's interdigitated electrodes Ea and Eb from a signal source (not shown). , as shown by the arrow in Figure 3,
Transducer T1. , longitudinal wave ultrasound beams are emitted toward the subject 2 at angles θ1 and θ2 (0<θ1<90°, 0<θ2<90°) into the liquid. This ultrasonic beam propagates through the liquid and reaches the subject 2, a part of which is reflected by the surface of the subject 2 (dotted line), and the rest of it travels inside and is reflected (solid line). The reflected longitudinal ultrasound beam passes through the liquid again to the transducer T.

ut and is converted into electricity No. 43 SO.

The transducers T in and T unless there is elasticity at and near the reflection point. Since ut has a confocal point on the central axis of its circle, the transducer T ov+L
Detected by the electrical signal S. It is closed and taken out. If the transmission medium of the ultrasound beam is homogeneous, the electrical signal SO has a delayed form of the electrical signal S, but there may be elastic non-uniformity on the surface or inside of the object 2 irradiated by the ultrasound beam. When there is a change in the propagation speed of sound waves,
It has a correspondingly changed amplitude and phase difference. Therefore, an electrical signal S O having such an amplitude and phase difference
By analyzing the signal, it is possible to detect the surface and internal conditions of the object 2, such as cracks on the surface of the object and its vicinity.

(Problems to be solved by the invention) However, according to the ultrasonic device having such a configuration,
There are only a few transducers for transmitting and receiving ultrasonic beams, and 1) the resolution in the direction of propagation of the sound waves is inferior to that in the azimuthal direction.

This invention was made with the aim of solving the problems that the conventional technology had as described above, and it improved the resolution in both distance and azimuth directions. It is an object of the present invention to provide an ultrasonic imaging device that can obtain data necessary for two-dimensional display in a converted form.

(Means for Solving the Problems) The ultrasonic imaging device of the present invention has a transducer for transmitting an ultrasonic beam and a transducer for receiving an ultrasonic beam, each of which is arranged in an arc shape on one surface of a piezoelectric plate. A transducer is provided, the ultrasonic beam of the transmitting transducer is emitted to the subject, the ultrasonic beam reflected from the subject is received by the direct receiving transducer, and the ultrasonic beam of the transmitting transducer is emitted to the subject. A detection signal 13 representing the state is obtained, and a plurality of the transmitting transducers and the receiving transducers are arranged in pairs so as to transmit and receive ultrasonic beams that are orthogonal to each other. Also, a moving means for moving the direct subject to be scanned by the ultrasonic beam, and a series of direct detection signals obtained by the scanning based on the movement of the moving means, to perform RF training on the subject. and data processing means for generating an image.

(Operation) According to this invention, since it is configured as follows,
scanning the direct sample with the ultrasonic beam without moving the fertilizer liquid sample using the direct transfer stage, and processing data based on the series of detection signals obtained from the sample;
A sound habit image is generated for the subject.

(Example) FIG. 1 is a block diagram showing one embodiment of the present invention.

The piezoelectric plate 1 is made of, for example, a piezoelectric ceramic sold under the trade name of NEPE (Nie 6), and has a diameter of 14non and a thickness of 220 μm. The interdigital electrode 1a functions as two ultrasonic transducers.

lb, lc and 1d are formed.

The interdigital electrodes 1a, lb, lc, and 1d are arranged in such a manner that one circle is divided into four parts, and the electrode length is 430 μm.
．． It consists of 5 pairs. Interdigital electrodes 1'a, 1b
is driven by an electric signal S+ supplied from a circuit not shown, and functions as a transmitting electrode for an ultrasound beam. Further, the interdigital electrodes lc and ld are connected to a circuit described below, and function as receiving electrodes for ultrasonic beams. The ultrasonic beam emitted from the horizontal type J = jla, lb is
As shown in FIG. 4, the light is emitted through the liquid to the subject 2 placed near its convergence point.

Subject 2 is, for convenience of explanation, as shown in FIG. 5 from L.
Two types are available. The subject 2 shown in FIG. 5 has a vertical X of 4
It is made of a copper plate with a diameter of 0 mm, a width y of 30 mm, and a thickness d of 1 mm, and the bottom surface thereof is provided with lattice-like grooves etched in a grid pattern at intervals of 1 mm, and the width of the grooves is approximately 250 μm.
m, and the depth of the groove is approximately 100 μmm.

The ultrasonic beam reflected by the subject 2 is incident on the corresponding interdigital interdigital electrodes 1c and ld, and an electrical signal S is generated. I, converted to S62. The signals Sol and Sn2 are input manually to the detection circuit 3. The detection circuit 3 is connected to the Katei No. 3 generator 4, and has an analog switch (not shown) that is opened and closed by a gate signal 4a inputted from the kneader. By opening and closing this analog switch,
Signals Sol and Sn2 are gated and supplied to an analog-to-digital converter (80C) 5 as a signal 3a. The analog-to-digital converter 5 is connected via a bus 6 to a computer (CPU) 7 as a data processing means;
Display device ((1:RT) 8 and printer (P
RN) 9 and subject 2 to X for scanning subject 2.
A motor drive circuit 10 as a moving means for driving a motor (not shown) provided for movement in the direction, and an external storage device 11 for storing data of the computer 7.
and is connected to.

Next, the operation will be explained. FIG. 4 is a layout diagram showing the positional correspondence between the piezoelectric plate 1 and the subject 2 shown in FIG. 1. Figure 4 shows the piezoelectric plate 1 shown in Figure 4a along the line x-x'
FIG. 4C shows a state in which the subject 2 is cut at the same position. Stick 1
The ultrasonic beams emitted from a and lb reach the subject 2 through the liquid at an angle θ, as shown in FIG.

In the subject 2, a part of the light is directly reflected on the surface of the subject 2, and the other part travels inside and is reflected.

Here, the ultrasonic beam of the pole 1a and the ultrasonic beam of the interdigital electrode 1b are very orthogonal to each other,
If the object 2 has no elastic anisotropy due to scratches, etc.
There is no phase difference between the two.

However, due to scratches etc. on the subject 2, elastic r, IIi
When there is directionality, a phase difference appears in the reflected ultrasonic beams of the interdigital electrodes 1a and lb.

Signal S of interdigital electrodes 1c and 1d. 3. Sn2 is manually input to the detection circuit 3. Signal S. 1. Since Sn2 contains components of unnecessary reflected waves generated in the propagation path, the detection circuit 3 detects the sixth signal by the gate signal 4a.
A signal S as shown in the figure. 1. Extract a certain signal component from Sn2 and manually input it to the analog-to-digital converter 5 as No. 13 3a. Analog-digital converter 5
converts the signal 3a from the detection circuit 3 into a digital signal. The computer 7 stores this signal in the external storage device 11 as detection data. Below, motor drive circuit 10
By controlling the object 2 to move stepwise in the X and Y directions and repeating this series of operations,
The subject 2 is scanned by ultrasonic beams from interdigital electrodes la and lb.

The computer 7 performs image processing using the series of detection data stored in the external storage device 11 in this way, and
An acoustic image as shown in the figure is displayed on the display screen of the display device 8 or outputted by the printer 9.

Figure 7a shows the subject 2 shown in Figure 5 on the side without the grid (
This is an acoustic image obtained by scanning the lower part of the figure with an ultrasonic beam. In this case, the scanning interval, ie the movement step, is 100 μm. The line xx' shown in FIG. 1 is the case where the ultrasonic beam is propagated from the interdigital electrode 1a to the interdigital electrode 1c, and this is called the X mode. Also, Y-Y
' is the case where the ultrasonic beam is propagated from the interdigital electrode 1b to the interdigital electrode 1d, and this is called Y mode. The interdigital electrodes IC and 1d convert the ultrasonic beam incident through the path shown in the arrow direction into an electrical signal and output the electrical signal.

Acoustic images obtained in the X mode or Y mode are obtained using a single ultrasonic beam, so they have excellent azimuth resolution, but have a problem with distance resolution. However, X mode or Y
These problems can be solved by logically ANDing or ORing the acoustic images obtained in the modes. For example, FIG. 7a is an acoustic machine diagram obtained by superimposing acoustic images obtained in X mode and Y mode, that is, by ORing them. Also,
FIG. 7 is an acoustic machine diagram obtained by logical product of acoustic images obtained in X mode and Y mode.

(Effects of the Invention) As explained above, in the present invention, since the object is scanned by ultrasonic beams that are orthogonal to each other,
This has the effect of increasing the resolution of an ultrasonic imaging device for generating two-dimensional acoustic images.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an ultrasonic imaging device according to an embodiment of the present invention, FIG. 2 is a plan view of a conventional ultrasonic device, FIG. 3 is a path diagram of an ultrasonic beam by a conventional ultrasonic device, and FIG. 4
The figures are a layout diagram of the piezoelectric plate and the subject in Figure 1, Figure 5 is a perspective view showing the shape of the subject, Figure 6 is a waveform diagram of the signal input to the detection circuit, and Figure 7 is according to the present invention. This is a diagram of a sound machine. 1... Piezoelectric plate, la, lb, lc, ld-... interdigital electrode, 3...
Detection circuit, 5... Analog-digital converter, 7... Computer, 10-... Motor drive circuit.

Claims (1)

[Scope of Claims] A transducer for transmitting an ultrasonic beam and a transducer for receiving an ultrasonic beam are arranged in an arc shape on one plane of a piezoelectric plate, and the ultrasonic beam of the transmitting transducer is emitted to a subject. , an ultrasonic imaging device configured to receive an ultrasonic beam reflected from the subject by the receiving transducer to obtain a detection signal representing a state of the subject; a plurality of pairs of the transmitting transducer and the receiving transducer; a moving means for moving the subject to be scanned by the ultrasonic beam; and a data processing means for generating an acoustic image of the subject using the series of detection signals.