JPS63302361A - Ultrasonic scanning apparatus - Google Patents

Abstract

PURPOSE:To obtain a three-dimensional image of a body to be inspected, by a construction wherein the body to be inspected is scanned by ultrasonic beams emitted from a plurality of directions intersecting each other perpendicularly. CONSTITUTION:When an RF pulse signal 2a is impressed from a pulse modulator 2 on the surface of a hole 9a of a body 9 to be inspected, through the intermediary of blindlike electrodes 1a and 1b, ultrasonic beams of longitudinal wave are emitted at an angle theta and in the directions of X and Y axes through a liquid L. These ultrasonic beams are reflected from the surface and the inside of the body 9 to be inspected. Moreover, reflecting points of the body 9 are controlled to be shifted in the directions of X and Y axes and scanned. The ultrasonic beams of longitudinal wave reflected in this scanning are made to enter blindlike electrodes 1c and 1d through the liquid L again and are converted into detection signals S01 and S02 containing informations on amplitudes and phases being perpendicular to each other. These signals S01 and S02 are made to pass through amplifiers 3a, 3b, a phase comparator 4 and an X-Y recorder 5, so that a two-dimensional output picture be drawn. Moreover, a switch 8 is turned ON and OFF repeatedly and thereby a current accumulated 7 is made to flow through the body 9 to be inspected, through a wire 8a and a copper leaf 10, so as to be discharged. Then the distortion of the part of the hole 9a is increased and thus a three-dimensional image is obtained.

Description

Detailed Description of the Invention (Industrial Application Field) This invention scans a 111th object with an ultrasonic beam emitted around the object and obtains ff's about the surface and internal state of the object. The present invention relates to an ultrasonic scanning device that obtains a unique detection signal.

(Prior Art) Conventionally, as an ultra-r1 wave device that emits an ultrasonic beam toward a subject and observes the surface and interior of the subject, for example, the one disclosed in Japanese Patent Application No. 58-22978 has been used. there were. FIG. 2 shows such an ultra-j'f wave scanning device. That is, on one P-plane of the piezoelectric plate 1, arc-shaped transducers T in and T o ++ 1 are arranged so as to divide one circle into two.

Transducers T1,1 and T. 14. are a pair of sagging electrodes Ea and E arranged in a concentric circle 1-.
b; Set Ec and Ed to I-. Transducer Ti
+, is super? ``functions as an electrode that transmits an f-wave beam,
The transducer T o u L functions as an electrode that receives reflected waves of the ultrasound beam.

In order to function as an ultrasonic scanning device, the piezoelectric plate 1 is 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. Placed. Furthermore, a subject 9 is placed at a position in the liquid that opposes the piezoelectric plate 1 .

An electric 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 interdigital electrodes Ea and Eb of the transducer T In from a signal source (not shown). As a result, as shown by the arrow in FIG.
1. A longitudinal ultrasonic beam is emitted to the liquid by θ2 (0 x θ1 <90°, 0 x θ2 <90°). This ultrasonic beam propagates through the liquid and reaches the subject 9. Part of it is reflected from the surface of the subject 9 (dotted line), and the rest travels inside and is reflected (solid line). The reflected longitudinal ultrasound beam passes through the liquid again to the transducer T. u
t and is converted into an electrical signal So.

As long as there is no elastic anisotropy at and near the reflection point, the transducers T in and T. ut is the central axis of the circle -
The transducer T has a confocal point at the front. , t, and an electrical signal S. It is closed and taken out. If the transmission medium of the ultrasound beam is homogeneous, the electrical signal S. has a delayed electrical signal S1, but if there is elastic non-uniformity on the surface or inside of the object 9 irradiated with the ultrasound beam, the propagation speed of the sound wave will change, and the It has a changed amplitude and phase difference. Therefore,
When signal analysis is performed on the electric signal So having such an amplitude and phase difference, it is possible to detect cracks on the surface of the subject 9 and in the vicinity thereof.

(Problems to be Solved by the Invention) However, according to the conventional M Ff wave scanning device having such a configuration, since there is only one transducer that receives the ultrasonic beam, the MM of such a transducer Even if the object to be examined is scanned with a wave beam, there is a problem in that only (...-) amplitude and phase can be obtained.

This invention was made with the aim of solving the problems of the conventional techniques as described above, and it is possible to obtain a detection signal of [-] for a subject.
[1] It is an object of the present invention to provide a sonic scanning device. Another object of the present invention is to enable short-term measurement of non-destructive testing using heat waves.

(Means for Solving the Problems) The ultrasonic scanning device of the present invention has an ultrasonic beam transmitting transducer and a receiving transducer arranged in an arc shape on one plane 4- of a piezoelectric plate. Equipped with Usa,
11 "The ultrasonic beam of the delivery transducer is emitted to the subject, and the ultrasonic beam reflected from the subject is received by the receiving transducer to create acoustically independent 1) η mud waves. A plurality of pairs of the transmitting and receiving transducers are provided so as to transmit and receive ultrasound beams orthogonal to each other, and a detection signal regarding the specimen is obtained.
Each one operates acoustically independently.

(Operation) According to this invention, since it is configured as described above,
Detection signals having signal components orthogonal to each other about the subject are derived from the reception transducer, and the detection signals are subjected to signal processing to draw a three-dimensional image of the state of the subject.

(Embodiment) FIG. 1 is a perspective view showing an embodiment of the present invention. The piezoelectric plate 1 functions as a Lamb wave device, and is a thin plate-shaped piezoelectric ceramic, for example, about 0.2 mm thick and 16 mm in diameter.
It is made of 91A material and has a TD of mm, and functions as a transducer that emits four sets of ultrasonic beams on its ~ plane (lower side in the figure), and 4-drop-shaped electrodes 1a, 1b, and an IC.
and 1d are formed. Interdigital electrodes 1a, 1b,
The IC and l1d are arranged in such a manner that one circle is divided into four parts, and the distance between the electrodes facing each other is 7n+Ω, and the aperture angle is 60°. The interdigital electrodes 1a and 1b are grounded at one end in order to function as transmitting electrodes for ultrasound beams.
The other end is connected to the output end of the RF frequency pulse modulator 2,
The output RF pulse signal 2a (for example, 12.5Mtl
z, gate start time 9.2 μs, gate width 1.2
μs) is input. Moreover, the interdigital electrodes 1c, 1d
In order to function as a receiving electrode, one end is grounded, and the other end is connected to the input ends of amplifiers 3a and 3b, converting the received ultrasonic beam into an electric signal, which is converted into a detection signal S. 1
and S. It is output as 2.

Amplifiers 3a and 3b are connected to a phase comparator 4,
Detection signals S of the sagging type gH1c and ld amplified to this
. I and S. 2, that is, the output signals S3a and S3b are supplied to the phase comparator 4. The phase comparator 4 is connected to the X-Y recorder 5, and outputs the results of detailed signal analysis, that is, the output signal S3a and the output signal S3. The result of the comparison is supplied as an output signal S4.

On the other hand, a power source 6 is provided, and applies a voltage of 25 V to the capacitor 7, for example. The capacitor 7 is provided to temporarily generate thermal distortion in the subject 9 by discharging, and has a capacitance of 66,000 μF. 7 and is connected to one end of a normally open switch 8. The output end f of the switch 8 is connected to one end of the copper foil 10 by a wire 8a. The copper foil 10 is bonded to one side of the subject 9 using an epoxy adhesive while ensuring electrical contact. The adhesive material was coated with I5 to have an average film thickness of 150 μm. Also, the copper foil 10 has a length of 10 mm and a width of 5 mm.
, the thickness is about 30 μm, and the electrical resistance is 10.4 n+Ω.

The subject 9 is not a component of the present invention, but is shown to explain the configuration and operation of the present invention. The test object 9 in this case consists of an aluminum plate placed at a distance of 6.2n+m from the piezoelectric plate 1, and as shown in FIG. , a hole 9a is provided from the F side to the one side. The hole 9a has a diameter of 14 mm and a thickness of 400 μm at the central 9 mm portion, leaving a thickness of 250 μm at the other portions. The piezoelectric plate 1 is a fold-down type Vila,
lb.

The surface having 1c and 1d is directed toward the subject 9, and this surface and the subject 9 are shown facing each other with a liquid (eg, pure water) L in between.

Next, the operation will be explained. Frequency 12.5 MIIz from pulse modulator 2, gate start time 9.2 μs,
When a 220 μs RF pulse signal 2a is applied to the surface of the hole 9a of the object 9 from the interdigital electrodes 1a, lb, an angle θ (0〈 (θ<90°) and a longitudinal ultrasound beam is emitted through the liquid stream in the X-axis and Y-axis directions.

This ultrasonic beam propagates through the liquid and reaches the subject 9, a portion of which is directly reflected by the surface of the subject 9, and the rest of which travels inside and is reflected. Historically, the object 9 is scanned by controlling the reflection point of the object 9 to be moved by a width of 22 mm in the X-axis direction and in steps of 39 μm in the Y-axis direction.

In such a scan, each reflected longitudinal sound beam is again incident on the interdigital electrodes lc, ld via the liquid reservoir, and a detection signal S containing mutually orthogonal amplitude and phase information is generated. 1 and S. Converted to 2.

Detection signals S o I and Sl of the cascading electrodes 1c and 1d
, 2 are manually amplified by amplifiers 3a and 3b, and the amplifiers 3a and 3b output the detection signal S. I and S. The output signals S3a and S3h, which are amplified by 2, are input to the phase comparator 4. The phase comparator 4 outputs an output signal S4 as a result of phase comparison between the output signals S3a and S:r++ to the X-Y recorder 5,
Draw a two-dimensional output image.

When the switch 8 is turned on and off repeatedly, for example, 200 times, the current due to the charge accumulated in the capacitor 7 flows through the wire 8a and the copper foil 10 to the subject 9 and is discharged. Therefore, due to the electrical resistance of the subject 9, it is converted into electrical energy or thermal energy, so a heat wave as shown in FIG. This increases distortion, especially distortion in the hole 9a portion. As a result, an image in which the entire image of the subject 9 is emphasized is obtained. Distortion caused by heat waves disappears as thermal energy disappears.

In the embodiment of the present invention described here, the object to be examined is plastically deformed, but the present invention may also be used in a thermoelastic region.

(Effects of the Invention) As described in detail in F-11 above, since the object is scanned by ultrasonic beams emitted from a plurality of orthogonal directions, ultrasonic beams containing mutually orthogonal components are transmitted from the object. A detection signal is obtained, and a three-dimensional image of the subject can be formed based on this detection signal, and this image can be displayed with emphasis by heat waves.

[Brief explanation of drawings]

Fig. 1 is a block diagram of an ultrasonic scanning device according to an embodiment of the present invention, Fig. 2 is an 11-plane view of a conventional ultrasonic device, and Fig. 3 is a path diagram of an M sound beam by a conventional ultrasonic device. ,
FIG. 4 is a plan cross-sectional view of the hole. 1... Piezoelectric plate, la, lb, lc, 1 d -... interdigital electrode, 7.
...Capacitor.

Claims (2)

[Claims] (1) 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, and In the ultrasonic scanning device, the ultrasonic beam reflected from the specimen is received by the receiving transducer to obtain acoustically independent detection signals for the specimen, wherein the transmitting and receiving transducers are connected to each other. 1. An ultrasonic scanning device comprising a plurality of pairs so as to transmit and receive orthogonal ultrasonic beams, each of which operates acoustically independently. (2) The ultrasonic scanning device according to claim 1, wherein the subject is heated by intermittent discharge current of the capacitor while transmitting and receiving the ultrasonic beam.