JPS6232356A - Method and device for transmitting and receiving ultrasonic wave - Google Patents

Abstract

PURPOSE:To display a defect in a body to be inspected with a real time, by applying an ultrasonic transmitting signal to an array element without delaying it, and scanning an ultrasonic beam by changing the internal of its transmitting array element. CONSTITUTION:Continuous wave signals P1-P8 from a continuous wave oscillator 2 are applied to an array probe 9 through an isolator 8 and each switch 16, 17 of transmission/reception switching and transmitting/receiving pattern switching. On the other hand, ultrasonic receiving signals u1-u8 received by the probe 9 are added 4 through the switch 17. An addition signal (u) is detected and amplified by an amplifying circuit 5 and becomes a detecting signal U, and inputted to a displaying circuit 6. Also, by on/off states of the switch 17, the deflection angle theta of a side lobe, and the position signal L of an array element are outputted to the circuit 6. In the circuit 6, sectional images (a surface image 71, a bottom image 72, and a defect image 73) in a body to be inspected 10 are obtained on a CRT 7 by the signals U, L. Accordingly, a delaying circuit and an operating circuit for controlling it become unnecessary, a device can be made small in size, and a display with a real time can be executed.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to an ultrasonic transmitting/receiving method and apparatus for scanning an ultrasonic beam to detect flaws in, for example, steel materials, and in particular, relates to an ultrasonic transmitting/receiving method and apparatus for scanning an ultrasonic beam to detect flaws in, for example, steel materials, and in particular, an ultrasonic transmitting/receiving method and apparatus that uses an array probe and is easy to use. The present invention relates to an electronic scanning ultrasonic transmitting/receiving method and apparatus that scans an ultrasonic beam with such a configuration.

[Background of the Invention] As an electronic scanning ultrasonic probe device using an array probe, each array element is excited and the ultrasonic waves are superimposed by timing control for transmitting and receiving ultrasonic waves, and ultrasonic waves are generated inside the subject. Methods of deflecting and focusing the beam are known.

An example of this type is "electronic scanning ultrasonic flaw detection technology and equipment."

The Journal of the Japan Society of Mechanical Engineers, Vol. 87, No. 793, Issues 23-28.

An example of a device configuration using the electronic scanning ultrasonic flaw detection method is shown in FIG. The pulse voltage from the ultrasonic receiving circuit 103 is applied to the array probe 10 via the delay circuit 102.
6.

As a result, the ultrasonic waves emitted from each play element interfere to form a wavefront, and the ultrasonic waves are transmitted in a predetermined direction within the subject 108. At this time, the ultrasonic wave is deflected in the θ direction according to the delay time set in the delay circuit 102.

Ultrasonic reflector of object 108 (surface 110, bottom 111
．． The ultrasound reflected from the defect 109).

The signal is received by the array probe 106, goes backward through the delay circuit 102, and is sent to the ultrasound receiving circuit 104. This ultrasonic reception signal is detected and rectified by an ultrasonic reception circuit 104 and then sent to a display circuit 105.An ultrasonic beam position signal is separately sent from an ultrasonic beam control circuit 101 to a 0 display circuit 105.

Based on these signals, a surface image 11 is displayed on the CRT 107.
2. Bottom image 113. A defect image 114 is displayed.

However, in this type of example, a delay circuit is used to control the timing of ultrasonic transmission and reception, and the timing is controlled by switching the amount of signal delay, so the number of delay circuits equal to the number of array elements is required, and the wiring is complicated. Coils are normally used in this large and enormous delay circuit, but they require sophisticated manufacturing techniques and are expensive (approximately 300,000 yen/piece). Therefore, it is difficult to miniaturize the ultrasonic transmitter/receiver, and the cost is high.

[Purpose of the invention]

An object of the present invention is to provide an electronic scanning ultrasonic transmitting/receiving method and apparatus that can set the beam direction without using expensive delay circuits that occupy a large space, and can display defects in the object in real time. It is to provide.

[Summary of the invention]

In order to achieve the above object, the present invention uses lobes generated in a specific direction due to interference between transmitted ultrasonic waves in an array probe. Ultrasonic transmission signals are simultaneously applied to the seven array elements of the array contactor without delay, and the interval between the transmission array elements is changed or selected at a desired interval and the ultrasound beam is scanned to inspect the object. It is characterized by

Next, the principle of the ultrasonic transmission/reception method of the present invention will be explained.

Figure 2 shows the principle of lobe generation used in the present invention.

FIG. 3 shows the sound pressure distribution of the ultrasonic beam. As shown in FIG. 2, when each element of the array probe 9 is made to emit at the same time (the emitting elements are shown in black in the figure), a spherical wave is emitted from each element. These spherical waves interfere in the front, and the 0-wave ultrasonic waves that form the wavefront form an interference band in the 0° direction, which is called the main lobe.In addition to this, interference bands of ultrasonic waves are also formed in the 0-degree direction. This is called a side lobe. This occurs because spherical waves shifted by one wavelength interfere between adjacent elements and form a wavefront also in the θ direction. The side lobe occurrence angle θ is determined from the hatched triangle in FIG. 1 using the following equation (1).

λ sir+θ;-...(1) Here, d is the distance between adjacent elements, and λ is the wavelength.

By changing the spacing between adjacent elements as shown in equation (1), the deflection angle θ of the side lobe can be changed. The present invention uses side lobes to scan an ultrasonic beam by changing the spacing between transmitting elements of the array probe 9.

FIG. 3 shows the spread of the ultrasonic beam when the array probe is emitted as shown in FIG. 2. 0, where the ultrasonic sound pressure is maximum in the direction directly below the array probe 9
There is a main lobe 14 of the next interference wave. Also, ±θ
Also in the force direction, side lobes 15 of interference waves of the ±1st order exist, where the sound pressure of the ultrasonic wave is at its maximum. Generally, the sound pressure of the side lobe is lower than the sound pressure of the main lobe.

Next, a method of transmitting ultrasonic waves when using an array probe will be explained. Figure 4 shows the conventional ultrasonic transmission method, Figure 5
The figure shows the method of transmitting ultrasonic waves according to the present invention. Conventionally, as shown in FIG. 4, a high voltage spike pulse was applied to the array probe. Then, each array element emits an ultrasonic signal having two to three continuous wavelengths. Therefore, interference of ultrasonic waves between elements separated by 2.3 or more elements does not occur. Conventionally, only the main lobe was considered because the sound pressure of the side lobe is low.

On the other hand, in the present invention, as shown in FIG.

A sine wave with n consecutive predetermined wavelengths λ is transmitted.

Moreover, the number n of wavelengths in the duration a of the emitted wave is made the same as the number of array elements. In this way, the ultrasonic waves emitted from each element of the array probe will all interfere,
The sound pressure of side lobes can be increased.

FIG. 6 shows the experimental results of the sound pressure distribution of transmitted ultrasonic waves when pulse waves and sine waves are transmitted.

The experimental conditions were: spacing between transmitting elements of 8 m, element width of 2 m, and wavelength of 2.62 m. As is clear from this result, the sound pressure of the sidelobe is higher when the sine wave of the present invention is transmitted than when the conventional pulse wave is transmitted, and the sound pressure is about twice that when the pulse wave is transmitted. As described above, according to the present invention, an ultrasonic beam with a high sound pressure for transmitting an ultrasonic wave in the form of a sine wave can be obtained.

[Embodiments of the invention]

Next, the present invention will be explained in detail. FIG. 1 is a block diagram showing the configuration of an embodiment of an ultrasonic transmitter/receiver according to the present invention. In FIG. 0, continuous wave signals P1 to P8 are transmitted from a continuous wave transmitter 2 to an isolator 8. Via the transmission/reception changeover switch 16 and the transmission/reception pattern changeover switch 17,
is applied to the array probe 9. On the other hand, the ultrasonic signals u1 to ua received by the array probe 9 are input to the addition circuit 4 via the transmission/reception pattern changeover switch 17.

The adding circuit 4 adds the ultrasonic reception signals u1 to u8.

The added ultrasonic reception signal U is detected and rectified by an amplifier circuit,
It is further amplified to become a detection signal U, which is input to the display circuit 6.

The switch control circuit 3 is, for example, a microprocessor, and turns on the transmission/reception changeover switch 16 and the transmission/reception pattern changeover switch 17.

A control signal C1+Cm for controlling off is output. Also, depending on the on/off state of the transmission/reception pattern changeover switch 17, the deflection angle θ of the sidelobe and the position I of the array element used! ! Double number display circuit 6
1 display circuit 6 outputs a cross-sectional image (surface image 7) inside the object 10 on the CRT 7 based on the detection signal U2
1. The synchronization circuit 1 performs processing to obtain a bottom image 72, a defect image 73), and a continuous oscillator 2. A synchronizing signal T is applied to the amplifier circuit 511 display path 6° switch control circuit 3 to synchronize each circuit. The isolator 8 receives ultrasonic reception signals u1~
This prevents us from being added before being input to the adding circuit 4 by turning on the transmission/reception pattern changeover switch 17.

The flaw detection method of the present invention will be explained. Here, for simplicity, the number of array elements is set to eight.

Switch 161 of the transmission/reception changeover switch 16. ~164
is turned on, and the elements of the array probe 9 that transmit ultrasonic waves are set to 91 to 94. Next, the spacing between the transmitting elements is selected by the transmitting/receiving pattern changeover switches 171 to 174 so that a sidelobe is generated in the θ direction. Further, the spacing between the receiving elements is selected by the transmitting and receiving pattern changeover switches 175 to 178 so that side lobes are generated in the θ direction in the array elements 95 to 98 as well.

Thereafter, ultrasonic transmission signals P1 to P4 are applied to array elements 91 and 94 to generate side lobes in the θ direction. On the other hand, array elements 95 to 98 receive ultrasonic waves with a reception pattern that generates side lobes in the θ direction, and obtain reception signals u3 to ua. In this way, side lobes are used to transmit and receive ultrasound beams.

Of course, the array element may be used for both transmission and reception as is generally done.

Referring to FIG. 7, an embodiment will be described in which the difference in ultrasonic transmission and reception sensitivity depending on the number of selected array elements is corrected. The switch control circuit 3 includes a switch switching circuit 31
and a sensitivity correction circuit 32. Switch switching circuit 3
sends a switching control signal C1+Cx to the transmission/reception switch 16 and the transmission/reception pattern changeover switch 17 to control the ultrasound transmission/reception pattern. Further, an element selection signal S depending on the number of selected transmitting/receiving array elements is outputted to the sensitivity correction circuit 32. The sensitivity correction circuit 32 generates an amplitude control signal A for controlling the amplitude of the ultrasonic transmission voltage from the element selection signal S, and outputs the amplitude control signal A to the continuous wave transmitter 2.
Output to. The continuous wave oscillator 2 is a sine wave oscillator 22.
Peak value control circuit 23, trigger signal generator 21. Analog switch 24. It is composed of a power amplifier 25. A sine wave oscillator 22 generates a sine wave Sl, which is the basis of ultrasonic transmission. The peak value control circuit 23 changes the peak value of the sine wave S1 according to the amplitude control signal A to obtain a signal Sz. This sine wave signal St is.

The waveform is chopped by the analog switch 24 in response to the trigger signal K, resulting in a signal Ss. The chopped signal S8 is amplified by the power amplifier 25 to obtain the ultrasonic transmission signal P.

The operation of the circuit shown in FIG. 7 will be explained with reference to the time chart shown in FIG. SL is a basic sine wave signal. The peak value is adjusted by the peak value control circuit 23 according to the number of selected array elements, and a signal S2 is obtained. The signal is a signal for cutting out a sine wave. Only when the signal K is in the 1 state, the analog switch 24 cuts out the signal S2 to produce the chopped signal S8. This chip signal S8 is amplified by the power amplifier 25 and becomes the transmission signal P. in this way,
By changing the peak value of the ultrasonic transmission signal according to the number of elements to be transmitted and received (for example, when the number of elements to be transmitted and received is small, the peak value of the transmission signal is set high), the difference in transmission and reception sensitivity can be corrected and flaw detection can be performed. This is especially effective when the number of elements is small.

An ultrasonic transmission/reception method according to the present invention will be specifically explained with reference to FIG. Ultrasonic waves are transmitted into the subject 10 using the first to i-th array elements, and a side lobe 15 is generated in the θ direction.

On the other hand, the first order receives ultrasonic waves with a reception pattern that generates sidelobes 15 in the θ direction using the i+1st to jth array elements, and transmits ultrasonic waves using the second to i+1th array elements. Then, the ultrasonic waves are received using the i+2th to j+11th array elements. This operation is sequentially performed up to the 1mth element while shifting the transmitting and receiving array elements one by one.

After 0 or more operations of scanning the ultrasonic beam in the θ direction in the direction of the arrow in the subject 10 are completed, the deflection angle θ of the side lobe 15 is changed and the above operation is repeated. The inside of the subject 10 can be inspected by making the ultrasonic beam incident on the subject 10 at any angle.

The above is an example in which the spacing between the transmitting elements is equal, but Figs. 1-0 to 13 show examples in which the spacing between the transmitting elements is unequal. This is an example of transmitting sound with different sound pressures on the left and right sides. Moreover, FIG. 11 shows the sound pressure distribution obtained by the transmission. In FIG. 10, the elements of the array probe 9 are caused to emit ultrasonic waves so that they overlap at point P. The blacked part is the transmitting element 1-, PBz = a, PBz
=a+λ, PBa=a+2λ, PBn=a
Bs*82 of the element so that +nλ. +
Select Bn and make a call. Here, λ is the wavelength. By doing so, the sound pressure of the side lobe 15(a) becomes larger than that of the side lobe 15(b) as shown in FIG. 11, and the sound pressure can also be made higher.

FIG. 12 shows an example in which ultrasonic waves are transmitted so as to be concentrated directly below the array probe 9. Moreover, FIG. 13 shows the sound pressure distribution obtained by the transmission. In Figure 12, 0Bx = OBx' = Ja so that the ultrasonic waves overlap at point P.
L, ○Bz=OBz' = J2 aλ, -,0B
n=OB. '=5]1 (the so-called Fresnel half-wavelength band) is selected, and an ultrasonic wave is emitted. In this way, the ultrasonic beam 15 can be focused directly below the array probe 9 as shown in FIG.

Up to now, the example has been using a one-dimensional array probe, but an embodiment in which a two-dimensional array probe is used as the primary will be described with reference to FIGS. 14 and 15. Figure 14 is M
This is an example in which a two-dimensional array contactor 9 composed of XN elements is used. In this example, flaws are detected as a set of L elements. That is, (911~
91L).

(912~9], (L+1))・・・・・・・・・・・・
. . . and (91(N-L+1) to 91N) are sequentially detected, and then the flaw detection is performed on the next row.
21-92L), (922-92 (L+, 1.)
),...

And (92(N-L+1) to 92N) are sequentially tested, and in the same manner, (9M1 to 9ML)
, (9M2 to 9M (L+1)), ....

And repeat from (9M (NL+1) to 9MN1).

FIG. 15 shows an embodiment in which a two-dimensional array probe 9 is used to focus ultrasonic waves. When the two-dimensional array probe 9 emits a Fresnel pattern as shown in FIG. 15, the ultrasonic waves emitted from each element all overlap at point P of the subject, making it possible to realize a focused ultrasonic beam.

〔Effect of the invention〕

According to the present invention, each element of the array probe can be emitted simultaneously, and the interval between the transmitting elements can be changed to scan the ultrasonic beam to perform flaw detection on the object. This eliminates the need for additional arithmetic circuits. Therefore, it is possible to downsize electronic scanning ultrasonic flaw detection equipment,
The cost of the device can also be reduced.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the configuration of an embodiment of an ultrasonic transmitting/receiving device according to the present invention, Fig. 2 is a diagram showing the principle of lobe generation used in the present invention, and Fig. 3 is a sound pressure distribution of the ultrasonic beam. FIG. 4 is a diagram showing the conventional ultrasonic transmission method, FIG. 5 is a diagram showing the ultrasonic transmission method of the present invention, and FIG. 6 is the transmitted ultrasonic wave when pulse waves and sine waves are transmitted. 7 is a diagram showing a method for correcting the sensitivity difference depending on the number of elements, FIG. 8 is a time chart thereof, and FIG. 9 is a diagram showing an ultrasonic transmission/reception method according to the present invention. ,
Fig. 10 shows an example in which the spacing between the transmitting elements is unequal, Fig. 11 shows the sound pressure distribution, and Fig. 12 shows the ultrasonic wave by selecting Niremen 1- in the Fresnel half-wavelength band. Figures 1 and 3 are diagrams showing the sound pressure distribution, and Figures 1 and 4 are diagrams showing an example using a two-dimensional array probe. Fig. 15 shows an example of focusing ultrasonic waves using a two-dimensional array probe Fig. 2 Fig. 16 shows an example of a conventional electronic scanning type ultrasonic transmitting/receiving device 71... Synchronous circuit , 2... continuous wave oscillator, 3... switch control circuit,
4...Addition circuit, 5...Amplification circuit, 6...Display circuit, 7...CRT, 8...Isolator, 9...
Array probe, 10...Object, 11...Surface, 1
2... Bottom surface,] 3... Defect, 14... Main lobe, 15... Side lobe, 16... Transmission/reception changeover switch, 21... Trigger signal generator, 22...
Sine wave oscillator, 23... Peak value control circuit, 24...
・Analog switch, 35...Power amplifier, 31・
...Switch switching circuit, 32...Sensitivity correction circuit, 7
DESCRIPTION OF SYMBOLS 1... Surface image, 72... Bottom image, 73... Defect image, 101... Ultrasonic beam control circuit, 102... Delay circuit, 103... Ultrasonic transmitting circuit, 104...・Ultrasonic receiving circuit, 105...Display circuit, 106...Array box touch, 107...CRT. 1'08...Object, 109...Defect, 110...
·surface. 111... Bottom surface, 112... Surface image, 113...
Bottom image. 114...Defect image.

Claims (1)

[Claims] 1. Select some transducers from an array probe in which a plurality of ultrasound electrical transducers are arranged according to the beam direction to be set, and simultaneously emit ultrasound from the selected transducers. An ultrasonic transmission/reception method characterized by transmitting ultrasonic beams, causing them to interfere, propagating ultrasonic beams in a predetermined direction, and receiving the reflected waves. 2. The ultrasound transmission and reception method according to claim 1, wherein the ultrasound transmitted from the selected conversion element is a sine wave. 3. An ultrasonic transmission/reception method according to claim 1 or 2, characterized in that the conversion elements are selected at equal intervals. 4. An ultrasonic transmission/reception method according to claim 1 or 2, characterized in that the conversion elements are selected at non-uniform intervals. 5. An ultrasonic transmitting and receiving method according to claim 4, characterized in that a conversion element in a Fresnel half-wavelength band is selected and the beam is focused directly below the array probe. 6. An array probe consisting of a plurality of ultrasonic electrical transducer elements in contact with the subject, a continuous wave transmitter that outputs continuous waves to be applied to these probes, and between the probe and the transmitter. a transmitting/receiving switch and a transmitting/receiving pattern switching switch disposed in the transmitter/receiver switch, an adder circuit that receives and adds received signals from between both switches, an amplifier circuit that detects and amplifies the added signal, a display unit that displays the results, and the above-mentioned It is equipped with a switch control circuit that controls the operation of each part, and selects several conversion elements from the array probe using a transmission/reception pattern changeover switch according to the beam direction to be set, and simultaneously receives ultrasound from the selected conversion elements. The ultrasonic beam is transmitted to the specimen and made to interfere with each other to propagate the ultrasound beam in a predetermined direction, then the transmission/reception selector switch is switched and the reflected wave is input to the addition circuit.
An ultrasonic transmitting and receiving device characterized by processing and displaying. 7. In claim 6, the continuous wave oscillator includes a peak value control circuit, and the switch control circuit includes a sensitivity correction circuit, and changes the output of the continuous wave according to the selected conversion element pattern. An ultrasonic transmitting/receiving device characterized by correcting sensitivity differences due to changes. 8. An ultrasonic transmitting and receiving device according to claim 6 or 7, wherein the array probe is composed of two-dimensionally arranged conversion elements.