JPH03180759A - Ultrasonic inspecting device - Google Patents

Abstract

PURPOSE:To cancel multireflection components in a lens to exactly take out information dependent upon only a defect part by inputting a second ultrasonic signal to a first oscillator by a second oscillator and a second lens. CONSTITUTION:A second oscillator 22 generates ultrasonic oscillation synchro nously with a first oscillator 12 in accordance with the input of an ultrasonic pulse from an ultrasonic transmission means 41. A second lens 21 is held be tween the second oscillator 22 and the first oscillator 12, and the ultrasonic oscillation from the second oscillator 22 is inputted as a second ultrasonic signal P2 to the first oscillator 12. The ultrasonic oscillation generated by the oscillator 12 is radiated as a first ultrasonic signal from a boundary 11a to a body 50 to be inspected, and the input timing to the oscillator 12 and the amplitude level of an ultrasonic signal P are so set that a signal Pl which is reflected by the boundary 11a and is inputted to the oscillator 12 is cancelled by the ultrasonic signal P2. Thus, a reflected signal Pf from the body 50 to be inspected (defect 51) does not disappear by the reflected signal Pl and its multireflection signal.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to an ultrasonic inspection device used in an ultrasonic flaw detection device, an ultrasonic microscope, or the like.

B. Prior Art FIG. 6 is a sectional view showing the general structure of an ultrasonic probe used in an ultrasonic flaw detection device.

The ultrasonic probe 1 is composed of a transducer 3 housed in a case 2 of a predetermined shape and a lens 4 having a concave surface (interface) 4a. By applying the voltage, the transducer 3 generates ultrasonic vibration, and the ultrasonic signal is emitted to the subject 6 via the lens 4 having a predetermined focal length.

When attempting to detect a defect 7 existing inside the object 6, the ultrasonic probe I shown in FIG. The ultrasonic vibrating beam is placed so that the focus of the ultrasonic vibration beam is on the depth position of the subject 6 where the specimen 6 is expected to be located. In this state, an ultrasonic pulse is applied from the transmitter to the transducer 3 of the ultrasonic probe ↓. The ultrasonic pulse may be either an impulse wave or a burst wave, but
The following description will be made assuming that burst waves are used.

When an ultrasonic pulse is applied to the vibrator 3, the vibrator 3 generates ultrasonic vibrations, and this ultrasonic vibration becomes an ultrasonic signal and is emitted toward the subject 6. The ultrasound signal is transmitted to the object 6
It is reflected at the interface of the lens 4 leading to the defect 7, and is fed back to the vibrator 3. In FIG. 6, the concave surface 4a of the lens 4, the subject 6
The ultrasonic echo signals reflected from the surface of the sample and the defect 7 are shown as PQ, Ps, and Pf, respectively. A receiver (not shown) extracts only the echo signal Pf reflected by the defect 7 and determines the shape of the defect 7 and the like.

C0 Problems to be Solved by the Invention However, when determining the shape etc. of the defect 7 in this way, the ultrasonic signal PQ reflected on the concave surface 4a of the lens 4
repeats multiple reflections within the lens 4 at a constant time period depending on the speed of sound and the thickness of the lens 4. Therefore, there is a possibility that the reflected signal Pf from the defect 7 interferes with the multiple reflected signal and disappears, or that the two reflected signals cannot be distinguished, resulting in a problem that accurate defect information cannot be detected.

A technical problem of the present invention is to accurately extract information that depends only on the defective portion by canceling multiple reflection components within the lens.

06 Means for Solving the Problems The present invention will be explained in conjunction with FIG. 1 showing an embodiment of the invention. A first vibrator 12 that generates vibrations and an ultrasonic vibration generated by the first vibrator 12 that is used as a t-th ultrasonic signal to be transmitted to the subject 5 from the interface 11a.
from the first lens 11 which emits the light toward 0 and inputs the reflected signal to the first vibrator 12, and from the defect 51 of the object 50 included in the reflected signal input to the first vibrator 12. The present invention is applied to an ultrasonic inspection apparatus that includes a receiver 42 that extracts a reflected signal Pf of .

A second vibrator 22 generates ultrasonic vibrations in synchronization with the first vibrator 12 in response to input of ultrasonic pulses from the ultrasonic transmitting means 41; 1
The ultrasonic vibration from the second transducer 22 is used as the second ultrasonic signal P2 to transmit the ultrasonic vibration to the first transducer 1.
2, the signal PQ reflected from the interface 11a and input to the t-th transducer 12 is
The input timing and amplitude level of the second ultrasonic signal P2 to the first transducer 12 are set so that the second ultrasonic signal P2 is canceled out by the second ultrasonic signal P2, thereby achieving the above technical problem.

The reflected signal PQ reflected at the 80 working interface 11 a is input to the first vibrator 12 . On the other hand, the ultrasonic vibration generated by the second transducer 22 is input to the first transducer 12 as a 2' ultrasonic signal P2. The first of the second ultrasonic signal P2
Since the input timing to the transducer and the voltage level of this second ultrasonic signal are set to predetermined values, the reflected signal PQ from the interface 11a is canceled by the second ultrasonic signal P2. Therefore, the above-mentioned object 50 (defect 51
) is not erased by the reflected signal PQ and its multiple reflected signals, making it possible to accurately detect defects.

In the above-mentioned sections and section E, which describe the present invention in detail, figures of embodiments are used to make the present invention easier to understand, but the present invention is not limited to the embodiments.

F. Embodiment An embodiment in which the present invention is applied to an ultrasonic flaw detection device will be described with reference to FIGS. 1 and 2.

In FIG. 1 showing the overall configuration, 10 has a concave surface (
20 is a first ultrasonic probe consisting of a first lens 1■ on which an interface) lla is formed, and a first transducer 12 fixed to the upper surface of this lens 11. 1st above
A second lens 21 (made of the same material as the first lens 11) placed above the vibrator 12, and a second vibrator 22 fixed to the top surface of the second lens 21. The second lens 21 is a second ultrasonic probe that is similar to the first one.
．． It is held between the second vibrator 12.22. The thickness of this second lens 21 is the same as the dimension from the upper surface of the ↓-th lens 11 to the concave surface 11a. Further, the width X2 of the second vibrator 22 is the width x1 of the first vibrator 12.
is made shorter by a predetermined value.

Furthermore, a backing material 30 (
(made of the same material as the lens 11.21) are arranged. Here, for the (th) vibrator 12, the second lens 2
1 corresponds to the backing material. This backing material has the effect of making the waveform of ultrasonic vibrations the same by making the upper and lower parts of each vibrator 12.22 the same material.

The first transducer 12 includes an ultrasonic transmitter 41 that generates ultrasonic pulses and a reflected wave PQ, Ps, Pf that is input to the first transducer 12. A receiver 42 for extracting the signal Pf is connected to the second vibrator 22, and the transmitter 41. A receiver 42 is connected. The first vibrator 12 generates ultrasonic vibrations by ultrasonic pulses from the transmitter 41, and the ultrasonic vibrations pass through the first lens 11 and reach the concave surface 11a as a first ultrasonic signal.

The delay circuit 43 is for inputting the ultrasonic pulse from the transmitter 41 to the second transducer 22 after delaying the ultrasonic pulse from the transmitter 41 by a predetermined time (T/2) than the input to the first transducer L2. The time T is the time until the ultrasonic signal from the second transducer 12 is reflected by the four surfaces 11a and inputted again to the first transducer 12.The second transducer 22 is The input of the ultrasonic pulse causes ultrasonic vibration, and this ultrasonic vibration is transmitted through the second lens 21 to the first ultrasonic signal as a second ultrasonic signal.
is input to the vibrator 22 of.

Here, when the voltage level of the ultrasonic pulse is constant, the amplitude level of the ultrasonic signal depends on the area of the vibrator. Therefore, in this embodiment, the widths Xi and X2 of each vibrator 12.22 are determined as described above so that the amplitude level of the second ultrasonic signal is the same as the amplitude level of the reflected signal from the concave surface 11a. .

Next, the operation of the embodiment will be explained.

A medium (for example, water) 8 is interposed between the concave surface 11a of the first lens 11 and the subject 50, and the ultrasonic transmitter 41 generates ultrasonic pulses. This ultrasonic pulse generates ultrasonic vibration in the first transducer 12, and this ultrasonic vibration passes through the first lens 11 and reaches the concave surface 11a as a first ultrasonic signal, and a part of it reaches the concave surface 11a. reflected.

The other part is emitted from the concave surface 11a to the subject 50 and is reflected by the surface of the subject 50 and the defect 51 inside thereof. Reflection signals pQ and Ps reflected from the concave surface 11a, the surface of the object to be inspected, and the defect 51, respectively.

Pf passes through the inside of the first lens 11 and passes through the first vibrator 12.
to return to.

Further, the reflected signal PQ from the concave surface 11a repeats multiple reflections between the first vibrator 12 and the concave surface 11a as described above, and as shown in FIG. It returns to the vibrator 12.

Here, the phase of the ultrasonic signal does not change when it is reflected from an object with a small acoustic impedance to an object with a large acoustic impedance, and the phase is reversed when it is reflected from an object with a large acoustic impedance to an object with a small acoustic impedance. In the example of FIG. 1, the acoustic impedance of the first vibrator 12 is
Since water (having a smaller acoustic impedance than the first lens 11) is used as the medium, the reflected signal PQ is larger than the acoustic impedance of the first lens 11.
a, and not in the second transducer 12. Therefore, the input signal to the first transducer 12 has a peak waveform in the negative direction as shown in FIG. 2(b). Due to repeated reflections, the diffusion loss of the reflected signal PQ is large,
The peak wave rapidly decreases from W1 to W2 to W3.

On the other hand, due to the action of the delay circuit 43, the ultrasonic pulse from the transmitter 41 reaches the second vibrator 22 with a delay of time T/2 after reaching the first vibrator 12. As a result, ultrasonic vibrations are generated in the second vibrator 22, and the ultrasonic vibrations are input to the first vibrator 12 through the second lens 21 as a second ultrasonic signal P2.

Here, as mentioned above, the thickness of the second lens 2 is the same as the dimension from the top surface of the first lens 11 to the concave surface 11a, and the input of the ultrasonic pulse described in 1. Since the second ultrasonic signal P2 is delayed by the time (T/2), the second ultrasonic signal P2 is input to the ↓-th transducer 12 at the same time as the reflected signal 3PQ on the concave surface 11a, as shown in FIG. 2(a). Ru. 1st. Since the second lens ↓1 and 21 are made of the same material,
The damping constant is also the same, so both lenses 11
The waveforms of the ultrasonic signals transmitted within .degree. 21 are the same.

Further, since the phase of the second ultrasonic signal P2 is not inverted, it has a peak waveform in the positive direction, and since it is repeatedly reflected from one plane to another, the decrease in its peak value is gradual.

Therefore, from the above, the widths Xi, X of each vibrator 12.22
2 as appropriate, the amplitude level of the second ultrasonic vibration is adjusted to the peak waves Wl, W2 . By making it approximately equal to one of W3, that peak wave can be completely canceled out, and the levels of other peak waves can also be reduced. As a result, the reflected signal Pf from the defect 51 does not interfere with the multiple reflected signal PQ, and the receiver 42 can accurately extract the reflected signal Pf from the defect of the object 50, providing accurate defect information. It becomes possible to detect.

The backing material 30 was made of the same material as the lens 1.2, but normally, this backing material is made of resin mixed with tungsten powder. If the same material as the lens is used, there will be less damping effect, so the wave number will actually be higher than the waveform in Figure 2, but since the positive and negative waves are opposite to each other, it is necessary to cancel out the two waves. I can do it.

In the above, by using the lens 11°2 (of the same thickness) and delaying the ultrasonic pulse with the delay circuit 43, the second reflected signal P2 and the reflected signal PQ on the concave surface 11a are simultaneously transmitted to the (oscillator). I made it input to 12, but
Even without using this delay circuit 43, for example, if the thickness of the second lens 21 is twice that of the first lens 11, both of the above signals can be simultaneously input to the first vibrator (2). .

Also number 1. l1li of the second oscillator 12.22? The amplitude levels of both signals are made almost equal by adjusting X1°X2 appropriately, but the widths Xi and X2 are arbitrary, and the amplitude levels are changed using an attenuator 61 as shown in FIG. 3, for example. You can do it like this. That is, the attenuator (changing means) 61 connects the first and second vibrators 12 .
22, and by changing the voltage level, the amplitude level of the second ultrasonic signal P2 is changed to the reflected signal P from the concave surface 11a.
It can be made almost the same as Q. According to this, since the amplitude level of the ultrasonic pulse can be adjusted arbitrarily, any one of the peak waves Wl, W2°W3 of the reflected signal PQ can be selectively extinguished.

Furthermore, for example, as shown in FIG. 4, two ultrasonic transmitters 41a and 41b whose ultrasonic pulse voltage levels are different are provided.
and these transmitters 41a.

If 41b is synchronized and ultrasonic pulses are applied to each of the transducers 12 and 22, the width of the transducer ↓2゜22
Regardless of ↓ and X2, the amplitude levels of both the signals P2 and PQ can be made almost the same.

Further, as shown in FIG. 5, a variable amplitude level transmitter 41c may be used in place of the above-mentioned transmitter 41b, and a delay circuit 43 may be used to give an extra delay time to the ultrasonic pulse. In this case as well, since the voltage level of the ultrasonic pulse can be arbitrarily adjusted as described above, any one of the peak waves Wl-W3 of the reflected signal PQ can be selectively extinguished.

Note that although the ultrasonic flaw detection device has been described above, the present invention can also be applied to other ultrasonic inspection devices such as an ultrasonic microscope.

G1 Effects of the Invention According to the present invention, the second ultrasonic signal is input to the first transducer by the second transducer and the second lens, and the reflected signal from the first lens interface is reflected from the second ultrasonic signal by the second transducer and the second lens. Since the ultrasound signal is canceled by the ultrasonic signal, the reflected signal from the defect in the object does not interfere with the multiple reflected signal, and accurate defect information can be detected.

[Brief explanation of drawings]

1 and 2 show an embodiment of the present invention, FIG. 1 is a sectional view showing an embodiment of the ultrasonic inspection apparatus according to the present invention, and FIG. 2 shows the second ultrasonic signal level and Waveform diagrams showing temporal changes in the reflected signal level from the concave surface, Figures 3 to 5
Each figure is a sectional view of an ultrasonic inspection apparatus showing another embodiment. FIG. 6 is a sectional view of a conventional ultrasonic inspection device. IO=first probe 11: first lens 11a: concave surface 12: first transducer 20: second probe 2
1: Second lens 22: Second transducer 41.41a, 41b, 41c: Ultrasonic transmitter 42: Receiver 43: Delay circuit 50: Subject 5↓: Defect 61: Annotator

Claims (1)

[Claims] 1) an ultrasonic transmitter that generates ultrasonic pulses; a first vibrator that generates ultrasonic vibrations in response to input of the ultrasonic pulses; and the first vibrator generates ultrasonic vibrations. a first lens that emits the ultrasonic vibration as a first ultrasonic signal toward the object from the interface and inputs the reflected signal to the first transducer; In the ultrasonic inspection apparatus, the ultrasonic inspection apparatus includes a receiver for extracting a reflected signal from a defect of the object included in an input reflected signal, and the first a second transducer that generates ultrasonic vibrations in synchronization with the transducer; and a second transducer that is sandwiched between the second transducer and the first transducer and that generates ultrasonic vibrations from the second transducer. a second lens that inputs a second ultrasonic signal to the first transducer, and the signal reflected from the interface and input to the first transducer is canceled by the second ultrasonic signal. An ultrasonic inspection apparatus characterized in that the input timing and amplitude level of the second ultrasonic signal of the oscilloscope to the first transducer are set. 2) a delay circuit that delays the arrival time of the ultrasonic pulse to the second transducer by a predetermined time from the arrival time of the ultrasonic pulse to the first transducer; 2. The ultrasonic inspection apparatus according to claim 1, wherein the input is applied to the transducers almost simultaneously. 3) A changing means is provided for changing the voltage level of the ultrasonic pulses guided to the first and second transducers, and by changing the voltage level, the amplitude levels of both the signals are made to be approximately the same. Claim 1 or 2 characterized by
The ultrasonic testing device described in . 4) The ultrasonic transmitting means consists of two ultrasonic transmitters that generate ultrasonic pulses of different voltage levels,
3. The ultrasonic inspection apparatus according to claim 1, wherein the amplitude levels of the two signals are made substantially the same due to the difference in voltage levels.