JPH0129354B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ultrasonic probe used for nondestructive testing, medical diagnosis, and the like.

Conventional ultrasonic probes of this type, for example,
As shown in the figure, using one ultrasonic transducer 1,
A backing material 3 was provided on one acoustic radiation surface 2 of the ultrasonic transducer 1, and a single or multilayer acoustic impedance modification layer 4 was provided on the other acoustic radiation surface 2. Note that 5 is a lead wire.

This type of ultrasonic probe is used for inspection using the so-called pulse echo method, in which the ultrasonic transducer 1 is excited with impulses and transmits and receives ultrasonic pulses with a short pulse width to inspect the test material with good distance resolution. It is also used for inspections that apply so-called pulse compression technology, which is widely used in the field of microwaves such as radar.

FIG. 2 shows an example of the waveform of an ultrasonic wave transmitted into a material to be inspected in an inspection using pulse compression technology.

As shown in FIG. 2, the transmitted ultrasonic wave is a sine wave, a binary condensed irregular signal,
For example, it is phase modulated using a Barker sequence or the like.

In Fig. 2, as an example, a pseudo-irregular code sequence (++-+) of length 4 consisting of a positive sign + and a negative sign -
This shows the case where a waveform is transmitted with phase modulation of (0°, 0°, 180°, 0°) corresponding to each code. In other words, 0° corresponds to a positive sign, and 180° corresponds to a negative sign.

Now, since the conventional ultrasonic probe of this type was constructed using one ultrasonic transducer 1,
In order to obtain ultrasonic waves having a waveform as shown in the figure, it was necessary to excite the ultrasonic transducer 1 with an excitation waveform as shown in FIG. For this reason, there was a drawback that a special excitation external circuit was required in addition to the ultrasonic probe.

Similarly, when demodulating reflected echoes from defects in the inspected material, a special external circuit for processing received signals is required.

In the present invention, a plurality of ultrasonic transducers 1 are stacked and arranged so that the acoustic radiation surfaces 2 of each ultrasonic transducer 1 correspond to each other, and the direction of the electric field applied to each ultrasonic transducer 1 is irregular. This solves the above-mentioned drawbacks, and will be explained in detail below using an embodiment shown in FIG.

FIG. 3 is a block diagram of an embodiment of the ultrasonic probe according to the present invention, in which eight ultrasonic transducers 1 are
The acoustic radiation surfaces 2 of each ultrasonic wave transducer 1 are stacked and arranged so as to face each other.

3 is a packing material similar to the conventional one, and 4 is an acoustic impedance change layer similar to the conventional one.

5 is a lead wire, and the extraction surface of the lead wire 5 from each ultrasonic transducer 1 is shown in FIG.
It is changed according to the Barker series, and the wires are connected as shown in Figure 3. 6 is an insulating film whose thickness is sufficiently thin compared to the wavelength.

Now, when the ultrasonic probe according to the present invention is subjected to impulse excitation, each ultrasonic transducer 1 excites an ultrasonic wave having a resonant frequency whose thickness is half a wavelength.

As shown in FIG. 3, the lead wires 5 are connected and the direction of the electric field applied to each ultrasonic transducer 1 is changed for each ultrasonic transducer 1, making it possible to perform impulse excitation, which is commonly done in the past. As a result, the waveform of the ultrasonic waves transmitted into the specimen material becomes the same as that shown in FIG. 2. That is, in FIG. 3, an electric field is applied to each ultrasonic transducer 1 in the direction indicated by the arrow in the figure. Each ultrasonic transducer 1 is excited by a half wave,
The phase of the waves excited at that time differs by 180° where the electric field direction is opposite. Therefore, a waveform as shown on the left side of FIG. 3 is excited, and this wave is transmitted into the specimen material.

This waveform is the same as in FIG. That is, in the ultrasonic probe according to the present invention, as in the conventional case,
No special external excitation circuit is required, and the required waveform can be achieved by testing using pulse compression technology.
Furthermore, it is clear that the ultrasonic probe according to the present invention can similarly demodulate echoes reflected from defects in the test material without requiring a special external circuit for processing received signals.

The above description has been given for the case of one embodiment shown in FIG. 3, but the direction of the electric field applied to each ultrasonic transducer 1 may be changed along other condensed irregular signals such as Barker series or M series. Good too.

Furthermore, the present invention can be applied to an oblique ultrasonic probe that transmits and receives ultrasonic waves obliquely to the surface of a test material, and a surface wave probe that transmits and receives ultrasound along the surface of a test material. Good too.

As described above, in the ultrasonic probe according to the present invention, a plurality of ultrasonic transducers 1 are stacked and arranged with the acoustic radiation surfaces 2 of each ultrasonic transducer 1 facing each other, and each ultrasonic vibration By configuring the device so that the direction of the electric field applied to the sensor 1 is irregular, there is an advantage that inspection using pulse compression technology can be performed without requiring a special external circuit unlike the conventional method.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing a conventional ultrasound probe, FIG. 2 is an ultrasound waveform diagram, and FIG. 3 is a configuration diagram showing an embodiment of an ultrasound probe according to the present invention. .
In the figure, 1 is an ultrasonic transducer, 2 is an acoustic radiation surface, 3 is a backing material, 4 is an acoustic impedance transformation layer,
5 is a lead wire, and 6 is an insulating film. In addition, in the figure,
Identical or equivalent parts are designated by the same reference numerals.

Claims (1)

[Claims] 1 A plurality of ultrasonic transducers are stacked and arranged with the acoustic radiation surfaces of each ultrasonic transducer facing each other, and the direction of the electric field applied to each ultrasonic transducer is determined from a positive sign and a negative sign. An ultrasonic probe characterized in that the probe changes in response to each code of a pseudo-irregular code series.