JPH01126543A - Sector scan type ultrasonic flaw detector - Google Patents

Abstract

PURPOSE:To obtain excellent bearing resolutions, by using a flaw detector having an array type vibrator to scan working elements thereof with an electron-mode switching. CONSTITUTION:A sector scanning is performed centered on a beam incoming point 41 on the object 4 to be inspected by an ultrasonic beam 3a incident into the body 4 being inspected through a lens 3. Reflected wave from a defect 43 in the body 4 being inspected arrives again at vibration elements, for example, (2i... and 2i+n-1) which transmitted the beam 3a to receive. Then, a reception scanning section 7 perform a scanning moving sequentially from the elements (2i+1...2i+n) to those (2i+2... and 2i+n+1).... With such an arrangement, transmitting/receiving operation of the beam 3a undergoing a sector scanning over a range 42 centered on the incoming point 41 is accomplished by a transmitting scan section 6 and a receiving scan section 7. Moreover, an imaging processing section 11 determines the position of the defect 43 from angle information 8c pertaining to the direction of the beam 3a obtained from a scan control section 8 and a video signal 10a to form a tomographic image in a sector scan area of the object 4 being inspected, thereby assuring excellent bearing resolutions.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an ultrasonic flaw detection device, which enables smooth scanning of a probe while maintaining good ultrasonic transmission efficiency even for curved objects. The present invention relates to a configuration of a fan-shaped scanning ultrasonic flaw detection device that can obtain excellent azimuth resolution by performing a focused ultrasonic beam and forming a focused ultrasonic beam.

[Conventional technology]

A conventional ultrasonic imaging device that performs fan-shaped scanning of an ultrasonic beam electronically and is used for medical diagnosis or flaw detection is ``Ultrasonics'', July 1968 issue, pages 153 to 15.
As discussed on page 9, by controlling the phase of the transmission/reception operation of each transducer of the linear array transducer for ultrasound transmission and reception, the ultrasound beam is scanned in a fan shape in the required angular range, and an ultrasound echo image within the fan-shaped cross section is created. A method is used to display the

In addition, as another method, Hitachi Review Vol. 64, No. 3 (
As described in pages 45 to 50 (March 1982), scanning is performed to sequentially shift the transmission and reception operations of a series of element groups in an array transducer for ultrasonic transmission and reception arranged in an arc shape. Accordingly, a method of performing fan-shaped scanning of an ultrasound beam has also been used.

[Problem that the invention seeks to solve]

Among the above-mentioned conventional techniques, the former method of deflecting and scanning an ultrasonic beam by adjusting the phase or delay time of the transmitting/receiving operation of a linear array transducer is as follows: (1) At least the ultrasonic emission and Since it is necessary to bring the sensing surface into acoustic contact with the surface of the object to be examined, there is a problem in that when the surface of the object to be examined is curved or uneven, effective transmission of ultrasonic waves will not occur.

(2) In order to improve azimuth resolution, a method is adopted in which the relative phase relationship of each vibrating element is adjusted for each incident angle of the ultrasonic and acoustic beams to form a focal point at a predetermined position within the subject. However, it is effective only in a very limited focal range, and has the disadvantage that resolution drops outside the focal range.

(3) In order to deflect the ultrasonic beam, it is necessary to precisely control the delay operation of each vibrating element for each angle of incidence, which requires a function to adjust a complicated and costly delay circuit network. .

The latter method of deflecting the ultrasound beam by shifting the arcuate array transducer also improves the azimuth resolution by adjusting the phase of each operating element as in (2) above. However, in this case as well, there is a problem that the beam focusing area is extremely limited.

It is an object of the present invention to overcome the problems of the prior art as described above, to have excellent azimuth resolution over a wide range in all angular directions, and to provide good superimposition even when the object surface is curved. It is an object of the present invention to provide a fan-shaped scanning ultrasonic flaw detection device that has high sound wave transmission efficiency and also has a simple and low-cost circuit device for deflecting an ultrasonic beam at high speed by electronic operation.

[Means for solving problems]

In order to achieve the above object, the apparatus of the present invention first uses a flaw detector equipped with an array type vibrator in which ultrasonic transmitting and receiving vibrating elements are arranged in an arc shape.

By electronically switching and scanning its active elements, without complex control of delay line networks.

The ultrasonic beam was scanned in a fan-shaped manner.

In addition, by focusing the ultrasound beams transmitted and received by the array transducer at the point of incidence on the subject, the ultrasound can be transmitted sufficiently even if the contact surface between the subject and the probe is extremely small. I did it like that. Furthermore, in order to maintain excellent azimuth resolution over a wide range of flaw detection areas and obtain detailed flaw detection images.

An ultrasonic lens was placed in front of the array transducer so that the ultrasonic beam penetrating into the subject was focused over a wide range of path length.

[Effect]

The structure and operation of the probe section, which is the main point of the fan-shaped scanning ultrasonic flaw detection apparatus according to the present invention, will be explained with reference to FIG.

1 is a probe that transmits and receives ultrasonic waves, and includes a large number (N) of vibrating elements 2t, 22. ...A transducer array consisting of 2N elements, each element arranged in the shape of a circular arc, of which some 21 +
n pieces (n
The <N) operating vibrating element groups simultaneously transmit and receive ultrasonic waves, thereby transmitting and receiving a focused ultrasonic beam 2a. In front of the transducer array 2, an ultrasonic collimator lens 3 having a so-called diffusion function that converts a focused ultrasonic beam into a substantially parallel beam is provided. beam 3
It is converted into a and sent to the subject 4.

Now, by the action of the transmission scanning section 6B and reception scanning section 7B which have received the scanning signal 8a from the scanning control section 8, the elements in the operating state among the elements 21.2z, ... 2N of the transducer array are
2I+ 21"ll -・2 t"n-t) transitions sequentially, and (2l"IH2++2+ +++ 21"n-2
) T (21"2+2 ++3....2t"n-
3) When the switching operation is performed as in..., the transmission/reception angle θ of the ultrasonic beam 2a changes sequentially. Therefore, since the incident angle Φ of the incident beam 3a in the subject also changes sequentially, a fan-shaped scan of the ultrasonic beam within the subject is eventually performed.

For example, n
Each vibration element 21 H21"l, 21"n-1
The transmission command signal 8b sent from the transmission control section 8 is transmitted to a delay line circuit 6 consisting of delay lines 6A1, 6A2...6A.
Transmission signal 6 generated via A and transmission scanning section 6B
Transmission operation 2b is performed by b. The signal received by the vibrating element is transmitted to the reception scanning section 7B and the delay line interposed in its path. A1.

7A2. ...7An delay line circuit 7A, the phase is matched, and one reception signal 7a is obtained.

By doing so, the width of the ultrasonic beam 2a becomes slightly expanded when it passes through the center O of the circular arc array, and the beam control function by the lens 3 is improved.

After the ultrasonic beam 2a is once focused, it becomes a substantially parallel beam 3a by the collimator lens 3, so that excellent azimuth resolution can be obtained when detecting a reflection source within the object 4.
In addition, since the beam 3a has little energy dispersion even after propagating over a long path, the apparatus of the present invention has the great advantage that high flaw detection sensitivity can be obtained even at long distances.

Collimator lens 3. An ultrasonic transmission medium 5 is interposed between the objects 4, and is held by a highly flexible coating 5'. The speed of sound in 5 has a smaller value than the speed of sound in the material of the lens 3, and by making 3 a convex lens, it is possible to convert the convergent beam 2a into a substantially parallel beam 3a. .

By using the probe configured as described above, the boundary portion 41 where the ultrasonic beam 2a enters the subject 4 is filled with an extremely small area, and acoustic contact between the probe and the subject is prevented. It becomes easier to secure Moreover, since the ultrasonic beam 3a scans a wide fan-shaped area 42 inside the object, flaw detection over a wide range is performed at once.

〔Example〕

FIG. 2 is a block diagram showing one specific configuration of the apparatus of the present invention, and the operation of each part will be described below.

6 is a group of n operating elements 21 . ...21"n-1 to perform ultrasonic transmission/reception operation by selectively exciting the transducer element group to which the transducer excitation signal 6b as the output is applied sequentially (2t+t,...・21”n) 1(21
+2. . . 2++n"t)... is performed. Through such transmission scanning, the ultrasonic beam 3a that enters the subject 4 through the lens 3 reaches the beam incidence point 41 on the subject. By performing a fan-shaped scan centered at , conditions are obtained for receiving reflected waves from four internal acoustic boundaries with various directions.

The reflected waves reflected from the defect 43 and other acoustic boundaries within the object are transmitted to the vibrating element group that sent out the beam 3a again, for example (
2I, . . . 21"n-1) and is received.

In the receiving scanning section 7, the above-mentioned receiving operation is carried out by successive element groups (2t+i, . . . 2t"n) in the same manner as the above-mentioned transmitting operation theory.
+(21+2....2t+n'')... Since scanning is performed, the incident point of the beam is 41.
The transmitting and receiving operation of the ultrasonic beam 3a, which is fan-shaped and scanned over a range of 42 with the center at , is performed by the transmitting scanning section 6 and the receiving scanning section 7.

Reference numeral 8 denotes a scanning control unit which generates a control signal 8a and a transmission command signal 8b for switching the operation of the array transducer 2 which transmits and receives ultrasonic waves as described above. Through such an operating mechanism, the ultrasonic beam transmitted and received by the probe 1 having a circular array transducer scans one cross section of the object, and the echo signals 7a obtained from each direction are sent to the signal amplification section 9.
．． It becomes a video signal 10a after passing through a detection section 1o.

Reference numeral 11 denotes an image processing unit which receives angle information 8C regarding the direction of the ultrasonic beam 3a obtained from the scan control unit 8 and a video signal 1.
By determining the position of an echo source such as 43 based on 0a and addressing the video signal thereto, a tomographic image of the fan-shaped scanning area of the object is formed.

The display unit 12 displays the image signal 11a obtained as the output of the imaging processing unit 11 as a tomographic image, as in a normal ultrasound imaging device.

A second specific example of implementing the present invention will be explained with reference to FIG.

Reference numeral 1 designates a probe used in this specific example, which includes array transducers arranged in a circular arc shape. Ultrasonic collimator lens 3. Ultrasonic transmission medium 5. is stored inside the tire 13. Information on the position X on the surface of the subject 4 is detected by the detector 14, and is guided to the imaging process 11 as a signal 14a.

11, the position of the probe 1 is X1. By superimposing the echo signal images obtained in ... Therefore, even if the shape of the reflection source is relatively complex, it can be expressed well.

According to the fan-shaped scanning ultrasonic flaw detection apparatus of the present invention described above, the ultrasonic beam focused over an extremely wide beam path scans the inside of the object in a fan-shape, thereby detecting the area formed by the echo signals. Since the image of the acoustic boundary inside the specimen is displayed, the displayed image has excellent resolution over the entire surface, and is extremely detailed and close to the real shape. Therefore, for example, when detecting defects in a material, the size and shape of defects can be easily evaluated immediately from one displayed defect image.

In addition, in the device of the present invention, when the ultrasonic waves are incident on the subject, they are sufficiently focused, the center of the fan-shaped scan corresponds to the incident point, and the contact area between the probe and the subject is extremely limited. Therefore, even if the surface shape of the object to be examined is curved or uneven, the ultrasonic waves can be transmitted efficiently.

The conventional method used to achieve the effect of focusing an ultrasonic beam over its entire path is to sequentially move the position of the beam focal region by controlling the phase of a group of operating vibrating elements. , the flaw detection information obtained within each focal region was extracted and combined or combined.

However, when using such a method, a complex and large-scale delay line network and a control unit to switch and control its operation are required, which not only increases the cost of the equipment but also takes a long time to form a flaw detection image. There was a drawback.

The device of the present invention eliminates the need for a complex and large-scale delay line network for forming a focal region as described above, as well as its control function, resulting in significant simplification of the device, resulting in cost reduction and the time required for flaw detection formation. Shortening is achieved simultaneously.

Owing to the above-mentioned excellent effects, the apparatus of the present invention brings enormous benefits to the industrial field.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the configuration and operation of the probe section, which is the main function of the device of the present invention, Fig. 2 is a block diagram showing a specific example of the configuration of the device of the present invention, and Fig. 3 is the device of the present invention. FIG. 2...Circular vibrator array, 3...Collimator lens. 5... Ultrasonic transmission medium, 6... Transmission scanning unit, 7...
- Reception scanning section, 8... Scanning control section, 11... Imaging processing section. 13... Probe storage tire, 14... Position detector.

Claims (1)

[Claims] 1. A probe having an array of ultrasonic transmitting and receiving transducers arranged in an arc shape and an acoustic lens that focuses an ultrasonic beam transmitted or received by the transducer array; A scanning function section is provided to perform fan-shaped scanning of the ultrasonic beam by sequentially switching the transmitting and receiving operations of the operating element group in the child array, and obtains echo signals from within the subject by the transmitting and receiving operations of the operating element group. A fan-shaped scanning ultrasonic flaw detection device that performs flaw detection. 2. In claim 1, a delay line is connected to each element of the operating element group of the arc-shaped vibrator array, and transmission and reception is performed from the element group in a focused manner toward the center of the arc. A fan-shaped scanning ultrasonic flaw detection device characterized by being able to control the focal point of an ultrasonic beam. 3. Claim 2 is characterized by comprising an imaging processing unit that forms a cross-sectional image of the subject using echo signals obtained from within the subject, and a display unit that displays the cross-sectional image. Fan-shaped scanning ultrasonic flaw detection device. 4. Claim 2 is characterized in that the ultrasonic probe consisting of the array transducer and the acoustic lens is housed in a housing made of a flexible material along with a liquid ultrasonic transmission medium. A fan-shaped scanning ultrasonic flaw detection device. 5. The fan-shaped scanning ultrasonic flaw detection apparatus according to claim 4, wherein the flexible material storage body is a tire-shaped storage body that has a rotating shaft and can roll. 6. A fan-shaped scanning ultrasound according to claim 4 or 5, characterized in that the center of the fan-shaped scanning of the ultrasound beam is substantially aligned with the contact portion between the probe and the subject. Flaw detection equipment. 7. Claims 3, 4, 5, or 6
In paragraph 1, a position detection unit and an angle detection unit detect the position and angle at which the ultrasonic beam enters the object to perform flaw detection while running the probe along the surface of the object. Information on the position and reflection intensity of the reflection source from the information on the ultrasound beam incident position and angle obtained from both detection units and the reflected wave signal from the reflection source inside the subject of the transmitted ultrasound pulse. 1. A fan-shaped scanning ultrasonic flaw detection apparatus, wherein image information of a cross section of the object under the travel path of the probe is formed in an image processing section, read out and displayed.