JPS61201156A - Sector circuit in scanning type ultrasonic flaw detecting instrument - Google Patents

Abstract

PURPOSE:To facilitate delay time setting by delaying and transmitting ultrasonic waves from a row of ultrasonic transducers in the sequence of the disposition, inputting received signals in a memory circuit and reading with a delay in the sequence of the disposition of the transducers. CONSTITUTION:Drive signals from a delay time setting circuit 2 are transmitted to a driving circuit 3 and the start of transmission from each TJ of a raw (n) of ultrasonic transducers (TJ) is delayed in the order of disposition. The ultrasonic wave front is tilted an angle theta to the TJ row. This angle theta is adjusted by the delay time. The ultrasonic waves proceed through the object to be inspected and is scattered if defects exist. The scattered wave is received by the TJ row 4, A/D converted 6 and stored in a memory circuit 7. The output from the circuit 7 is read with a timing coincident with the delay time as set in each TJ, A/Dconverted 8, summed 9 and displayed 11. Hence, the delay time of both the transmitting and receiving circuits can be adjusted optionally and the proceeding direction of the ultrasonic waves can be changed as desired to provide for high accuracy flaw detection.

Description

[Detailed description of the invention] a. Industrial application field The present invention relates to a sector circuit for a scanning ultrasonic flaw detection device.

b. Conventional technology Figure 5 is a block diagram of a sector circuit of a scanning type ultrasonic flaw detector according to the prior art, and Figure 6 shows the ultrasonic wave transmitted from the ultrasonic transducer of the scanning type ultrasonic flaw detector. FIG. 2 is a conceptual diagram showing a traveling direction and a wave front.

The delay element 2a (
2□a...2na) delay time is selected, and each pulser 3a (3,a...3na) delays the reference signal by the delay time determined by the delay element (2,8...2na). The transmitted signal is sent to the ultrasonic transducer 4a.
(4,a...4na). At this time, a delay is made so that the phase of the ultrasound transmitted from the ultrasound transducers 4+a...4na into the subject changes in proportion to the distance from the end of the array of ultrasound transducers. The delay time of the element is set. As a result, as shown in FIG. 6, the ultrasonic waves traveling through the subject propagate in a direction inclined at a fixed angle θ with respect to the normal line of the ultrasonic transducer.

The ultrasonic waves are reflected by defects in the object, and the reflected ultrasonic waves are detected by the ultrasonic transducers and converted into electrical signals.

Electrical signals from the ultrasonic transducer are amplified by a preamplifier group 5a, and each output is sent to a delay element 2.2 with a corresponding delay time. ...Delay element 6a equal to the delay time of 2na (6, a...6 na
), the delay time of the summing amplification circuit is selected by a control signal from the control circuit 1a.

The above delay element 6. Since the phase is adjusted by a...6na, the output of the summing amplifier circuit 7a becomes a video signal of the defect viewed from a direction inclined at an angle θ with respect to a plane perpendicular to the ultrasonic transducer array. ing. The video signal is converted into a digital signal in an analog/digital conversion circuit 8a and then stored in a storage circuit 9a. The storage circuit is controlled by the control section 1a, and sends a video signal to a peripheral device 10a, such as a CRT, which is also controlled by the control section. At this time, the digital signal is stored in the storage circuit 9a in a form whose coordinates have been transformed by a control signal from an external coordinate transformation circuit. The coordinate conversion circuit is a circuit that changes an address signal when reading a digital signal into the storage circuit according to the angle θ, and is controlled by the control section. An A/D conversion section is connected to the storage circuit, and outputs a video signal according to a control signal from a control section,
For example, the above-mentioned CRT displays the above-mentioned defects as a B-1 image in this video signal.

C0 Problems to be solved by the invention In a scanning ultrasonic flaw detector, the direction of propagation θ of the ultrasonic waves can be changed by changing the delay time by the delay element of the transmitting/receiving circuit; The delay time is switched by switching the delay element group using a control signal. As a result, the following problem arises.

l) When the sector angle (the angle formed by the direction of ultrasound propagation with the normal to the row of ultrasound transducers) is 30',
The maximum delay time is close to 1 μ3, and in order to obtain a clear image, the value of the delay element must be accurately selected, making circuit design difficult.

1)) Conversely, when the sector angle is small, the delay time is 1
must be controlled on the order of ons.

iii) The line of the delay element and the circuit of the control section are complicated.

iv) When the number of ultrasonic transducers driven simultaneously increases, the load on the delay circuit of the receiving circuit becomes particularly large.

SUMMARY OF THE INVENTION An object of the present invention is to provide a sector circuit for a scanning ultrasonic flaw detection apparatus that can set the delay time of a transmitting circuit and a receiving circuit, or one of the circuits, without using a delay element.

d0 Means for Solving Problems The above object is to provide an array of ultrasonic transducers, a drive circuit array for driving each ultrasonic transducer in the array of ultrasonic transducers, and an array of ultrasonic transducers for each of the ultrasound transducers. a delay time setting circuit that delays the start of transmission in the order of the arrangement of the ultrasonic transducers; a control circuit that controls the delay time setting circuit; and a reflected ultrasound signal received by the ultrasonic transducer. an amplifier circuit array consisting of an amplifier circuit that amplifies the output of the amplifier circuit; an A/D conversion circuit that converts the output of the amplifier circuit from an analog signal to a digital signal; a storage circuit that holds the output of the A/D conversion circuit; D converting the output signal of the storage circuit, which is delayed and read out in the order of the arrangement of the ultrasonic transducers, from a digital signal to an analog signal according to a control signal from the circuit;
/A converter circuit, an adder circuit whose input is the output of each D/A converter circuit corresponding to the output of each ultrasonic transducer in the ultrasonic transducer array; and 1, displaying the output signal of the adder circuit. The problem was solved by a sector circuit of a scanning ultrasonic flaw detector that includes an interface circuit to the device.

A clock pulse is sent from the e0 action control circuit to the delay time setting circuit, and the delay time setting circuit sends a drive signal to the drive circuit array to sequentially drive each drive circuit in the drive circuit array in the order of their arrangement every certain number of clock pulses. send.

At this time, the number N of ultrasonic transformers and ducers included in the ultrasonic transducer row and the number n of ultrasonic transducers driven by a series of drive signals do not necessarily have to match. The position of the ultrasound transmission source can be spatially adjusted by driving sets of ultrasound transducers adjacent to each other using drive signals of Can be moved.

The time point at which each ultrasonic transducer starts transmitting ultrasonic waves is determined by the above drive signal, and is delayed in the order of the arrangement, so the phase of the ultrasonic waves transmitted from each ultrasonic transducer also differs from that of the adjacent ultrasonic transducer. It is delayed sequentially. Therefore, the wavefront of the ultrasound generated by the series of drive signals is inclined by an angle θ with respect to the array of ultrasound transducers. That is, it travels in a direction inclined by an angle θ with respect to the normal line of the ultrasonic transducer array.

The ultrasonic wave having the above-mentioned direction of travel travels through the object, and if a defect or the like exists in the object, it is scattered and scattered waves are generated. The scattered waves are received by an array of ultrasonic transducers, converted into electrical signals, and amplified by an amplifier circuit provided for each ultrasonic transducer. The output of the amplifier circuit is converted into a digital signal in a subsequent analog/digital conversion circuit, and is held in a subsequent storage circuit.

The content held in the memory circuit is read out by a read signal from the control circuit, and is converted from a digital signal to an analog signal in a digital/analog conversion circuit. At this time, by controlling the time point at which the signal corresponding to each ultrasonic transducer is read, it is possible to change the delay time between the time point at which the signal is inputted to the memory circuit and the time point at which the signal is output from the memory circuit. The delay time corresponding to each ultrasonic transducer is made to match the delay time set for each ultrasonic transducer in the delay time setting circuit of the transmitting circuit, and each ultrasonic transducer of the digital/analog conversion circuit is By calculating the sum of the digital signals corresponding to the user in an adding circuit, defects existing in a direction inclined by an angle θ from the ultrasonic transducer that transmitted the ultrasonic wave to the normal to the ultrasonic transducer array are detected. video signal can be obtained.

By spatially moving a set of ultrasonic transducers driven by a series of drive signals or by changing the above-mentioned angle θ, a defect image in the object can be displayed on a CRT or the like via an interface circuit. It can be displayed on the device.

f. Embodiment FIG. 1 is a block diagram of a preferred embodiment of a sector circuit of a scanning ultrasonic flaw detector according to the present invention, and FIG. 2 is an ultrasonic transformer of a sector circuit of a scanning ultrasonic flaw detector according to the present invention. FIG. 2 is a conceptual cross-sectional view showing an arrangement of deducers and ultrasonic waves generated by a series of drive signals.

A clock pulse is sent from the control circuit 1 to the delay time setting circuit 2, and the delay time setting circuit 2 sends a drive signal to the drive circuit array 3 to sequentially drive each drive circuit in the order of its arrangement every fixed number of clock pulses.

The delay time setting circuit 2 can be realized, for example, by a serial IN/parallel OUT shift register that receives a clock pulse as an input signal.

The time point at which each ultrasonic transducer (1...N) in the ultrasonic transducer array 4 starts transmitting ultrasonic waves is determined by the drive signal described above, and is delayed in the order of the array. The phase of the transmitted ultrasonic waves is also sequentially delayed. Therefore, the wavefront of the ultrasound generated by the series of drive signals is inclined by an angle θ with respect to the array of ultrasound transducers. That is, it travels in a direction inclined by an angle θ with respect to the normal line of the ultrasonic transducer array. Note that the angle θ is determined by the delay time, and the delay time can be changed by adjusting the period of the clock pulse of the control circuit 1, etc.

At this time, the number N of ultrasonic transducers included in the ultrasonic transducer array 4 and the number n of ultrasonic transducers driven by the series of drive signals do not necessarily have to match. N>n, and by driving a set of ultrasound transducers adjacent to each other with a series of drive signals, and moving the set of ultrasound transducers driven for each series of drive signals, the ultrasound transmission source is The position of can be moved spatially.

The ultrasonic wave having the above-mentioned direction of travel travels through the object, and if a defect or the like exists in the object, it is scattered and scattered waves are generated. The scattered waves are received by the ultrasonic transducer array 4, converted into electrical signals, and amplified by an amplifier circuit array 5 comprising an amplifier circuit provided for each ultrasonic transducer.

The output of the double-width circuit 5 is converted into a digital signal by an analog/digital conversion circuit 6 at a subsequent stage, and is held in a storage circuit 7 at a subsequent stage. The contents held in the storage circuit 7 are read out by a read signal from the control circuit 1 and converted from digital to analog signals in the digital/analog conversion circuit 8. At this time, by controlling the reading of the signal corresponding to each ultrasonic transducer, it is possible to change the time from when it is input to the memory circuit 7 to when it is output from the memory circuit, that is, the delay time is variable. It can be a delay circuit.

The delay time corresponding to each ultrasonic transducer is made to match the delay time set for each ultrasonic transducer in the delay time setting circuit 2 of the transmitting circuit, and each ultrasonic wave of the digital/analog conversion circuit 8 is By calculating the sum of the digital signals corresponding to the transducers in the adding circuit 9, the direction from the ultrasonic transducer group that transmitted the ultrasonic waves by an angle θ with respect to the normal to the ultrasonic transducer array is calculated. A video signal of the defect present in the image can be obtained.

Based on the video signal, an image of the defect is obtained as a B scope or a C scope.

For example, the B scope image is
0 is configured by an A/D conversion circuit storage circuit, a D/A conversion circuit, and a coordinate conversion circuit (all not shown), and is obtained by coordinate conversion. The video signal is converted into a digital signal by the A/D conversion circuit, and this digital signal is stored in the circuit. One frame from the beginning to the end of the ultrasonic transducer array is stored in the storage circuit at a position specified by the addressing control signal from the coordinate conversion circuit, which is controlled according to the angle θ by the control circuit l. The minute signal is memorized. The output of the storage circuit is sent to a display device 1) such as a CRT via a D/A conversion circuit controlled by a control signal from a control circuit 1, and is sent to a vertical video signal (B scope ) is output as Note that it is also possible to change the angle θ.

In addition, by moving the probe, the ultrasonic waves are moved in parallel within the subject while keeping the direction of propagation of the ultrasonic waves at a fixed angle θ, and the image signal obtained at that time is sent to the CR7 circuit via another interface circuit 10. It is also possible to display the defect in the object as a C scope on the display device 1).

In FIG. 2, the fifth to twelfth ultrasonic transducers (n=8) in the ultrasonic transducer array consisting of N ultrasonic transducers are driven by a series of drive signals, This is a state in which ultrasonic waves travel in a direction at an angle θ with respect to the normal line of the ultrasonic transducer array. The ultrasound transmission source is spatially translated by driving the sixth through thirteenth ultrasound transducers with the next series of drive signals. In addition, control of the analog/digital conversion circuit 6, address of the memory circuit 7, active/inactive control, control of the digital/analog conversion circuit 8,
Control of the adder circuit 9, ink face circuit 10 (A/D conversion circuit, memory circuit, D/A conversion circuit, coordinate conversion circuit) and display circuit 1) is realized by known technology using a micropro sensor etc. can do.

FIG. 3 is a conceptual cross-sectional view when the probe 12 of the scanning ultrasonic flaw detector using the sector circuit according to the present invention sends an ultrasonic wave 14 into the object 13 to detect a defect 15. When the arrangement direction of the ultrasonic transducer row is the X axis and the direction perpendicular to the surface of the subject is the two axes, the ultrasonic transmission source moves in the X direction for each series of drive signals, and An image 16 of the defect 15 is displayed as a B scope on, for example, a CRT.

Furthermore, by moving the probe 12 along the y-axis perpendicular to the x-axis, a two-dimensional image (C scope) of the defect can also be displayed.

FIG. 4 is an example of an image 16 of a defect 15 displayed on a CRT (B scope).

Note that by arranging the ultrasonic transducers in two dimensions (for example, in the xy plane in FIG. 3), it is possible to scan the two-dimensional image of the defect without moving the probe 12.

g8 Effects of the invention i) The delay times of the transmitting circuit and the receiving circuit can be arbitrarily and easily adjusted.

ii) Since the traveling direction of &H sound waves can be easily changed, defect detection ability is improved.

iii) The number of delay lines required when using the prior art is greatly reduced, and the frequency characteristics of the delay lines are inversely proportional to the amount of delay, resulting in improved frequency characteristics. That is, even if a high frequency probe is used, there is little decrease in sensitivity.

iv) Since the signal corresponding to the received wave of each ultrasonic transducer is held in the storage circuit, it is possible to digitally process it before the addition circuit. Therefore, image processing for obtaining a clear image and other image processing can be performed. In other words, since the video signal is digitized at an early stage, advanced signal processing can be easily performed without degrading the signal quality.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a preferred embodiment of a sector circuit of a scanning ultrasonic flaw detector according to the present invention, and FIG. 2 is an arrangement of ultrasonic transducers of a sector circuit of a scanning ultrasonic flaw detector according to the present invention. and a conceptual cross-sectional view showing ultrasonic waves generated by a series of drive signals. FIG. 3 is a probe 1 of a scanning ultrasonic flaw detection device using a sector circuit according to the present invention
2 is a conceptual cross-sectional view when sending the ultrasonic wave 14 into the object 13 to detect a defect 15, FIG. 4 is an example of an image of the defect 15 displayed on a CRT (B scope), and FIG. FIG. 6 is a block diagram of a sector circuit of a scanning ultrasonic flaw detector according to the prior art, and is a conceptual diagram showing the traveling direction and wavefront of an ultrasonic wave transmitted from an ultrasonic transducer of a scanning ultrasonic flaw detector. ■...Control circuit, 2...Delay time setting circuit, 3
... Drive circuit row, 4... Ultrasonic transducer row, 5... Amplifier circuit row, 6... A/D conversion circuit,
7... Memory circuit, 8... D/A conversion circuit, 9...
...addition circuit, 10...interface circuit,
1) Display device.

Claims (1)

[Claims] (1) An ultrasonic transducer array, a drive circuit array that drives each ultrasonic transducer in the ultrasonic transducer array, and a delay time setting that delays the start of transmission of each ultrasonic transducer in the order of the array of ultrasonic transducers. a control circuit that controls the delay time setting circuit, an amplifier circuit array that includes an amplifier circuit that amplifies the reflected ultrasound signal received by the ultrasound transducer, and converts the output of the amplifier circuit from an analog signal to a digital signal. an A/D conversion circuit that converts into a signal, a storage circuit that holds the output of the A/D conversion circuit, and the storage that is read out with a delay in the order of the ultrasonic transducer array according to a control signal from the control circuit. A D/A conversion circuit that converts the output signal of the circuit from a digital signal to an analog signal, and an addition circuit whose input and input are the outputs of each D/A conversion circuit corresponding to the output of each ultrasonic transducer in the ultrasonic transducer array. and an interface circuit for sending the output signal of the adding circuit to a display device. 2) The interface circuit includes an A/D conversion circuit, a storage circuit that stores the output of the A/D conversion circuit, a coordinate conversion circuit that specifies an address within the storage circuit, and converts the output of the storage circuit into an analog signal. The sector circuit of a scanning ultrasonic flaw detection apparatus according to claim 1, wherein the sector circuit is a B-scope display interface circuit comprising a D/A conversion circuit for converting into a B-scope display. 3) A sector circuit for a scanning ultrasonic flaw detection apparatus according to claim 1, wherein the interface circuit is a C scope display interface circuit.