JPH0827268B2 - Spatial scanning ultrasonic flaw detector - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an ultrasonic probe apparatus, and particularly to detecting a defect in a subject with high sensitivity and accurately measuring the position of the defect. The present invention relates to a suitable ultrasonic probe device.

[Conventional technology]

As a prior art of the present invention, Japanese Patent Application No.
There is No. 60-184604. This is because positive phase pulses are applied to the elements selected at a predetermined interval with the array probe, and reverse phase pulses are applied to the elements located in the middle of the selected elements, and the oblique-angle ultrasonic waves are generated by the interference between the transmitted waves. It was to generate a beam. FIG. 5 shows a transmission method when the deflection angle is changed by this device. Here, + and-indicate positive-phase and anti-phase pulses, respectively. The transmission pattern of the array probe 9 changes depending on the deflection angle, and the length D of the probe transmitting ultrasonic waves is
(Hereinafter, referred to as the effective aperture) of the case of the deflection angle theta ₁ D ₁
When the deflection angle is θ ₂ , the magnitude is different from D ₂ . When ultrasonic waves are transmitted with this transmission pattern, the respective ultrasonic intensity distributions are 10, 10 ', and the beam width Δ _r1 when the deflection angle is θ ₁ is wider than the beam width Δ _r2 when the deflection angle is θ ₂ . In this way, the beam width changes depending on the deflection angle.

By the way, in ultrasonic flaw detection, it is necessary to detect a defect in a subject with high sensitivity and accurately measure the position of the defect. An index of this capability is the lateral resolution of how well the defects that are laterally close to the probe can be separated and detected. This depends on the width of the transmitted ultrasonic beam.

Therefore, the prior art has a problem that the defect position cannot be accurately measured depending on the deflection angle of the ultrasonic beam.

[Problems to be solved by the invention]

In the above-mentioned prior art, since the width of the ultrasonic beam changes depending on the deflection angle of the ultrasonic beam, there is a problem that the position of the defect in the subject cannot be accurately measured regardless of the deflection angle.

An object of the present invention is to provide a spatial scanning ultrasonic flaw detector capable of accurately measuring the position of a defect in a subject with a constant azimuth resolution by equalizing the widths of transmitted ultrasonic beams regardless of the deflection angle. To provide.

[Means for solving problems]

In the spatial scanning ultrasonic flaw detector, the deflection angle of the ultrasonic beam is determined by the distance between the transmitting elements. When the deflection angle is small, the interval is large, and when the deflection angle is large, the interval is small. At this time, the length of the probe transmitting ultrasonic waves (hereinafter referred to as the effective aperture) is large when the deflection angle is small, and is small when the deflection angle is large. As a result, when the deflection angle is small, the beam width becomes thin, and when the deflection angle is large, the beam width becomes wide. Therefore, the number of transmitting elements is changed to transmit ultrasonic waves in a pattern in which the effective apertures are equal regardless of the deflection angle.

[Action]

The input value of the deflection angle of the ultrasonic beam is input by the input circuit. The effective aperture D ₁ is obtained by the arithmetic circuit from the input set value of the first deflection angle. Furthermore, the effective aperture D ₁ obtained here
And the number of transmitting elements at the second deflection angle that makes the aperture equal
Find n ₂ . The transmission patterns of the first and second deflection angles are set in the switching control circuit. The transmission circuit transmits ultrasonic waves in each transmission pattern. In this way, the effective apertures at the respective deflection angles can be made equal and ultrasonic waves can be transmitted.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. In the following, for simplification, there are two types of beam deflection angles, θ ₁ and θ ₂ . FIG. 3 is a diagram showing an outline of the present invention. The number n of transmitting elements is selected so that the effective aperture D ₁ of the array probe 9 when the deflection angle is large as θ ₁ is equal to the effective aperture D ₂ when the deflection angle is small as θ ₂ . Compared with the case where the deflection angle θ ₂ is two transmitting elements, the case where the deflection angle θ ₁ is 5 requires a large number of transmitting elements. Ultrasonic waves are transmitted according to the transmission patterns of θ ₁ and θ ₂ . As a result, the intensity distribution 10,1 of the ultrasonic waves transmitted at the deflection angles θ ₁ and θ ₂
0'becomes equal, and their beam widths Δr ₁ and Δr ₂ can be made equal.

FIG. 2 is a flow chart showing an outline of processing of the present invention. Enter the set values θ ₁ and θ ₂ of the deflection angle of the ultrasonic beam. From this first deflection angle setting value θ ₁ , the number of transmitting elements
Determine n ₁ and element spacing d ₁ . Furthermore, determining the effective aperture D ₁ of the deflection angle theta ₁ from the following equation (1).

Here, a is an element pitch.

Next, from the effective aperture D ₁ thus obtained, the number n ₂ of transmitting elements at the deflection angle θ ₂ that satisfies the following equation (2) is obtained.

However, d ₂ is the transmission interval at θ ₂ . The number of transmitting elements n _{2 obtained} here is a positive integer.

Ultrasonic waves are transmitted in the transmission pattern of the deflection angles θ ₁ and θ ₂ thus obtained.

FIG. 1 is a block diagram of the spatial scanning flaw detector of the present invention. The element number set value n ₁ at the set values θ ₁ and θ ₂ of the deflection angle of the ultrasonic beam is input from the input circuit 8 and stored. The arithmetic circuit 7 which becomes the set value signal S calculates the number n ₂ of child elements at the effective opening D ₁ and θ ₂ of θ ₁ from the set value signal S, and outputs the arithmetic data A to the switching control circuit 6. . The switching control circuit 6 outputs the switching pattern signal C of the switching circuit 5 according to the operation data A. The switching circuit 5 switches each element of the array probe 9 by the switching pattern signal C. The high voltage pulse P output from the transmission circuit 1 is applied to the array probe 9 via the switching circuit 5. The signals u _{1 to} u _n received by the array probe 9 are added and amplified by the receiving circuit 2 to become an ultrasonic tone U. The signal processing circuit 3 measures the propagation time between the transmission wave and the defect reflected wave in the ultrasonic signal U to measure the defect position. Waveform display 4 based on this measurement
The display signal D is output to. In the waveform display 4, the display signal D
The defect position is displayed based on.

FIG. 4 is a flowchart showing an outline of processing of an embodiment when the total number N of elements of the array probe is set. Setting values of deflection angles θ ₁ and θ ₂ Number of all elements of array probe N
Enter the setting value of. From this total number N of elements, the maximum number n ₂ of elements satisfying the following expression (3) is obtained.

However, d ₂ is the element spacing at θ ₂ , a is the element pitch, and n ₂ is a positive integer.

Based on the number of elements n ₂ obtained here, the effective aperture D of the deflection angle θ _2
2 is calculated from the following equation (4).

From this effective aperture D _2, the maximum number of elements n ₁ that satisfies the following equation (5) is obtained.

However, d ₁ is an element interval at θ ₁ , and n ₁ is a positive integer.

The ultrasonic waves are transmitted to the inside of the body to be detected in the transmission pattern with the deflection angles θ ₁ and θ ₂ thus obtained.

As described above, it is possible to accurately measure the position inside the subject by transmitting the ultrasonic waves with a transmission pattern having the same effective aperture regardless of the deflection angle and setting the ultrasonic beam width to a constant value. .

〔The invention's effect〕

In a spatial scanning ultrasonic flaw detector that transmits and receives ultrasonic waves without controlling the delay time and deflects the ultrasonic beam, it is possible to prevent the deterioration of the lateral resolution when the beam deflection angle is large and to accurately detect the defect position at any beam deflection angle. It can measure well.

[Brief description of drawings]

FIG. 1 is a block diagram of a spatial scanning flaw detector according to an embodiment of the present invention, FIG. 2 is a flow chart showing an outline of processing of the present invention, FIG. 3 is an outline of the present invention, and FIG. FIG. 5 is a flow chart showing an outline of processing of a modified example of the present invention, and FIG. 5 is a view showing an outline of an apparatus according to the prior art. 1 ... Transmission circuit, 2 ... Reception circuit, 5 ... Switching circuit, 6
...... Switching control circuit, 7 ... Calculation circuit, 8 ... Input circuit,
9 ... Array probe, 10 ... Ultrasonic intensity distribution.

Claims (1)

[Claims] 1. A transmission circuit for transmitting a pulsed sine wave signal, and a plurality of ultrasonic transmission / reception elements for transmitting an ultrasonic beam to an inspection object with a deflection angle by receiving the signal from the transmission circuit without delay. In a spatial scanning ultrasonic flaw detector equipped with an array probe and a receiving circuit that adds and amplifies each ultrasonic received signal without delay, from one ultrasonic beam deflection angle set value An arithmetic circuit that calculates the effective aperture, calculates the number of ultrasonic transmission / reception elements that satisfies the ultrasonic transmission / reception element spacing required to exhibit another ultrasonic beam deflection angle, and is an effective opening that is equal to the effective aperture, A switching control circuit for receiving a signal from the arithmetic circuit and inputting a signal from the transmission circuit to each ultrasonic transmission / reception element of the number of ultrasonic transmission / reception elements that satisfies the required ultrasonic transmission / reception element interval, It has spatial scanning ultrasonic flaw detection apparatus characterized by.