JP7428616B2 - Ultrasonic inspection equipment and ultrasonic inspection method - Google Patents

Description

The present disclosure relates to an ultrasonic inspection apparatus and an ultrasonic inspection method.

A method of inspecting a defective portion of an object to be inspected using an ultrasonic beam is known. For example, if there is a defect (such as a cavity) with low acoustic impedance, such as air, inside the object to be inspected, a gap in acoustic impedance will occur inside the object to be inspected, and the amount of ultrasound beam transmitted will be small. Therefore, by measuring the amount of transmission of the ultrasonic beam, a defective portion inside the object to be inspected can be detected.

A technique described in Patent Document 1 is known regarding an ultrasonic inspection device. In the ultrasonic inspection apparatus described in Patent Document 1, a rectangular wave burst signal consisting of a predetermined number of continuous negative rectangular waves is applied to a transmitting ultrasonic probe disposed opposite to a subject through the air. A receiving ultrasonic probe placed opposite the subject through the air converts the ultrasonic waves propagated through the subject into transmitted wave signals. Based on the signal level of this transmitted wave signal, the presence or absence of a defect in the object to be inspected is determined. In addition, transmitting ultrasound probes and receiving ultrasound probes are contact type in which the acoustic impedance of a transducer and a front plate attached to the ultrasound transmitting and receiving side of the transducer is used by contacting the subject. It is set lower than the ultrasonic probe.

JP 2008-128965 (especially the abstract)

The ultrasonic inspection apparatus described in Patent Document 1 has a problem in that when observing a minute defect in an object to be inspected, the resolution of the observed defect image decreases. That is, there is a problem that the outline of the image corresponding to the defective part becomes blurred. This is because even if a portion of the ultrasound beam is blocked by the defect, a change occurs in the received signal. This problem becomes particularly noticeable when the size of the defect to be detected is comparable to or smaller than the size (beam diameter) of the ultrasonic beam.
The problem to be solved by the present disclosure is to provide an ultrasonic inspection apparatus and an ultrasonic inspection method that have excellent defect detection performance, for example, resolution of displayed images.

An ultrasonic inspection apparatus according to the present disclosure is an ultrasonic inspection apparatus that inspects an object to be inspected by injecting an ultrasonic beam into the object through a fluid. The scanning measurement device includes a scanning measurement device that scans and measures the ultrasound beam, and a control device that controls driving of the scanning measurement device, and the scanning measurement device includes a transmitting probe that emits the ultrasound beam, and a transmission probe that receives the ultrasound beam. an eccentrically placed receiving probe, the eccentrically placed receiving probe is arranged such that an eccentric distance between the transmitting sound axis of the transmitting probe and the receiving sound axis of the eccentrically placed receiving probe is greater than zero; and the eccentrically arranged receiving probe scans in the x-axis direction or the y-axis direction, and the transmitting probe is arranged such that the transmitting sound axis is perpendicular to the xy plane formed by the x-axis and the y-axis. and a phase extractor that extracts phase information of the ultrasonic beam signal received by the eccentric receiving probe, and a phase extractor that calculates a phase change amount with respect to the scanning position of the extracted phase information. and a change amount calculation section . Other solutions will be described later in the detailed description.

According to the present disclosure, it is possible to provide an ultrasonic inspection apparatus and an ultrasonic inspection method that are excellent in defect detection performance, for example, in display image resolution.

FIG. 1 is a diagram showing the configuration of an ultrasonic testing apparatus according to a first embodiment. FIG. 2 is a diagram illustrating a transmitting sound axis, a receiving sound axis, and an eccentric distance, and is a diagram for explaining a transmitting sound axis and a receiving sound axis extending in the vertical direction. It is a figure explaining a transmission sound axis, a reception sound axis, and an eccentric distance, and is a case where a transmission sound axis and a reception sound axis extend in an inclined manner. FIG. 2 is a schematic cross-sectional diagram showing the structure of a transmitting probe. It is a received waveform from an eccentrically placed receiving probe, and is a diagram showing a received waveform at a healthy part N of the subject E. It is a received waveform from an eccentrically placed receiving probe, and is a diagram showing a received waveform at a defective portion D of an object to be inspected. FIG. 3 is a diagram showing an example of a plot of signal strength data. FIG. 3 is a diagram showing a propagation path of an ultrasound beam in the present embodiment, showing a case where the ultrasound beam is incident on a healthy part. FIG. 3 is a diagram illustrating a propagation path of an ultrasonic beam in the present embodiment, showing a case where the ultrasonic beam is incident on a defective portion. FIG. 3 is a diagram showing the propagation path of an ultrasound beam in a conventional ultrasound inspection method, and is a diagram showing the time of incidence on a healthy part. FIG. 3 is a diagram showing a propagation path of an ultrasonic beam in a conventional ultrasonic inspection method, and is a diagram showing the time of incidence on a defective part. FIG. 3 is a diagram showing a plot of signal intensity data in a conventional ultrasonic inspection method. FIG. 3 is a diagram illustrating the interaction between a defective part and an ultrasonic beam within the body to be inspected, and is a diagram illustrating how a direct ultrasonic beam is received. FIG. 3 is a diagram illustrating the interaction between a defective part and an ultrasonic beam within the body to be inspected, and is a diagram illustrating how scattered waves are received. It is a functional block diagram of a control device. FIG. 6 is a diagram schematically showing changes in the received signal of the eccentrically arranged receiving probe at each scanning position in the x-axis direction. It is a figure which shows the scanning position where an ultrasonic beam does not enter a defective part. FIG. 6 is a diagram showing a scanning position where an ultrasonic beam is incident on a defective portion but a transmission sound axis does not enter the defective portion. FIG. 4 is a diagram showing a scanning position where an ultrasonic beam enters a defective portion and a transmission sound axis enters the defective portion. FIG. 3 is a diagram showing the hardware configuration of a control device. It is a flow chart showing an ultrasonic inspection method of a 1st embodiment. It is a figure showing the composition of the ultrasonic inspection device in a 2nd embodiment. FIG. 2 is a functional block diagram of an ultrasonic inspection apparatus in a second embodiment. It is a figure showing the composition of the ultrasonic examination device of a 3rd embodiment. It is a figure showing the composition of the ultrasonic examination device of a 4th embodiment. It is a figure showing the composition of the ultrasonic inspection device in a 5th embodiment. It is a functional block diagram of an ultrasonic inspection apparatus in a 5th embodiment. FIG. 7 is a diagram showing the relationship between a transmitting probe and an eccentrically arranged receiving probe in an ultrasonic testing apparatus according to a sixth embodiment. FIG. 3 is a diagram illustrating the relationship between the beam incident area on a transmitting probe and the beam incident area on an eccentrically arranged receiving probe. FIG. 7 is a diagram showing an example of an eccentrically placed receiving probe according to a seventh embodiment. It is a figure which shows the structure of the scanning measurement device of the ultrasonic inspection apparatus based on 8th Embodiment. It is a figure explaining the reason why the effect by 8th Embodiment arises. It is a figure showing the composition of the ultrasonic inspection device concerning a 9th embodiment. It is a functional block diagram of the ultrasonic inspection device concerning a 9th embodiment. It is a figure which shows the arrangement|positioning of the eccentric arrangement|positioning receiving probe in 10th Embodiment. It is a figure which shows the arrangement|positioning of the eccentric arrangement|positioning receiving probe in 11th Embodiment, and is a figure in which the unit probe is arranged in an inclined manner. It is a figure which shows the arrangement|positioning of the eccentric arrangement|positioning receiving probe in 11th Embodiment, and is a figure which arrange|positioned the unit probe in the vertical direction. It is a figure showing the composition of the ultrasonic inspection device of a 12th embodiment. It is a figure showing the composition of the ultrasonic examination device of a 13th embodiment. It is a figure showing the composition of the ultrasonic inspection device of a 14th embodiment.

Hereinafter, modes for implementing the present disclosure (referred to as embodiments) will be described with reference to the drawings. However, the present disclosure is not limited to the following embodiments, and, for example, different embodiments may be combined or arbitrarily modified without significantly impairing the effects of the present disclosure. Further, the same members will be given the same reference numerals, and redundant explanations will be omitted. Furthermore, items having the same function shall be given the same name. The illustrated contents are merely schematic, and for convenience of illustration, the actual configuration may be changed within a range that does not significantly impair the effects of the present disclosure.

(First embodiment)
FIG. 1 is a diagram showing the configuration of an ultrasonic testing apparatus Z according to the first embodiment. In FIG. 1, the scanning measurement device 1 is shown in a schematic cross-sectional view. FIG. 1 shows a coordinate system of three orthogonal axes, including an x-axis in the horizontal direction of the paper, a y-axis in the direction perpendicular to the paper, and a z-axis in the vertical direction of the paper.

The ultrasonic inspection apparatus Z inspects the object E by making the ultrasonic beam U (FIG. 3) incident on the object E via the fluid F. The fluid F is, for example, a liquid W such as water (FIG. 17) or a gas G such as air, and the object E is present in the fluid F. In the first embodiment, air (an example of gas G) is used as the fluid F. Therefore, the inside of the housing 101 of the scanning measurement device 1 is a cavity filled with air. As shown in FIG. 1, the ultrasonic inspection apparatus Z includes a scanning measurement device 1, a control device 2, and a display device 3. Display device 3 is connected to control device 2 .

The scanning measurement device 1 scans and measures the ultrasonic beam U on the object E to be inspected, and includes a sample stage 102 fixed to a housing 101, on which the object E to be inspected is placed. be placed. The object to be inspected E is made of any material. The object to be inspected E is, for example, a solid material, more specifically, for example, a metal, glass, a resin material, or a composite material such as CFRP (Carbon-Fiber Reinforced Plastics). Furthermore, in the example of FIG. 1, the object to be inspected E has a defective portion D inside. The defective portion D is a cavity or the like. Examples of the defective portion D include a cavity, a foreign material different from the original material, and the like. In the object to be inspected E, a portion other than the defective portion D is referred to as a healthy portion N.

Since the defective part D and the healthy part N are made of different materials, the acoustic impedance is different between the two, and the propagation characteristics of the ultrasonic beam U change. The ultrasonic inspection device Z detects the defective portion D by observing this change.

The scanning measurement device 1 includes a transmitting probe 110 that emits an ultrasonic beam U and an eccentrically arranged receiving probe 120. The transmitting probe 110 is installed in the housing 101 via the transmitting probe scanning unit 103 and emits an ultrasonic beam U. The eccentrically placed receiving probe 120 is a receiving probe 121 that is installed on the opposite side of the transmitting probe 110 with respect to the subject E and receives the ultrasound beam U. The eccentrically placed receiving probe 120 has a receiving acoustic axis AX2 at a different position from the transmitting acoustic axis AX1 of the transmitting probe 110. The distance between the transmitting sound axis AX1 and the receiving sound axis AX2 is the eccentric distance L. The eccentrically arranged receiving probe 120 is installed in the housing 101 via the receiving probe scanning section 104.

In this specification, among the receiving probes 121 that receive the ultrasonic beam U, those placed at a position where the eccentric distance L is greater than zero are defined as the eccentrically placed receiving probes 120, and those where the eccentric distance L is zero are defined as the eccentric receiving probes 120. The probe placed at this position is defined as a coaxial receiving probe 140 (FIG. 2A, etc.). In other words, the reception probe 121 is a term that includes the eccentric reception probe 120 and the coaxial reception probe 140, and is a name that represents a probe that receives ultrasound regardless of the eccentric distance L.

Here, "the opposite side of the transmitting probe 110" means a space on the opposite side (opposite side in the z-axis direction) to the space where the transmitting probe 110 is located, of the two spaces separated by the object to be inspected E. However, this does not mean that the x and y coordinates are the same on opposite sides (that is, the positions are plane symmetrical with respect to the xy plane). As shown in FIG. 1, the transmitting probe 110 and the eccentrically arranged receiving probe 120 are installed so that the transmitting sound axis AX1 and the receiving sound axis AX2 are shifted by an eccentric distance L. Note that the specific details of the transmitting sound axis AX1, the receiving sound axis AX2, and the eccentric distance L will be described later.

As the reception probe scanning unit 104 moves, the eccentric reception probe 120 scans the sample stage 102 in the x-axis and y-axis directions. The transmitting probe 110 and the eccentrically arranged receiving probe 120 scan while maintaining an eccentric distance L in the x-axis direction or the y-axis direction with the object E to be inspected in between (thick double-headed arrow).

In addition, in the scanning measurement device 1, the eccentric distance L is set as follows, although details will be described later. That is, the eccentric distance L is set to a distance at which the scattered waves U1 generated by the scattering of the ultrasonic beam U at the defective portion D of the object E to be inspected can be received. Alternatively, the eccentricity is adjusted so that the received signal strength at the eccentrically arranged receiving probe 120 when the probe 120 enters the defective part D of the object E is greater than the received signal strength when the probe 120 enters the healthy part N of the object E. A distance L is set. Alternatively, the eccentric distance L is set to a distance at which no received signal other than noise is detected when the healthy part N of the subject E is irradiated.

The scanning measuring device 1 includes an eccentric distance adjustment section that adjusts the position of at least one of the transmitting probe 110 or the eccentrically arranged receiving probe 120 so that the eccentric distance L between the transmitting acoustic axis AX1 and the receiving acoustic axis AX2 is greater than zero. 105. The eccentric distance adjustment section 105 (eccentric distance adjustment mechanism) is provided in the reception probe scanning section 104 installed in the housing 101. The eccentric distance adjustment unit 105 is equipped with an eccentric receiving probe 120. The eccentric distance adjustment section 105 can move the eccentric receiving probe 120 independently of the position of the receiving probe scanning section 104, and can set the offset between the receiving acoustic axis AX2 and the transmitting acoustic axis AX1 to be the eccentric distance L. Note that the eccentric distance adjustment section 105 may be provided on the transmission probe scanning section 103 side. In other words, it is only necessary to set the deviation between the receiving acoustic axis AX2 and the transmitting acoustic axis AX1 to be the eccentric distance L. Therefore, even if the eccentric distance adjusting section 105 is provided on the receiving probe 121 side, it does not need to be provided on the transmitting probe 110 side. You can.

A control device 2 is connected to the scanning measurement device 1 . The control device 2 controls the driving of the scanning measurement device 1, and controls the movement (scanning) of the transmitting probe 110 and the eccentrically arranged receiving probe 120 by instructing the transmitting probe scanning section 103 and the receiving probe scanning section 104. Control. By moving the transmitting probe scanning section 103 and the receiving probe scanning section 104 in synchronization in the x-axis and y-axis directions, the transmitting probe 110 and the eccentrically arranged receiving probe 120 scan the test object E in the x-axis and y-axis directions. do. Furthermore, the control device 2 emits the ultrasonic beam U from the transmitting probe 110 and performs waveform analysis based on the signal acquired from the eccentrically arranged receiving probe 120.

In this embodiment, the test object E is fixed to the casing 101 via the sample stage 102, that is, the test object E is fixed to the casing 101, and the transmission probe 110 and the eccentric An example of scanning with a placed receiving probe 120 is shown. On the contrary, a configuration may be adopted in which the transmitting probe 110 and the eccentrically placed receiving probe 120 are fixed to the housing 101, and scanning is performed by moving the inspected object E.

In the illustrated example, gas G (an example of fluid F; liquid W (FIG. 17) may also be used) is present between the transmitting probe 110 and the subject E, and between the eccentric receiving probe 120 and the subject E. intervenes. Therefore, since the transmitting probe 110 and the eccentrically arranged receiving probe 120 can be inspected without contacting the subject E, the relative position in the xy plane direction can be changed smoothly and at high speed. That is, by interposing the fluid F between the transmitting probe 110, the eccentrically arranged receiving probe 120, and the subject E, smooth scanning becomes possible.

The transmission probe 110 is a convergent type transmission probe 110. On the other hand, the eccentrically placed receiving probe 120 uses a probe whose convergence is looser than that of the transmitting probe 110. In this embodiment, the eccentric receiving probe 120 is a non-convergent probe whose probe surface is flat. By using such a non-convergent eccentrically placed receiving probe 120, information on the defective portion D can be collected over a wide range.

In this embodiment, the eccentrically arranged receiving probe 120 is disposed offset from the transmitting probe 110 by an eccentric distance L in the x-axis direction in FIG. An eccentrically placed receiving probe 120 may be placed. Alternatively, the eccentric receiving probe 120 may be arranged at L1 in the x-axis direction and L2 in the y-axis direction (i.e., at the position (L1, L2) when the origin is the position of the transmitting probe 110 on the xy plane). .

FIG. 2A is a diagram illustrating the transmitting sound axis AX1, the receiving sound axis AX2, and the eccentric distance L, and shows a case where the transmitting sound axis AX1 and the receiving sound axis AX2 extend in the vertical direction. FIG. 2B is a diagram illustrating the transmitting sound axis AX1, the receiving sound axis AX2, and the eccentric distance L, and shows a case where the transmitting sound axis AX1 and the receiving sound axis AX2 extend obliquely.

The acoustic axis is defined as the central axis of the ultrasound beam U. Here, the transmission acoustic axis AX1 is defined as the acoustic axis of the propagation path of the ultrasound beam U emitted by the transmission probe 110. In other words, the transmission acoustic axis AX1 is the central axis of the propagation path of the ultrasound beam U emitted by the transmission probe 110. The transmission sound axis AX1 includes refraction due to the interface of the object to be inspected E, as shown in FIG. 2B. In other words, as shown in FIG. 2B, when the ultrasonic beam U emitted from the transmitting probe 110 is refracted at the interface of the inspected object E, the center of the propagation path (acoustic axis) of the ultrasonic beam U is the transmitter. The sound axis becomes AX1.

Further, the reception acoustic axis AX2 is defined as the acoustic axis of the propagation path of the virtual ultrasound beam when it is assumed that the eccentrically arranged reception probe 120 emits the ultrasound beam U. In other words, the receiving acoustic axis AX2 is the central axis of a virtual ultrasound beam when it is assumed that the eccentrically arranged receiving probe 120 emits the ultrasound beam U.

As a specific example, we will discuss the case of a non-convergence type receiving probe in which the probe surface is planar. In this case, the direction of the reception sound axis AX2 is the normal direction of the probe surface, and the axis passing through the center point of the probe surface becomes the reception sound axis AX2. If the probe surface is rectangular, the center point is defined as the intersection of the diagonals of the rectangle.

The reason why the direction of the receiving sound axis AX2 is the normal direction to the probe surface is that the virtual ultrasound beam U emitted from the receiving probe 121 is emitted in the normal direction to the probe surface. When receiving the ultrasonic beam U, it is possible to receive the ultrasonic beam U incident in the normal direction of the probe surface with high sensitivity.

The eccentric distance L is defined as the distance of deviation between the transmission sound axis AX1 and the reception sound axis AX2. Therefore, as shown in FIG. 2B, when the ultrasonic beam U emitted from the transmitting probe 110 is refracted, the eccentric distance L is the distance of the deviation between the refracted transmitting sound axis AX1 and the receiving sound axis AX2. defined. In the ultrasonic testing apparatus Z of the present embodiment, the transmitting probe 110 and the eccentrically arranged receiving probe 120 are adjusted by the eccentric distance adjusting section 105 (FIG. 1) so that the eccentric distance L defined in this way becomes a distance greater than zero. be adjusted. This reduces the ultrasonic beam U (Fig. 3) emitted from the transmitting probe 110 and transmitted around the defective part D (Fig. 1), making it easier to detect signal changes originating from the defective part D in the receiving probe 121. can.

However, in this embodiment, as a preferable example, the eccentric receiving probe 120 receives the scattered wave U1 (FIG. 6B) caused by the scattering of the ultrasound beam U at the defective portion D, as described above. Since the scattered waves U1 are generated due to the presence of the defective portion D, the detection accuracy of the defective portion D can be further improved by detecting the scattered waves U1. In the following example, in order to simplify the explanation, the present embodiment will be described by taking as an example the eccentrically placed receiving probe 120 installed at a position where the scattered wave U1 can be received.

FIG. 2A shows a case where the transmitting probe 110 is arranged in the normal direction on the surface of the object E to be inspected. In FIGS. 2A and 2B, the transmission sound axis AX1 is indicated by a solid arrow. Further, the reception sound axis AX2 is indicated by a dashed-dotted arrow. In addition, in FIGS. 2A and 2B, the position of the receiving probe 121 indicated by the broken line is the position where the eccentric distance L is zero, and the receiving probe 121 where the transmitting acoustic axis AX1 and the receiving acoustic axis AX2 coincide is the coaxially arranged receiving probe 140. It is. Further, the receiving probe 121 shown by a solid line is an eccentrically arranged receiving probe 120 arranged at a position with an eccentric distance L greater than zero. When the transmission probe 110 is installed so that the transmission acoustic axis AX1 is perpendicular to the horizontal plane (the xy plane in FIG. 1), the propagation path of the ultrasound beam U is not refracted. In other words, the transmission acoustic axis AX1 is not refracted.

FIG. 2B is a diagram showing a case where the transmitting probe 110 is arranged at an angle α from the normal direction on the surface of the object E to be inspected. In FIG. 2B, as in FIG. 2A, the transmission sound axis AX1 is shown by a solid line arrow, and the reception sound axis AX2 is shown by a dashed-dotted line arrow. In the case of the example shown in FIG. 2B, as described above, the propagation path of the ultrasonic beam U is refracted at the refraction angle β at the interface between the object E and the fluid F. Therefore, the transmission sound axis AX1 is bent (refracted) as shown by the solid arrow in FIG. 2B. In this case, the position of the coaxially disposed receiving probe 140 indicated by the broken line is located on the transmission acoustic axis AX1, and is therefore a position where the eccentric distance L is zero. As described above, even if the ultrasonic beam U is refracted, the eccentric receiving probe 120 is arranged so that the distance between the transmitting acoustic axis AX1 and the receiving acoustic axis AX2 is L. In the example shown in FIG. 1, the transmitting probe 110 is installed in the normal direction on the surface of the object to be inspected E, so the eccentric distance L is as shown in FIG. 2A.

The eccentric distance L is set at a position such that the signal intensity at the defective portion D of the object E to be inspected is greater than the received signal at the healthy portion N. This point will be discussed later.

FIG. 3 is a schematic cross-sectional view showing the structure of the transmitting probe 110. In FIG. 3, only the outline of the emitted ultrasonic beam U is shown for the sake of simplicity, but in reality, the entire area of the probe surface 114 is covered, and the direction of the normal vector of the probe surface 114 is A large number of ultrasonic beams U are emitted.

Transmitting probe 110 is configured to focus ultrasound beam U. Thereby, minute defects D in the object E to be inspected can be detected with high precision. The reason why the minute defective portion D can be detected will be described later. The transmission probe 110 includes a transmission probe housing 115, and includes a backing 112, a vibrator 111, and a matching layer 113 inside the transmission probe housing 115. An electrode (not shown) is attached to the vibrator 111, and the electrode is connected to the connector 116 by a lead wire 118. Furthermore, the connector 116 is connected to a power supply device (not shown) and the control device 2 by a lead wire 117.
In this specification, the probe surface 114 of the transmitting probe 110 or the receiving probe 121 is defined as the surface of the matching layer 113 when the matching layer 113 is provided, and the surface of the transducer 111 when the matching layer 113 is not provided. It is defined as That is, the probe surface 114 is a surface that emits the ultrasonic beam U in the case of the transmitting probe 110, and is a surface that receives the ultrasonic beam U in the case of the receiving probe 121.

FIG. 4A is a received waveform from the eccentrically placed receiving probe 120, and is a diagram showing the received waveform at a healthy part N of the subject E. FIG. 4B is a received waveform from the eccentrically placed receiving probe 120, and is a diagram showing the received waveform at the defective portion D of the object E to be inspected. FIG. 4B shows a received signal when the transmitting probe 110 is placed at the xy coordinate position of a cavity (defect part D) with a width of 2 mm provided in the object E to be inspected. Note that in FIGS. 4A and 4B, time indicates the elapsed time after the burst wave is applied to the transmission probe 110, and a stainless steel plate with a thickness of 2 mm was used as the object E to be inspected. A burst wave with a frequency of 800 KHz was applied to the transmitting probe 110. More specifically, a burst wave composed of 10 sine waves was applied to the test object E at regular intervals.

In FIG. 4A, no significant signal is observed, whereas in FIG. 4B, a significant signal is observed 90 microseconds after the burst wave is applied to transmit probe 110. The delay of 90 microseconds until this significant signal is observed is because it takes time from the emission of the ultrasonic beam U to the arrival of the scattered wave U1 to the eccentrically arranged receiving probe 120. Specifically, while the speed of sound in the air is 340 (m/s), it is around 6000 (m/s) in the stainless steel that makes up the object E, so a delay of 90 microseconds occurs. .

FIG. 5 is a diagram illustrating an example of a plot of signal strength data. In this example, the transmitting probe 110 and the eccentrically placed receiving probe 120 are scanned in the x-axis direction for a defective portion D with a width of 2 mm, and a signal is extracted from the received signal at the x-axis position (the received signal shown in FIG. 4B). Intensity data (signal amplitude for each scanning position) is plotted. In this embodiment, the signal strength data was extracted by extracting the Peak To Peak value of the received signal shown in FIG. 4B, that is, the difference between the maximum value and the minimum value in an appropriate time domain. As another example of the method for extracting signal strength data, the received signal shown in FIG. 4B may be converted into frequency components by signal processing such as short-time Fourier transform, and the strength of the appropriate frequency component may be extracted. Furthermore, a correlation function may be calculated as the signal strength data using an appropriate reference wave as a reference. In this manner, signal strength data is obtained corresponding to each scanning position of the transmitting probe 110.

In the plot of signal intensity data shown in FIG. 5, the 2 mm wide cavity (defect D) corresponds to the symbol D1 in FIG. While the signal is at a noise level in the healthy part N (parts other than code D1) of the object E to be inspected, the received signal is significantly larger in the position where there is an internal defective part D (code D1). I understand.

Therefore, the eccentricity distance adjusting unit 105 adjusts the eccentricity distance L so that the received signal strength at the eccentrically arranged receiving probe 120 when entering the defective part D is greater than the receiving signal strength when entering the healthy part N. Adjustment is preferred. By doing so, the defective portion D can be detected based on the received signal strength. Such an eccentric distance L is, for example, the distance between the receiving acoustic axis AX2 of the eccentrically arranged receiving probe 120 and the transmitting acoustic axis AX1 of the transmitting probe 110, which are arranged at a position where the scattered waves U1 (FIG. 6B) can be received. The eccentric distance adjustment section 105 is configured by, for example, an actuator, a motor, etc., although none of them are shown.

Moreover, it is preferable that the eccentricity distance adjustment unit 105 adjusts the eccentricity distance L to a distance at which no received signal other than noise is detected when the healthy part N is irradiated. That is, it is preferable that the eccentricity distance adjusting section 105 sets the eccentricity distance L so that no significant received signal is output in the healthy part N of the subject E. By doing so, the S/N ratio can be increased, the defective portion D can be determined from the location where a received signal other than noise is detected, and the defective portion D can be detected.

The eccentric distance L can be determined using, for example, a standard sample that is made of the same material as the object to be inspected E and has a defective portion D inside. Then, the eccentric distance L can be determined based on the position where the defective portion D of the standard sample is irradiated with the ultrasonic beam U and the ultrasonic beam U or the scattered wave U1 can be received.

When the transmitting probe 110 is scanned in one dimension only in the x-axis direction, a graph of signal strength data shown in FIG. 5 is displayed on the display device 3. In the case where the scanning direction of the transmitting probe 110 is two-dimensional in the x-axis direction and the y-axis direction, the position of the defective portion D is shown as a two-dimensional image by plotting the signal intensity data, which is displayed on the display device 3. Is displayed.

FIG. 6A is a diagram illustrating a propagation path of the ultrasound beam U in this embodiment, and shows a case where the ultrasound beam U is incident on a healthy part N. FIG. 6B is a diagram showing a propagation path of the ultrasonic beam U in this embodiment, and shows a case where the ultrasonic beam U is incident on the defective portion D.

As shown in FIGS. 6A and 6B, the ultrasonic beam U emitted from the transmitting probe 110 is incident on the object E to be inspected. As shown in FIG. 6A, when the ultrasound beam U is incident on the healthy part N, the ultrasound beam U passes through so as to converge toward the transmission sound axis AX1. Therefore, no reception signal is observed in the eccentrically arranged receiving probe 120, which is arranged with the eccentric distance L maintained. On the other hand, as shown in FIG. 6B, when the ultrasonic beam U is incident on the defective part D, the ultrasonic beam U is scattered at the defective part D, and the scattered wave U1 is transmitted to the eccentrically installed receiving probe. It is received at 120. Therefore, a significant received signal is observed.

In this way, the scattered waves U1 scattered by the defective portion D in the inspected object E are observed by the eccentrically arranged receiving probe 120. Therefore, the received signal at the defective part D is larger than the received signal at the healthy part N. That is, it is determined that the defective portion D exists at a position where the signal is large. Therefore, it is preferable that the eccentricity distance adjusting unit 105 adjusts the eccentricity distance L to a distance at which the scattered waves U1 generated by the scattering of the irradiated ultrasonic beam U at the defective part D of the inspected object E can be received. . By doing so, the scattered wave U1 specific to the defective portion D can be detected, and the detection accuracy of the defective portion D can be improved.

Preferably, the eccentric distance L is a length that allows selective reception of only the scattered waves U1 without receiving the ultrasonic beam U emitted from the transmitting probe 110. Thereby, the signal-to-noise ratio can be increased, and the detection performance of the defective portion D, particularly the detection sensitivity, can be improved. Here, "high detection sensitivity" means that a smaller defective portion D can be detected than in the conventional method. That is, the lower limit of the size of the detectable defective portion D is smaller than that of the conventional method.

Here, a conventional ultrasonic inspection method will be described as a comparative example.

FIG. 7A is a diagram showing a propagation path of an ultrasound beam U in a conventional ultrasound inspection method, and is a diagram showing the time of incidence on a healthy part N. FIG. 7B is a diagram showing the propagation path of the ultrasonic beam U in the conventional ultrasonic inspection method, and is a diagram showing the time of incidence on the defective part D. In the conventional ultrasonic inspection method, for example, as described in Patent Document 1, a receiving probe 140 is coaxially arranged as a transmitting probe 110 and a receiving probe 121 so that a transmitting sound axis AX1 and a receiving sound axis AX2 coincide with each other. is placed.

As shown in FIG. 7A, when the ultrasonic beam U is incident on the healthy part N of the object to be inspected E, the ultrasonic beam U passes through the object to be inspected E and reaches the coaxially arranged receiving probe 140. Therefore, the received signal becomes larger. On the other hand, as shown in FIG. 7B, when the ultrasonic beam U is incident on the defective portion D, the received signal decreases because the defective portion D blocks the ultrasonic beam U from passing through. In this way, the defective portion D is detected by the decrease in the received signal. This is as shown in Patent Document 1.

Here, as shown in FIGS. 7A and 7B, the reception signal is reduced by blocking the transmission of the ultrasonic beam U at the defective portion D, and the method of detecting the defective portion D is herein referred to as the “blocking method.” ” I will call it. On the other hand, the inspection method for detecting the scattered waves U1 at the defective portion D as in this embodiment will be referred to as a "scattering method."

FIG. 8 is a diagram showing a plot of signal intensity data in a conventional ultrasonic inspection method. This figure shows the ultrasonic inspection method using the blocking method shown in FIGS. 7A and 7B, that is, the arrangement in which the transmitting sound axis AX1 and the receiving sound axis AX2 are aligned, which was used in FIG. 5 above. It is a signal intensity graph obtained by inspecting an object to be inspected E having the same defective portion D as the object to be inspected. In FIG. 8, a portion D1 corresponds to the defective portion D. In FIG.

In FIG. 8, a decrease in the signal is observed at the center position of the defective portion D (position 0 mm), but the amount of decrease is small. This is considered to be due to the fact that in the defect portion D, which is smaller in size than the ultrasonic beam U, a large amount of the ultrasonic beam U is transmitted around the defect portion D. For this reason, in the blocking method in which the transmission acoustic axis AX1 and the reception acoustic axis AX2 are made coincident, it is difficult to detect a signal change originating from the defective portion D, and the detection sensitivity is low.

On the other hand, by shifting the transmitting sound axis AX1 and the receiving sound axis AX2, out of the signal intensity received by the eccentrically placed receiving probe 120, the The signal of the sound wave beam U can be reduced. Thereby, the amount by which the signal intensity due to the defective portion D is reduced is relatively increased, and the detection performance of the defective portion D, particularly the detection sensitivity, can be improved. Among them, as shown in FIG. 5 above, according to the configuration using the scattering method suitable for this embodiment, it is found that the position of the defective portion D can be clearly detected when compared with the results shown in FIG. 8 using the blocking method. In other words, when comparing the reception result shown in FIG. 8, which is a comparative example, and the reception result of the method according to the present embodiment shown in FIG. 5, the method according to the present embodiment shown in FIG. 5 obtains a higher SN ratio. .

The reason why the scattering method of this embodiment can obtain a high S/N ratio will be explained with reference to FIGS. 9A and 9B.

FIG. 9A is a diagram showing the interaction between the defective part D and the ultrasonic beam U in the inspected object E, and shows how the direct ultrasonic beam U (hereinafter referred to as "direct wave U3") is received. FIG. The direct wave U3 will be described later. FIG. 9B is a diagram showing the interaction between the defective part D and the ultrasonic beam U within the inspected object E, and is a diagram showing how the scattered waves U1 are received. Here, a case will be considered in which the size of the defective portion D is smaller than the width of the ultrasonic beam U (hereinafter referred to as beam width BW). The beam width BW here is the width of the ultrasonic beam U when it reaches the defective portion D.

Furthermore, since FIGS. 9A and 9B schematically show the shape of the ultrasonic beam U in a minute area near the defective part D, the ultrasonic beam U is drawn in parallel, but in reality it is converged. This is an ultrasonic beam U. Further, the position of the receiving probe 121 in FIGS. 9A and 9B is a conceptual position for easy explanation, and the position and shape of the receiving probe 121 are not accurately scaled. That is, when considering the shapes of the defective portion D and the ultrasonic beam U on an enlarged scale, the receiving probe 121 is located at a position further away from the position shown in FIGS. 9A and 9B in the vertical direction of the drawing. Here, the receiving probe 121 means the coaxially arranged receiving probe 140 in FIG. 9A and the eccentrically arranged receiving probe 120 in FIG. 9B.

The ultrasonic beam U has a certain finite width near the defective portion D even if it is converged and incident. This is defined as the beam width BW at the position of the defective portion D. Incidentally, FIGS. 9A and 9B show a case where the beam width BW at the position of the defective part D is wider than the size of the defective part D.

FIG. 9A is a diagram showing a case of a blocking method in which the transmission sound axis AX1 and the reception sound axis AX2 are made coincident. If the defective portion D is smaller than the beam width BW, part of the ultrasonic beam U is blocked, so the received signal decreases, but does not become zero. For example, when the cross-sectional area of the defective portion D is 20% of the beam cross-sectional area defined by the beam width BW, the received signal decreases by approximately 20%, making it difficult to detect the defective portion D. That is, in the case shown in FIG. 9A, the received signal decreases by only 20% at the location where the defective portion D exists (see FIG. 8).

FIG. 9B is a diagram illustrating a preferred method of this embodiment, that is, a scattering method. In the scattering method, when the ultrasonic beam U does not hit the defective portion D, the ultrasonic beam U does not enter the eccentric receiving probe 120, so the received signal is zero. As shown in FIG. 9B, even when a part of the ultrasonic beam U hits the defective part D, the scattered wave U1 is observed by the eccentric receiving probe 120. Easy to detect. That is, if the defective part D does not exist, the received signal becomes zero, and if the defective part D exists, even if it is minute, the received signal becomes non-zero. Therefore, it becomes possible to increase the SN ratio (see FIG. 5).

In this way, according to the method (scattering method) according to this embodiment, a defective portion D smaller than the beam width BW can be detected with high sensitivity. Here, "can be detected with high sensitivity" means that it is possible to detect a smaller defect D than the conventional method. That is, the lower limit of the size of the detectable defective portion D is smaller than that of the conventional method.

Further, as shown in FIG. 9A, in the blocking method, the defective portion D is determined based on the amount of decrease from the received signal amount corresponding to the healthy portion N as a reference. Therefore, it is preferable that the received signal in the healthy part N has a constant value. However, the intensity of the ultrasonic waves propagating in the gas G, especially in the fluid F, reaching the receiving probe 121 is extremely low compared to the ultrasonic waves propagating in the liquid W (FIG. 17). Therefore, it is preferable to amplify the received signal with a high amplification factor (gain). Therefore, a highly accurate signal amplification circuit is preferable to keep the gain constant. On the other hand, in the scattering method according to the present embodiment, as shown in FIG. 5, the signal is almost zero in the healthy part N, and the signal is observed in the defective part D, so the requirement for gain stability of the signal amplification circuit is satisfied. can be made smaller. However, in FIG. 5 above, the signal strength value is raised by the offset value.

Further, in this embodiment, a positive image is obtained. That is, in the scattering method, no signal is generated in the healthy portion N, or the signal is small even if it is generated, and a signal is newly generated or the signal becomes large in the defective portion D. In other words, a positive image of the defective portion D is obtained. On the other hand, in the blocking method, the signal is large in the healthy part N and decreases in the defective part D. In other words, a negative image of the defective portion D is obtained.

FIG. 10 is a functional block diagram of the control device 2. As shown in FIG. The control device 2 includes a transmission system 210, a reception system 220, a data processing section 201, a scan controller 204, a drive section 202, and a position measurement section 203.

The transmission system 210 is a system that generates a voltage to be applied to the transmission probe 110. The transmission system 210 includes a waveform generator 211 and a signal amplifier 212. A waveform generator 211 generates a burst wave signal. The generated burst wave signal is then amplified by the signal amplifier 212. The voltage output from the signal amplifier 212 is applied to the transmission probe 110.

The receiving system 220 is a system that detects the received signal output from the eccentrically arranged receiving probe 120. The signal output from the eccentric receiving probe 120 is input to the signal amplifier 222 and amplified. The amplified signal is input to the waveform analysis section 221. The waveform analysis unit 221 generates signal strength data (FIG. 5) from the received signal. The generated signal strength data is sent to the data processing section 201.

The reception system 220 includes a phase extraction section 231. The output signal of the signal amplifier 222 is input to the phase extractor 231 . The phase extraction unit 231 extracts phase information of the signal of the ultrasound beam U (scattered wave U1) received by the eccentric receiving probe 120. The extracted phase information is sent to the phase change amount calculation unit 232 of the data processing unit 201.

The phase of a signal is the delay time from when the ultrasound beam U is emitted from the transmitting probe 110 until it reaches a specific position of the received signal. The specific position of the received signal represents a characteristic position of the received signal from which the delay time can be easily calculated. For example, if a burst wave of 10 waves is used, this is the position of the third wave.

Furthermore, the delay time within the fundamental period of the signal may be used as the phase of the signal. The fundamental period of a signal is the reciprocal of the fundamental frequency f0. For example, when using a burst wave with a fundamental frequency f0 = 800 kHz, the fundamental period is 1.25 μs. The phase extraction unit 231 calculates where a specific position of the received signal, for example, a zero crossing point, is located in the fundamental period. In this embodiment, the phase extraction unit 231 calculates the phase within the basic period by calculating the remainder when the delay time is divided by the basic period T0 of the signal.

The data processing section 201 includes a phase change amount calculation section 232. The phase change amount calculation unit 232 receives phase information as an input signal, and also receives scanning position information from the scan controller 204. Using these two pieces of information, the phase change amount calculation unit 232 calculates the phase change amount of the phase information extracted by the phase extraction unit 231 regarding the scanning position (the phase change amount for each scanning position). This amount of change corresponds to the spatial differential amount of the phase information of the signal with respect to the scanning position.

"Amount of phase change related to scanning position" includes not only the amount of change (spatial differential amount), but also the signal amount (amount of change) that represents the change in the magnitude of the amount of change (spatial differential amount), such as its square value and absolute value. Also included. By scanning on the xy two-dimensional plane and calculating the amount of change with respect to this two-dimensional scanning position (x, y), an image in which the contour of the defective portion D can be easily grasped can be obtained.

The method of calculating the amount of change in phase information in the phase change amount calculation unit 232 includes, for example, calculation processing by a CPU (central processing unit) or a microcomputer (microcontroller), digital signal processing by an FPGA (field-programmable gate array), etc. Including signal processing using analog circuits.

In this way, the phase extraction section 231 and the phase change amount calculation section 232 extract the phase change of the signal at each scanning position in the x-axis direction and the y-axis direction, and calculate the phase change amount regarding the scanning position. Signal changes due to differences in scanning position are explained below.

FIG. 11 is a diagram schematically showing changes in the received signal of the eccentrically arranged receiving probe 120 at each scanning position in the x-axis direction. The vertical broken line is the location of the defective portion D, and the width of the defective portion D is WD. For reference, a graph G1 shows the signal amplitude when the coaxial receiving probe 140 based on the transmission method is installed. Graph G2 shows the signal amplitude of the signal received by the eccentric receiving probe 120, and is the output signal of the waveform analysis section 221. In both graphs G1 and G2, the signal amplitude becomes large near the defective portion D, indicating that the defective portion D can be detected.

However, in both graphs G1 and G2, the width of the signal is wider than WD, which is the size (width) of the defective portion D. The reason for this is that the beam size of the ultrasound beam U is large. That is, since the scattered wave U1 is generated even when a portion of the ultrasonic beam U is irradiated onto the defective portion D, the signal amplitude of the scattered wave U1 in the vicinity of the defective portion D gradually increases. Therefore, the signal amplitude becomes wider than the actual size of the defective portion D. This corresponds to a state in which, when displayed on the display device 3, the size of the defective portion D is apparently larger than it actually is, and the resolution is lowered. Therefore, based only on the graphs G1 and G2, the resolution of the image displayed on the display device 3 and showing the outline of the defective portion D may decrease.

The graph G3 is a plot of the phase of the signal of the scattered wave U1, and is the output signal of the phase extractor 231 (FIG. 10). It can be seen that the phase signal of the scattered wave U1 (FIG. 6B) changes sharply at the position of the defective portion D (FIG. 6B). The reason for this will be described later with reference to FIGS. 12A to 12C. Graph G4 is a plot of the phase change amount of the phase signal of the scattered wave U1 with respect to the scanning position in the x-axis direction, and is an output signal of the phase change amount calculation unit 232 (FIG. 10). Graph G4 corresponds to a signal obtained by spatially differentiating the phase signal of scattered wave U1 with respect to the scanning position in the x-axis direction. Further, graph G5 is a plot of the values of graph G4 squared. Based on the graphs G4 and G5, it can be seen that a signal corresponding to the contour of the defective portion D, that is, a high-resolution image showing the contour of the defective portion D is obtained. Therefore, by comparing the graph G2 with the graphs G3 to G5, it can be seen that the defective portion D can be detected with high resolution by calculating the amount of phase change in the phase of the signal of the scattered wave U1 with respect to the scanning position.

FIG. 12A is a diagram showing a scanning position where the ultrasonic beam U does not enter the defective portion D. FIG. 12B is a diagram showing a scanning position where the ultrasonic beam U is incident on the defective portion D, but the transmission sound axis AX1 does not enter the defective portion D. FIG. 12C is a diagram showing a scanning position where the ultrasonic beam U enters the defective portion D and the transmission acoustic axis AX1 enters the defective portion D. The reason why the phase of the scattered wave U1 changes sharply at the position of the defective portion D is presumed to be due to the following reason, according to the study conducted by the present inventor.

During scanning at the scanning position (x1) where the ultrasonic beam U does not enter the defective portion D (FIG. 12A), the scattered waves U1 are not generated, so the signal amplitudes shown in the graphs G1 and G2 of FIG. 11 do not change. However, when scanning at a scanning position (x2) where the ultrasound beam U is incident on the defective part D but the transmission sound axis AX1 does not enter the defective part D (Fig. 12B), a part of the ultrasound beam U enters the defective part D. Scattered waves U1 are generated even if only the incident light is incident. Therefore, as shown in the graphs G1 and G2 of FIG. 11, a change is observed in the signal amplitude. However, as shown in graphs G3 to G5 in FIG. 11 above, the phase does not change. This is considered to be because the eccentric receiving probe 120 receives reception components including the scattered waves U1 and the ultrasound beams U from various directions, and as a result of these being mixed, it becomes difficult to confirm the change in phase.

As shown in FIG. 12C, at the scanning position (x3) where the ultrasound beam U enters the defective part D and the transmission sound axis AX1 enters the defective part D, the graphs G3 to G5 in FIG. The phase changes noticeably. This is considered to be because the transmission acoustic axis AX1 of the ultrasonic beam U is incident on the defective portion D, so that the ultrasonic beam U is incident on the defective portion D in a state suitable for scattering at the defective portion D. This is considered to be because the eccentrically placed receiving probe 120 receives a received component that includes most of the scattered waves U1, causing a significant change in phase.

In this way, when the transmitted acoustic axis AX1 of the ultrasonic beam U is irradiated onto the defective part D, that is, when most of the received components at the eccentrically arranged receiving probe 120 are scattered waves U1, the phase of the scattered waves U1 is Changes can be clearly seen. Therefore, the position of the defective portion D can be determined based on the phase change of the scattered wave U1.

Returning to FIG. 10, the data processing unit 201 processes the acquired information into a desired form, such as converting information regarding the defective portion D of the inspected object E into an image or detecting the presence or absence of the defective portion D. do. Note that the images and information generated by the data processing unit 201 are displayed on the display device 3.

The scan controller 204 drives and controls the transmission probe scanning unit 103 and reception probe 104 shown in FIG. Drive control of the transmission probe scanning section 103 and the reception probe 104 is performed through the drive section 202. Further, the scan controller 204 measures position information (each scanning position in the x-axis direction and the y-axis direction; xy coordinates) of the transmitting probe 110 and the eccentrically arranged receiving probe 120 via the position measuring unit 203.

Based on the positional information of the transmitting probe 110 and the eccentrically arranged receiving probe 120 received from the scan controller 204, the data processing unit 201 plots signal strength data at each position, converts it into an image, and displays the image on the display device 3. As described above, the signal strength data acquired in the defective part D is larger than the signal strength data in the healthy part N. Therefore, by plotting the signal strength data against the scanning position of the transmitting probe 110, an image showing where the defective portion D is located can be obtained. The display device 3 displays this image.

The data processing unit 201 also generates an image by plotting the output signal from the phase change amount calculation unit 232 with respect to the scanning position of the transmission probe 110, and displays it on the display device 3. As will be described later, the output signal from the phase change amount calculation unit 232 provides an image corresponding to the contour image of the defective portion D.

The two images, the image generated by the signal strength data and the image output by the phase change amount calculation unit 232, may be superimposed and displayed as one image. The superimposed image is an image that is displayed by superimposing the second image on the first image. At this time, the first image and the second image are superimposed so that the scanning positions of the two images correspond. For example, it is preferable to display the image of the signal strength data as a black and white image with gradation, and display the image output by the phase change amount calculation unit 232 in a different color such as yellow in a superimposed manner.

FIG. 13 is a diagram showing the hardware configuration of the control device 2. As shown in FIG. The control device 2 includes a memory 251 such as a RAM (Random Access Memory), a CPU (Central Processing Unit) 252, a storage device 253 such as a ROM (Read Only Memory), an HDD (Hard Disk Drive), and a NIC (NIC). Network Interface Card) etc. The communication device 254, I/F (Interface) 255, and the like are configured.

In the control device 2, a predetermined control program stored in the storage device 253 is loaded into the memory 251 and executed by the CPU 252. As a result, the data processing section 201, position measurement section 203, scan controller 204, phase extraction section 231, phase change amount calculation section 232, etc. shown in FIG. 3 are realized.

FIG. 14 is a flowchart showing the ultrasonic testing method of the first embodiment. The ultrasonic inspection method of the first embodiment can be executed by the above-mentioned ultrasonic inspection apparatus Z, and will be described with reference to FIGS. 1 and 10 as appropriate. In the ultrasonic inspection method of the first embodiment, an object to be inspected E is inspected by making an ultrasonic beam U incident on the object to be inspected E (FIG. 1) via a gas G (FIG. 1). Although this ultrasonic inspection method will be described with reference to an embodiment using gas G as fluid F, this ultrasonic inspection method is also effective for an embodiment using liquid W (FIG. 17) as fluid F. Needless to say.

First, in response to a command from the control device 2 (FIG. 10), a discharge step S101 is performed in which the ultrasonic beam U (FIG. 6B) is discharged from the transmission probe 110 (FIG. 1). Subsequently, a receiving step S102 is performed in which the eccentric receiving probe 120 (FIG. 1) receives the ultrasonic beam U (scattered wave U1 in this example).

Thereafter, a phase extraction step S103 is performed to extract phase information of the signal based on the signal (for example, a waveform signal) of the ultrasound beam U (scattered wave U1 in this example) received by the eccentric receiving probe 120. The phase extraction step S103 is performed by the phase extraction section 231 (FIG. 10), and the phase extraction section 231 extracts (generates) signal phase information from the received signal shown in FIG. 4B, for example.

The output signal of the phase extraction section 231 is input to the phase change amount calculation section 232 (FIG. 10), and a phase change amount calculation step S104 is performed to calculate the phase change amount with respect to the scanning position of the extracted phase information. In the phase change amount calculation step S104, the amount of phase change per unit length change of the scan position is calculated with reference to the scan position information (coordinate position) sent from the scan controller 204 (FIG. 10). Phase change amount calculation step S104 is performed by the phase change amount calculation section 232.

Scanning position information of the transmitting probe 110 and the eccentrically placed receiving probe 120 is transmitted from the position measuring unit 203 (FIG. 10) to the scan controller 204 (FIG. 10). The data processing unit 201 (FIG. 10) plots the amount of phase change at each scanning position with respect to the scanning position information of the transmitting probe 110 acquired from the scan controller 204. In this way, for example, the graphs G3 to G5 shown in FIG. 11 are obtained, and the amount of phase change is visualized.

Note that FIG. 11 above shows the case where the scanning position information is one-dimensional (one direction), and when the scanning position information is two-dimensional (x, y), the outline of the defective part D can be determined by plotting the amount of phase change. The information is shown as a two-dimensional image, which is displayed on the display device 3.

After the phase change amount calculation step S104, a shape display step S105 is performed. The shape display step S105 determines whether the phase change amount related to the scanning position of the phase information generated in the phase change amount calculation step S104 is equal to or larger than a preset threshold value, thereby detecting defects in the inspected object E. The shape of section D is displayed on the display device 3, for example. The display device 3 displays, for example, an image depicting the scanning position exceeding the threshold value. This is more preferable since it is possible to clearly show the outline of the defective portion D. Shape display step S105 is performed by the data processing unit 201.

The data processing unit 201 determines whether scanning is completed (step S111). If the scanning is completed (Yes), the control device 2 ends the process. If the scanning is not completed (No), the data processing unit 201 outputs a command to the driving unit 202 (FIG. 10) to move the transmitting probe 110 and the eccentrically arranged receiving probe 120 to the next scanning position (step S112), the process returns to the discharge step S101.

According to the ultrasonic inspection apparatus Z and the ultrasonic inspection method described above, the detection performance of the defective part, for example, the resolution of the displayed image, can be improved, and the position of the defective part D can be easily grasped.

Note that the fluid F may be a gas G (FIG. 1) as described above, or a liquid W (FIG. 17) as described later. However, when a gas G such as air is used as the fluid F, a more preferable effect is provided for the following reasons.

The amount of attenuation of ultrasonic waves in the gas G is greater than that in the liquid W. It is known that the amount of attenuation of ultrasonic waves in gas G is proportional to the square of the frequency. Therefore, the upper limit for propagating ultrasonic waves in gas G is about 1 MHz. In the liquid W, even ultrasonic waves of 5 MHz to several tens of MHz propagate, so the usable frequency in the gas G is smaller than that in the liquid W.

Generally, as the frequency of ultrasound becomes lower, it becomes difficult to converge the ultrasound beam U. Therefore, the 1 MHz ultrasonic beam propagating in the gas G has a convergable beam diameter larger than that of the ultrasonic beam U in the liquid W. For this reason, the resolution of the amplitude image detected by the coaxial receiving probe 140 (FIG. 2A) may be low when the gas G is used as the fluid F.

However, according to the present disclosure, even when the gas G is used as the fluid F, the amount of phase change (spatial differential amount) of the scattered wave U1 detected by the eccentrically arranged receiving probe 120 with respect to the scanning position is An image close to the contour image of D is obtained. Therefore, high resolution can be obtained not only when liquid W is used as fluid F but also when gas G is used. In this way, the effects of the present disclosure are even higher when gas G is used as the fluid F.

(Second embodiment)
FIG. 15 is a diagram schematically showing the configuration of an ultrasonic testing apparatus Z according to the second embodiment. In the second embodiment, the scanning measurement device 1 includes a coaxially placed receiving probe 140 in addition to the eccentrically placed receiving probe 120 . Here, the coaxially arranged receiving probe 140 is the receiving probe 121 arranged at a position where the eccentric distance L is zero. That is, the receiving acoustic axis AX2 of the coaxially arranged receiving probe 140 is the same as the transmitting acoustic axis AX1 of the transmitting probe 110.

FIG. 16 is a diagram showing the configuration of the control device 2 according to the second embodiment. The output signal of the eccentrically arranged receiving probe 120 is input to the receiving system 220a, and phase information is extracted by a phase extraction section 231 therein. The phase information is input to the data processing section 201, and a phase change amount calculation section 232 therein calculates the amount of phase change regarding the scanning position of the phase of the signal. This amount of phase change corresponds to the contour of the defective portion D, as described above. The phase change amount calculation unit 232 generates contour image data.

The output signal of the coaxial receiving probe 140 is input to the receiving system 220b, and after being amplified by the signal amplifier 223, the waveform analysis section 221 extracts the amplitude information of the signal. Since the receiving acoustic axis AX2 of the coaxially arranged receiving probe 140 is installed so as to coincide with the transmitting acoustic axis AX1 of the transmitting probe 110, the amount of transmission of the ultrasound beam U is blocked at the defective part D. The amplitude of the received signal of the receiving probe 140 decreases at the defective portion D. This is a conventional defect detection method in "blocking mode". The output signal of the waveform analysis section 221 of the reception system 220b to which the coaxial arrangement reception probe 140 is connected is input to the data processing section 201, and the amplitude image generation section 224 therein generates amplitude image data.

With the above procedure, contour image data is generated from the signal of the eccentrically placed receiving probe 120, and amplitude image data is generated from the signal of the coaxially placed receiving probe 140. These two image data are input to the image composition section 225 of the data processing section 201. The image synthesis unit 225 synthesizes (superimposes) amplitude image data (first image) and contour image data (second image). As described above, the amplitude image data is an image of the defective portion D inside the inspected object E, which is generated by the amplitude image generation unit 224 based on the amplitude of the direct wave U3 (FIG. 9A) received by the coaxial receiving probe 140. It indicates the location. The contour image data indicates the contour of the defective portion D inside the object to be inspected E, which is generated by the phase change amount calculation unit 232 based on the phase change amount regarding the scanning position. The combined image is input to the display device 3 and displayed.

When observing a defect D smaller than the convergence size of the ultrasound beam U, the amplitude image data gives an image with a blurred outline, but the contour image data gives a sharp shape closer to the actual size of the defect D. Therefore, according to the second embodiment, there is an effect that the defective portion D can be imaged with higher resolution.

In the second embodiment, information (contour image data) from the phase change amount calculation unit 232 obtained from the signal received by the eccentrically arranged receiving probe 120, and information obtained from the signal received by the coaxially arranged receiving probe 140, The information (amplitude image data) from the amplitude image generation unit 224 was combined and displayed in a superimposed manner on the display device 3. However, in the present disclosure, the method of utilizing these two pieces of information, that is, the amount of phase change and the amplitude information, is not limited to combining two images.

Another embodiment of how to utilize these two pieces of information is described below. In the following embodiments, by appropriately combining the amount of phase change obtained from the signal received by the eccentrically arranged receiving probe 120 and the amplitude obtained from the signal received by the coaxially arranged receiving probe 140, the defect portion D with high resolution can be obtained. images can be generated and displayed.

As a first example of the method of combining these two signals, the output signal of the waveform analysis section 221 from the coaxially arranged receiving probe 140 is That is, when the amount of change in the amplitude signal exceeds a predetermined threshold value, it can be determined that the defective portion D exists at that scanning position. Information about the defective portion D determined in this way is displayed on the display device 3 as an image of the defective portion D together with scanning position information. This makes it possible to suppress the occurrence of false detection of the defective portion D even when a signal change occurs due to unintentional noise contamination or the like in calculating the phase change amount, which is the spatial change amount of the phase change.

In the second example, the output signal of the phase change amount calculation unit 232 is used as the contour information of the defective portion D, and the amplitude value of the received signal of the coaxially disposed receiving probe 140 is used to determine which of the images partitioned by the contour line. It is possible to determine which region corresponds to the position of the defective portion D. Based on the determination, a defect image is displayed on the display device 3. Thereby, the defective portion D can be displayed with high resolution.

(Third embodiment)
FIG. 17 is a diagram showing the configuration of an ultrasonic testing apparatus Z according to the third embodiment. In the third embodiment, the fluid F is a liquid W, which in the illustrated example is water. The ultrasonic inspection apparatus Z inspects the object to be inspected E by making an ultrasonic beam U incident on the object to be inspected E via a liquid W that is a fluid F. The object to be inspected E is placed below the liquid level L0 of the liquid W and is immersed in the liquid W. The ultrasonic inspection device Z includes a scanning measurement device 1, a control device 2, and a display device 3. Display device 3 is connected to control device 2 .

The scanning measurement device 1 scans and measures the ultrasonic beam U on the object E to be inspected, and includes a sample stage 102 fixed to a housing 101, on which the object E to be inspected is placed. placed. The object to be inspected E is made of any material. The object to be inspected E is, for example, a solid material, more specifically, for example, metal, glass, resin material, or the like. Further, the object to be inspected E has a defective portion D inside. The defective portion D is a cavity or the like. Examples of the defective portion D include a cavity, a foreign material different from the original material, and the like. In the object to be inspected E, a portion other than the defective portion D is referred to as a healthy portion N.

Since the defective part D and the healthy part N are made of different materials, the acoustic impedance is different between the two, and the propagation characteristics of the ultrasonic beam change. The ultrasonic inspection device Z observes this change and detects the defective portion D.

The scanning measurement device 1 includes a transmitting probe 110 that emits an ultrasonic beam U and an eccentrically arranged receiving probe 120. The transmitting probe 110 is installed in the housing 101 via the transmitting probe scanning unit 103, and emits an ultrasonic beam U. The eccentrically placed receiving probe 120 is a receiving probe 121 that is installed on the opposite side of the transmitting probe 110 with respect to the subject E and receives the ultrasound beam U. The eccentrically arranged receiving probe 120 has a receiving acoustic axis AX2 at a different position from the transmitting acoustic axis AX1 of the transmitting probe 110. The distance between the transmitting sound axis AX1 and the receiving sound axis AX2 is the eccentric distance L. The eccentrically arranged receiving probe 120 is installed in the housing 101 via the receiving probe scanning section 104.

Note that even when a liquid W such as water is used as the fluid F, among the receiving probes 121 (FIG. 18) that receive ultrasonic waves, those arranged at positions where the eccentric distance L is greater than or equal to zero are called eccentrically arranged receiving probes. 120, and a coaxial receiving probe 140 (FIG. 18) is defined as a coaxially arranged receiving probe 140 (FIG. 18). In other words, the reception probe 121 is a term that includes the eccentric reception probe 120 and the coaxial reception probe 140.

In the third embodiment, the eccentrically arranged receiving probe 120 is disposed offset from the transmitting probe 110 by an eccentric distance L in the x-axis direction in FIG. The eccentrically placed receiving probe 120 may be placed. Alternatively, the eccentric receiving probe 120 may be arranged at L1 in the x-axis direction and L2 in the y-axis direction (i.e., at the position (L1, L2) when the origin is the position of the transmitting probe 110 on the xy plane). .

In the third embodiment, as a preferable example, the eccentric receiving probe 120 receives scattered waves U1 (FIG. 6B) caused by scattering of the ultrasound beam U at the defective portion D. Since the scattered waves U1 are generated due to the presence of the defective portion D, the detection accuracy of the defective portion D can be further improved by detecting the scattered waves U1. In the following example, in order to simplify the explanation, the present embodiment will be described by taking as an example the eccentrically placed receiving probe 120 installed at a position where the scattered wave U1 can be received.

The eccentric distance L is set at a position such that the signal intensity at the defective portion D of the object E to be inspected is greater than the received signal at the healthy portion N. This point is similar to the first embodiment.

The control device 2 provided in the ultrasonic inspection apparatus Z of the third embodiment will be described with further reference to FIG. 10 above. Also in the third embodiment, the control device 2 includes a transmission system 210, a reception system 220, a data processing section 201, a scan controller 204, a drive section 202, and a position measurement section 203. The configuration and operation of the control device 2 are similar to those in the first embodiment.

The reception system 220 includes a phase extraction section 231. The output signal of the signal amplifier 222 is input to the phase extractor 231 . The phase extractor 231 generates the above phase information from the received signal. The generated phase information is sent to the data processing section 201.

The data processing section 201 includes a phase change amount calculation section 232. The phase change amount calculation unit 232 receives phase information as an input signal, and also receives scanning position information from the scan controller 204. Using these two pieces of information, the phase change amount calculating section 232 calculates the amount of phase change due to a change in the scanning position.

Similar to the first embodiment, the amount of phase change due to this change in scanning position corresponds to the contour information of the defective portion D. Therefore, by converting this amount of phase change into an image corresponding to the scanning position, it is possible to obtain a high-resolution image of the defective portion.

(Fourth embodiment)
FIG. 18 is a diagram showing the configuration of an ultrasonic testing apparatus Z according to the fourth embodiment. In the fourth embodiment, the scanning measurement device 1 includes a coaxially arranged receiving probe 140 in addition to the eccentrically arranged receiving probe 120. Here, the coaxially arranged receiving probe 140 is the receiving probe 121 arranged at a position where the eccentric distance L is zero. That is, the receiving acoustic axis AX2 of the coaxially arranged receiving probe 140 is the same as the transmitting acoustic axis AX1 of the transmitting probe 110.

Further, in the fourth embodiment, the fluid F is a liquid W, and the liquid W is, for example, water. The ultrasonic inspection apparatus Z of the fourth embodiment is controlled by, for example, the control device 2 shown in FIG. 16.

In the fourth embodiment, as in the second embodiment, amplitude image data (first image) based on the signal received by the coaxial receiving probe 140 is scanned based on the signal received by the eccentric receiving probe 120. The contour image data (second image) based on the amount of phase change related to the change in position is synthesized. The composition is performed by the image composition section 225 (FIG. 16). Thereby, the defective portion D can be detected with high resolution.

(Fifth embodiment)
FIG. 19 is a diagram showing the configuration of an ultrasonic testing apparatus Z in the fifth embodiment. In the fifth embodiment, a transmitting/receiving probe 119 is provided in place of the transmitting probe 110 of the ultrasonic inspection apparatus Z (FIG. 17) of the third embodiment. The transmitting/receiving probe 119 has the functions of the coaxially arranged receiving probe 140 (FIG. 18) in the fourth embodiment and the transmitting probe 110 (FIG. 17) in the third embodiment. Therefore, the transmitting/receiving probe 119 emits the ultrasonic beam U and receives reflected waves from the object to be inspected E (including the defective portion D).

FIG. 20 is a functional block diagram of the ultrasonic testing apparatus Z in the fifth embodiment. The transmitting/receiving probe 119 emits an ultrasonic beam U when an excitation pulse output from the transmitting system 210 of the control device 2 is applied. Thereafter, the connection destination of the transmitting/receiving probe 119 is immediately switched to the receiving system 220b of the control device 2. Switching is typically performed using a switch 235 within the control device 2. In the fifth embodiment, for example, the switch 235 is a relay element or a semiconductor analog switch.

The ultrasonic beam U (reflected wave) reflected at the defective portion D is detected by the transmitting/receiving probe 119. In the transmitting/receiving probe 119, the reflected acoustic wave is converted into an electrical signal, which is input to the receiving system 220b via the switch 235. The amplitude information of the reflected wave signal is extracted in the waveform analysis unit 221 in the reception system 220b, and the amplitude image generation unit 224 generates amplitude image data (first image) based on the amplitude of the direct wave received by the transmission/reception probe 119. do.

On the other hand, the signal detected by the eccentrically arranged receiving probe 120 is input to the receiving system 220a, and the phase information of the signal is extracted by the phase extraction section 231. By calculating the phase change amount regarding the scanning position of this phase information, the phase change amount calculation unit 232 generates contour image data (second image). The image synthesis unit 225 synthesizes and superimposes the amplitude image data and the contour image data, and outputs the result to the display device 3. In this way, the two combined images are displayed in a superimposed manner on the display device 3.

As described above, the shape of the defective portion D can be detected with higher resolution based on the amount of phase change in the phase of the scattered wave signal with respect to the scanning position. Therefore, the defective portion D can be imaged with higher resolution. Further, since the transmitting/receiving probe 119 has the functions of the transmitting probe 110 (FIG. 17) and the coaxially arranged receiving probe 140 (FIG. 18), the configuration of the scanning measurement device 1 can be simplified.

Moreover, the ultrasonic inspection apparatus Z according to the fifth embodiment can be realized by simply shifting the position of the coaxially disposed receiving probe 140 of the conventional blocking ultrasonic inspection apparatus by the eccentric distance L. In other words, the ultrasonic testing equipment that has been used up to now can be used, reducing installation costs.

(Sixth embodiment)
FIG. 21 is a diagram showing the relationship between the transmitting probe 110 and the eccentrically arranged receiving probe 120 in the ultrasonic testing apparatus Z according to the sixth embodiment. In the sixth embodiment, the convergence relationship between the transmitting probe 110 and the eccentrically placed receiving probe 120 will be described.

In the sixth embodiment, the convergence of the eccentrically arranged receiving probe 120 is made looser than the convergence of the transmitting probe 110. The propagation path of the scattered wave U1 changes somewhat depending on the depth of the defective portion D inside the object E to be inspected, the shape of the defective portion D, the inclination, and the like. Therefore, in the second embodiment, the convergence of the eccentric receiving probe 120 is made loose so that the eccentric receiving probe 120 can detect the scattered wave U1 even if the path of the scattered wave U1 changes.

The magnitude relationship of convergence is defined by the magnitude relationship of the beam incident areas T1 and T2 on the surface of the object E to be inspected. The beam incident areas T1 and T2 will be explained.

FIG. 22 is a diagram illustrating the relationship between the beam incident area T1 on the transmitting probe 110 and the beam incident area T2 on the eccentrically arranged receiving probe 120. The beam incidence area T1 of the transmitting probe 110 is the intersection area of the ultrasonic beam U emitted from the transmitting probe 110 on the surface of the object E to be inspected. In addition, the beam incidence area T2 of the eccentrically placed receiving probe 120 is the intersection area between the virtual ultrasonic beam U2 and the surface of the object to be inspected E, assuming that the ultrasonic beam U is emitted from the eccentrically placed receiving probe 120. be.

In addition, in FIG. 22, the path of the ultrasonic beam U is the path in the case where the object to be inspected E is not present. When there is an object to be inspected E, the ultrasonic beam U is refracted at the surface of the object to be inspected, so that the ultrasonic beam U propagates along a path different from the path shown by the broken line. Here, as shown in FIG. 22, the beam incidence area T2 of the eccentrically arranged receiving probe 120 on the subject E is larger than the beam incidence area T1 of the transmitting probe 110 on the subject E. By doing so, the convergence of the eccentrically arranged reception probe 120 can be made looser than the convergence of the transmission probe 110.

Furthermore, the focal length R2 of the eccentrically placed receiving probe 120 is longer than the focal length R1 of the transmitting probe 110. Even in this case, the convergence of the eccentrically arranged receiving probe 120 can be made looser than the convergence of the transmitting probe 110. At this time, the distances from the subject E to the transmitting probe 110 and the eccentrically placed receiving probe 120 are, for example, the same, but they do not have to be the same.

In this way, in the sixth embodiment, the convergence of the eccentrically placed receiving probe 120 is made looser than that of the transmitting probe 110. That is, the focal length R2 of the eccentrically arranged receiving probe 120 is set longer than the focal length R1 of the transmitting probe 110. As a result, the beam incident area T2 of the eccentrically arranged receiving probe 120 becomes wider, so that scattered waves U1 can be detected over a wider range. Thereby, even if the propagation path of the scattered wave U1 changes somewhat, the scattered wave U1 can be detected by the eccentrically arranged receiving probe 120. As a result, defective portions D can be detected over a wide range.

Further, the focal point of the eccentrically arranged receiving probe 120 is located closer to the transmitting probe 110 (in the illustrated example, above) than the focal point of the transmitting probe 110. By shifting the focus in this manner, the scattered waves U1 can be easily received by the eccentrically arranged receiving probe 120, and the scattered waves U1 can be easily detected.

Note that the non-convergent probe used in the first embodiment may be used as the eccentric receiving probe 120. Since the focal length R2 of a non-convergent probe is infinite, it is longer than the focal length R1 of the transmitting probe 110. That is, even in the case of the non-convergent eccentric receiving probe 120, the convergence of the eccentric receiving probe 120 is slower than that of the transmitting probe 110.

(Seventh embodiment)
FIG. 23 is a diagram showing an example of an eccentrically placed receiving probe 120 according to the seventh embodiment. FIG. 2 is a plan view of the ultrasonic inspection apparatus Z, when the transmitting probe 110 and the eccentrically arranged receiving probe 120 are viewed from the minus side of the z-axis. That is, FIG. 23 is a diagram seen from the eccentrically arranged receiving probe 120 side. In the third embodiment, the length b of the transducer 111 (FIG. 3) of the eccentrically arranged receiving probe 120 in the eccentric direction of the receiving acoustic axis AX2 with respect to the transmitting acoustic axis AX1 is in the direction along the surface of the object E to be inspected and It is longer than the length a in the direction perpendicular to the eccentric direction. Lengths a and b are characteristic lengths, and for a rectangular oscillator, they mean the length of the sides of the rectangle, and for an elliptical oscillator, they mean the length of the long or short axis of the ellipse. means.

By setting the aspect ratio of the eccentric receiving probe 120 in this way, even if the depth of the defective portion D changes and the arrival position of the scattered wave U1 changes, the scattered wave U1 can be detected by the eccentric receiving probe 120. .

The scattered wave U1 is scattered in the radial direction centering on the transmission acoustic axis AX1. Therefore, when the eccentrically arranged receiving probe 120 is arranged at the position shown in FIG. 23, the scattered waves U1 are scattered in the longitudinal direction of the eccentrically arranged receiving probe 120 (the direction in which "length b" extends). In other words, the extending direction of the "length b" is the direction in which the scattered wave U1 is radiated. Therefore, by increasing the value of "length b", it is possible to detect the scattered waves U1 scattered at the defect D at various depths. In other words, even if the depth of the defective portion D changes and the arrival position of the scattered wave U1 changes, the scattered wave U1 can be detected by the eccentric receiving probe 120.

There is no limit to the lengths a and b, and it is sufficient that length b is longer than length a, that is, 1 < b/a, but the upper limit is b/a (length b divided by length a). value) is, for example, 100 or less, preferably 50 or less.

Although FIG. 23 shows a rectangular parallelepiped (rectangular) eccentrically arranged receiving probe 120 as the eccentrically arranged receiving probe 120, the same effect can be obtained even if the eccentrically arranged receiving probe 120 is made into an ellipse shape and the major axis ratio and short axis ratio are set similarly. is obtained.

(Eighth embodiment)
FIG. 24 is a diagram showing the configuration of the scanning measurement device 1 of the ultrasonic inspection device Z according to the eighth embodiment. In the eighth embodiment, the scanning measurement device 1 includes an installation angle adjustment section 106 that adjusts the inclination of the eccentrically arranged receiving probe 120. Thereby, the strength of the received signal can be increased, and the SN ratio (Signal to Noise ratio) of the signal can be increased. The installation angle adjustment section 106 is configured by, for example, an actuator, a motor, etc., although neither is shown in the drawings.

Here, the angle θ formed by the transmitting sound axis AX1 and the receiving sound axis AX2 is defined as the receiving probe installation angle. In the case of FIG. 24, since the transmitting probe 110 is installed in the vertical direction, the transmitting sound axis AX1 is in the vertical direction. This is the angle formed with the normal line of the probe surface of the receiving probe 120. Then, the installation angle adjustment unit 106 tilts the angle θ toward the side where the transmission sound axis AX1 exists, and sets the angle θ to a value larger than zero. That is, the eccentrically arranged receiving probe 120 is arranged at an angle. Specifically, the eccentrically arranged receiving probe 120 is arranged at an angle such that 0°<θ<90°, and the angle θ is, for example, 10°, but is not limited thereto.

Further, the eccentric distance L when the eccentrically arranged reception probe 120 is arranged at an angle is defined as follows. An intersection C2 between the receiving sound axis AX2 and the probe surface of the eccentrically arranged receiving probe 120 is defined. Furthermore, an intersection C1 between the transmission acoustic axis AX1 and the probe surface of the transmission probe 110 is defined. The distance between the coordinate position (x4, y4) obtained by projecting the position of the intersection C1 onto the xy plane and the coordinate position (x5, y5) obtained by projecting the position of the intersection C2 onto the xy plane is defined as an eccentric distance L.

When the present inventor actually detected the defective portion D by arranging the eccentric receiving probe 120 at an angle as described above, the signal strength of the received signal increased three times compared to the case where θ=0. .

FIG. 25 is a diagram illustrating the reason why the effects of the eighth embodiment are produced. The scattered wave U1 propagates in a direction away from the transmission acoustic axis AX1. Therefore, as shown in FIG. 25, when the scattered wave U1 reaches the outside of the object E, it forms a non-zero angle α2 with respect to the normal vector of the surface of the object E. incident on . The angle of the scattered wave U1 emitted from the surface of the object E to be inspected has an angle β2, which is a non-zero emission angle, with respect to the normal direction of the surface of the object E to be inspected. The scattered wave U1 can be received most efficiently when the normal vector of the probe surface of the eccentrically arranged receiving probe 120 is made to match the traveling direction of the scattered wave U1. That is, by arranging the eccentric receiving probe 120 at an angle, the received signal strength can be increased.

Note that when the angle β2 of the ultrasonic beam U emitted from the object E to be inspected matches the angle θ formed by the transmitting sound axis AX1 and the receiving sound axis AX2, the receiving effect will be highest. However, even if the angle β2 and the angle θ do not completely match, the effect of increasing the received signal can be obtained, so as shown in FIG. You can.

Note that the scanning measurement device 1 (FIG. 24) is provided with an installation angle adjustment section 106, and the eccentric arrangement receiving probe 120 is installed by the installation angle adjustment section 106. The installation angle adjustment unit 106 can adjust the reception probe installation angle of the eccentrically arranged reception probe 120. Since the path of the scattered wave U1 changes somewhat depending on the material, thickness, etc. of the object to be inspected E, the optimal value of the installation angle of the eccentrically arranged receiving probe 120 also changes. Therefore, by making the reception probe installation angle adjustable by the installation angle adjustment section 106, the installation angle of the eccentric reception probe 120 can be adjusted appropriately according to the material, thickness, etc. of the object E to be inspected.

Further, in the eighth embodiment, the eccentric receiving probe 120 is arranged in an inclined state with respect to the horizontal plane, but the transmitting probe 110 may also be arranged in an inclined state. Alternatively, the transmitting probe 110 may be arranged so as to be inclined with respect to the horizontal plane, and the probe surface of the eccentrically arranged receiving probe 120 may be arranged so as to be parallel to the horizontal plane (xy plane). In either case, as shown in FIG. 2B above, the transmitting sound axis AX1 and the receiving sound axis AX2 are arranged in a shifted state.
Note that in order to obtain the effect of the tilted arrangement described in this embodiment, the angle θ (tilt angle) is set in the range of 0°<θ<90°. On the other hand, it goes without saying that in other embodiments of the present disclosure, θ may be 0°.

(Ninth embodiment)
FIG. 26 is a diagram showing the configuration of an ultrasonic testing apparatus Z according to the ninth embodiment. In the ninth embodiment, the eccentrically arranged receiving probe 120 includes a plurality of unit probes 120a. In the illustrated example, there are three unit probes 120a. The unit probes 120a are arranged at positions with different eccentric distances L (distances from the transmission sound axis AX1).

The path of the scattered wave U1 changes somewhat depending on the depth, shape, inclination, etc. of the defective portion D. For example, the scattering angle at the time of scattering (the angle formed by the scattered wave U1 with respect to the transmission acoustic axis AX1) is usually approximately the same. Therefore, the deeper the defective portion D is, the closer the scattered wave U1 is to the transmission acoustic axis AX1, and the shallower the defective portion D is, the farther the scattered wave U1 is from the transmission acoustic axis AX1. Therefore, information regarding the defective portion D (such as the depth of the defective portion D) can be obtained by using a plurality of unit probes 120a and using information about which position of the unit probe 120a receives the signal.

As the plurality of unit probes 120a, an array type probe 122 (FIGS. 28 and 29) in which a plurality of sound sensing elements 122a (FIGS. 28 and 29) are housed in one housing may be used. In this case, the unit probes 120a in FIG. 26 each correspond to a sound-sensing element, and they are housed in one housing. A sound sensing element is an element that converts ultrasonic waves into electrical signals. As the sound sensing element, a capacitive sound sensing element (CMUT, Capacitive Micro-machined Ultrasonic Transducer) or the like may be used in addition to a piezoelectric element.

FIG. 27 is a functional block diagram of the ultrasonic testing apparatus Z according to the ninth embodiment. The plurality of unit probes 120a are connected to respective receiving systems 220c, 220d, and 220e. The configuration of each receiving system 220c, 220d, and 220e is similar to the configuration of receiving system 220 shown in FIG. That is, each of the receiving systems 220c, 220d, and 220e includes a signal amplifier 222, a waveform analysis section 221, and a phase extraction section 231, as shown in FIG. 10 although not shown in FIG. Signals from each unit probe 120a are amplified by a signal amplifier 222 and input to a waveform analysis section 221 and a phase extraction section 231. The waveform analysis section 221 outputs the amplitude of the received signal (scattered wave U1), and the phase extraction section 231 outputs phase information of the received signal (scattered wave U1). Outputs from each of these receiving systems 220c, 220d, and 220e are input to the defect information determining section 205.

The defect information determination unit 205 is provided in the control device 2 and receives scattered waves U1 generated by scattering of the irradiated ultrasonic beam U at the defective portion D of the inspected object E from among the plurality of unit probes 120a. Based on the received signal of the unit probe 120a, information regarding the defective portion D in the object E to be inspected (depth of the defective portion D, etc.) is determined. Specifically, the defect information determination unit 205 determines the optimal reception system 220 for observing the scattered wave U1 based on the amplitude information from the waveform analysis unit 221 in each of the reception systems 220c, 220d, and 220e. In the ninth embodiment, the defect information determination unit 205 selects the receiving system 220 with the largest amplitude. Then, the phase information from the phase extraction section 231 of the selected reception system 220 is output to the data processing section 201.

The defect information determining unit 205 determines information regarding the defective portion D based on the waveform analysis results in each of the receiving systems 220c, 220d, and 220e. Based on the received signal means which unit probe 120a detects how much of the received signal (scattered wave U1). By doing so, the accuracy of the positional information of the defective portion D can be improved.

The output of the defect information determination section 205 is input to the data processing section 201. The data processing section 201 includes a phase change amount calculation section 232. The phase change amount calculating unit 232 calculates the amount of phase change of the received signal regarding the change in the scanning position by combining the information with the scanning position information from the scan controller 204 that scans the probe. As described above, the amount of phase change related to this change in scanning position provides an image corresponding to the contour information of the defective portion D. This information is converted into an image and displayed on the display device 3.

Note that the defect information determination section 205 may be provided as a part of the data processing section 201.

(10th embodiment)
FIG. 28 is a diagram showing the arrangement of the eccentrically placed receiving probe 120 in the tenth embodiment. This example is a plan view of the transmission probe 110 and the eccentric reception probe 120 viewed from the minus side of the z-axis in FIG. 1, that is, from the eccentric reception probe 120 side. In the tenth embodiment, the eccentrically placed receiving probe 120 is two-dimensionally placed in the xy plane direction. That is, the eccentrically arranged reception probe 120 includes a plurality of unit probes 120a that are rectangular in plan view, and the plurality of unit probes 120a are arranged radially around the transmission acoustic axis AX1. In the illustrated example, there are eight unit probes 120a.

The direction of the scattered wave U1 changes somewhat depending on the shape of the defective portion D, the direction of inclination, and the like. Therefore, as shown in FIG. 28, by arranging the unit probes 120a radially and recording in which direction the scattered waves U1 are detected, information such as the shape and inclination direction of the defective portion D can be obtained with higher accuracy. be able to.

(Eleventh embodiment)
FIG. 29 is a diagram showing the arrangement of the eccentrically arranged receiving probe 120 in the eleventh embodiment, and is a diagram in which the unit probe 120a is arranged at an angle. A plurality of unit probes 120a are arranged symmetrically with respect to the transmission sound axis AX1. Therefore, at least two unit probes 120a are arranged at positions having the same eccentric distance L. In the illustrated example, three unit probes 120a are symmetrically arranged on both sides of the transmission sound axis AX1 in a plan view including the transmission sound axis AX1. Then, two unit probes 120a are arranged at each position of three different eccentric distances L. Note that the unit probe 120a is arranged at an angle, similar to the eighth embodiment (FIG. 25).

FIG. 30 is a diagram showing the arrangement of the eccentrically arranged receiving probe 120 in the eleventh embodiment, and is a diagram in which the unit probe 120a is arranged in the vertical direction. A set of unit probes 120a are arranged symmetrically with respect to the transmission sound axis AX1. Therefore, at least two unit probes 120a are arranged at positions having the same eccentric distance L.

By arranging at least two unit probes 120a at positions having the same eccentric distance L, scattered waves U1 scattered in a plurality of directions can be detected. Further, by arranging at least two unit probes 120a on both sides of the transmission acoustic axis AX1 in a plan view (FIGS. 29 and 30) including the transmission acoustic axis AX1, a wide range of scattered waves U1 can be received. Furthermore, when the control device 2 detects the scattered waves U1 with the unit probes 120a on both sides, it actually detects the defective part D, and when the scattered waves U1 are detected only on either side, it determines that it is an error. Can be done. Thereby, the detection accuracy of the defective portion D can be improved.

(12th embodiment)
FIG. 31 is a diagram showing the configuration of an ultrasonic testing apparatus Z according to the twelfth embodiment. In the twelfth embodiment, the focal length R3 of the coaxially disposed receiving probe 140 is shorter than the focal length R2 of the eccentrically disposed receiving probe 120. As a result, the convergence of the coaxial receiving probe 140 is higher than that of the eccentric receiving probe 120.

By making the focal length R3 of the coaxial receiving probe 140 shorter than the focal length R2 of the eccentrically arranged receiving probe 120, the ultrasonic beam U on the receiving acoustic axis AX2 out of the ultrasonic beam U emitted from the transmitting probe 110 can be efficiently received by the coaxial receiving probe 140. On the other hand, since the scattered wave U1 has a plurality of propagation paths, the eccentrically arranged receiving probe 120 that receives it can sufficiently receive the scattered wave U1 by lowering the convergence. Therefore, defects can be detected more efficiently by using the reception probe 121 that has convergence properties that match the characteristics of the direct wave U3 and the scattered wave U1.

(13th embodiment)
FIG. 32 is a diagram showing the configuration of an ultrasonic testing apparatus Z according to the thirteenth embodiment. In the thirteenth embodiment, an array type probe 122 having the functions of both the eccentric receiving probe 120 and the coaxial receiving probe 140 is used. The array type probe 122 is a receiving probe 121 in which a plurality of acoustic sensing elements 122a (which also functions as a unit probe 120a (FIG. 26)) are arranged one-dimensionally (FIG. 32) or two-dimensionally (FIG. 33). be.

The array type probe 122 is arranged so that the receiving sound axis AX2 of one constituent sound sensing element 122a coincides with the transmitting sound axis AX1. The sound-sensing element 122a placed at this position functions as a coaxial receiving probe 140. Similar to the example shown in FIG. 26 above, the remaining sound sensing elements 122a are arranged continuously and symmetrically in the horizontal direction of the paper in FIG. Function. In this example, the sound sensing elements 122a are arranged one-dimensionally.

By using the array type probe 122 and arranging the sound sensing elements 122a one-dimensionally, the installation cost of the array type probe 122 can be reduced because the number of installed sound sensing elements 122a is small, and the installation cost of the array type probe 122 can be reduced. 122a can receive the scattered wave U1. Further, even if the defective portion D is small and ultrasonic propagation is completely blocked, the sound sensing element 122a, which has the receiving sound axis AX2 coinciding with the transmitting sound axis AX1, can detect a decrease in the signal amount. Thereby, it is possible to efficiently detect small defective parts D to large defective parts D.

(14th embodiment)
FIG. 33 is a diagram showing the configuration of an ultrasonic testing apparatus Z according to the fourteenth embodiment. FIG. 33 is a plan view of the transmission probe 110 and the array type probe 122 viewed from the negative side of the z-axis in FIG. 1, that is, from the array type probe 122 side. In FIG. 32 above, the sound sensing elements 122a constituting the array type probe 122 are one-dimensionally arranged in only one direction. However, in the array type probe 122 shown in FIG. 33, the sound sensing elements 122a are two-dimensionally arranged in the x and y directions. In the illustrated example, the same number of sound sensing elements 122a (seven pieces) are arranged in each direction of x and y, and are arranged in a square shape. However, the sound-sensing elements 122a are not limited to being arranged in a square shape, but may be arranged in various shapes such as a rectangle, a circle, an ellipse, and the like.

By using the array type probe 122 and arranging the sound-sensing elements 122a two-dimensionally, the scattered waves U1 can be received by many sound-sensing elements 122a, and the failure to detect the scattered waves U1 can be suppressed. Further, even if the defective portion D is large and ultrasonic propagation is completely blocked, the sound sensing element 122a, which has the receiving sound axis AX2 coinciding with the transmitting sound axis AX1, can detect a decrease in the signal amount. Thereby, it is possible to efficiently detect small defective parts D to large defective parts D.

In each of the above embodiments, an example is described in which the defective portion D is a cavity, but the defective portion D may be a foreign substance mixed with a material different from the material of the object to be inspected E. In this case as well, since there is a difference (Gap) in acoustic impedance at the interface where different materials come into contact, scattered waves U1 are generated, so the configurations of the above embodiments are effective. Although the ultrasonic inspection apparatus Z according to the present embodiment is premised on being an ultrasonic defect imaging apparatus, it may also be applied to a non-contact inline internal defect inspection apparatus.

The present disclosure is not limited to the embodiments described above, and includes various modifications. For example, the embodiments described above are described in detail to explain the present disclosure in an easy-to-understand manner, and the embodiments are not necessarily limited to having all the configurations described. Furthermore, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace some of the configurations of each embodiment with other configurations.

In addition, a part or all of the above-described configurations, functions, and units constituting the block diagram may be realized in hardware by, for example, designing an integrated circuit. Further, as shown in FIG. 13, each of the above-described configurations, functions, etc. may be realized by software by a processor such as the CPU 252 interpreting and executing a program for realizing each function. In addition to being stored on the HDD, information such as programs, tables, and files that realize each function is stored in a memory, a recording device such as an SSD (Solid State Drive), or an IC (Integrated Circuit) card, or an SD (Secure Digital). It can be stored in a recording medium such as a card or a DVD (Digital Versatile Disc).

Furthermore, in each embodiment, control lines and information lines are shown that are considered necessary for explanation, and not all control lines and information lines are necessarily shown in terms of the product. In reality, almost all configurations can be considered interconnected.

1 Scanning measurement device 101 Housing 102 Sample stage 103 Transmission probe scanning unit 104 Receiving probe scanning unit 105 Eccentric distance adjustment unit 106 Installation angle adjustment unit 110 Transmission probe 111 Transducer 112 Backing 113 Matching layer 114 Probe surface 115 Transmission probe housing Body 116 Connectors 117, 118 Lead wires 119 Transmission/reception probe 120 Eccentric arrangement reception probe 120a Unit probe 121 Reception probe 122 Array type probe 122a Sound sensor element 140 Coaxial arrangement reception probe 2 Control device 201 Data processing section 202 Drive section 203 Position measurement section 204 Scan controller 205 Defect information determination unit 210 Transmission system 211 Waveform generator 212 Signal amplifiers 220, 220a, 220b Reception system 221 Waveform analysis units 222, 223 Signal amplifier 224 Amplitude image generation unit 225 Image synthesis unit 231 Phase extraction unit 232 Phase change amount Calculation unit 235 Switch 251 Memory 252 CPU
253 Storage device 254 Communication device 255 I/F
3 Display device AX1 Transmission sound axis AX2 Reception sound axis D Defect part E Test object F Fluid G Gas G1, G2, G3, G4, G5 Graph N Healthy part S101 Release step S102 Reception step S103 Phase extraction step S104 Phase change amount calculation Step S105 Shape display steps S111, S112 Step U Ultrasonic beam U1 Scattered wave U2 Ultrasonic beam U3 Direct wave Z Ultrasonic inspection device

Claims (19)

An ultrasonic inspection device that inspects an object to be inspected by injecting an ultrasonic beam into the object through a fluid,
comprising a scanning measurement device that scans and measures the ultrasonic beam on the object to be inspected, and a control device that controls driving of the scanning measurement device,
The scanning measurement device includes:
comprising a transmitting probe that emits the ultrasonic beam and an eccentrically placed receiving probe that receives the ultrasonic beam,
The eccentrically arranged receiving probe is arranged such that an eccentric distance between the transmitting sound axis of the transmitting probe and the receiving sound axis of the eccentrically arranged receiving probe is greater than zero,
The transmitter probe and the eccentrically arranged receiver probe scan in the x-axis direction or the y-axis direction,
The transmitting probe is arranged such that the transmitting sound axis is perpendicular to the xy plane formed by the x-axis and the y-axis,
The control device includes:
a phase extraction unit that extracts phase information of a signal of the ultrasound beam received by the eccentrically arranged receiving probe;
An ultrasonic inspection apparatus, comprising: a phase change amount calculation unit that calculates a phase change amount regarding the scanning position of the extracted phase information. The ultrasonic inspection apparatus according to claim 1, wherein the eccentric distance is set to a distance at which scattered waves generated by scattering of the ultrasonic beam at a defective part of the object to be inspected can be received. The eccentric distance is set such that the received signal strength at the eccentrically arranged receiving probe when the probe is incident on a defective part of the object to be inspected is greater than the received signal intensity when it is incident on a healthy part of the object to be inspected. The ultrasonic inspection apparatus according to claim 1 or 2, wherein the ultrasonic inspection apparatus is set. The ultrasonic inspection apparatus according to claim 1 or 2, wherein the eccentric distance is set to a distance at which no received signal other than noise is detected when irradiating a healthy part of the object to be inspected. The ultrasonic inspection apparatus according to claim 1 or 2, further comprising an eccentric distance adjustment section that adjusts the position of at least one of the transmitting probe and the eccentrically arranged receiving probe. The ultrasonic inspection apparatus according to claim 1 or 2, wherein a focal length of the eccentrically arranged receiving probe is longer than a focal length of the transmitting probe. The ultrasonic inspection apparatus according to claim 1 or 2, wherein the focal point of the eccentrically arranged receiving probe is located closer to the transmitting probe than the focal point of the transmitting probe. The ultrasonic inspection apparatus according to claim 1 or 2, wherein a beam incident area of the eccentrically arranged receiving probe on the inspected object is larger than a beam incident area of the transmitting probe on the inspected object. . The scanning measurement device includes an installation angle adjustment unit that adjusts the inclination of the eccentrically arranged receiving probe so that the angle θ formed by the transmitting sound axis and the receiving sound axis satisfies 0°<θ<90°. The ultrasonic inspection apparatus according to claim 1 or 2, characterized in that: The ultrasonic inspection apparatus according to claim 1 or 2, wherein the eccentrically arranged receiving probe includes a plurality of unit probes. Among the plurality of unit probes, the control device controls the control device based on the received signal of the unit probe that has received a scattered wave caused by scattering of the irradiated ultrasonic beam at a defective part of the object to be inspected. The ultrasonic inspection apparatus according to claim 10, further comprising a defect information determination unit that determines information regarding a defective portion in the object to be inspected. The ultrasonic inspection apparatus according to claim 1 or 2, wherein the scanning measurement device includes a coaxial receiving probe arranged at a position where the eccentric distance is zero. An ultrasonic inspection device that inspects an object to be inspected by injecting an ultrasonic beam into the object through a fluid,
comprising a scanning measurement device that scans and measures the ultrasonic beam on the object to be inspected, and a control device that controls driving of the scanning measurement device,
The scanning measurement device includes:
comprising a transmitting probe that emits the ultrasonic beam and an eccentrically placed receiving probe that receives the ultrasonic beam,
The eccentrically arranged receiving probe is arranged such that an eccentric distance between the transmitting sound axis of the transmitting probe and the receiving sound axis of the eccentrically arranged receiving probe is greater than zero,
further comprising a coaxial receiving probe disposed at a position where the eccentric distance is zero;
The control device includes:
a phase extraction unit that extracts phase information of a signal of the ultrasound beam received by the eccentrically arranged receiving probe;
a phase change amount calculation unit that calculates a phase change amount regarding the scanning position of the extracted phase information;
a first image showing the position of a defect inside the object to be inspected, which is generated based on the amplitude of the direct wave received by the coaxial receiving probe;
a second image showing an outline of a defective part inside the object to be inspected, which is generated by the phase change amount calculation unit based on the amount of phase change regarding the scanning position;
an image synthesis section that synthesizes the
Ultrasonic inspection equipment. The ultrasonic inspection apparatus according to claim 1 or 2, wherein the transmitting probe is a transmitting/receiving probe that emits the ultrasonic beam and receives reflected waves from the object to be inspected. An ultrasonic inspection device that inspects an object to be inspected by injecting an ultrasonic beam into the object through a fluid,
comprising a scanning measurement device that scans and measures the ultrasonic beam on the object to be inspected, and a control device that controls driving of the scanning measurement device,
The scanning measurement device includes:
comprising a transmitting probe that emits the ultrasonic beam and an eccentrically placed receiving probe that receives the ultrasonic beam,
The transmitting probe is a transmitting/receiving probe that emits the ultrasonic beam and receives reflected waves from the object to be inspected,
The eccentrically arranged receiving probe is arranged such that an eccentric distance between the transmitting sound axis of the transmitting probe and the receiving sound axis of the eccentrically arranged receiving probe is greater than zero,
The control device includes:
a phase extraction unit that extracts phase information of a signal of the ultrasound beam received by the eccentrically arranged receiving probe;
a phase change amount calculation unit that calculates a phase change amount regarding the scanning position of the extracted phase information;
a first image showing the position of a defective part inside the object to be inspected, which is generated based on the amplitude of the direct wave received by the transmitting/receiving probe;
a second image showing an outline of a defective part inside the object to be inspected, which is generated by the phase change amount calculation unit based on the amount of phase change regarding the scanning position;
an image synthesis section that synthesizes the
Ultrasonic inspection equipment. The ultrasonic inspection apparatus according to claim 1 or 2, wherein the fluid is a gas. An ultrasonic inspection method for inspecting an object to be inspected by injecting an ultrasonic beam into the object through a fluid, the method comprising:
The transmitter probe and the eccentrically positioned receiver probe scan in the x-axis direction or the y-axis direction,
The transmitting probe is arranged such that the transmitting sound axis of the transmitting probe is perpendicular to the xy plane formed by the x-axis and the y-axis,
emitting an ultrasound beam from the transmitting probe;
a receiving step of receiving the ultrasonic beam in the eccentrically arranged receiving probe having a receiving sound axis at a position different from the transmitting sound axis;
a phase extraction step of extracting phase information of a signal of the ultrasound beam received by the eccentrically arranged receiving probe;
An ultrasonic inspection method comprising: calculating a phase change amount of the extracted phase information with respect to a scanning position. The shape of the defective portion of the object to be inspected is determined by determining whether the phase change amount regarding the scanning position of the phase information generated in the phase change amount calculation step is equal to or larger than a preset threshold value. The ultrasonic inspection method according to claim 17, further comprising the step of displaying a shape. The ultrasonic inspection method according to claim 17 or 18, wherein the fluid is a gas.

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