Ultrasonic inspection device and ultrasonic inspection method

Abstract

The present invention provides an ultrasonic inspection device which can detect a defect portion with a small size, for example, a defect that can be detected, and can detect even a minute defect. A control device (2) for an ultrasonic testing device (Z) is provided with a signal processing unit (250). The signal processing unit (250) is provided with: a frequency conversion unit (230) that converts a signal received by a reception probe (121) into a frequency component; an imaging unit (262) that generates an image indicating a defect position using a portion of a frequency component specified by a frequency parameter among the converted frequency components; and a display unit (263) that displays on a display device (3). The display unit (263) displays on the display device (3) a frequency spectrum corresponding to the frequency component converted by the frequency conversion unit (230) and an input unit that accepts an input of the frequency parameter.

Description

Technical Field

[0001] The invention relates to an ultrasonic inspection device and an ultrasonic inspection method. Background Art

[0002] A method for inspecting defects of an object to be inspected using an ultrasonic beam is known. For example, when there is a defect (such as a cavity) with a small acoustic impedance such as air inside the object to be inspected, a gap in acoustic impedance is generated inside the object to be inspected, so the amount of ultrasonic beam transmitted becomes small. Therefore, by measuring the amount of ultrasonic beam transmitted, it is possible to detect defects inside the object to be inspected.

[0003] Regarding ultrasonic inspection devices, the technology described in Patent Document 1 is known. In the ultrasonic inspection device described in Patent Document 1, a rectangular wave burst signal including a predetermined number of continuous negative rectangular waves is applied to a transmitting ultrasonic probe arranged opposite to the subject through the air. The ultrasonic wave transmitted to the subject is converted into a transmission wave signal by a receiving ultrasonic probe arranged opposite to the subject through the air. Based on the signal level of the transmission wave signal, it is determined whether the subject has defects. In addition, the acoustic impedance of the transducer and the front panel on the ultrasonic transmission and reception side of the transducer installed in the transmitting ultrasonic probe and the receiving ultrasonic probe is set to be lower than that of a contact ultrasonic probe used in contact with the subject.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2008-128965 Summary of the invention

[0007] Problems to be solved by the invention

[0008] The ultrasonic inspection device described in Patent Document 1 has a problem that it is difficult to detect minute defects in the object to be inspected. In particular, when the size of the defect to be detected is smaller than the ultrasonic beam, it becomes difficult to detect the defect.

[0009] The problem to be solved by the present invention is to provide an ultrasonic inspection device and an ultrasonic inspection method with improved defect detection performance, for example, a small defect size can be detected, and even a minute defect can be detected.

[0010] Technical solutions to the problem

[0011] The ultrasonic inspection device of the present invention inspects the inspected body by irradiating an ultrasonic beam onto the inspected body via a fluid, and includes: a scanning and measuring device for scanning and measuring the inspected body with the ultrasonic beam, and a control device for controlling the driving of the scanning and measuring device, wherein the scanning and measuring device has a transmitting probe for emitting the ultrasonic beam; and a receiving probe for receiving the ultrasonic beam, and the control device has a signal processing unit, and the signal processing unit includes: a frequency conversion unit for converting the receiving signal of the receiving probe into a frequency component; an imaging unit, which uses the part of the frequency component specified by the frequency parameter in the converted frequency component to generate an image representing the defect location; and a display unit for displaying on a display device, wherein the display unit displays the spectrum corresponding to the frequency component converted by the frequency conversion unit, and an input unit for receiving the input of the frequency parameter on the display device. Other solutions will be described later in the specific implementation.

[0012] Effects of the Invention

[0013] According to the present invention, it is possible to provide an ultrasonic inspection device and an ultrasonic inspection method that have excellent defect detection performance, for example, the defect size that can be detected is small, and even micro defects can be detected. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a diagram showing the configuration of the ultrasonic inspection apparatus according to the first embodiment.

[0015] Figure 2 It is a schematic cross-sectional view showing the structure of the transmitting probe.

[0016] Figure 3A This is a diagram showing a propagation path of an ultrasonic beam in a conventional ultrasonic inspection method, and shows a case where the ultrasonic beam enters a healthy part.

[0017] Figure 3B This is a diagram showing a propagation path of an ultrasonic beam in a conventional ultrasonic inspection method, and shows a case where the ultrasonic beam enters a defective portion.

[0018] Figure 4 This is a diagram showing the interaction between a defect in the subject and an ultrasonic beam, and a diagram showing the situation of receiving a direct ultrasonic beam.

[0019] Figure 5 This is a diagram schematically showing an ultrasonic beam interacting with a defect, that is, a scattered wave.

[0020] Figure 6 This is a functional block diagram of an ultrasonic inspection device.

[0021] Fig. 7A This shows an example of a database.

[0022] Figure 7B It is a three-dimensional representation Fig. 7A Diagram of the database shown.

[0023] Figure 8 It is a diagram schematically showing the distribution (spectrum) of the frequency components of the received signal.

[0024] Fig.9A This indicates the change in the position of the signal strength information when the transmitting probe and the receiving probe are scanned in a manner that crosses the defective portion.

[0025] Fig. 9B This is the result of calculating and plotting the signal feature quantity from frequency component data containing a plurality of appropriate frequencies.

[0026] Fig.10 This shows the voltage waveform of the burst wave applied to the transmission probe.

[0027] Fig.11 express Fig.10 Frequency component distribution of the received signal under the conditions shown.

[0028] Fig.12 This is a diagram comparing measured data of the frequency component distribution (spectrum) of the received signal at a healthy part and a defective part.

[0029] Fig.13 It is a diagram schematically showing a configuration example of an operation screen of an ultrasonic inspection apparatus in an example of the present invention.

[0030] Fig.14 This is a functional block diagram of an ultrasonic inspection device according to another embodiment.

[0031] Fig.15 It is a diagram showing the processing flow in the example of the present invention.

[0032] Fig.16 It is a diagram schematically showing a configuration example of an operation screen according to the second embodiment.

[0033] Fig.17 It is a diagram showing the processing flow of this example of the second embodiment.

[0034] Fig.18 This is a functional block diagram of an ultrasonic inspection apparatus according to a third embodiment.

[0035] Fig.19 It is a diagram showing the processing flow of the third embodiment.

[0036] Fig. 20A This is a diagram schematically showing a propagation path of an ultrasonic beam when the focal length of the transmitting probe and the focal length of the receiving probe are made equal in the fourth embodiment.

[0037] Fig. 20B This is a diagram schematically showing a propagation path of an ultrasonic beam when the focal length of the receiving probe is made longer than the focal length of the transmitting probe in the fourth embodiment.

[0038] Fig.21 This is a diagram for explaining the relationship between the ultrasonic beam incident area in the transmitting probe and the ultrasonic beam incident area in the receiving probe.

[0039] Fig. 22 It is a diagram showing the configuration of an ultrasonic inspection apparatus in the fifth embodiment.

[0040] Fig.23A 1 is a diagram for explaining the transmission acoustic axis, the reception acoustic axis, and the eccentricity, and shows a case where the transmission acoustic axis and the reception acoustic axis extend in the vertical direction.

[0041] Fig. 23B FIG. 1 is a diagram for explaining the transmission acoustic axis, the reception acoustic axis, and the eccentricity, and shows a case where the transmission acoustic axis and the reception acoustic axis extend obliquely.

[0042] Fig.24 It is a diagram showing the structure of an ultrasonic inspection apparatus in the sixth embodiment.

[0043] Fig.25 This is a diagram for explaining the reason why the effects of the sixth embodiment are produced.

[0044] Fig.26 A diagram showing the configuration of an ultrasonic inspection apparatus according to a seventh embodiment.

[0045] Fig. 27 This figure shows the hardware configuration of the control device.

[0046] Fig.28 A flowchart showing the ultrasonic inspection method according to each of the above-mentioned embodiments. DETAILED DESCRIPTION

[0047] Hereinafter, the method for implementing the present invention (referred to as an embodiment) will be described with reference to the drawings. However, the present invention is not limited to the following embodiments, and for example, different embodiments may be combined with each other, or may be arbitrarily changed within the scope that does not significantly damage the effect of the present invention. In addition, the same figure marks are attached to the same parts, and repeated descriptions are omitted. Furthermore, the same names are attached to parts with the same functions. The contents of the icons are always schematic, and for the convenience of illustration, they are sometimes changed according to the actual structure within the scope that does not significantly damage the effect of the present invention.

[0048] (First embodiment)

[0049] Figure 1 FIG. 1 is a diagram showing the structure of an ultrasonic inspection device Z according to the first embodiment. Figure 1In FIG. 1 , the scanning measuring device 1 is shown in a schematic cross-sectional view. Figure 1 , represents a coordinate system including three orthogonal axes: the x-axis as the left-right direction of the paper, the y-axis as the orthogonal direction of the paper, and the z-axis as the up-down direction of the paper.

[0050] The ultrasonic inspection device Z inspects the object E by irradiating an ultrasonic beam U (described later) to the object E through a fluid F. The fluid F is, for example, a liquid W (described later) such as water 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 the gas G) is used as the fluid F. Therefore, the interior of the housing 101 of the scanning measurement device 1 becomes a cavity filled with air. Figure 1 As shown, the ultrasonic inspection device Z comprises a scanning measurement device 1 , a control device 2 and a display device 3 . The display device 3 is connected to the control device 2 .

[0051] The scanning measuring device 1 performs scanning and measurement of the object E to be inspected by the ultrasonic beam U, and has a sample table 102 fixed to a housing 101, on which the object E to be inspected is placed. The object E to be inspected is made of any material. The object E to be inspected is, for example, a solid material, more specifically, a composite material such as metal, glass, resin material, or CFRP (Carbon-Fiber Reinforced Plastics). Figure 1 In the example, the object E to be inspected has a defective portion D inside. The defective portion D (defect) is a cavity, etc. Examples of the defective portion D are a cavity, a foreign material different from the material that should be present, etc. In the object E to be inspected, the portion other than the defective portion D is referred to as a healthy portion N.

[0052] Since the defective portion D and the healthy portion N are made of different materials, the acoustic impedance between the two is different, and the transmission characteristics of the ultrasonic beam U change. The ultrasonic inspection device Z detects the defective portion D by observing this change.

[0053] The scanning measurement device 1 has a transmitting probe 110 for transmitting an ultrasonic beam U and a receiving probe 121 for receiving the ultrasonic beam U. The transmitting probe 110 is provided in the housing 101 via the transmitting probe scanning unit 103, and transmits the ultrasonic beam U. The receiving probe 121 is provided on the opposite side of the transmitting probe 110 with respect to the object E to be inspected, and receives the ultrasonic beam U, and includes a receiving probe 140 (coaxially arranged receiving probe) which is coaxially arranged with the transmitting probe 110 (the eccentric distance L described later is zero). Therefore, in the present invention, the eccentric distance L (distance) between the transmitting acoustic axis AX1 (acoustic axis) of the transmitting probe 110 and the receiving acoustic axis AX2 (acoustic axis) of the receiving probe 140 is 0. Fig.23A , Fig. 23B ) is zero. Thus, the transmitting probe 110 and the receiving probe 140 can be easily set.

[0054] Here, "the opposite side of the transmitting probe 110" refers to the space on the opposite side of the space where the transmitting probe 110 is located (the opposite side in the z-axis direction) in the two spaces divided by the object E, and does not mean that the x and y coordinates are limited to the same opposite side (i.e., positions that are plane-symmetrical about the xy plane).

[0055] In the example of the present invention, the transmission probe 110 is arranged so that the transmission acoustic axis AX1 of the transmission probe 110 is perpendicular to the mounting surface 1021 of the sample stage 102. That is, the transmission probe 110 is arranged so that the transmission acoustic axis AX1 is in the normal direction of the mounting surface 1021 of the object E to be inspected of the sample stage 102. In this way, in the plate-shaped object E to be inspected, since the transmission acoustic axis AX1 is arranged perpendicular to the surface of the object E to be inspected, there is an effect that the correlation between the scanning position and the position of the defective portion D can be easily understood.

[0056] However, the present invention is not limited to setting the transmitting probe 110 in a manner that the transmitting acoustic axis AX1 is perpendicular to the mounting surface 1021 of the test object E of the sample stage 102. The effect of the present invention is achieved even when the transmitting acoustic axis AX1 is not perpendicular to the mounting surface 1021 of the test object E of the sample stage 102. In the latter case, in order to accurately know the position of the defect D, the path of the transmitting acoustic axis AX1 can be calculated based on the slope of the transmitting acoustic axis AX1 from the vertical direction.

[0057] Here, the positional relationship between the transmitting probe 110 and the receiving probe 121 is described. The distance between the transmitting acoustic axis AX1 of the transmitting probe 110 and the receiving acoustic axis AX2 of the receiving probe 121 is defined as the eccentric distance L as described above. In the present invention, as described above, the eccentric distance L is set to zero. That is, the receiving probe 121 is configured so that the transmitting acoustic axis AX1 and the receiving acoustic axis AX2 are coaxial. This is called a coaxial configuration. In addition, in the present invention, the eccentric distance L is not limited to 0.

[0058] In the present invention, as the configuration position of the receiving probe 121, the coaxial configuration of the transmitting acoustic axis AX1 and the receiving acoustic axis AX2 is referred to as a coaxial configuration, and the configuration in which two acoustic axes (the transmitting acoustic axis AX1 and the receiving acoustic axis AX2) are offset (i.e., an eccentric configuration) is referred to as an eccentric configuration. The present invention is effective in both the case of the coaxial configuration of the receiving probe 121 and the case of the eccentric configuration. Therefore, the present invention includes both the coaxial configuration and the eccentric configuration as the configuration of the receiving probe 121. A specific diagram of the eccentric configuration is shown. Fig. 22 after.

[0059] In the present invention, especially when the receiving configuration position is specified, the coaxially configured receiving probe 121 is recorded as the receiving probe 140 (coaxially configured receiving probe), and the eccentrically configured receiving probe 121 is recorded as the receiving probe 120 (eccentrically configured receiving probe).

[0060] When the receiving probe 121 is described, the coaxial arrangement or the eccentric arrangement is not particularly specified.

[0061] The acoustic axis is defined as the central axis of the ultrasonic beam U. Here, the transmission acoustic axis AX1 is defined as the acoustic axis of the transmission path of the ultrasonic beam U emitted by the transmission probe 110. In other words, the transmission acoustic axis AX1 is the central axis of the transmission path of the ultrasonic beam U emitted by the transmission probe 110. The transmission acoustic axis AX1 is described below. Fig.21 B includes refraction caused by the interface of the subject E. That is, as shown in the figure, when the ultrasonic beam U emitted from the transmission probe 110 is refracted at the interface of the subject E, the center (acoustic axis) of the propagation path of the ultrasonic beam U becomes the transmission acoustic axis AX1.

[0062] Furthermore, the reception acoustic axis AX2 is defined as the acoustic axis of the transmission path of a virtual ultrasonic beam when the reception probe 121 is assumed to transmit the ultrasonic beam U. In other words, the reception acoustic axis AX2 is the central axis of the virtual ultrasonic beam when the reception probe 121 is assumed to transmit the ultrasonic beam U.

[0063] As a specific example, the case where the probe surface is a planar non-convergent receiving probe is described. In this case, the direction of the receiving acoustic axis AX2 is the normal direction of the probe surface, and the axis passing through the center point of the probe surface becomes the receiving acoustic axis AX2. When the probe surface is a rectangle, its center point is defined as the intersection of the diagonal lines of the rectangle.

[0064] The 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 receiving probe 121 by instructing the transmitting probe scanning unit 103 and the receiving probe scanning unit 104. The transmitting probe 110 and the receiving probe 121 scan the object E in the x-axis and y-axis directions by synchronously moving the transmitting probe scanning unit 103 and the receiving probe scanning unit 104. Furthermore, the control device 2 transmits the ultrasonic beam U from the transmitting probe 110, and performs waveform analysis based on the signal obtained from the receiving probe 121. In addition, the plane formed by the two axes of the x-axis and y-axis directions, that is, the scanning direction of the transmitting probe 110, is called a scanning plane.

[0065] In addition, in the present invention, an example is shown in which the transmitting probe 110 and the receiving probe 121 are scanned in a state where the inspection object E is fixed to the housing 101 via the sample stage 102, that is, in a state where the inspection object E is fixed relative to the housing 101. On the contrary, it is also possible to configure the transmitting probe 110 and the receiving probe 121 to be fixed relative to the housing 101, and scanned by moving the inspection object E.

[0066] In the example shown in the figure, gas G (an example of fluid F. It may also be liquid W (described later)) is between the transmitting probe 110 and the object E to be inspected, and between the receiving probe 121 and the object E to be inspected. Therefore, since the transmitting probe 110 and the receiving probe 121 can be inspected without contact with the object E to be inspected, the relative position in the xy plane direction can be changed smoothly and at high speed. That is, by having the fluid F between the transmitting probe 110 and the receiving probe 121 and the object E to be inspected, smooth scanning can be performed.

[0067] The transmitting probe 110 is a convergent type transmitting probe 110. On the other hand, the receiving probe 121 uses a probe with a slower convergence than the transmitting probe 110. In the present invention, a non-convergent type probe whose probe surface is a plane is used as the receiving probe 121. By using such a non-convergent type receiving probe 121, it is possible to collect information on the defective portion D in a wide range.

[0068] Figure 2 FIG. 1 is a cross-sectional schematic diagram showing the structure of the transmitting probe 110. Figure 2 In FIG. 1 , for simplicity, only the outer contour of the transmitted ultrasonic beam U is illustrated, but in fact, a plurality of ultrasonic beams U are transmitted in the normal vector direction of the probe surface 114 over the entire area of ​​the probe surface 114 .

[0069] The transmitting probe 110 is configured to converge the ultrasonic beam U. Thus, a micro defect D in the object E can be detected with high accuracy. The reason why the micro defect D can be detected will be described later. The transmitting probe 110 has a transmitting probe housing 115, and a backing 112, a transducer 111, and a matching layer 113 are provided inside the transmitting probe housing 115. An electrode (not shown) is mounted on the transducer 111, and the electrode is connected to a connector 116 via a lead 118. Furthermore, the connector 116 is connected to a power supply device (not shown) and a control device 2 via a lead 117.

[0070] In the present invention, 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 present, and is defined as the surface of the transducer 111 when the matching layer 113 is not present. That is, the probe surface 114 is the surface for transmitting the ultrasonic beam U in the case of the transmitting probe 110, and is the surface for receiving the ultrasonic beam U in the case of the receiving probe 121.

[0071] Here, a conventional ultrasonic inspection method will be described as a comparative example.

[0072] Figure 3A 1 is a diagram showing a propagation path of an ultrasonic beam U in a conventional ultrasonic inspection method, and is a diagram showing a case where the ultrasonic beam enters a healthy part N. FIG. Figure 3B The figure is a diagram showing the transmission path of the ultrasonic beam U in the conventional ultrasonic inspection method, and is a diagram showing the case where the ultrasonic beam U is incident on the defective portion D. In the conventional ultrasonic inspection method, for example, as described in Patent Document 1, a transmitting probe 110 and a receiving probe 140 as a receiving probe 121 are arranged so that the transmitting acoustic axis AX1 and the receiving acoustic axis AX2 coincide with each other.

[0073] like Figure 3A As shown in FIG. 1 , when the ultrasonic beam U is incident on the healthy part N of the subject E, the ultrasonic beam U passes through the subject E and reaches the receiving probe 140. Therefore, the received signal becomes larger. Figure 3B As shown in FIG. 1 , when the ultrasonic beam U is incident on the defective portion D, the received signal decreases because the defective portion D blocks the transmission of the ultrasonic beam U. Thus, the defective portion D is detected by the decrease in the received signal. This is shown in Patent Document 1.

[0074] Here, if Figure 3A and Figure 3B As shown, the method of detecting the defective portion D by blocking the transmission of the ultrasonic beam U in the defective portion D to reduce the received signal is referred to herein as a "blocking method."

[0075] The problem with the prior art is that if the defect size is smaller than the beam size, detection becomes difficult. Figure 4 Explain this point.

[0076] Figure 4 A diagram showing the interaction between the defect D and the ultrasonic beam U in the inspected body E, and a diagram showing the situation of receiving the direct ultrasonic beam U (hereinafter referred to as the "direct wave U3"). The direct wave U3 will be described later. Here, the situation where the size of the defect D is greater than the width of the ultrasonic beam U (hereinafter referred to as the beam width BW) is considered. The beam width BW here refers to the width of the ultrasonic beam U when it reaches the defect D.

[0077] And, because Figure 4 The shape of the ultrasonic beam U in the micro region near the defect D is schematically shown, so the ultrasonic beam U is drawn in parallel, but it is actually a convergent ultrasonic beam U. Figure 4 The position of the receiving probe 121 in the figure is recorded as a conceptual position for easy understanding, and the position and shape of the receiving probe 121 are not correctly scaled. That is, if the magnification scale of the defect D and the shape of the ultrasonic beam U is considered, the receiving probe 121 is located at a relatively Figure 4The position shown is further away in the upper and lower directions of the figure.

[0078] exist Figure 4 In FIG. 1 , the blocking method of making the transmission sound axis AX1 and the reception sound axis AX2 coincide with each other is shown. When the defect D is smaller than the beam width BW, a part of the ultrasonic beam U is blocked, so the received signal decreases, but it is not zero. For example, when the cross-sectional area of ​​the defect D is 5% of the beam cross-sectional area specified by the beam width BW, the received signal remains at a decrease of approximately 5%, so it is difficult to detect the defect D. That is, if Figure 4 In the case shown, the received signal is reduced by 5% at the location of the defect D. Thus, when the defect D is smaller than the beam width BW, more beams pass through without interacting with the defect D, so the defect detection accuracy is reduced.

[0079] Figure 5 FIG. 1 is a diagram schematically showing an ultrasonic beam U interacting with a defect D, that is, a scattered wave U1. In this specification, the ultrasonic beam U interacting with a defect D is referred to as a scattered wave U1. Therefore, the "scattered wave U1" in this specification refers to the ultrasonic wave interacting with the defect D. The scattered wave U1 also includes Figure 5 The scattered wave U1 is a wave that changes direction as shown. In addition, there are also waves in which at least one of the phase or frequency of the wave changes due to the interaction with the defect D, but the traveling direction does not change. The ultrasonic wave that passes through without interacting with the defect D is called a direct wave U3. If only the scattered wave U1 can be detected to distinguish it from the direct wave U3, a smaller defect D can be easily detected. In the present invention, the scattered wave U1 is effectively detected by focusing on the difference in frequency.

[0080] Figure 6 : is a functional block diagram of the ultrasonic inspection device Z. The control device 2 controls the driving of the scanning and measuring device 1. The control device 2 has a transmitting system 210, a receiving system 220, a data processing unit 201, a scanning controller 204, a driving unit 202, a position measuring unit 203, and a signal processing unit 250. The driving unit 202 changes the relative positions of the transmitting probe 110 and the receiving probe 121 with respect to the object E to be inspected by, for example, driving the transmitting probe 110 and the receiving probe 121. The position measuring unit 203 measures the scanning position. The scanning controller 204 drives the transmitting probe 110 and the receiving probe 121 through the driving unit 202. The scanning positions of the transmitting probe 110 and the receiving probe 121 are input to the scanning controller 204 through the position measuring unit 203.

[0081] The receiving system 220 and the data processing unit 201 are collectively referred to as a signal processing unit 250. The signal processing unit 250 performs signal processing to extract meaningful information from the signal from the receiving probe 121 through amplification processing, frequency selection processing, and the like.

[0082] The transmission system 210 is a system for generating a voltage to be applied to the transmission probe 110. The transmission system 210 has a waveform generator 211 and a signal amplifier 212. A burst wave signal is generated in the waveform generator 211. And, the generated burst wave signal is amplified by the signal amplifier 212. The voltage output from the signal amplifier 212 is applied to the transmission probe 110.

[0083] The signal processing unit 250 has a data processing unit 201 and a receiving system 220. The receiving system 220 is a system for detecting a received signal output from the receiving probe 121. The signal output from the receiving probe 121 is input to the signal amplifier 222 and amplified. The amplified signal is input to the frequency conversion unit 230. The frequency conversion unit 230 is equipped in the signal processing unit 250, and converts (signal processing) the received signal of the receiving probe 121 into a frequency component. In the example of the present invention, the time domain waveform, that is, the received signal is converted into a frequency component. The size of the component of each frequency (spectrum). As the frequency component, for example, a method of expressing it in a complex number and by a combination of a real part and an imaginary part, a method of expressing it by an amplitude (absolute value) and a phase, etc. can be cited.

[0084] The conversion in the frequency conversion unit 230 can be performed, for example, by Fourier transform. In addition, the conversion can also be performed together with extracting only the frequency components of a pre-specified frequency range (frequency parameter). The signal converted into the frequency component by the frequency conversion unit 230 is input to the data processing unit 201. In addition, the frequency conversion unit 230 can also be set inside the data processing unit 201. That is, the conversion into the frequency component can also be performed in the data processing unit.

[0085] (Accumulation of frequency component data)

[0086] In the example of the present invention, the frequency conversion unit 230 converts the time domain waveform into frequency component data and stores it in the storage unit 261 together with the position information. In addition, the imaging unit 262, which will be described in detail later, uses the frequency component part specified by the frequency parameter in the converted frequency component to generate an image 273 ( Fig.13 ). That is, the imaging unit 262 images the signal feature based on the input frequency parameter. That is, when the subject E is measured once, the conversion to the frequency component data is completed once, and the signal feature is extracted multiple times from the frequency component data.

[0087] This structure is preferable in the following two points.

[0088] The first is the time required for calculation. The conversion process to the frequency component data in the frequency conversion unit 230 takes time. Typically, although Fourier transform is used as described above, even if the fast Fourier transform (FFT) known as a high-speed operation algorithm is used, the processing time of this conversion is relatively long. On the other hand, although the calculation of the signal feature quantity is performed using the following formula (1), the time required for this calculation is relatively short. As a typical example, even for 100 columns × 100 rows of measurement points, the processing is completed in less than 0.2 seconds.

[0089] Therefore, according to an example of the present invention, which will be described in detail later, when the frequency parameter is "updated", an instantaneously updated image 273 ( Fig.13 ). In this way, by storing the frequency component data in the storage unit 261, a frequency set suitable for improving defect detectability can be selected in a short time.

[0090] The second is the reduction of the amount of data. The signal waveform of the receiving probe 140 has about 100,000 points in the time domain waveform for one measurement position, while the frequency component data only needs to have complex numbers for 20 to 100 frequencies. That is, the amount of data for the subject E can be reduced to about 1 / 1000. This also has the advantage of significantly reducing the amount of data stored in the storage unit 261.

[0091] The data processing unit 201 also receives information about the scanning position from the scanning controller 204. In this way, data related to the frequency component of the received signal at the current two-dimensional scanning position (x, y) (hereinafter referred to as frequency component data) is obtained. The data processing unit 201 stores the scanning position (x, y) and the frequency component data of the position in the storage unit 261 in correspondence. In addition, by determining the signal feature amount determined from the frequency component data for each scanning position, an image 273 about the defective portion D is generated.

[0092] Frequency component data is a frequency component corresponding to a plurality of frequencies. In a typical example, the frequency component data is a spectrum obtained by Fourier transforming a received signal. As described above, it is more preferable that the frequency component also includes phase information in addition to the amplitude (absolute value). This is synonymous with treating the frequency component as a complex number. As described later, by also including phase information, a higher-performance signal feature quantity can be calculated.

[0093] In the example of the present invention, the control device 2 has a database 261a in the storage unit 261 constituting the data processing unit 201. The database 261a associates information that affects the detection accuracy of the defective portion D of the inspected object E (hereinafter referred to as "information about the inspected object E") with frequency parameters. The information described here includes, for example, the inspection conditions of the inspected object E. Depending on the inspection conditions, the appropriate frequency parameters may be different. The appropriate frequency parameters described here are frequency parameters that increase the difference between the frequency spectrum of the healthy portion N and the frequency spectrum of the defective portion D to an extent that the defective portion D can be detected. The frequency parameters represent a frequency set {ωn} suitable for the detection of the defective portion D. Therefore, by the user inputting the inspection conditions into the input unit 272 ( Fig.13 ), can be specified for image 273 ( Fig.13 ) of the generated spectrum.

[0094] The inspection conditions include, for example, at least one of the material of the inspection object E, the thickness of the inspection object E, the structure of the inspection object E (e.g., the difference between a single-layer structure and a multi-layer structure), the position of the inspection object E relative to the receiving probe 121 and the transmitting probe 110 (e.g., the position in the z direction), and the type of the fluid F. Since such information may affect the appropriate frequency parameters, the user inputs at least one of such information to determine the appropriate frequency parameters.

[0095] Fig. 7A 261a. The frequency parameter in the example of the present invention is relative to the transmission frequency f0 ( Fig.10 ) is a set of ratios f / f0. Fig. 7A In the example shown, the preferred frequency parameter relative to the information about the object under test E is expressed as a certain range. The information described here is, as an example for illustration, the thickness and material of the object under test E. Figure 1 The ultrasonic inspection device Z shown performs measurement and accumulates information in the database 261a when repeatedly registering, that is, updating, the optimal frequency parameters.

[0096] Figure 7B It is a three-dimensional representation Fig. 7A The information about the subject E is multidimensional information with multiple axes. That is, if the information about the subject E is divided into components It[k] (k is an integer greater than 1), then k=1, 2, ... corresponds to each axis of the multidimensional information. Figure 7B In the example shown, It[1] is the thickness of the object E to be inspected, and It[2] is the material of the object E to be inspected as an example for explanation.

[0097] exist Fig. 7A In the above example, the multidimensional information, i.e., the information about the subject E, is abstracted into one axis. If described specifically, it is as follows: Figure 7B As shown, the information on the subject E is composed of a plurality of axes. Therefore, in the example of the present invention, the database 261a is a database having the multidimensional information, that is, the subject information, as an axis.

[0098] The database 261a can be expressed in a tabular form. That is, each multidimensional information about the subject E can be represented as one record (column), and a table describing a preferred frequency parameter can be generated. Furthermore, when the database 261a is processed by a computer or the like, it can be expressed in a tabular form or in a database form in which each multidimensional information about the subject E is represented as one record.

[0099] return Figure 6 The data processing unit 201 includes an imaging unit 262. The imaging unit 262 is provided in the signal processing unit 250, and generates an image 273 ( ) indicating the position of the defective portion D (defective position) by using the portion of the frequency component specified by the frequency parameter among the converted frequency components. Fig.13 Specifically, the imaging unit 262 generates an image 273 based on the change (amount of change) of the signal caused by the defective portion D of the inspection object E in the frequency spectrum of the portion corresponding to the input frequency parameter in the frequency spectrum corresponding to the frequency component converted by the frequency conversion unit 230. In this way, the image 273 can be generated.

[0100] The change in the signal described here (the change in the received signal) is a signal feature in the example of the present invention. Therefore, the imaging unit 262 first calculates the signal feature based on the part of the frequency parameter input by the user in the spectrum corresponding to the converted frequency component. The signal feature is, as described above, a value representing the change in the signal, calculated based on the frequency component data in a manner that appropriately includes defect information (such as the position of the defect D). An example of a specific calculation method for the signal feature will be described later. By plotting the signal feature obtained in this way relative to the scanning position (x, y), a two-dimensional image (defect image) of the defect D present inside the inspected object E is generated.

[0101] The data processing unit 201 (signal processing unit 250) includes a display unit 263 for displaying on the display device 3. The display unit 263 outputs the image 273 to the display device 3 for display. The display device 3 is, for example, a monitor or a display. The display unit 263 displays the spectrum 271 ( Fig.13 At the same time, the display unit 263 displays the input unit 272 ( Fig.13). The input is performed by, for example, the user of the ultrasonic inspection device Z, but may also be input from another device (not shown). In the present invention, as an example, a case where the user inputs a frequency parameter is described.

[0102] By performing the above procedure while changing the scanning position (x, y), the desired range can be scanned. When the scanning is completed, the frequency component data and signal feature quantity corresponding to the scanning position (x, y) are stored in the storage unit 261 in the data processing unit 201. In the present invention, the signal feature quantity is calculated each time a signal is acquired at the scanning position. However, the frequency component data can also be stored in the storage unit 261 during the measurement, and the defect image can be generated by centrally calculating the signal feature quantity after the measurement.

[0103] (Frequency component data)

[0104] Here, the knowledge found by the present inventors regarding frequency component data will be described, and based on this knowledge, a method for calculating a signal feature amount will also be described.

[0105] In the present invention, when a received signal is decomposed into frequency components by Fourier transform or the like, the frequency with the largest component intensity is called the maximum component frequency. The component intensity is the amplitude when the frequency component is expressed by amplitude and phase, and is the absolute value when the frequency component is expressed by a complex number. The maximum intensity frequency component is the frequency component at the maximum component frequency. And the distribution of the component intensity of each frequency component is called a spectrum.

[0106] Figure 8 is a diagram schematically showing the distribution (spectrum) of the frequency components of the received signal. Figure 8 In the figure, the horizontal axis represents frequency and the vertical axis represents intensity (component intensity). The vertical axis is represented by a logarithmic scale, schematically representing a wide range of intensities.

[0107] The maximum component frequency, which is the frequency with the highest intensity, is defined as fm. The maximum component frequency fm is substantially equal to the fundamental frequency f0 of the burst wave transmitted from the transmitting probe 110. The frequency components of the signal have a spread before and after the maximum component frequency fm, which is referred to as a fundamental band W1.

[0108] The component of frequency N times the maximum component frequency fm (N×fm) is a harmonic. The component of frequency 1 / N times the maximum component frequency fm (fm / N) is a subharmonic. Here, N is an integer of N≥2. Harmonics and subharmonics also have extensions, respectively. In the example of the present invention, when it is particularly emphasized that harmonics and subharmonics have frequency extension, they are respectively referred to as harmonic bands and subharmonic bands. Therefore, even in the case of simply being recorded as "harmonics", they have frequency extension. Harmonic bands and subharmonic bands are generated by nonlinear phenomena and are generated when the sound pressure of the ultrasonic beam U input to the object E is extremely strong.

[0109] As shown in the example of the present invention, when the gas G is between the transmitting probe 110 and the object E, it is generally difficult to inject the ultrasonic beam U with a strong sound pressure into the object E, so at least one of the high harmonic band and the subharmonic band cannot be observed in many cases. Even under the conditions in the example of the present invention, the high harmonic band and the subharmonic band are below the detection limit.

[0110] like Figure 8 As shown, the basic band W1 has an extension in frequency. In the basic band W1, the frequency components other than the component of the maximum component frequency fm are called "basic components W3". The basic part W3 also includes the side lobes of the basic wave.

[0111] In the example of the present invention, the signal processing unit 250 calculates the above-mentioned signal feature by extracting the frequency component specified by, for example, the frequency parameter input by the user from the frequency component of the fundamental band W1 including the maximum component frequency. By inputting the appropriate frequency parameter, the detection performance of the defective portion D can be improved as described later.

[0112] Fig.9A It shows the change of the position of the signal strength information when the transmitting probe 110 and the receiving probe 121 are scanned in a manner crossing the defect D. Fig.9A , the result of the existing signal processing method, i.e., plotting the peak-to-peak voltage (Peak-to-Peak) of the received time domain waveform, is shown. The signal strength in the healthy part N is v0. On the other hand, at the position corresponding to the defective part D (x=0), the signal strength decreases by Δv, and the defective part D can be detected. However, the rate of change of the signal strength (Δv / v0) is small. Here, the rate of change of the signal strength is defined as the value obtained by dividing the signal change Δv in the defective part D by the signal strength v0 in the healthy part N.

[0113] Fig. 9B The results of calculating and plotting signal feature quantities based on frequency component data including appropriate multiple frequencies are shown. It can be seen that the rate of change (Δv / v0) of signal intensity at the defective portion D increases, and the detectability of the defective portion D improves.

[0114] Description Get Fig.9A and Fig. 9B The experimental conditions of the experimental results.

[0115] Fig.10The voltage waveform of the burst wave applied to the transmitting probe 110 is shown. The horizontal axis is time and the vertical axis is voltage. 10 waves of a sine wave with a basic frequency f0 of 0.82 MHz are applied. These 10 waves are called a beam. In addition, the reciprocal of the basic frequency f0 is called the basic period T0. The basic period T0 is the period of the wave that constitutes one beam as shown in the figure. The beam is applied with a repetition period Tr = 5ms.

[0116] Fig.11 express Fig.10 The frequency component distribution of the received signal under the conditions shown. The figure plots the measured data with the horizontal axis being the frequency and the vertical axis being the component strength at each frequency. The 0.82 MHz with the largest component strength is the maximum component frequency fm( Figure 8 ). Basic band W1( Figure 8 ) extends from 0.74 MHz to 0.88 MHz, where the components other than the maximum component frequency fm are the basic components W3( Figure 8 In the example of the present invention, the maximum component frequency fm is equal to the fundamental frequency f0 of the ultrasonic wave transmitted by the transmitting probe 110 ( Fig.10 ). Therefore, in most cases, the maximum component frequency fm is approximately equal to the fundamental frequency f0 of the transmitted ultrasonic wave.

[0117] Fig.12 This is a graph of measured data comparing the frequency component distribution (spectrum) of the received signal in the healthy part N (solid line) and the defective part D (dashed line). When the maximum component frequency fm = 0.82 MHz, the difference in component intensity (signal size) is small in the healthy part N and the defective part D. On the other hand, for the basic component W3 other than the maximum component frequency fm, especially in the low-frequency band, the difference between the healthy part N and the defective part D becomes larger. The larger the difference, the easier it is to distinguish the spectrum of the defective part D from the spectrum of the healthy part N, and the defective part D can be detected. Therefore, in Fig.12 In the case shown, by specifying the frequency parameter to be less than 0.82 MHz, the detection accuracy of the defect D can be improved.

[0118] Thus, the signal processing unit 250 reduces the maximum component frequency fm ( Figure 8 ) in the basic waveband W1 of the signal, to calculate the signal characteristic quantity representing the change of the signal. And, if the frequency parameters are set in this way to calculate the signal characteristic quantity, the detection accuracy of the defective part D can be further improved, and a better effect can be obtained. That is, the influence of the frequency component of the maximum component frequency fm can be reduced. Although "reduction" means, for example, exclusion of the frequency component of the maximum component frequency fm, the example of reduction is not limited to exclusion. And, although it is better to exclude completely, it is also possible to exclude only a part. For example, the frequency component (original frequency component) of the received signal can be reduced.

[0119] Furthermore, if the frequency parameter is selected in such a way as not to include the frequency component of the maximum component frequency fm, a better effect can be obtained. That is, if the signal feature amount is calculated from the basic component W3 of the basic band W1, a better effect can be obtained.

[0120] The reason why the basic component W3 of the fundamental band W1 changes sensitively to the defect D is considered to be as follows.

[0121] The propagation direction, phase, frequency, etc. of the direct wave U3 that does not interact with the defective portion D do not change. Therefore, the direct wave U3 accounts for a large proportion of the signal component of the maximum component frequency fm. Therefore, the change between the defective portion D and the sound portion N is small.

[0122] As mentioned above Figure 5 As shown, the scattered wave U1 interacting with the defect D has both a component that changes the propagation direction and a component that does not change the propagation direction but changes at least one of the phase or frequency. Therefore, the proportion of the component of the ultrasonic beam U interacting with the defect D, that is, the scattered wave U1, increases in the basic component W3 of the basic wave band W1, which is the component shifted from the maximum frequency fm. Therefore, the change between the defect D and the sound part N becomes larger. In this way, by reducing the component of the maximum component frequency fm and detecting the basic component W3 of the basic wave band W1, the detection performance of the defect D can be improved.

[0123] As described above, the inventors investigated the frequency components of the received signal and found that the difference between the sound part N and the defective part D of the basic component W3 is larger than the maximum component frequency fm. Based on this knowledge, it was found that by extracting the frequency component with a large difference between the sound part N and the defective part D (in Figure 1 In the example, it is a frequency region less than the maximum component frequency fm), and the signal feature value is calculated to improve the detectability of the defective portion D.

[0124] Therefore, the spectrum includes a spectrum representing the defective portion D in the object E to be inspected (the first spectrum) and a spectrum representing the portion other than the defective portion D in the object E to be inspected (the second spectrum). By including these, the magnitude of the difference between the first spectrum and the second spectrum can be determined. Fig.12 The second spectrum is in Fig.12 The solid line graph is in the middle.

[0125] By emitting (scanning) ultrasonic waves to the healthy part N other than the defective part D, for example, Fig.12 On the other hand, by emitting (scanning) ultrasonic waves to the defective portion D, for example, Fig.12The first spectrum is shown by the dotted line. Therefore, by scanning the subject E, the first spectrum is obtained in a certain part, and the second spectrum is obtained in a certain part. Therefore, the total spectrum obtained by scanning includes the first spectrum and the second spectrum.

[0126] The following describes a method for obtaining a first spectrum corresponding to a defective portion D and a second spectrum corresponding to a healthy portion N. In the example of the present invention, a standard test body whose position of the defective portion D is known is used, and the spectrum of the defective portion D is obtained as the first spectrum, and the spectrum of the healthy portion N is obtained as the second spectrum.

[0127] The method of obtaining the first spectrum and the second spectrum is not limited to the method using a standard test body. For example, first, the inspected body E is scanned, the received signal at each coordinate position is measured, and a defect image is generated using the frequency components in a specified frequency range, thereby determining the position of the defect D. Subsequently, the frequency spectra of the defect D and the sound part N may be measured and set as the first spectrum and the second spectrum, respectively. By appropriately resetting the frequency range used for imaging based on the first spectrum and the second spectrum obtained in this way, a defect image with higher accuracy can be obtained.

[0128] Furthermore, the imaging unit 262 ( Figure 6 ), in the spectrum of the part of the spectrum corresponding to the input frequency parameter, an image 273 is generated based on the difference between the first spectrum and the second spectrum ( Fig.13 ). Thus, an image 273 appropriately showing the position of the defective portion D can be generated.

[0129] (Calculation of signal feature quantity)

[0130] A method of calculating a signal feature amount from frequency component data used in an example of the present invention will be described.

[0131] Here, in order to make the numerical formula easier to understand, the frequency f is represented by an angular frequency ω. The angular frequency ω is the frequency f multiplied by 2π. The frequency component represented by a complex number is represented by H(ω). h(t) is calculated according to the following formula (1).

[0132] [Mathematical formula 1]

[0133]

[0134] [Mathematical formula 2]

[0135]

[0136] Here, in formula (1), j is an imaginary unit, and in formula (2), Re[ ] is a process of extracting the real part of a complex number. In formula (1), the subscript ω of the Σ symbol represents the frequency set of the accumulated angular frequency components. In formula (1), the accumulated angular frequency components are performed on the frequency set {ω} input by the user. This point is one of the characteristics of the present invention, and as described later, it is possible to obtain an image of the defective portion D more clearly.

[0137] The h(t) obtained by formula (2) is a signal waveform of a time region synthesized from a frequency set input by a user. In the example of the present invention, the difference between the maximum value and the minimum value (Peak-to-Peak value) of h(t) is used as a signal feature. In the example of the present invention, the difference between the maximum value and the minimum value (Peak-to-Peak value) is abbreviated as PP value.

[0138] In formula (1), H(ω) and exp(jωt) are both complex numbers and are calculated as complex numbers. That is, the signal feature quantity is calculated by also considering the phase information of the frequency component H(ω). In this way, a signal feature quantity that accurately reflects the position information of the defect D can be obtained, which is more preferable.

[0139] In equation (1), what is important is the selection of the set {ω} of frequencies included in the accumulation. The selection is performed, for example, by the user. Fig.12 From the spectrum, we can see that if we select the basic band W1 ( Figure 8 ) in the frequency range of the portion where the difference between the healthy portion N and the defective portion D is large, the image of the defective portion D can be obtained more clearly. Therefore, it is preferred that the user input the frequency range (frequency parameter) of the portion where the difference between the healthy portion N and the defective portion D is large. The "large" mentioned here can be, for example, a difference to the extent that the user can clearly identify the difference between the two frequency spectra, or a predetermined threshold value or more.

[0140] In addition, the signal feature quantity only needs to be a value calculated from the frequency component data in a manner that appropriately includes the position information of the defect portion D, and is not limited to the above-mentioned calculation method. In the above example, although the PP value of the signal waveform h(t) in the time region is used as the signal feature quantity, the absolute value of h(t) can also be calculated, and the area of ​​h(t) can be calculated and set as the signal feature quantity. Here, the area calculation procedure only needs to sample h(t) at appropriate time intervals and calculate the sum of h(t) at the sampling points. In addition, the square value of h(t) can also be used instead of the absolute value of h(t). In addition, instead of using equations (1) and (2), the absolute value of the total frequency component H(ω) of the input frequency set {ω} can be used as the signal feature quantity.

[0141] (Frequency selection)

[0142] Fig.13270 is a diagram schematically showing an example of the configuration of an operation screen 270 of the ultrasonic inspection device Z in the example of the present invention. The operation screen 270 is displayed through the display unit 263 ( Figure 6 ) is displayed on the display device 3 ( Figure 6 As described above, the display unit 263 displays the same information as that displayed by the frequency conversion unit 230 ( Figure 6 ) and an input unit 272 for receiving a frequency parameter input from a user. In the example of the present invention, the display unit 263 displays an operation screen 270 of the ultrasonic inspection device Z on the display device 3, and displays the spectrum 271 and the input unit 272 on the operation screen 270. Thus, the user can operate the input unit 272 while checking the operation screen 270 including the spectrum 271.

[0143] exist Fig.13 In the figure, an image 273 is displayed on the left side, and the image 273 indicates the position of the defective part D of the inspected object E. A spectrum 271 is displayed in the upper part of the right side. Here, if the spectrum 271 of multiple parts of the inspection position can be displayed, it can be compared, so it is preferred. In particular, the spectrum 271 includes the above-mentioned first spectrum shown by the dotted line and the above-mentioned second spectrum shown by the solid line. Thereby, the user can compare the spectra with each other, and the user can input appropriate frequency components. However, the displayed spectrum 271 may be either the first spectrum or the second spectrum. Since the user has a certain degree of experience, it is possible to determine the better frequency parameters based on the frequency parameters of only one of them.

[0144] The input unit 272 is used by the user to input frequency parameters. In the example of the present invention, the input unit 272 is a frequency selection unit composed of a sliding bar whose length and position can be adjusted. The user can input a frequency range (frequency set) for extracting signal feature quantities by adjusting the length and position of the sliding bar to a position corresponding to the frequency position of the spectrum using, for example, a mouse or keyboard. The frequency range input here is a frequency parameter.

[0145] When the user selects (one way of inputting) a frequency and presses the update button 274, the imaging unit 262 ( Figure 6 ) uses the newly selected frequency set {ωn} to calculate the signal feature quantity for each scanning position by the above method. The imaging unit 262 generates a two-dimensional image of the defect D inside the inspected object E, i.e., an image 273, by plotting the signal feature quantity relative to the scanning position (x, y). The display unit 263 displays the image 273 on the display device 3. The user visually recognizes the image 273 based on the newly calculated signal feature quantity, and if necessary, adjusts the input unit 272 again to update the signal feature quantity.

[0146] By setting the frequency parameter (frequency set {ωn}) for calculating the signal feature value in this way, the rate of change of the signal intensity of the image 273 showing the defective portion D can be increased. As a result, the contrast for distinguishing the defective portion D from the healthy portion N can be improved. In addition, since the rate of change of the signal intensity is increased, a smaller defective portion D can be detected, and the detection performance is improved.

[0147] The display unit 263 displays an input unit 275 for receiving information about the subject E on the display device 3. The information described here is the same as the information described in the above-mentioned database 261a. Fig.13 As an example, the input unit 275 for receiving the material of the object E to be inspected and the shape (thickness) of the object E to be inspected is displayed. In addition, the input unit 275 may not be displayed on the display device 3, for example, it may be read in the form of a configuration file. In this case, the input unit 275 constitutes the data processing unit 201 ( Figure 6 ) part.

[0148] The appropriate frequency parameters may vary depending on the material, shape, etc. of the inspected object E as described above. In addition, since there are multiple combinations of frequency parameters, it is not easy to determine the appropriate frequency parameters. Therefore, in the example of the present invention, by displaying the frequency spectra of multiple positions, the user can compare the spectra with each other and determine the frequency parameters. Thus, by visually recognizing the image 273 based on the determined frequency parameters, the contrast (ease of observation) of the defect D can be confirmed. As a result, a frequency set suitable for obtaining the image 273 of the defect D can be selected. Therefore, by improving the contrast of the image 273, etc., the detection performance of the defect D can be improved.

[0149] In the example of the present invention, Fig.13 As shown, the frequency parameter is input using a slider, but the input is not limited to the slider, and any method is acceptable as long as it can be input. For example, a mouse, keyboard, etc. may be used to input a desired frequency value. Fig.12 The configuration example of the operation screen 270 shown is just an example, and the present invention is not limited to this configuration.

[0150] In addition, as about Fig.13 In another embodiment, the display unit 263 ( Figure 6 ) The display device 3 displays the input unit 275 (first input unit) and displays the input unit 272 (second input unit). The input unit 275 receives information that affects the detection accuracy of the defect D in the object E to be inspected (information about the object E to be inspected). The input unit 272 receives input of a frequency parameter. The input is performed, for example, by a user. In this embodiment, as an example, the database 261a is provided in the signal processing unit 250.

[0151] The spectrum 271 is preferably displayed, but may not be displayed. When it is not displayed, for example, the imaging unit 262 retrieves the spectrum from the database 261a ( Figure 6 ) determines the frequency parameter corresponding to the received information about the subject E as the initial frequency parameter through the input unit 275. In the case where there is no corresponding frequency parameter, the frequency parameter corresponding to the information closest to the information is determined. The imaging unit 262 generates an image 273 ( Fig.13 ). By utilizing the information in the database 261a, the detection accuracy of the defective portion D can be improved.

[0152] Fig.14 This is a functional block diagram of an ultrasonic inspection device Z according to another embodiment. The signal processing unit 250 has an updating unit 291 (frequency parameter updating unit). The updating unit 291 automatically updates the frequency parameters. The following is an example of a more specific process of the updating unit 291. The imaging unit 262 calculates the signal feature quantity while changing the frequency parameter of the received signals at two points of the defective part D and the healthy part N. Furthermore, the updating unit 291 searches for and determines the frequency parameter with the largest difference in the signal feature quantity between the defective part D and the healthy part N. The imaging unit 262 generates an image 273 using the frequency parameter updated by the updating unit 291. Furthermore, the frequency parameter updated in this way is registered in the database 261a, and the database 261a is updated.

[0153] The determined frequency parameter may also be displayed on the display device 3. Furthermore, instead of automatically updating the frequency parameter by the updating unit 291, the user may designate the frequency parameter by the input unit 272 while observing the image 273. Even in this way, the detection accuracy of the defective portion D can be further improved.

[0154] In addition, the above Fig.13 The frequency resolution of the spectrum 271 shown may be different from the resolution of the frequency conversion during defect inspection of the object under inspection E. For example, a higher frequency resolution than the frequency conversion unit 230 during defect inspection may be measured and displayed. Fig.13 Specifically, for two representative points at the defective portion D and the sound portion N, the frequency resolution of the frequency conversion unit 230 may be set to be improved, and the spectrum may be remeasured. In addition, the frequency range of the measured spectrum 271 may be expanded compared to the condition during defect inspection. In this way, the frequency parameters can be set based on more detailed spectrum information.

[0155] Fig.15 1 is a diagram showing a processing flow in an example of the present invention. The processing of the present invention is roughly divided into a measurement step S1 and an imaging step S2. In the measurement step S1, the frequency conversion unit 230 ( Figure 6) performs frequency conversion on the received signal of the ultrasonic beam U at each scanning position (x, y) (step S11). Thus, the frequency conversion unit 230 ( Figure 6 ) obtain frequency component data (step S12).

[0156] In the imaging step S2, the imaging unit 262 ( Figure 6 ) Using the frequency component data obtained in step S12, using the frequency set {ω} pre-set as the initial frequency parameter, image 273 ( Fig.13 ) is visualized (step S21). The visualized image 273 is used as the operation screen 270 ( Figure 6 ) is displayed on the display device 3 ( Fig.13 ). Display unit 263 ( Figure 6 ) in the display device 3 ( Fig.13 )Display spectrum 271( Fig.13 ) as the operation screen 270 ( Figure 6 )(Step S22).

[0157] The user inputs frequency parameters while referring to the spectrum 271 displayed on the operation screen 270 (step S23). The input is preferably performed by selecting an appropriate range such as an image 273 that appropriately displays the defective portion D. Specifically, it is preferable to select a frequency component in which the difference between the spectrum of the defective portion D and the spectrum of the healthy portion N is as large as possible. The imaging unit 262 recalculates the signal feature quantity of each scanning position (x, y) using the reset frequency parameter, specifically the frequency set {ω}. The imaging unit 262 updates the image 273 using the recalculated signal feature quantity (step S24). At the same time, the display unit 263 displays the operation screen 270 ( Figure 6 ) displays the updated image (step S24).

[0158] Fig.16 2 is a diagram schematically showing a configuration example of the operation screen 270 according to the second embodiment. In the second embodiment, frequency parameter learning is further performed in the first embodiment.

[0159] In the example of the present invention, the display unit 263 ( Figure 6 ) also has a registration button 276. As described above, since the appropriate frequency parameters may differ depending on information such as the examination conditions, it is not easy to input the appropriate frequency parameters. In other words, if information such as the measurement conditions of the subject E is determined, the appropriate frequency parameters can be predicted to a certain extent. Therefore, in the example of the present invention, after the user inputs the appropriate frequency parameters, if the user presses the registration button 276, the control device 2 associates the information about the subject E (examination conditions, etc.) with the input frequency parameters and updates the database 261a ( Figure 6). Thus, every time the number of inspections increases, the data recorded in the database 261a increases, and it is easy to image based on the data. Therefore, the user can save the time of checking and inputting the spectrum.

[0160] Fig.17 FIG. 2 is a diagram showing the processing flow of this embodiment of the second embodiment. In the second embodiment, in addition to the measurement step S1 and the imaging step S2, a learning step S3 is further included. In the learning step S3, information about the subject E and the frequency parameter (appropriate frequency set {ωn}) are registered in the database 261a ( Figure 6 ) to learn the frequency parameters associated with the information about the subject E. That is, when the user presses the registration button 276 ( Fig.16 ) (step S31), the control device 2 ( Figure 6 Specifically, the imaging unit 262 associates the information about the subject E with the input frequency parameters and updates the database 261a (step S32). Then, the initial frequency parameters for a new measurement are set based on the learned database 261a (step S25). Thus, even if the initial frequency parameters are used for imaging, an image 273 with good performance can be obtained.

[0161] By updating the frequency parameters to a more optimal frequency set {ωn}, the result of imaging with the initial parameters can be updated to a frequency parameter with better defect detectability. By registering this result, the database 261a is further updated.

[0162] The present invention is characterized in that the know-how accumulated by the users of the ultrasonic inspection device Z through the experience of measurement can be stored in the ultrasonic inspection device Z as a database 261a. Since the know-how of measurement is stored in the ultrasonic inspection device Z, the defect detection performance in the imaging result under the initial frequency parameter can be improved as the number of measurements (experience) increases. In addition, since the know-how of measurement is stored in the ultrasonic inspection device Z itself, the know-how of measurement can be automatically used even if the user changes.

[0163] Fig.18 This is a functional block diagram of the ultrasonic inspection device Z of the third embodiment. In the third embodiment, the database 261a is stored in, for example, a server 281 that is provided at a location away from the ultrasonic inspection device Z. The ultrasonic inspection device Z (especially the control device 2) can be connected to the network 280. Furthermore, the ultrasonic inspection device Z (especially the control device 2) is connected to the database 261a via the network 280. Thus, the database 261a can be used regardless of the location where the ultrasonic inspection device Z is installed. In particular, by connecting a plurality of ultrasonic inspection devices Z to one database 261a, the number of updates of the database 261a can be increased, and the accuracy of the information recorded in the database 261a can be improved.

[0164] Fig.19 : is a diagram showing the processing flow of the third embodiment. The general flow is similar to the flow in the second embodiment ( Fig.17 ) is the same as above, but in step S321, the database 261a ( Fig.18 . That is, the online connected database 261a).

[0165] In addition, the control device 2 ( Figure 6 ) can be database 261a ( Figure 6 ) is provided locally, and in addition, the control device 2 can be connected to the remote database 261a online via the network 280. Thus, the content of the local database 261a is connected through the online connection, and the online database 261a can be updated.

[0166] (Fourth embodiment. Focal length of the receiving probe 121)

[0167] In the fourth embodiment, the focal length R2 of the receiving probe 121 is preferably longer than the focal length R1 of the transmitting probe 110. This is because, as described later, more components of the scattered wave U1 can be detected. As described above, since the ultrasonic beam U interacts with the scattered wave U1 and the defect D, the greater the proportion of the scattered wave U1 component, the easier it is to detect the defect D.

[0168] use Fig. 20A and Fig. 20B The reason why more scattered wave components can be detected when the focal length of the receiving probe 121 is made longer is described.

[0169] Fig. 20A 2 is a diagram schematically showing the propagation path of the ultrasonic beam U when the focal length R1 of the transmitting probe 110 and the focal length R2 of the receiving probe 121 are made equal in the fourth embodiment. Fig. 20B The cone C3 is described in FIG. Fig. 20A In the example shown, the convergence point of the ultrasonic beam U transmitted from the transmitting probe 110 is the same as the convergence point of the virtual beam virtually emitted from the receiving probe 121. Therefore, the ultrasonic beam U whose propagation direction does not change at the defect D can be effectively received. On the other hand, the ultrasonic beam U whose propagation direction changes at the defect D is difficult to detect.

[0170] Fig. 20BThis is a diagram schematically showing the propagation path of the ultrasonic beam U when the focal length R2 of the receiving probe 121 is made longer than the focal length R1 of the transmitting probe 110 in the fourth embodiment. The receiving probe 121 can detect the ultrasonic beam U within the cone (shape) C3 of the virtual beam virtually emitted from the receiving probe 121. Therefore, even if it is a scattered wave U1 whose propagation direction changes slightly in the defect portion D, it can be detected as long as it enters the range of the cone C3. In this way, by making the focal length R2 of the receiving probe 121 longer than the focal length R1 of the transmitting probe 110, the detectable scattered waves U1 can be increased. As described above, since the scattered wave U1 is a wave that interacts with the defect portion D, the detection performance of the defect portion D can be further improved.

[0171] The magnitude relationship of the convergence is also defined as the magnitude relationship between the ultrasonic beam incident areas T1 and T2 on the surface of the object E. The ultrasonic beam incident areas T1 and T2 will be described.

[0172] Fig.21 1 is a diagram for explaining the relationship between the ultrasonic beam incident area T1 in the transmitting probe 110 and the ultrasonic beam incident area T2 in the receiving probe 121. The ultrasonic beam incident area T1 of the transmitting probe 110 on the subject E is the intersection area of ​​the ultrasonic beam U emitted from the transmitting probe 110 on the surface of the subject E. Furthermore, the ultrasonic beam incident area T2 of the receiving probe 121 is the intersection area of ​​a virtual ultrasonic beam U2 and the surface of the subject E when the ultrasonic beam U is emitted from the receiving probe 121.

[0173] In addition, Fig.21 In FIG. 1 , the path of the ultrasonic beam U indicates the path when there is no object E. When there is an object E, the ultrasonic beam U is refracted on the surface of the object E, so the ultrasonic beam U is transmitted along a path different from the path shown by the dotted line. Fig.21 As shown, the ultrasonic beam incident area T2 of the receiving probe 121 on the subject E is larger than the ultrasonic beam incident area T1 of the transmitting probe 110 on the subject E. Thus, the convergence of the receiving probe 121 can be made slower than that of the transmitting probe 110.

[0174] Furthermore, the focal length R2 of the receiving probe 121 is longer than the focal length R1 of the transmitting probe 110. Even so, the convergence of the receiving probe 121 can be made slower than the convergence of the transmitting probe 110. At this time, the distances from the subject E to the transmitting probe 110 and the receiving probe 121 are, for example, the same, but may be different.

[0175] Thus, in the example of the present invention, the convergence of the receiving probe 121 is made slower than the convergence of the transmitting probe 110. That is, the focal length R2 of the receiving probe 121 is set longer than the focal length R1 of the transmitting probe 110. As a result, since the ultrasonic beam incident area T2 of the receiving probe 121 becomes wider, it is possible to detect a wide range of scattered waves U1. Thus, even if the propagation path of the scattered waves U1 is slightly changed, the scattered waves U1 can be detected by the receiving probe 121. As a result, a wide range of defective parts D can be detected.

[0176] Furthermore, the focus P1 of the receiving probe 121 is located closer to the transmitting probe 110 (in the example shown in the figure, above) than the focus P2 of the transmitting probe 110. By shifting the focuses P1 and P2 in this way, the receiving probe 121 can easily receive the scattered wave U1, and the scattered wave U1 can be easily detected.

[0177] In addition, as a configuration in which the focal length R2 of the receiving probe 121 is longer than the focal length R1 of the transmitting probe 110, a non-convergent probe (not shown) may be used as the receiving probe 121. In the non-convergent probe, since the focal length R2 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 receiving probe 121, the convergence of the receiving probe 121 is slower than the convergence of the transmitting probe 110.

[0178] (Fifth embodiment)

[0179] Fig. 22 1 is a diagram showing the configuration of an ultrasonic inspection apparatus Z in the fifth embodiment. In the fifth embodiment, the transmission acoustic axis AX1 of the transmission probe 110 and the reception acoustic axis AX2 of the reception probe 121 are arranged to be offset. That is, the reception probe 121 in the second embodiment has a reception probe 120 (eccentrically arranged reception probe) whose reception acoustic axis AX2 is arranged at a position different from the transmission acoustic axis AX1 of the transmission probe 110. Therefore, the eccentric distance L (distance) between the transmission acoustic axis AX1 (acoustic axis) of the transmission probe 110 and the reception acoustic axis AX (acoustic axis) of the reception probe 120 is greater than zero.

[0180] By setting such a configuration, it is possible to detect the wave whose spatial direction changes in the scattered wave U1. Fig.12 ) and the principle of extracting the spatial scattered wave U1 using eccentric configuration can further improve the detectability of the defect D.

[0181] In the fifth embodiment, although the transmitting probe 110 is Fig. 22 The receiving probe 120 is configured to be staggered by an eccentric distance L in the x-axis direction, but it can also be configured to be staggered by an eccentric distance L in the x-axis direction. Fig. 22Alternatively, the receiving probe 120 may be arranged at L1 in the x-axis direction and at L2 in the y-axis direction (i.e., the position of the transmitting probe 110 in the xy plane as the origin (L1, L2)).

[0182] Fig.23A 1 is a diagram for explaining the transmission acoustic axis AX1, the reception acoustic axis AX2, and the eccentric distance L, and shows a case where the transmission acoustic axis AX1 and the reception acoustic axis AX2 extend in the vertical direction. Fig. 23B 1 is a diagram for explaining the transmission acoustic axis AX1, the reception acoustic axis AX2, and the eccentric distance L, and shows a case where the transmission acoustic axis AX1 and the reception acoustic axis AX2 extend obliquely. Fig.23A and Fig. 23B In FIG. 1 , for reference, the receiving probe 140 (coaxially configured receiving probe) is also illustrated in dashed lines.

[0183] The direction of the receiving sound axis AX2 is the probe surface 114 ( Figure 2 The reason is that the virtual ultrasonic beam U radiated from the receiving probe 121 is emitted in the normal direction of the probe surface 114. When receiving the ultrasonic beam U, the ultrasonic beam U incident in the normal direction of the probe surface 114 can also be received with good sensitivity.

[0184] The eccentric distance L is defined by the distance that the transmitting acoustic axis AX1 is offset from the receiving acoustic axis AX2. Fig. 23B As shown in FIG. 1 , when the ultrasonic beam U emitted from the transmitting probe 110 is refracted, the eccentric distance L is defined by the distance by which the refracted transmitting acoustic axis AX1 and the receiving acoustic axis AX2 are offset. In the ultrasonic inspection apparatus Z of the fifth embodiment, the eccentric distance L defined in this way is set to a distance greater than zero by adjusting the eccentric distance L by the eccentric distance adjusting unit 105 ( Fig. 22 ) to adjust the transmitting probe 110 and the receiving probe 120.

[0185] exist Fig.23A , it is shown that the transmitting probe 110 is arranged in the normal direction of the surface of the object E. Fig.23A and Fig. 23B In FIG. 1 , the transmission sound axis AX1 is shown by a solid arrow. Also, the reception sound axis AX2 is shown by a dashed arrow. Fig.23A and Fig. 23B In the figure, the position of the receiving probe 121 shown by the dotted line is the position where the eccentric distance L is zero, and the receiving probe 121 whose transmission acoustic axis AX1 and the receiving acoustic axis AX2 coincide with each other is the receiving probe 140 as a coaxially configured receiving probe. In addition, the receiving probe 121 shown by the solid line is the receiving probe 120 configured at the position where the eccentric distance L is greater than zero (eccentrically configured receiving probe). Fig. 22When the transmitting probe 110 is set in a manner perpendicular to the xy plane of the sample stage 102, the transmission path of the ultrasonic beam U is not bent. That is, the transmission acoustic axis AX1 is not bent. This corresponds to the case where the transmitting probe 110 is set in a manner perpendicular to the mounting surface 1021 of the sample stage 102.

[0186] exist Fig. 23B , the transmission probe 110 is arranged at an angle α tilted from the normal direction of the surface of the object E. Fig. 23B Zhong Ye and Fig.23A Likewise, the transmission acoustic axis AX1 is indicated by a solid arrow, and the reception acoustic axis AX2 is indicated by a dashed-dotted arrow. Fig. 23B In the example shown in FIG. 1 , as described above, the transmission path of the ultrasonic beam U is refracted at the interface between the object E and the fluid F at a refraction angle β. Therefore, the transmission acoustic axis AX1 is as shown in FIG. Fig. 23B In this case, the position of the receiving probe 140 shown by the dotted line is a position where the eccentric distance L is zero because it is located on the transmission sound axis AX1. Moreover, as described above, even when the ultrasonic beam U is refracted, the receiving probe 120 is configured in such a way that the distance between the transmission sound axis AX1 and the reception sound axis AX2 is L. Fig. 22 In the example shown, since the transmitting probe 110 is set in the normal direction of the surface of the object E, the eccentric distance L is as follows: Fig.23A shown.

[0187] The eccentric distance L is further preferably set to a position where the signal intensity at the defective portion D is greater than the received signal at the healthy portion N of the object E to be inspected.

[0188] (Sixth Implementation Method)

[0189] Fig.24 1 is a diagram showing the structure of the ultrasonic inspection device Z in the sixth embodiment. In the sixth embodiment, the scanning measurement device 1 has a setting angle adjustment unit 106 for adjusting the slope of the receiving probe 120. As a result, the strength of the received signal can be increased, and the SN ratio (Signal to Noise ratio) of the signal can be increased. The setting angle adjustment unit 106 is not shown in the figure, but is composed of an actuator, a motor, etc.

[0190] Here, the angle θ between the transmission acoustic axis AX1 and the reception acoustic axis AX2 is defined as the receiving probe setting angle. Fig.24In the case of , since the transmitting probe 110 is set in the vertical direction, the transmitting acoustic axis AX1 is in the vertical direction, and therefore the receiving probe setting angle, that is, the angle θ, is the angle between the transmitting acoustic axis AX1 (i.e., the vertical direction) and the normal of the probe surface of the receiving probe 120. Furthermore, by setting the angle adjustment unit 106, the angle θ is tilted toward the side where the transmitting acoustic axis AX1 is located, and the angle θ is set to a value greater than zero. That is, the receiving probe 120 is tilted. Specifically, the receiving probe 120 is tilted in a manner that satisfies 0°<θ<90°, and the angle θ is, for example, 10°, but is not limited thereto.

[0191] In addition, the eccentric distance L in the case of the receiving probe 120 being arranged at an angle is defined as follows. The intersection C2 of the receiving acoustic axis AX2 and the probe surface of the receiving probe 120 is defined. In addition, the intersection C1 of the transmitting acoustic axis AX1 and the probe surface of the transmitting probe 110 is defined. The distance between the position of the intersection C1 projected onto the coordinate position (x4, y4) of the xy plane (not shown) and the position of the intersection C2 projected onto the coordinate position (x5, y5) of the xy plane (not shown) is defined as the eccentric distance L.

[0192] When the present inventors actually inspected the defective portion D by configuring the receiving probe 120 in an inclined manner, the signal strength of the received signal increased to 3 times compared to the case where θ=0.

[0193] Fig.25 1 is a diagram for explaining the reason why the effect of the sixth embodiment is produced. The scattered wave U1 propagates in a direction deviating from the transmission sound axis AX1. Fig.25 As shown, when the scattered wave U1 reaches the outside of the object E, it has a non-zero angle α2 with the normal vector of the surface of the object E and enters the interface between the object E and the outside. In addition, the angle of the scattered wave U1 emitted from the surface of the object E has an angle β2 which is a non-zero exit angle with respect to the normal direction of the surface of the object E. When the normal vector of the probe surface of the receiving probe 120 is aligned with the traveling direction of the scattered wave U1, the scattered wave U1 can be received most effectively. That is, by tilting the receiving probe 120, the received signal strength can be increased.

[0194] In addition, when the angle β2 of the ultrasonic beam U emitted from the subject E coincides with the angle θ formed by the transmission acoustic axis AX1 and the reception acoustic axis AX2, the reception effect is the best. However, even when the angle β2 and the angle θ do not coincide with each other, the reception signal can be increased. Fig.25 As shown, the angle β2 and the angle θ may not be completely consistent.

[0195] (Seventh Implementation Method)

[0196] Fig.261 is a diagram showing the configuration of an ultrasonic inspection apparatus Z according to a seventh embodiment. In the seventh embodiment, the fluid F is a liquid W, and in the example shown in the figure, it is water. The ultrasonic inspection apparatus Z inspects the object E by causing an ultrasonic beam U to be incident on the object E through the fluid F, i.e., the liquid W. The object E is arranged below the liquid surface L0 of the liquid W and immersed in the liquid W.

[0197] Alternatively, the fluid F may be a gas G as described above ( Figure 1 ), or it may be a liquid W as in the present embodiment ( Fig.26 However, when a gas G such as air is used as the fluid F, a better effect is obtained for the following reasons.

[0198] The attenuation of ultrasonic waves in gas G is greater than that in liquid W. It is known that the attenuation of ultrasonic waves in gas G is proportional to the square of the frequency. Therefore, in order to transmit ultrasonic waves in gas G, the upper limit is about 1 MHz. In the case of liquid W, since ultrasonic waves of 5 MHz to several tens of MHz are also transmitted, the frequency that can be used in gas G is lower than that in liquid W.

[0199] Generally speaking, if the frequency of the ultrasonic beam U becomes lower, it becomes difficult to converge the ultrasonic beam U. Therefore, the 1 MHz ultrasonic beam U propagating in the gas G has a larger beam diameter that can be converged than the ultrasonic beam U in the liquid W. On the other hand, as mentioned above Figure 4 As shown, in the conventional method, i.e., the blocking mode, it is difficult to detect a defect D smaller than the beam size. However, according to the present invention, as described above Figure 5 As shown, since the proportion of the scattered wave component is increased for detection, a defect D smaller than the beam size can be detected.

[0200] When gas G is used as fluid F, it is more difficult to reduce the beam size of ultrasonic beam U, so the effect of the present invention is more effective. Thus, when gas G is used as fluid F, the present invention can achieve better effects.

[0201] Fig. 27 2 is a diagram showing the hardware configuration of the control device 2. The above-mentioned configurations, functions, and components of the block diagram may be implemented in hardware by, for example, designing a part or all of them by integrated circuits. Fig. 27As shown, the above-mentioned various structures, functions, etc. can also be realized by software by interpreting and executing the program for realizing each function through a processor such as a CPU (Central Processing Unit) 252. The control device 2 has, for example, a memory 251, a CPU 252, a storage device 253 (SSD (Solid State Drive), HDD (Hard Disc Drive), etc.), a communication device 254, and an I / F (Interface) 255. In addition to being stored in the HDD, the information of the program, table, file, etc. for realizing each function can also be stored in a recording device such as a memory, SSD (Solid State Drive), or a recording medium such as an IC (Integrated Circuit) card, an SD (Secure Digital) card, or a DVD (Digital Versatile Disc).

[0202] Fig.28 The ultrasonic inspection method of the present invention can be executed by the control device 2 of the ultrasonic inspection device Z as an example, and as appropriate, refer to Figure 1 and Figure 6 The ultrasonic inspection method of the present invention is to pass the gas G ( Figure 1 . An example of fluid F) to the inspected object E ( Figure 1 ) to inspect the object E. In addition, although the ultrasonic inspection method is described for an embodiment using gas G as the fluid F, the ultrasonic inspection method is also applicable to an embodiment using liquid W ( Fig.24 ) is also effective as an implementation scheme of fluid F.

[0203] The ultrasonic inspection method of the present invention includes steps S101, S102, S103, S104, S105, S111, S112, S120, S121, S122, and S123. First, according to the instruction of the control device 2, the transmitting probe 110 performs step S101 (transmitting step) of transmitting the ultrasonic beam U from the transmitting probe 110. Then, the receiving probe 121 performs step S102 (receiving step) of receiving the ultrasonic beam U.

[0204] Subsequently, the frequency conversion unit 230 performs step S103 (conversion step) of converting the signal (e.g., waveform signal) of the ultrasonic beam U received in step S102 into a frequency component. The frequency component data is sent to the data processing unit 201, and the data processing unit 201 performs step S104 (signal feature amount calculation step) of calculating the signal feature amount from the frequency component data. Specifically, the data processing unit 201 integrates the frequency components of a preset frequency set in consideration of the phase, thereby calculating the signal feature amount.

[0205] Next, step S105 (shape display step) is performed. The scanning position information of the transmitting probe 110 and the receiving probe 121 is sent from the position measurement unit 203 to the scanning controller 204. The data processing unit 201 plots the signal strength data of each scanning position for the scanning position information of the transmitting probe 110 obtained from the scanning controller 204. In this way, the image is generated based on the spectrum and signal feature determined by the signal strength data. This is step S105 (shape display step).

[0206] Here, for the case where the scanning position information is one-dimensional (one direction) and the case where the scanning position information is two-dimensional x and y, the signal strength data is plotted. Fig.13 As shown, the defective portion D is displayed as a two-dimensional image 273 and is displayed on the display device 3 .

[0207] The data processing unit 201 determines whether the scan is completed (step S111). If the scan is completed (yes), the control device 2 ends the measurement process (step S120). If the scan is not completed (no), the data processing unit 201 outputs a command to the drive unit 202 to move the transmitting probe 110 and the receiving probe 121 to the next scanning position (step S112), and returns the process to step S101. As described above, the display device 3 displays the initial image 273 ( Fig.13 ).

[0208] Next, the input unit 272 ( Fig.13 ) receives input of frequency parameters in the frequency component (step S121, input step). The input is performed by the user, for example. The imaging unit 262 ( Figure 6 ) uses the input frequency parameter to determine the signal feature quantity (step S122, imaging step). The imaging unit 262 generates an image 273 ( Fig.13) (Step S122, imaging step). The generated image 273 is displayed on the display device 3. When the user selects to end the inspection (Yes in Step S123), a series of controls are ended. On the other hand, if the user does not select to end the inspection (No in Step S123), the input unit 272 receives the input of the frequency parameter again, so the steps after Step S121 are performed.

[0209] According to the ultrasonic inspection device Z and the ultrasonic inspection method described above, the performance of detecting the defective portion D, for example, the performance of detecting micro defects can be improved.

[0210] In the above embodiments, although the defect D is described as a hollow example, the defect D may be a foreign object mixed with a material different from that of the object to be inspected E. In this case, since there is a difference (Gap) in acoustic impedance at the interface where different materials meet, a scattered wave U1 is generated, and thus the configuration of the above embodiments is effective. The ultrasonic inspection device Z of the above embodiments is based on an ultrasonic defect imaging device, but it can also be applied to a non-contact in-line internal defect inspection device.

[0211] The present invention is not limited to the above-mentioned embodiments, and includes various variations. For example, the above-mentioned embodiments are described in detail to explain the present invention in an easy-to-understand manner, and are not necessarily limited to all the structures described. In addition, a part of the structure of a certain embodiment may be replaced with a structure of another embodiment, and a structure of another embodiment may be added to a structure of a certain embodiment. In addition, other structures may be added, deleted, or replaced with a part of the structure of each embodiment.

[0212] Furthermore, in each embodiment, control lines and information lines are shown if necessary for explanation, and the product is not necessarily limited to showing all control lines and information lines. In fact, it can be considered that almost all components are connected to each other.

[0213] Description of Reference Numerals

[0214] 1 Scanning measurement device

[0215] 102 Sample table

[0216] 1021 Loading surface

[0217] 110 Send probe

[0218] 120 Receiving probe

[0219] 121 Receiving probe

[0220] 140 Receiving probe

[0221] 2 Control device

[0222] 201 Data Processing Department

[0223] 202 Drive unit

[0224] 203 Position measurement unit

[0225] 204 Scan Controller

[0226] 210 Sending system

[0227] 211 Waveform Generator

[0228] 212 Signal Amplifier

[0229] 220 Receiving System

[0230] 222 Signal Amplifier

[0231] 230 Frequency conversion unit

[0232] 250 Signal Processing Unit

[0233] 261 Storage

[0234] 261a Database

[0235] 262 Visualization Department

[0236] 263 Display

[0237] 270 Operation screen

[0238] 271 Spectrum

[0239] 272 Input

[0240] 273 images

[0241] 274 Update button

[0242] 275 Input

[0243] 276 Register Button

[0244] 280 Network

[0245] 281 Server

[0246] 291 Update Department

[0247] 3 Display device

[0248] Z Ultrasonic inspection device.

Claims

1. An ultrasonic inspection device for inspecting an object by injecting an ultrasonic beam into the object through a fluid, characterized in that: include: a scanning measurement device for scanning and measuring the object to be inspected with the ultrasonic beam, and a control device for controlling the driving of the scanning measurement device, The scanning measuring device comprises a transmitting probe for transmitting the ultrasonic beam and a receiving probe for receiving the ultrasonic beam. The control device includes a signal processing unit. The signal processing unit comprises: A frequency conversion unit for converting a received signal of the receiving probe into a frequency component; an imaging unit that generates an image indicating a defect position using a portion of the frequency components specified by the frequency parameter among the converted frequency components; and a display unit for displaying on a display device, The display unit displays the frequency spectrum corresponding to the frequency component converted by the frequency conversion unit and the input unit for receiving the input of the frequency parameter on the display device.

2. The ultrasonic inspection device according to claim 1, characterized in that: The display unit displays an operation screen of the ultrasonic inspection device on the display device, and displays the frequency spectrum and the input unit on the operation screen.

3. The ultrasonic inspection device according to claim 1, characterized in that: The focal length of the receiving probe is longer than the focal length of the transmitting probe.

4. The ultrasonic inspection device according to claim 1, characterized in that: The ultrasonic beam incident area of ​​the receiving probe is larger than the ultrasonic beam incident area of ​​the transmitting probe.

5. The ultrasonic inspection device according to claim 1, characterized in that: The fluid is a gas.

6. The ultrasonic inspection device according to claim 1, characterized in that: The control device includes a database in which information affecting the detection accuracy of the defective portion in the inspection object is associated with the frequency parameter.

7. The ultrasonic inspection device according to claim 1, characterized in that: The ultrasonic inspection device can be connected to a network. The control device is connected to a database in which information that affects detection accuracy of a defect in the inspection object and the frequency parameter are associated with each other via the network.

8. The ultrasonic inspection device according to claim 6, characterized in that: The control device associates the information with the input frequency parameter to update the database.

9. The ultrasonic inspection device according to claim 6, characterized in that: The information includes the inspection conditions of the object to be inspected.

10. The ultrasonic inspection device according to claim 9, characterized in that: The inspection condition includes at least one of the material of the inspection object, the thickness of the inspection object, the structure of the inspection object, the position of the inspection object relative to the receiving probe and the transmitting probe, and the type of the fluid.

11. The ultrasonic inspection device according to claim 1, characterized in that: The signal processing unit extracts a frequency component specified by the frequency parameter from frequency components of a fundamental band including a maximum component frequency, and calculates a signal feature amount indicating a change in the signal.

12. The ultrasonic inspection device according to claim 1, characterized in that: The signal processing unit calculates a signal feature amount indicating a change in a signal by reducing a frequency component of the maximum component frequency in a fundamental band including the maximum component frequency.

13. The ultrasonic inspection device according to claim 1, characterized in that: The frequency spectrum includes a first frequency spectrum indicating a defective portion in the inspection object and a second frequency spectrum indicating a healthy portion which is a portion other than the defective portion in the inspection object.

14. The ultrasonic inspection device according to claim 13, characterized in that: The imaging unit generates the image based on a difference between the first spectrum and the second spectrum in a portion of the spectrum corresponding to the input frequency parameter.

15. The ultrasonic inspection device according to claim 1, characterized in that: The distance between the acoustic axis of the transmitting probe and the acoustic axis of the receiving probe is greater than zero.

16. The ultrasonic inspection device according to claim 1, characterized in that: The distance between the acoustic axis of the transmitting probe and the acoustic axis of the receiving probe is zero.

17. The ultrasonic inspection device according to claim 1, characterized in that: The transmitting probe is provided so that a transmission acoustic axis of the transmitting probe is perpendicular to a placement surface of a sample stage on which the test object is placed.

18. An ultrasonic inspection device for inspecting an object to be inspected by irradiating an ultrasonic beam onto the object to be inspected via a fluid, characterized in that: include: a scanning measurement device for scanning and measuring the object to be inspected with the ultrasonic beam, and a control device for controlling the driving of the scanning measurement device, The scanning measuring device comprises a transmitting probe for transmitting the ultrasonic beam and a receiving probe for receiving the ultrasonic beam. The control device includes a signal processing unit. The signal processing unit comprises: A frequency conversion unit for converting a received signal of the receiving probe into a frequency component; an imaging unit that generates an image representing a defect position using a portion of the frequency components specified by the frequency parameter among the converted frequency components; a database that associates information that affects the accuracy of detecting a defect in the inspected object with the frequency parameter; and a display unit for displaying on a display device, The display unit displays a first input unit for receiving information affecting the detection accuracy of the defective portion in the inspection object on the display device.

19. The ultrasonic inspection device according to claim 18, characterized in that: The ultrasonic inspection device can be connected to a network. The control device is connected to a database in which information that affects detection accuracy of a defect in the inspection object is associated with the frequency parameter via the network.

20. An ultrasonic inspection method for inspecting an object to be inspected by incidenting an ultrasonic beam onto the object to be inspected via a fluid, characterized in that: include: A transmitting step of transmitting an ultrasonic beam from a transmitting probe; A receiving step in which the probe receives the ultrasonic beam; a conversion step of converting the signal of the ultrasonic beam received in the receiving step into a frequency component; An input step of accepting an input of a frequency parameter in the frequency component; and An imaging step of generating an image representing the defect location using the input frequency parameters.

Images