JP2016205858A - Defect inspection device and control method thereof, program, and storage medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mechanism capable of, when a reflected ultrasonic wave from a bubble is detected in the same way as a reflected ultrasonic wave from a defect, grasping whether or not a reflected ultrasonic wave from a bubble has been detected.SOLUTION: A defect inspection device comprises: a bubble detection gate setting part 132 for setting, as a bubble detection gate, a period from when a transmission part 121 transmits an ultrasonic wave to when a reception part 122 receives a surface reflected ultrasonic wave, which is a reflected ultrasonic wave reflected by an inspection object surface 210; a reflected ultrasonic waveform acquisition part 134 for acquiring a reflected ultrasonic waveform showing signal strength of the reflected ultrasonic wave received by the reception part 122, with respect to a lapse time from when the transmission part 121 has transmitted the ultrasonic wave; and a bubble/defect determination part 135 for determining, when the reflected ultrasonic waveform shows that there is a reflected ultrasonic wave with signal strength equal to or higher than a predetermined threshold in the bubble detection gate, that a bubble 311 exists in liquid 310 between the inspection object surface 210 and an ultrasonic probe 110.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a defect inspection apparatus for inspecting whether or not a defect exists in an inspection object by propagating an ultrasonic wave through the liquid by interposing a liquid between the surface of the inspection object and an ultrasonic probe, and The present invention relates to a control method, a program for causing a computer to execute the control method, and a computer-readable storage medium storing the program.

  Conventionally, in order to detect a defect in an object to be inspected, the object to be inspected is detected by immersing the object in water that is liquid and propagating ultrasonic waves and detecting ultrasonic waves returning from the defects. There are methods for detecting internal defects. In such a water immersion type ultrasonic flaw detection method, when bubbles are mixed in water, reflected ultrasonic waves from the bubbles may be detected in the same manner as reflected ultrasonic waves from the defect, causing a false detection of the defect. It becomes a factor. Examples of the technique related to bubbles by the water immersion ultrasonic flaw detection technique include the techniques of Patent Document 1, Patent Document 2, and Patent Document 3 below.

  Specifically, Patent Document 1 describes a technique for performing flaw detection by suppressing the generation of bubbles by increasing the temperature of water. In Patent Document 2, flaw detection is performed with the same detection performance as when there are no bubbles by detecting the decrease in intensity of the surface reflected ultrasonic waves due to bubbles adhering to the surface of the object to be inspected or bubbles in the water, and correcting the sensitivity. The technique to be performed is described. Patent Document 3 describes a technique for detecting a bubble by detecting the presence of a bubble from a decrease in intensity of a predetermined echo, mechanically vibrating the probe, and removing the bubble.

JP 2010-25678 A JP-A-6-308102 JP-A-6-331604

  However, in the above-described conventional technology, it is difficult to grasp whether or not the reflected ultrasonic wave from the bubble is detected when the reflected ultrasonic wave from the bubble is detected in the same manner as the reflected ultrasonic wave from the defect. there were.

  The present invention has been made in view of such problems, and when reflected ultrasonic waves from bubbles are detected in the same manner as reflected ultrasonic waves from defects, are reflected ultrasonic waves detected from bubbles? The purpose is to provide a mechanism that can grasp whether or not.

In the defect inspection apparatus of the present invention, a liquid is interposed between the surface of the object to be inspected and an ultrasonic probe, and whether or not a defect exists in the object to be inspected by propagation of ultrasonic waves through the liquid. A defect inspection apparatus for inspecting, comprising: a transmitting unit that transmits ultrasonic waves from the ultrasonic probe to the object to be inspected; and a reception that receives the reflected ultrasonic waves as reflected ultrasonic waves via the ultrasonic probe And the reception means for transmitting the surface-reflected ultrasonic wave, which is the reflected ultrasonic wave reflected from the surface of the object to be inspected from the time when the ultrasonic wave is transmitted from the ultrasonic probe by the transmission means via the ultrasonic probe. First period setting means for setting a period up to the time point of reception as a first period, and the reflection with respect to the elapsed time from the time when the ultrasonic wave is transmitted from the ultrasonic probe by the transmission means. Waveform acquisition means for acquiring a reflected ultrasonic waveform indicating the signal intensity of the sound wave, and a first reflected ultrasonic wave that is the reflected ultrasonic wave having a signal intensity equal to or greater than a predetermined threshold in the first period in the reflected ultrasonic waveform And determining means for determining that bubbles exist in the liquid between the surface of the object to be inspected and the ultrasonic probe.
The present invention also includes a control method for the above-described defect inspection apparatus, a program for causing a computer to execute the control method, and a computer-readable storage medium that stores the program.

  ADVANTAGE OF THE INVENTION According to this invention, when the reflected ultrasonic wave from a bubble is detected similarly to the reflected ultrasonic wave from a defect, it can be grasped | ascertained whether the reflected ultrasonic wave by a bubble was detected.

It is a figure which shows an example of schematic structure of the defect inspection apparatus which concerns on embodiment of this invention. It is a figure for demonstrating the bubble determination by the bubble and defect determination part shown in FIG. It is a figure for demonstrating the defect determination by the bubble and defect determination part shown in FIG. It is a flowchart which shows an example of the process sequence in the control method of the defect inspection apparatus which concerns on embodiment of this invention. It is a figure which shows the mode of experiment of Example 1 in embodiment of this invention. It is a figure which shows the result of the experiment of Example 1 in embodiment of this invention, and shows an example of the reflected ultrasonic waveform when a bubble does not exist between the ultrasonic probe and to-be-inspected object shown in FIG. It is a figure which shows the result of the 1st experiment of Example 2 in embodiment of this invention, and shows an example of the reflected ultrasonic waveform when a bubble exists between an ultrasonic probe and a to-be-inspected object. It is a figure which shows the result of the 1st experiment of Example 2 in embodiment of this invention, and shows the calculation result of the magnitude | size of a bubble and the position of a bubble. It is a figure which shows the result of the 2nd experiment of Example 2 in embodiment of this invention, and shows an example of the reflected ultrasonic waveform when a bubble exists between an ultrasonic probe and a to-be-inspected object. It is a figure which shows the result of the 2nd experiment of Example 2 in embodiment of this invention, and shows the calculation result of a bubble size and a bubble position.

  Hereinafter, embodiments (embodiments) for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram illustrating an example of a schematic configuration of a defect inspection apparatus 100 according to an embodiment of the present invention. In the defect inspection apparatus 100 according to the present embodiment, water that is the liquid 310 is interposed between the surface 210 of the object to be inspected and the ultrasonic probe 110, and the object 200 to be inspected by propagation of ultrasonic waves through the water. This is an apparatus for inspecting whether or not a defect 201 exists. Here, in the present embodiment, an example in which a steel plate is assumed as the inspection object 200 will be described. However, in the present invention, the present invention is not limited to this steel plate, and the defect 201 is detected by propagation of ultrasonic waves. Other things can be applied as long as they can. Further, the device under test 200 shown in FIG. 1 is disposed in the liquid 310 in the water tank 300.

  As shown in FIG. 1, the defect inspection apparatus 100 includes an ultrasonic probe 110, an ultrasonic transmission / reception apparatus 120, and a control / processing apparatus 130.

  The ultrasonic probe 110 is used to transmit an ultrasonic wave to the inspection object 200 and receive a reflected ultrasonic wave as a reflected ultrasonic wave. Further, in the present embodiment, the ultrasonic probe 110 moves in parallel with the surface 210 of the inspection object and scans based on the control of the control / processing device 130 to detect a defect of the inspection object 200. . In this embodiment, the defect detection is performed by moving the ultrasonic probe 110 with respect to the inspection object 200. However, the present invention is not limited to this configuration, and the ultrasonic probe 110 is not affected. A form in which the defect 200 is detected by moving the inspection body 200 is also applicable.

  Under the control of the control / processing device 130, the ultrasonic transmission / reception device 120 transmits the ultrasonic wave from the ultrasonic probe 110 to the inspected object 200, and the reflected ultrasonic wave is reflected as reflected ultrasonic waves. The receiver 122 is configured to receive via the acoustic probe 110.

  The control / processing device 130 comprehensively controls the operation of the defect inspection device 100 and performs various processes related to detection of bubbles 311 present in the liquid 310 and detection of defects 201 present in the inspection object 200. . The control / processing device 130 includes an information input unit 131, a bubble detection gate setting unit 132, a defect detection gate setting unit 133, a reflected ultrasonic waveform acquisition unit 134, a bubble / defect determination unit 135, a bubble size calculation unit 136, a bubble A position calculation unit 137 and a recording / display unit 138 are provided.

  The information input unit 131 performs, for example, a process of inputting various pieces of information input by an inspector to each component of the control / processing device 130 as necessary. For example, the information input unit 131 includes information on the distance between the surface 210 of the object to be inspected and the ultrasonic probe 110, information on the velocity of the ultrasonic wave propagating through the liquid 310, and the lengths of the surface 210 and the back surface 220 of the object 200 to be inspected. (L) Information, velocity information of ultrasonic wave propagating through the inspection object 200, signal detection threshold information in the bubble detection gate set by the bubble detection gate setting unit 132, defect detection set by the defect detection gate setting unit 133 A process of inputting information of a signal detection threshold value in the gate is performed.

  The bubble detection gate setting unit (first period setting unit) 132 is a surface reflection ultrasonic wave that is a reflected ultrasonic wave reflected from the surface 210 of the object to be inspected from the time when the transmission unit 121 transmits the transmission ultrasonic wave from the ultrasonic probe 110. During the period up to the time point when the signal is received by the receiving unit 122 via the ultrasonic probe 110, the process of setting the bubble detection gate that is the first period is performed. Here, in the present embodiment, the bubble detection gate setting unit 132 receives the distance information between the surface 210 of the object to be inspected and the ultrasonic probe 110 input from the information input unit 131 and the ultrasonic wave propagating through the liquid 310. The bubble detection gate is set based on the speed information. In the present invention, the present invention is not limited to this form, and includes a form in which the bubble detection gate is set by performing the following processing. Specifically, first, a preliminary experiment is performed in advance in the defect inspection system shown in FIG. 1, and the signal intensity of the reflected ultrasonic wave with respect to the elapsed time from the time when the transmission ultrasonic wave is transmitted from the ultrasonic probe 110 by the transmission unit 121 is shown. Obtain the reflected ultrasound waveform. Then, the reflected ultrasonic waveform obtained by this preliminary experiment is displayed on the recording / display unit 138, for example, and the examiner designates the bubble detection gate from the displayed reflected ultrasonic waveform via the information input unit 131. And the bubble detection gate setting part 132 is a form which performs the setting of the bubble detection gate designated via the information input part 131. FIG. The bubble detection gate (first period) set by the bubble detection gate setting unit 132 is configured to transmit the surface reflection ultrasonic wave via the ultrasonic probe 110 from the time when the transmission unit 121 transmits the transmission ultrasonic wave from the ultrasonic probe 110. In the present invention, since the transmission unit 121 transmits the transmission ultrasonic wave from the ultrasonic probe 110, the surface reflection ultrasonic wave is transmitted from the ultrasonic probe 110 to the reception point 122. In addition, a mode in which the period up to the time of reception by the receiving unit 122 is set in the bubble detection gate setting unit 132 as a bubble detection gate is included.

  The defect detection gate setting unit (second period setting unit) 133 is a reflected ultrasonic wave reflected by the back surface 220 of the object to be inspected from the time when the above-described surface reflection ultrasonic wave is received by the receiving unit 122 via the ultrasonic probe 110. A process of setting a defect detection gate that is a second period is performed during a period up to a point in time when a certain back-surface reflected ultrasonic wave is received by the receiving unit 122 via the ultrasonic probe 110. Here, in this embodiment, the defect detection gate setting unit 133 receives the distance information between the surface 210 of the object to be inspected and the ultrasonic probe 110 input from the information input unit 131 and the ultrasonic wave propagating through the liquid 310. Of setting the defect detection gate based on the speed information of the surface, the length (L) information of the front surface 210 and the back surface 220 of the inspection object 200, and the speed information of the ultrasonic wave propagating through the inspection object 200 I do. In the present invention, the present invention is not limited to this mode, and includes a mode in which a defect detection gate is set by performing the following processing. Specifically, first, a preliminary experiment is performed in advance in the defect inspection system shown in FIG. 1, and the signal intensity of the reflected ultrasonic wave with respect to the elapsed time from the time when the transmission ultrasonic wave is transmitted from the ultrasonic probe 110 by the transmission unit 121 is shown. Obtain the reflected ultrasound waveform. Then, the reflected ultrasonic waveform obtained by this preliminary experiment is displayed on, for example, the recording / display unit 138, and the inspector designates a defect detection gate via the information input unit 131 from the displayed reflected ultrasonic waveform. And the defect detection gate setting part 133 is a form which performs the setting of the defect detection gate designated via the information input part 131. FIG. It should be noted that the defect detection gate (second period) set by the defect detection gate setting unit 133 is such that the back surface reflected ultrasonic wave is received by the ultrasonic probe 110 from the time when the front surface reflected ultrasonic wave is received by the receiving unit 122 via the ultrasonic probe 110. Therefore, in the present invention, the back-surface reflected ultrasonic wave from the time when the front-surface reflected ultrasonic wave is received by the receiving unit 122 via the ultrasonic probe 110 is set. It is also assumed that the defect detection gate setting unit 133 sets a period until the point of time when the signal is received by the reception unit 122 via the ultrasonic probe 110 as a defect detection gate.

  The reflected ultrasonic waveform acquisition unit 134 performs a process of acquiring a reflected ultrasonic waveform indicating the signal intensity of the reflected ultrasonic wave with respect to the elapsed time from the time when the ultrasonic wave is transmitted from the ultrasonic probe 110 by the transmission unit 121.

  The bubble / defect determination unit 135 receives information from the information input unit 131 in the bubble detection gate (first period) set by the bubble detection gate setting unit 132 in the reflected ultrasound waveform acquired by the reflected ultrasound waveform acquisition unit 134. When there is a first reflected ultrasonic wave that is a reflected ultrasonic wave having a signal intensity equal to or higher than a signal detection threshold value (a predetermined threshold value or higher) in the input bubble detection gate, the surface 210 of the object to be inspected and the ultrasonic probe 110 It is determined that bubbles 311 are present in the liquid 310 between them. Furthermore, the bubble / defect determination unit 135 includes an information input unit in the defect detection gate (second period) set by the defect detection gate setting unit 133 in the reflected ultrasonic waveform acquired by the reflected ultrasonic waveform acquisition unit 134. In the case where there is a second reflected ultrasonic wave that is a reflected ultrasonic wave having a signal intensity equal to or higher than a signal detection threshold value (a predetermined threshold value or higher) in the defect detection gate input from 131, the bubble 311 exists in the liquid described above. If it is determined, the second reflected ultrasonic wave is determined to be a reflected ultrasonic wave caused by the bubble 311.

  Here, the bubble determination by the bubble / defect determination unit 135 will be described in detail with reference to FIG.

  FIG. 2 is a diagram for explaining bubble determination by the bubble / defect determination unit 135 shown in FIG. Specifically, FIG. 2A shows a state where the ultrasonic probe 110 shown in FIG. 1 is at the position of the solid line. FIG. 2B shows the reflected ultrasonic waveform acquired by the reflected ultrasonic waveform acquisition unit 134, that is, the reflection with respect to the elapsed time (t) from the time when the transmission ultrasonic wave T is transmitted from the ultrasonic probe 110 by the transmission unit 121. The reflected ultrasonic waveform which shows the signal strength of an ultrasonic wave is shown.

  As shown in FIG. 2A, when the ultrasonic wave transmitted from the ultrasonic probe 110 is reflected by the surface 210 of the object to be inspected, the ultrasonic wave propagates along the path indicated by S. This is detected as the surface reflected ultrasound S in the reflected ultrasound waveform shown in FIG.

  As shown in FIG. 2A, when the ultrasonic wave transmitted from the ultrasonic probe 110 is reflected by the back surface 220 of the object to be inspected, the ultrasonic wave propagates along the path indicated by B. This is detected as the back-surface reflected ultrasound B in the reflected ultrasound waveform shown in FIG.

  Here, in FIG. 2B, the bubble detection gate setting unit 132 sets the period between the time when the ultrasonic probe 110 transmits the transmission ultrasonic wave T and the time when the surface reflection ultrasonic wave S is received. A bubble detection gate 401 is shown. In FIG. 2B, the defect detection gate setting unit 133 sets the period between the time when the ultrasonic probe 110 receives the front surface reflected ultrasonic wave S and the time when the rear surface reflected ultrasonic wave B is received. The defect detection gate 402 is shown.

  Furthermore, when the bubble 311 is mixed in the ultrasonic propagation path from the ultrasonic probe 110, the ultrasonic wave transmitted from the ultrasonic probe 110 is reflected on the upper portion of the bubble 311 (the portion of the bubble 311 on the ultrasonic probe 110 side). , The ultrasonic wave propagates along the path indicated by C1. This is detected as the first reflected ultrasound C1 before the surface reflected ultrasound S in the reflected ultrasound waveform shown in FIG. Further, the ultrasonic wave transmitted from the ultrasonic probe 110 is reflected by the surface 210 of the object to be inspected, then reflected by the lower part of the bubble 311 (the part of the bubble 311 on the object 200 side), and again, the object to be inspected. When the light is reflected by the surface 210, the ultrasonic wave propagates along the path indicated by C2. This is detected as the second reflected ultrasound C2 after the surface reflected ultrasound S in the reflected ultrasound waveform shown in FIG.

  As described with reference to FIG. 2, the bubble / defect determination unit 135 determines that the first reflected ultrasound C1 exists within the period of the bubble detection gate 401 in the reflected ultrasound waveform shown in FIG. In addition, it is determined that the bubble 311 exists in the liquid 310 between the surface 210 of the object to be inspected and the ultrasonic probe 110. Furthermore, the bubble / defect determination unit 135 is a case where the second reflected ultrasonic wave C2 exists within the period of the defect detection gate 402 in the reflected ultrasonic waveform shown in FIG. When the first reflected ultrasound C1 exists within the period, it is determined that the second reflected ultrasound C2 is a reflected ultrasound caused by the bubble 311.

Here, it returns to description of FIG. 1 again.
In addition, the bubble / defect determination unit 135 uses the information input unit in the defect detection gate (second period) set by the defect detection gate setting unit 133 in the reflected ultrasonic waveform acquired by the reflected ultrasonic waveform acquisition unit 134. In the case where there is a second reflected ultrasonic wave that is a reflected ultrasonic wave having a signal intensity equal to or higher than a signal detection threshold value (a predetermined threshold value or higher) in the defect detection gate input from 131, bubble detection is performed in the above-described reflected ultrasonic waveform. When it is determined that the first reflected ultrasonic wave does not exist at the gate and the bubble 311 does not exist in the liquid 310, it is determined that the defect 201 exists in the inspection target 200.

  Here, the defect determination by the bubble / defect determination unit 135 will be described in detail with reference to FIG.

  FIG. 3 is a diagram for explaining defect determination by the bubble / defect determination unit 135 shown in FIG. Specifically, FIG. 3A shows a state where the ultrasonic probe 110 shown in FIG. 1 is at the position of the broken line. FIG. 3B shows the reflected ultrasonic waveform acquired by the reflected ultrasonic waveform acquisition unit 134, that is, the reflection with respect to the elapsed time (t) from the time when the transmission ultrasonic wave T is transmitted from the ultrasonic probe 110 by the transmission unit 121. The reflected ultrasonic waveform which shows the signal strength of an ultrasonic wave is shown.

  As shown in FIG. 3A, when the ultrasonic wave transmitted from the ultrasonic probe 110 is reflected by the surface 210 of the object to be inspected, the ultrasonic wave propagates along the path indicated by S. This is detected as the surface reflected ultrasound S in the reflected ultrasound waveform shown in FIG.

  Further, as shown in FIG. 3A, when the ultrasonic wave transmitted from the ultrasonic probe 110 is reflected by the back surface 220 of the object to be inspected, the ultrasonic wave propagates along the path indicated by B. This is detected as the back-surface reflected ultrasonic wave B in the reflected ultrasonic wave waveform shown in FIG.

  Here, in FIG. 3B, the bubble detection gate setting unit 132 sets the period from the time when the ultrasonic probe 110 transmits the transmission ultrasonic wave T to the time when the surface reflected ultrasonic wave S is received. A bubble detection gate 401 is shown. Also, in FIG. 3B, the defect detection gate setting unit 133 sets the period between the time when the ultrasonic probe 110 receives the front surface reflected ultrasonic wave S and the time when the rear surface reflected ultrasonic wave B is received. The defect detection gate 402 is shown.

  Further, when the defect 201 exists in the ultrasonic propagation path from the ultrasonic probe 110, the ultrasonic wave transmitted from the ultrasonic probe 110 and passing through the surface 210 of the inspection object is inside the inspection object 200. When the light is reflected by the defect 201, the ultrasonic wave propagates along the path indicated by F. This is detected as the second reflected ultrasound F after the surface reflected ultrasound S in the reflected ultrasound waveform shown in FIG.

  As described with reference to FIG. 3, the bubble / defect determination unit 135 determines that the second reflected ultrasonic wave F exists within the period of the defect detection gate 402 in the reflected ultrasonic waveform shown in FIG. When it is determined that the first reflected ultrasonic wave does not exist and the bubble 311 does not exist in the liquid 310 within the period of the bubble detection gate 401, the defect 201 exists in the inspection object 200. Make a decision.

Here, it returns to description of FIG. 1 again.
When the bubble size calculation unit 136 determines that the bubble 311 is present in the liquid 310 by the bubble / defect determination unit 135, the bubble size calculation unit 136 and the first reflected ultrasonic wave C1 in the reflected ultrasonic waveform shown in FIG. A first time t1 between the reflected ultrasound S, a second time t2 between the surface reflected ultrasound S and the second reflected ultrasound C2 in the reflected ultrasound waveform shown in FIG. A process of calculating the size d of the bubble 311 is performed based on the velocity of the ultrasonic wave propagating through. Specifically, the bubble size calculation unit 136 calculates the size d of the bubble 311 using the following equation (1). In the equation (1), Cw is the velocity of the ultrasonic wave that propagates through the liquid 310.

  When the bubble position calculation unit 137 determines that the bubble 311 is present in the liquid 310 by the bubble / defect determination unit 135, the surface reflection ultrasonic wave S and the second reflection in the reflected ultrasonic waveform shown in FIG. Based on the second time t2 between the ultrasonic wave C2 and the velocity of the ultrasonic wave propagating through the liquid 310, the position w of the bubble 311 indicated by the distance from the surface 210 of the test object to the bubble 311 is calculated. Perform the process. Specifically, the bubble position calculation unit 137 calculates the position w of the bubble 311 using the following equation (2). In Equation (2), Cw is the velocity of the ultrasonic wave that propagates through the liquid 310.

  The recording / display unit 138 displays the determination result by the bubble / defect determination unit 135, the size d of the bubble 311 calculated by the bubble size calculation unit 136, the position w of the bubble 311 calculated by the bubble position calculation unit 137, and the like. Each information is recorded and displayed. Further, the recording / display unit 138 records various information input from the information input unit 131, the reflected ultrasonic waveform acquired by the reflected ultrasonic waveform acquisition unit 134, and the like as necessary. Perform the process.

  Next, a processing procedure in the control method of the defect inspection apparatus 100 according to the present embodiment will be described.

  FIG. 4 is a flowchart illustrating an example of a processing procedure in the control method of the defect inspection apparatus 100 according to the embodiment of the present invention.

  First, the inspector determines the arrangement positions of the inspection object 200 and the ultrasonic probe 110, and provides the defect inspection apparatus 100 with distance information between the surface 210 of the inspection object and the ultrasonic probe 110, and the inspection object. When the length (L) information of the front surface 210 and the back surface 220 of the body 200 is input, in step S101, the information input unit 131 inputs the front surface 210 of the object to be inspected and the ultrasonic probe 110 input by the inspector. And the distance (L) information between the front surface 210 and the back surface 220 of the inspection object 200 are input.

  Furthermore, when the inspector operates and inputs the velocity information of the ultrasonic wave propagating through the liquid 310 and the velocity information of the ultrasonic wave propagating through the inspection object 200 to the defect inspection apparatus 100, then in step S102. The information input unit 131 performs a process of inputting the velocity information of the ultrasonic wave propagating through the liquid 310 and the velocity information of the ultrasonic wave propagating through the inspection object 200, which are input by the inspector.

  Subsequently, in step S103, the control / processing device 130 determines each ultrasonic wave (transmission ultrasonic wave T, surface shown in FIG. 2B or FIG. 3B) based on the information input in steps S101 and S102. The position (time) of the reflected ultrasonic wave S and the back reflected ultrasonic wave B) is set.

  Subsequently, in step S <b> 104, the bubble detection gate setting unit 132 is a surface reflection ultrasound that is a reflected ultrasound reflected from the surface 210 of the object to be inspected from the time when the transmission unit 121 transmits the transmission ultrasound T from the ultrasound probe 110. During the period up to the time point when the sound wave S is received by the receiving unit 122 via the ultrasonic probe 110, a process of setting the bubble detection gate that is the first period is performed. Specifically, here, processing for setting the bubble detection gate 401 shown in FIGS. 2B and 3B is performed. Here, in the present embodiment, the bubble detection gate setting unit 132 receives the distance information between the surface 210 of the object to be inspected and the ultrasonic probe 110 input from the information input unit 131 and the ultrasonic wave propagating through the liquid 310. Based on the speed information, the bubble detection gate 401 is set. In the present invention, the present invention is not limited to this mode, and includes a mode in which the bubble detection gate 401 is set by performing the following processing. Specifically, first, a preliminary experiment is performed in advance in the defect inspection system shown in FIG. 1, and the signal intensity of the reflected ultrasonic wave with respect to the elapsed time from the time when the transmission ultrasonic wave T is transmitted from the ultrasonic probe 110 by the transmission unit 121 is determined. The reflected ultrasonic waveform shown is acquired. Then, the reflected ultrasonic waveform obtained by this preliminary experiment is displayed on the recording / display unit 138, for example, and the examiner designates the bubble detection gate 401 via the information input unit 131 from the displayed reflected ultrasonic waveform. . And the bubble detection gate setting part 132 is a form which performs the setting of the bubble detection gate 401 designated via the information input part 131. FIG. Note that the bubble detection gate (first period) set by the bubble detection gate setting unit 132 causes the ultrasonic probe 110 to transmit the surface reflected ultrasonic wave S from the time when the transmission unit 121 transmits the transmission ultrasonic wave T from the ultrasonic probe 110. In the present invention, since the transmission unit 121 transmits the transmission ultrasonic wave T from the ultrasonic probe 110, the surface reflection ultrasonic wave S is transmitted from the ultrasonic probe 110 to the ultrasonic wave. A mode in which a period up to the point of reception by the receiving unit 122 via the acoustic wave probe 110 is set as the bubble detection gate 401 in the bubble detection gate setting unit 132 is also included.

  Subsequently, in step S <b> 105, the defect detection gate setting unit 133 reflects the reflected ultrasound reflected on the back surface 220 of the object to be inspected from the time when the reception surface 122 receives the surface reflection ultrasound S described above via the ultrasound probe 110. During the period up to the time point when the back surface reflected ultrasonic wave B is received by the receiving unit 122 via the ultrasonic probe 110, a process of setting the defect detection gate that is the second period is performed. Here, processing for setting the defect detection gate 402 shown in FIGS. 2B and 3B is performed. Here, in this embodiment, the defect detection gate setting unit 133 receives the distance information between the surface 210 of the object to be inspected and the ultrasonic probe 110 input from the information input unit 131 and the ultrasonic wave propagating through the liquid 310. The defect detection gate 402 is set based on the velocity information, the length (L) information of the front surface 210 and the back surface 220 of the inspection object 200, and the ultrasonic velocity information propagating through the inspection object 200. Process. In the present invention, the present invention is not limited to this form, and includes a form in which the defect detection gate 402 is set by performing the following processing. Specifically, first, a preliminary experiment is performed in advance in the defect inspection system shown in FIG. 1, and the signal intensity of the reflected ultrasonic wave with respect to the elapsed time from the time when the transmission ultrasonic wave T is transmitted from the ultrasonic probe 110 by the transmission unit 121 is determined. The reflected ultrasonic waveform shown is acquired. Then, the reflected ultrasonic waveform obtained by the preliminary experiment is displayed on the recording / display unit 138, for example, and the inspector designates the defect detection gate 402 via the information input unit 131 from the displayed reflected ultrasonic waveform. . The defect detection gate setting unit 133 is configured to set the defect detection gate 402 designated via the information input unit 131. It should be noted that the defect detection gate (second period) set by the defect detection gate setting unit 133 is the ultrasonic wave of the back surface reflected ultrasonic wave B from the time when the front surface reflected ultrasonic wave S is received by the receiving unit 122 via the ultrasonic probe 110. Since it is set during a period until it is received by the receiving unit 122 via the probe 110, in the present invention, the back surface to the back surface from the time when the receiving unit 122 receives the surface reflection ultrasonic wave S via the ultrasonic probe 110. It is assumed that the defect detection gate setting unit 133 sets a period up to the time point when the reflected ultrasonic wave B is received by the receiving unit 122 via the ultrasonic probe 110 as the defect detection gate 402.

  Further, when the inspector operates and inputs the signal detection threshold information in the bubble detection gate and the signal detection threshold information in the defect detection gate to the defect inspection apparatus 100, then in step S106, the information input unit 131 performs a process of inputting information on the signal detection threshold in the bubble detection gate and information on the signal detection threshold in the defect detection gate, which are input by the inspector.

  Subsequently, in step S107, the transmission unit 121 transmits an ultrasonic wave from the currently disposed ultrasonic probe 110 to the object 200 based on the time of the transmission ultrasonic wave T set in step S103. In addition, the receiving unit 122 receives the reflected ultrasonic waves as reflected ultrasonic waves via the ultrasonic probe 110 that is currently arranged.

  Subsequently, in step S108, the reflected ultrasonic waveform acquisition unit 134 acquires a reflected ultrasonic waveform indicating the signal intensity of the reflected ultrasonic wave with respect to the elapsed time from the time when the ultrasonic wave is transmitted from the ultrasonic probe 110 by the transmission unit 121. Perform the process.

  Subsequently, in step S109, has the bubble / defect determination unit 135 detected the second reflected ultrasound within the period of the defect detection gate set in step S105 in the reflected ultrasound waveform acquired in step S108? Judge whether or not. Here, whether or not the second reflected ultrasonic wave has been detected is determined based on the signal detection threshold information in the defect detection gate input in step S106.

As a result of the determination in step S109, when the second reflected ultrasonic wave cannot be detected (S109 / NO), the process proceeds to step S110.
In step S110, the bubble / defect determination unit 135 determines that the defect 201 does not exist at the position of the inspection object 200 corresponding to the position of the ultrasonic probe 110 currently arranged.

On the other hand, as a result of the determination in step S109, if the second reflected ultrasonic wave can be detected (S109 / YES), the process proceeds to step S111.
In step S111, the bubble / defect determination unit 135 detects whether or not the first reflected ultrasonic wave is detected within the bubble detection gate period set in step S104 in the reflected ultrasonic waveform acquired in step S108. Determine whether. Here, whether or not the first reflected ultrasonic wave has been detected is determined based on the signal detection threshold information in the bubble detection gate input in step S106.

As a result of the determination in step S111, when the first reflected ultrasonic wave can be detected (S111 / YES), the process proceeds to step S112.
In step S112, the bubble / defect determination unit 135 determines that the bubble 311 is present in the liquid 310 between the ultrasonic probe 110 and the surface 210 of the object to be inspected.

  Subsequently, in step S113, the bubble size calculation unit 136, for example, a first time t1 between the first reflected ultrasound C1 and the surface reflected ultrasound S in the reflected ultrasound waveform shown in FIG. 2B, for example, The second time t2 between the surface reflected ultrasound S and the second reflected ultrasound C2 in the reflected ultrasound waveform shown in FIG. 2B, and the velocity of the ultrasound propagating through the liquid 310 input in step S102. Based on the information, a process of calculating the size d of the bubble 311 is performed. Specifically, the bubble size calculation unit 136 calculates the size d of the bubble 311 using the above-described equation (1).

  Subsequently, in step S114, the bubble position calculation unit 137, for example, the second time t2 between the surface reflected ultrasound S and the second reflected ultrasound C2 in the reflected ultrasound waveform shown in FIG. Based on the velocity information of the ultrasonic wave propagating through the liquid 310 input in step S102, a process of calculating the position w of the bubble 311 indicated by the distance from the surface 210 of the test object to the bubble 311 is performed. Specifically, the bubble position calculation unit 137 calculates the position w of the bubble 311 using the above-described equation (2).

On the other hand, as a result of the determination in step S111, if the first reflected ultrasonic wave cannot be detected (S111 / NO), the process proceeds to step S115.
In step S115, the bubble / defect determination unit 135 determines that the defect 201 is present at the position of the inspection object 200 corresponding to the position of the ultrasonic probe 110 that is currently arranged.

When the process of step S110 is completed, when the process of step S114 is completed, or when the process of step S115 is completed, the process proceeds to step S116.
In step S116, the recording / display unit 138 calculates the determination result by the bubble / defect determination unit 135 in step S110, step S114, or step S115, the size d of the bubble 311 calculated in step S113, and the calculation in step S114. Each information such as the position w of the bubble 311 is recorded and displayed. Furthermore, the recording / display unit 138 records various information input in steps S101, S102, and S106, the reflected ultrasonic waveform acquired in step S108, and the like as necessary. Do.

  Subsequently, in step S <b> 117, the control / processing device 130 determines whether or not the entire region of the object 200 has been scanned with the ultrasonic probe 110.

As a result of the determination in step S117, if the entire region of the object 200 has not been scanned with the ultrasonic probe 110 (S117 / NO), the process proceeds to step S118.
In step S118, the control / processing device 130 performs control to move the ultrasonic probe 110 to a predetermined position. After that, the process returns to step S107, ultrasonic waves are transmitted and received at the position of the ultrasonic probe 110 moved in step S118, and the processes after step S108 are performed.

  On the other hand, as a result of the determination in step S117, when the entire region of the object 200 is scanned with the ultrasonic probe 110 (S117 / YES), the processing of the flowchart shown in FIG.

  According to the embodiment of the present invention described above, when the reflected ultrasonic wave from the bubble 311 is detected in the same manner as the reflected ultrasonic wave from the defect 201, it is determined whether or not the reflected ultrasonic wave by the bubble 311 is detected. I can grasp it.

  Next, examples based on the above-described embodiment of the present invention will be described.

[Example 1]
FIG. 5 is a diagram illustrating an experiment in Example 1 according to the embodiment of the present invention. In FIG. 5, the same reference numerals are given to the same components as those shown in FIG. In FIG. 5, the description of the ultrasonic transmission / reception device 120 and the control / processing device 130 shown in FIG. 1 that are electrically connected to the ultrasonic probe 110 is omitted.

  In the experiment of Example 1, as shown in FIG. 5, the ultrasonic probe 110 and the device under test 200-1 are arranged at predetermined positions in the liquid 310 in the water tank 300. Furthermore, a tube for sending air for generating bubbles 311 is arranged at a predetermined position in the liquid 310 in the water tank 300.

  As the ultrasonic probe 110, an ultrasonic probe having an ultrasonic frequency of about 15 MHz, an aperture of about 12 mm, and an ultrasonic focus distance of about 100 mm was used. The object to be inspected 200-1 used a SUS plate having a plate thickness (L) of about 10 mm, and provided a vertical hole with a depth of about 1 mm and a depth of about 5 mm as the defect 201.

  Further, the speed of the ultrasonic wave propagating through the water 310 as the liquid 310 is about Cw = 1480 m / s, and the speed of the ultrasonic wave propagating through the SUS constituting the inspected object 200-1 is about Cs = 5660 m / s. It is. In the experiment of Example 1 shown in FIG. 5, the focal point of the ultrasonic wave is about 5 mm deep by setting the distance between the ultrasonic probe 110 and the inspection object 200-1 to about 80 mm. Arranged to come.

  FIG. 6 shows the result of the experiment of Example 1 in the embodiment of the present invention, and the reflected ultrasonic waveform when the bubble 311 does not exist between the ultrasonic probe 110 and the device under test 200-1 shown in FIG. It is a figure which shows an example. Specifically, in FIG. 6, the horizontal axis indicates the elapsed time (μs) from the time when the transmission ultrasonic wave is transmitted from the ultrasonic probe 110, and the vertical axis indicates the signal intensity (V) of the reflected ultrasonic wave.

  In the reflected ultrasonic waveform shown in FIG. 6, the front surface reflected ultrasonic wave S and the back surface reflected ultrasonic wave B are observed. 6 shows a bubble detection gate 401 set by the bubble detection gate setting unit 132 and a defect detection gate 402 set by the defect detection gate setting unit 133. At this time, the defect detection gate setting unit 133 sets the defect detection gate 402 in consideration of a period during which the signal intensity of the surface reflected ultrasound S is sufficiently low.

  In the experiment of the first embodiment, the signal detection threshold value in the bubble detection gate 401 is set to an absolute value of the signal strength of 0.15V, and the signal detection threshold value in the defect detection gate 402 is set to an absolute value of the signal strength of 0.15V. Shall be set. In this case, in the reflected ultrasonic waveform shown in FIG. 6, the bubble / defect determination unit 135 does not include the first reflected ultrasonic wave in the bubble detection gate 401. Therefore, the ultrasonic probe 110 and the inspected object 200- shown in FIG. 1, it is determined that the bubble 311 does not exist, and since the second reflected ultrasonic wave F exists in the defect detection gate 402, it is determined that the defect 201 exists in the inspection target 200.

[Example 2]
In the experiment of Example 2, the inspection object 200-2 without the defect 201 was used instead of the inspection object 200-1 provided with the defect 201 artificially. About another structure, it is the same as that of the experiment of Example 1 shown in FIG.

  FIG. 7 shows the result of the first experiment of Example 2 in the embodiment of the present invention, and an example of the reflected ultrasonic waveform when the bubble 311 exists between the ultrasonic probe 110 and the inspection object 200-2. FIG. Specifically, in FIG. 7, the horizontal axis indicates the elapsed time (μs) from the time when transmission ultrasonic waves are transmitted from the ultrasonic probe 110, and the vertical axis indicates the signal intensity (V) of reflected ultrasonic waves.

  In the reflected ultrasonic waveform shown in FIG. 7, the front surface reflected ultrasonic wave S and the back surface reflected ultrasonic wave B are observed. 7 shows the bubble detection gate 401 set by the bubble detection gate setting unit 132 and the defect detection gate 402 set by the defect detection gate setting unit 133. At this time, the defect detection gate setting unit 133 sets the defect detection gate 402 in consideration of a period during which the signal intensity of the surface reflected ultrasound S is stable.

  In the first experiment of Example 2, the signal detection threshold value in the bubble detection gate 401 is set to an absolute value of the signal intensity of 0.15 V, and the signal detection threshold value in the defect detection gate 402 is set to an absolute value of the signal intensity of 0. It shall be set to 15V. In this case, in the reflected ultrasonic waveform shown in FIG. 7, since the first reflected ultrasonic wave C1 is present in the bubble detection gate 401, the bubble / defect determination unit 135 causes the ultrasonic probe 110 and the object 200-2 to be inspected. It is determined that the bubble 311 exists between them. Further, the bubble / defect determination unit 135 uses the second reflected ultrasonic wave C2 existing in the defect detection gate 402 because the first reflected ultrasonic wave C1 exists in the bubble detection gate 401 in the reflected ultrasonic waveform shown in FIG. It is determined that the reflected ultrasonic wave is caused by the bubble 311.

  In FIG. 7, the first time t1 between the first reflected ultrasonic wave C1 and the surface reflected ultrasonic wave S is 3.18 μs, and the second time between the surface reflected ultrasonic wave S and the second reflected ultrasonic wave C2 is shown. The time t2 is shown to be 2.33 μs.

  FIG. 8 shows the result of the first experiment of Example 2 in the embodiment of the present invention, and shows the calculation result of the size d of the bubble 311 and the position w of the bubble 311.

  When the bubble size calculation unit 136 determines that the bubble 311 exists in the liquid 310 by the bubble / defect determination unit 135, the bubble size calculation unit 136 performs the first operation between the first reflected ultrasound C 1 and the surface reflected ultrasound S shown in FIG. One hour t1 (3.18 μs), a second time t2 (2.33 μs) between the surface reflected ultrasonic wave S and the second reflected ultrasonic wave C2 shown in FIG. 7, and the velocity of the ultrasonic wave propagating through the liquid 310 Based on (Cw = 1480 m / s), the size d = 0.63 mm of the bubble 311 is calculated using the above-described equation (1).

  In addition, when the bubble / defect determination unit 135 determines that the bubble 311 is present in the liquid 310, the bubble position calculation unit 137 determines that there is a gap between the surface reflection ultrasonic wave S and the second reflection ultrasonic wave C2 illustrated in FIG. Based on the second time t2 (2.33 μs) and the velocity of the ultrasonic wave propagating through the liquid 310 (Cw = 1480 m / s), using the above-described equation (2), The position w = 1.72 mm of the bubble 311 indicated by the distance to the bubble 311 is calculated.

  FIG. 9 shows the result of the second experiment of Example 2 in the embodiment of the present invention, and an example of the reflected ultrasonic waveform when the bubble 311 exists between the ultrasonic probe 110 and the inspection object 200-2. FIG. Specifically, in FIG. 9, the horizontal axis indicates the elapsed time (μs) from the time when the transmission ultrasonic wave is transmitted from the ultrasonic probe 110, and the vertical axis indicates the signal intensity (V) of the reflected ultrasonic wave.

  In the reflected ultrasonic waveform shown in FIG. 9, the front surface reflected ultrasonic wave S and the back surface reflected ultrasonic wave B are observed. 9 shows the bubble detection gate 401 set by the bubble detection gate setting unit 132 and the defect detection gate 402 set by the defect detection gate setting unit 133. At this time, the defect detection gate setting unit 133 sets the defect detection gate 402 in consideration of a period during which the signal intensity of the surface reflected ultrasound S is stable.

  Also in the second experiment of Example 2, the signal detection threshold value in the bubble detection gate 401 is set to an absolute value of the signal intensity of 0.15 V, and the signal detection threshold value in the defect detection gate 402 is set to an absolute value of the signal intensity of 0. It shall be set to 15V. In this case, in the reflected ultrasonic waveform shown in FIG. 9, since the first reflected ultrasonic wave C1 is present in the bubble detection gate 401, the bubble / defect determination unit 135 causes the ultrasonic probe 110 and the object 200-2 to be inspected. It is determined that the bubble 311 exists between them. The bubble / defect determination unit 135 uses the second reflected ultrasonic wave C2 present in the defect detection gate 402 because the first reflected ultrasonic wave C1 exists in the bubble detection gate 401 in the reflected ultrasonic waveform shown in FIG. It is determined that the reflected ultrasonic wave is caused by the bubble 311.

  In FIG. 9, the first time t1 between the first reflected ultrasound C1 and the surface reflected ultrasound S is 3.24 μs, and the second time between the surface reflected ultrasound S and the second reflected ultrasound C2 is shown. The time t2 is shown to be 2.67 μs.

  FIG. 10 shows the result of the second experiment of Example 2 in the embodiment of the present invention, and shows the calculation result of the size d of the bubble 311 and the position w of the bubble 311.

  When the bubble size calculation unit 136 determines that the bubble 311 is present in the liquid 310 by the bubble / defect determination unit 135, the bubble size calculation unit 136 performs the first operation between the first reflected ultrasound C 1 and the surface reflected ultrasound S shown in FIG. One hour t1 (3.24 μs), a second time t2 (2.67 μs) between the surface reflected ultrasonic wave S and the second reflected ultrasonic wave C2 shown in FIG. 9, and the velocity of the ultrasonic wave propagating through the liquid 310 Based on (Cw = 1480 m / s), the size d = 0.42 mm of the bubble 311 is calculated using the above-described equation (1).

  In addition, when the bubble / defect determination unit 135 determines that the bubble 311 is present in the liquid 310, the bubble position calculation unit 137 determines that the bubble position calculation unit 137 is between the surface reflection ultrasonic wave S and the second reflection ultrasonic wave C2 illustrated in FIG. Based on the second time t2 (2.67 μs) and the velocity of the ultrasonic wave propagating through the liquid 310 (Cw = 1480 m / s), the above equation (2) is used to determine whether the surface 210 from the surface 210 of the object to be inspected. The position w = 1.98 mm of the bubble 311 indicated by the distance to the bubble 311 is calculated.

(Other embodiments)
In the above-described embodiment of the present invention, an example in which water having high versatility is used as the 310 interposed between the surface 210 of the object to be inspected and the ultrasonic probe 110 has been shown, but the present invention is limited to this. It is not a thing. For example, an embodiment in which oil or the like is used as the 310 interposed between the surface 210 of the inspection object and the ultrasonic probe 110 from the viewpoint of preventing rust in the inspection object 200 is also applicable to the present invention.

The present invention can also be realized by executing the following processing.
That is, software (program) that realizes the functions of the above-described embodiments is supplied to a system or apparatus via a network or various storage media, and a computer (or CPU, MPU, etc.) of the system or apparatus reads the program. It is a process to be executed.
This program and a computer-readable storage medium storing the program are included in the present invention.

  Note that the above-described embodiments of the present invention are merely examples of implementation in practicing the present invention, and the technical scope of the present invention should not be construed as being limited thereto. It is. That is, the present invention can be implemented in various forms without departing from the technical idea or the main features thereof.

DESCRIPTION OF SYMBOLS 100 Defect inspection apparatus, 110 Ultrasonic probe, 120 Ultrasonic transmission / reception apparatus, 121 Transmission part, 122 Reception part, 130 Control / processing apparatus, 131 Information input part, 132 Bubble detection gate setting part, 133 Defect detection gate setting part, 134 Reflected ultrasonic waveform acquisition unit, 135 bubble / defect determination unit, 136 bubble size calculation unit, 137 bubble position calculation unit, 138 recording / display unit, 200 inspected object, 201 defect, 210 surface of inspected object, 220 object Back side of test object, 300 water tank, 310 liquid, 311 bubbles

Claims (8)

A defect inspection apparatus for inspecting whether or not a defect exists in the inspection object by propagating an ultrasonic wave through the liquid by interposing a liquid between a surface of the inspection object and an ultrasonic probe. ,
Transmitting means for transmitting ultrasonic waves from the ultrasonic probe to the object to be inspected;
Receiving means for receiving the reflected ultrasonic waves as reflected ultrasonic waves via the ultrasonic probe;
The receiving means receives the surface reflected ultrasound, which is the reflected ultrasound reflected from the surface of the object to be inspected from the time when the ultrasound is transmitted from the ultrasound probe by the transmitting means, via the ultrasound probe. First period setting means for setting a period up to the time point as a first period;
Waveform acquisition means for acquiring a reflected ultrasonic waveform indicating a signal intensity of the reflected ultrasonic wave with respect to an elapsed time from the time when the ultrasonic wave is transmitted from the ultrasonic probe by the transmission means;
In the reflected ultrasonic waveform, when there is a first reflected ultrasonic wave that is the reflected ultrasonic wave having a signal intensity equal to or higher than a predetermined threshold in the first period, the surface between the surface of the object to be inspected and the ultrasonic probe. And a determination means for determining that bubbles are present in the liquid. The back-surface reflected ultrasound, which is the reflected ultrasound reflected from the back surface of the object to be inspected from the time when the surface-reflected ultrasonic wave is received by the receiving means via the ultrasonic probe, is received via the ultrasonic probe. A second period setting means for setting a period until the time of reception by the means as the second period;
The determination means further includes a case where there is a second reflected ultrasound that is the reflected ultrasound having a signal intensity equal to or higher than a predetermined threshold in the second period in the reflected ultrasound waveform, and the reflected ultrasound waveform In the first period, when it is determined that the first reflected ultrasonic wave does not exist and the bubble does not exist in the liquid, it is determined that a defect exists in the inspection object. The defect inspection apparatus according to claim 1. The back-surface reflected ultrasound, which is the reflected ultrasound reflected from the back surface of the object to be inspected from the time when the surface-reflected ultrasonic wave is received by the receiving means via the ultrasonic probe, is received via the ultrasonic probe. A second period setting means for setting a period until the time of reception by the means as the second period;
The determination means is a case where there is a second reflected ultrasonic wave that is the reflected ultrasonic wave having a signal intensity equal to or higher than a predetermined threshold in the reflected ultrasonic waveform in the second period, and the bubbles are present in the liquid. The defect inspection apparatus according to claim 1, wherein when it is determined that the second reflected ultrasonic wave exists, the second reflected ultrasonic wave is determined to be a reflected ultrasonic wave caused by the bubble.   When it is determined by the determination means that the bubbles are present in the liquid, a time t1 between the first reflected ultrasound and the surface reflected ultrasound in the reflected ultrasound waveform, and in the reflected ultrasound waveform A bubble size calculating means for calculating the size of the bubble based on a time t2 between the surface reflected ultrasonic wave and the second reflected ultrasonic wave and a velocity of the ultrasonic wave propagating through the liquid; The defect inspection apparatus according to claim 2, further comprising:   When it is determined by the determination means that the bubbles are present in the liquid, the time t2 between the surface reflected ultrasonic wave and the second reflected ultrasonic wave in the reflected ultrasonic waveform and the liquid propagate 4. A bubble position calculating means for calculating a position of the bubble indicated by a distance from the surface of the object to be inspected to the bubble based on a velocity of the ultrasonic wave. The defect inspection apparatus described in 1. A method for controlling a defect inspection apparatus, in which a liquid is interposed between a surface of an object to be inspected and an ultrasonic probe, and whether or not a defect exists in the object to be inspected by propagation of ultrasonic waves through the liquid Because
A transmission step of transmitting ultrasonic waves from the ultrasonic probe to the object to be inspected by a transmission means;
A receiving step of receiving the reflected ultrasonic waves as reflected ultrasonic waves via the ultrasonic probe by a receiving means;
The receiving means receives the surface reflected ultrasound, which is the reflected ultrasound reflected from the surface of the object to be inspected from the time when the ultrasound is transmitted from the ultrasound probe by the transmitting means, via the ultrasound probe. A first period setting step for setting a period up to the time point as a first period;
A waveform acquisition step of acquiring a reflected ultrasonic waveform indicating a signal intensity of the reflected ultrasonic wave with respect to an elapsed time from a time point when the ultrasonic wave is transmitted from the ultrasonic probe in the transmission step;
In the reflected ultrasonic waveform, when there is a first reflected ultrasonic wave that is the reflected ultrasonic wave having a signal intensity equal to or higher than a predetermined threshold in the first period, the surface between the surface of the object to be inspected and the ultrasonic probe. And a determination step for determining that air bubbles are present in the liquid. A method for controlling a defect inspection apparatus, in which a liquid is interposed between a surface of an object to be inspected and an ultrasonic probe, and whether or not a defect exists in the object to be inspected by propagation of ultrasonic waves through the liquid A program for causing a computer to execute
A transmission step of transmitting ultrasonic waves from the ultrasonic probe to the object to be inspected by a transmission means;
A receiving step of receiving the reflected ultrasonic waves as reflected ultrasonic waves via the ultrasonic probe by a receiving means;
The receiving means receives the surface reflected ultrasound, which is the reflected ultrasound reflected from the surface of the object to be inspected from the time when the ultrasound is transmitted from the ultrasound probe by the transmitting means, via the ultrasound probe. A first period setting step for setting a period up to the time point as a first period;
A waveform acquisition step of acquiring a reflected ultrasonic waveform indicating a signal intensity of the reflected ultrasonic wave with respect to an elapsed time from a time point when the ultrasonic wave is transmitted from the ultrasonic probe in the transmission step;
In the reflected ultrasonic waveform, when there is a first reflected ultrasonic wave that is the reflected ultrasonic wave having a signal intensity equal to or higher than a predetermined threshold in the first period, the surface between the surface of the object to be inspected and the ultrasonic probe. A program for causing a computer to execute a determination step of determining that air bubbles are present in the liquid.   A computer-readable storage medium storing the program according to claim 7.

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