DEFECT INSPECTION SYSTEM, DEFECT INSPECTION APPARATUS, AND DEFECT INSPECTION METHOD

Abstract

This defect inspection system (100) comprises an excitation unit (10) for exciting elastic waves in an inspection object (P), a measurement unit (30) for imaging a measurement region (Pa) of the outer surface of the inspection object (P) to measure the measurement region (Pa), a body casing part (40) inside which the measurement unit (30) is disposed, a movement mechanism (60) disposed such that the body casing part (40) can be moved along the outer surface of the inspection object (P), and a control unit (70) configured so as to sequentially acquire linear imaging results (D) in each of a plurality of measurement positions of the measurement region (Pa) with the movement by the movement mechanism (60), and acquire a two-dimensional distribution of excitation states for defect inspection in the measurement region (Pa) on the basis of the linear imaging results (D).

Description

[Technical field]

[0001] The present invention relates to a defect inspection system, a defect inspection apparatus, and a defect inspection method. [Background technology]

[0002] 2. Description of the Related Art A defect inspection method and a defect inspection apparatus are known in the art. Such a defect inspection method and defect inspection apparatus are disclosed in Japanese Patent No. 6451695, for example.

[0003] The defect inspection device described in the above-mentioned Japanese Patent No. 6451695 includes an excitation unit for exciting elastic waves in the object to be inspected, an illumination unit for strobe-illuminating a measurement area on the surface of the object to be inspected, and a displacement measurement unit. The displacement measurement unit measures the displacement of each point in the measurement area using laser interferometry. In the laser interferometry, a reflected laser light irradiated from the illumination unit, which is a laser light source, and reflected at each point in the measurement area is interfered with by a reference laser light irradiated from the illumination unit and passing through a different optical path from the reflected laser light. Then, the displacement of each point in the measurement area is measured by measuring the intensity of the interference light caused by interference between the reflected laser light and the reference laser light. The displacement measurement unit measures the vibration state (amplitude and phase) of each point in the measurement area based on the measured displacement. The above-mentioned Patent Publication No. 6,451,695 discloses a configuration in which an image is created in which differences in displacement due to vibration are represented by differences in brightness of the image based on the vibration state (amplitude and phase) of each point in the measured measurement area, and an inspector visually checks the created image, thereby detecting discontinuities in the vibration state as defects. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6451695 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the defect inspection device described in the above-mentioned Japanese Patent No. 6451695, since the size of the measurement area to be measured is limited, when measuring an object to be inspected (inspection target object) having an area larger than the measurement area that can be measured by one measurement, it is necessary to change the position of the measurement area (installation position of the device) and perform the measurement multiple times. In that case, it is necessary to lift up and install the excitation unit that excites elastic waves, the illumination unit (illumination unit) that performs strobe irradiation, and the displacement measurement unit that measures the displacement each time the measurement area (installation position) is changed to a different installation position. Therefore, every time the excitation unit, illumination unit, and displacement measurement unit are moved, the installation position and the measurement field of view need to be adjusted, which increases the workload of the inspection operator. Therefore, it is desired to suppress the increase in the workload of the inspection operator even when measuring an inspection target object having a relatively large area.

[0006] The present invention has been made to solve the problems described above, and one object of the present invention is to provide a defect inspection system, a defect inspection device, and a defect inspection method that are capable of suppressing an increase in the workload of inspection operators even when measuring inspection objects with a relatively large area. [Means for solving the problem]

[0007] In order to achieve the above object, a defect inspection system according to a first aspect of the present invention comprises: an excitation unit that excites elastic waves in an object to be inspected; a measurement unit that includes imaging elements arranged in a line and that captures and measures a line-shaped image of a measurement area on an outer surface of the object to be inspected in a state in which elastic waves are excited by the excitation unit; a main body housing unit in which the measurement unit is arranged; a movement mechanism that arranges the main body housing unit to be movable along the outer surface of the object to be inspected; and a control unit configured to sequentially obtain line-shaped image results by the measurement unit at each of a plurality of measurement positions of the measurement area as the movement mechanism moves along the outer surface of the main body housing unit, and to obtain a two-dimensional distribution of vibration conditions for defect inspection in the measurement area based on the line-shaped image results sequentially obtained. The moving mechanism is configured to contact the outer surface of the object to be inspected, and the excitation unit is disposed inside the moving mechanism.Note that the term "line-shaped" used here is used as a broad concept including not only a line-shaped (straight line) having one pixel in the width direction (short axis direction) but also a line-shaped (straight line) having multiple pixels in the width direction.

[0008] The defect inspection system according to the first aspect of the present invention includes a control unit configured to sequentially obtain linear imaging results by the measurement unit at each of a plurality of measurement positions in the measurement area as the moving mechanism moves along the outer surface of the main body housing, and to obtain a two-dimensional distribution of vibration conditions for defect inspection in the measurement area based on the sequentially obtained linear imaging results. As a result, the measurement unit can be moved along the outer surface of the measurement area of ​​the object to be inspected by moving the main body housing in which the measurement unit is disposed by the moving mechanism. Therefore, unlike a case in which the measurement unit is lifted up one by one and installed at a different installation position without a moving mechanism, linear imaging results can be easily obtained at each of a plurality of measurement positions in the measurement area without adjusting the installation position and measurement field of view of the measurement unit. Therefore, by combining the linear imaging results captured at each of the plurality of measurement positions, imaging results over the entire measurement area can be easily obtained. As a result, even when an inspection object with a relatively large area is measured, an increase in the workload of the inspection operator can be suppressed.

[0009] A defect inspection device according to a second aspect of the present invention includes an excitation unit that excites an elastic wave in an object to be inspected, a measurement unit including imaging elements arranged in a line and that images and measures a measurement area on an outer surface of the object to be inspected in a line state in which elastic waves are excited by the excitation unit, a main body housing unit in which the measurement unit is arranged, and a movement mechanism that arranges the main body housing unit so that it can move along the outer surface of the object to be inspected. The moving mechanism is configured to contact the outer surface of the object to be inspected, and the excitation unit is disposed inside the moving mechanism. .

[0010] In a second aspect of the present invention, the defect inspection device includes a measurement unit that includes imaging elements arranged in a line and that captures and measures a measurement area on the outer surface of an object to be inspected in a line-like manner when elastic waves are excited by an excitation unit. The device further includes a main body housing unit in which the measurement unit is arranged, and a moving mechanism that moves the main body housing unit along the outer surface of the object to be inspected. As a result, the measurement unit can be moved along the outer surface of the measurement area of ​​the object to be inspected by moving the main body housing unit in which the measurement unit is arranged by the moving mechanism. Therefore, unlike a case where the measurement unit is lifted up one by one and installed in a different installation position without a moving mechanism, it is possible to easily obtain imaging results captured in a line-like manner at each of a plurality of measurement positions in the measurement area without adjusting the installation position and measurement field of view of the measurement unit. Therefore, it is possible to easily obtain imaging results over the entire measurement area by combining the linear imaging results measured at each of a plurality of measurement positions. As a result, it is possible to provide a defect inspection device that can suppress an increase in the workload of an inspection operator even when an object to be inspected having a relatively large area is measured.

[0011] A defect inspection method according to a third aspect of the present invention includes the steps of exciting an elastic wave in an inspection object, and determining a measurement position at each of a plurality of measurement positions in a measurement region on an outer surface of the inspection object in a state in which the elastic wave is excited. A moving mechanism configured to contact the outer surface of the inspection object The method includes the steps of: sequentially acquiring line-shaped imaging results by imaging and measuring line-shaped images while moving; and acquiring a two-dimensional distribution of vibration conditions for defect inspection in a measurement area based on the sequentially acquired line-shaped imaging results. The step of exciting an elastic wave in the test object includes a step of exciting an elastic wave in the test object by an excitation unit arranged inside the moving mechanism. .

[0012] In a defect inspection method according to a third aspect of the present invention, a line-shaped image result is sequentially obtained by imaging and measuring a line-shaped image at each of a plurality of measurement positions in a measurement area on the outer surface of an object to be inspected while an elastic wave is excited, while moving the measurement position. Then, a two-dimensional distribution of a vibration state for defect inspection in the measurement area is obtained based on the sequentially obtained line-shaped image results. As a result, since line-shaped image results can be sequentially obtained by imaging and measuring a line-shaped image at each of a plurality of measurement positions while moving the measurement position, unlike a case where a moving mechanism for moving the measurement position is not provided and a measuring unit for performing measurement is lifted one by one and moved to another measurement position, a line-shaped image result can be easily obtained at each of a plurality of measurement positions in the measurement area without adjusting the measurement position and the measurement field of view. Therefore, by combining the line-shaped image results measured at each of a plurality of measurement positions, an image result over the entire measurement area can be easily obtained. As a result, a defect inspection method can be provided that can suppress an increase in the workload of an inspection operator even when an inspection object with a relatively large area is measured. Effect of the Invention

[0013] According to the present invention, as described above, it is possible to provide a defect inspection system, a defect inspection apparatus, and a defect inspection method that can suppress an increase in the workload of inspection operators even when measuring inspection objects with a relatively large area. [Brief description of the drawings]

[0014] [Figure 1] 1 is a schematic diagram showing a configuration of a defect inspection system according to a first embodiment. [Diagram 2] FIG. 1 is a diagram showing a configuration of a defect inspection device according to a first embodiment. [Diagram 3] FIG. 2 is a diagram for explaining a wheel unit and a vibrator according to the first embodiment. [Figure 4]5A to 5C are diagrams for explaining a method for acquiring imaging results while changing a measurement position according to the first embodiment. [Diagram 5] 4 is a diagram for explaining the period of elastic wave vibration and the exposure time for imaging by a measurement unit according to the first embodiment. FIG. [Figure 6] FIG. 4 is a diagram showing an example of a vibration state image according to the first embodiment. [Figure 7] FIG. 2 is a diagram (flowchart) for explaining a defect inspection method according to the first embodiment. [Figure 8] FIG. 13 is a schematic diagram showing the configuration of a defect inspection system according to a second embodiment. [Figure 9] FIG. 13 is a diagram showing the configuration of a defect inspection device according to a second embodiment. [Figure 10] 13 is a diagram for explaining the period of vibration of an elastic wave and the rate of imaging by a measurement unit according to the second embodiment. FIG. [Figure 11] FIG. 13 is a schematic diagram showing the configuration of a defect inspection system according to a third embodiment. [Figure 12] FIG. 13 is a diagram showing the configuration of a defect inspection device according to a third embodiment. [Figure 13] 13 is a diagram for explaining the phase of an elastic wave and irradiation of laser light by an irradiating unit according to the third embodiment. FIG. [Figure 14] 10A to 10C are diagrams showing examples of defect images according to the modified examples of the first to third embodiments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

[0016] [First embodiment] The configuration of a defect inspection system 100 according to a first embodiment of the present invention will be described with reference to FIGS.

[0017] (Configuration of defect inspection system) As shown in FIG. 1, a defect inspection system 100 is used to perform non-destructive defect inspection by laser interference on a measurement area Pa (see FIG. 2) of an inspection object P, which is, for example, an aircraft part. The inspection object P is, for example, a honeycomb material or a carbon fiber reinforced polymer (CFRP). A defective portion Q includes a crack and peeling occurring inside (a surface layer or a top surface) of the measurement area Pa. The defect inspection system 100 according to the first embodiment includes a defect inspection device 101 and a processing device 102. The defect inspection device 101 and the processing device 102 are connected by a cable C and configured to be capable of transmitting and receiving signals to and from each other. The defect inspection device 101 and the processing device 102 may be configured to be capable of transmitting and receiving signals to and from each other by wireless communication.

[0018] (Configuration of defect inspection device) The defect inspection device 101 includes a vibrator 10, an irradiation unit 20, a measurement unit 30 (see FIG. 2), a housing 40, a grip unit 50, and a wheel unit 60. The vibrator 10 is an example of an "excitation unit" in the claims. The wheel unit 60 is an example of a "movement mechanism" in the claims. The housing 40 is an example of a "main housing unit" and a "shielding unit" in the claims.

[0019] The transducer 10 excites an elastic wave in the test object P. Specifically, in the first embodiment, the transducer 10 is disposed inside a wheel unit 60 (wheel unit 60a) described later. The transducer 10 is configured to excite an elastic wave in the test object P by propagating vibrations through the wheel unit 60. The transducer 10 converts an AC signal from a signal generator 90 of a processing device 102 described later into mechanical vibrations. The transducer 10 includes, for example, a piezoelectric element. The transducer 10 vibrates along a direction perpendicular to the outer surface of the test object P. The transducer 10 is disposed so as to propagate vibrations along a direction perpendicular to the test object P. That is, the transducer 10 excites an elastic wave so that the test object P vibrates (displaces) along the out-of-plane direction (Z direction) of the outer surface by propagating vibrations along the Z direction in FIG. 1. The elastic wave excited in the test object P is propagated in the in-plane direction (X direction and Y direction) of the outer surface in the test object P. That is, the elastic waves excited in the test object P propagate along the surface of the measurement area Pa of the test object P (along the XY plane) not only in the direction in which the laser light from the irradiation unit 20 described later is diffused (extends) in a line shape (X direction), but also in a direction including a direction perpendicular to the shaft portion 61 (see Figure 3) of the wheel unit 60 described later (a direction parallel to the movement direction, Y direction).

[0020] The irradiation unit 20 irradiates the measurement area Pa of the test object P in a state in which an elastic wave is excited by the transducer 10 with laser light. The irradiation unit 20 includes a laser light source (not shown). The laser light source is, for example, a laser diode, and irradiates laser light (near-infrared light) with a wavelength of 785 nm. The irradiation unit 20 also includes an illumination light lens 21. The illumination light lens 21 includes a cylindrical lens that diffuses linear laser light into a sheet shape (planar shape). The laser light irradiated from the laser light source is diffused planarly along the X direction by the illumination light lens 21, as shown by the dashed dotted line L in FIG. 1 and FIG. 3. That is, in the first embodiment, the irradiation unit 20 is configured to irradiate the measurement area Pa in a line shape (straight line shape) with planar sheet light obtained by diffusing the laser light in a direction (X direction) in which the image pickup elements of the measurement unit 30 described later are arranged in a line shape. In addition, the sheet light (laser light) diffused into a sheet (plane) shape extending along the X direction is irradiated onto the outer surface of the measurement area Pa of the test object P in a diffused state having a certain width in the Y direction as well due to interference in the measurement unit 30 described later.

[0021] As shown in FIG. 2, in the first embodiment, the measurement unit 30 captures and measures a line-shaped measurement area Pa of the outer surface of the test object P in a state where an elastic wave is excited by the vibrator 10 along the X direction. The measurement unit 30 is also configured to cause the reflected laser light, which is the laser light irradiated by the irradiation unit 20 and reflected at the measurement area Pa, to interfere with the reference laser light irradiated by the irradiation unit 20 by laser interferometry. The measurement unit 30 then captures and measures the interference light caused by the interference between the reflected laser light and the reference laser light. Specifically, the measurement unit 30 includes, for example, a speckle shearing interferometer. The measurement unit 30 uses the laser light reflected at two different positions (positions Pa1 and Pa2) in the Y direction of the measurement area Pa excited by the vibrator 10 as the reflected laser light and the reference laser light, and causes the reflected laser light and the reference laser light to interfere with each other by laser interferometry. That is, the reference laser light is the laser light reflected at a position (nearby position) different from the reflection position of the reflected laser light in the measurement area Pa. The measurement unit 30 also includes a beam splitter 31, a first reflecting mirror 32a, a second reflecting mirror 32b, a condenser lens 33, and an image sensor .

[0022] The beam splitter 31 includes a half mirror. The beam splitter 31 is disposed at a position where the laser light reflected in the measurement area Pa of the inspection object P is incident. The beam splitter 31 reflects the incident laser light toward the first reflecting mirror 32a as shown by the optical path indicated by the straight line S1 in FIG. 2, and transmits the incident laser light toward the second reflecting mirror 32b as shown by the optical path indicated by the dashed line S2 in FIG. 2. The beam splitter 31 transmits the incident laser light reflected by the first reflecting mirror 32a toward the image sensor 34 as shown by the optical path indicated by the straight line S1 in FIG. 2, and reflects the laser light reflected by the second reflecting mirror 32b toward the image sensor 34 as shown by the dashed line S2 in FIG. 2.

[0023] The first reflecting mirror 32a is disposed on the optical path of the laser light reflected by the beam splitter 31 at an angle of 45 degrees with respect to the reflecting surface of the beam splitter 31. The first reflecting mirror 32a reflects the laser light reflected by the beam splitter 31 towards the beam splitter 31.

[0024] The second reflecting mirror 32b is disposed on the optical path of the laser light passing through the beam splitter 31 at an angle slightly tilted from 45 degrees with respect to the reflecting surface of the beam splitter 31. The second reflecting mirror 32b reflects the laser light passing through the beam splitter 31 toward the beam splitter 31. Since the second reflecting mirror 32b is slightly tilted from 45 degrees with respect to the reflecting surface of the beam splitter 31, the second reflecting mirror 32b reflects the reflected laser light at a position (position Pa2) in the measurement region Pa that is slightly shifted toward the Y2 direction side from the position Pa1 at which the laser light entering the first reflecting mirror 32a is reflected.

[0025] The condenser lens 33 is disposed between the beam splitter 31 and the image sensor 34, and condenses the laser light (straight line S1 in FIG. 2) that has passed through the beam splitter 31 and the laser light (dashed line S2 in FIG. 2) that has been reflected by the beam splitter 31. This causes the laser light reflected at two different points in the Y direction of the measurement area Pa to interfere with each other.

[0026] The image sensor 34 captures (measures) a line of interference light caused by the interference of the laser beams. The image sensor 34 is disposed on the optical path of the laser beam (straight line S1 in FIG. 2) that is reflected by the beam splitter 31, then reflected by the first reflecting mirror 32a, and transmitted through the beam splitter 31, and the laser beam (dashed line S2 in FIG. 2) that is reflected by the beam splitter 31, then reflected by the second reflecting mirror 32b.

[0027] Moreover, the image sensor 34 has imaging elements arranged in a line. For example, the image sensor 34 has pixels (imaging elements) of 1×1024 pixels. That is, in the image sensor 34, a plurality of imaging elements are arranged in a line along the X direction. Then, by one measurement (imaging), a one-dimensional linear imaging result D (see FIG. 4) with the number of pixels of 1×1024 is captured. The image sensor 34 includes, for example, a CMOS image sensor or a CCD image sensor.

[0028] In the measurement unit 30, for example, the laser light reflected by the position Pa1 on the outer surface of the measurement area Pa and the first reflecting mirror 32a (straight line S1 in FIG. 2) and the laser light reflected by the position Pa2 on the outer surface of the measurement area Pa and the second reflecting mirror 32b (broken line S2 in FIG. 2) interfere with each other and enter the imaging element of the image sensor 34 (detected by the same element). The positions Pa1 and Pa2 are positions spaced apart from each other by a small distance in the Y direction. The laser light (reflected laser light and reference laser light) reflected from different positions (Pa1 and Pa2) in each measurement position of the measurement area Pa is guided by the measurement unit 30 to become interference light, which enters each of the linearly arranged imaging elements of the image sensor 34. Details of the imaging (measurement) of the interference light by the measurement unit 30 will be described later.

[0029] In the first embodiment, the housing 40 has the irradiation unit 20 and the measurement unit 30 disposed therein. The housing 40 also shields the laser light by surrounding the irradiation unit 20 and the measurement unit 30. Specifically, the housing 40 has a side wall portion 41 that surrounds the irradiation unit 20 and the measurement unit 30 from the X1, X2, Y1, and Y2 direction sides. The housing 40 also has a top surface portion 42 on the Z1 direction side. The side wall portion 41 and the top surface portion 42 suppress (shield) the laser light from the irradiation unit 20 from leaking to the outside of the device (outside of the housing 40). The side wall portion 41 and the top surface portion 42 also suppress (shield) the environmental light (disturbance light) from the outside of the device (outside of the housing 40) from entering the inside of the device (inside the housing 40). The housing 40 also includes a bottom surface portion 43 on the Z2 direction side. An opening 43a is provided in the bottom surface 43, and the laser light emitted from the irradiation unit 20 is irradiated through the opening 43a onto the outer surface of the measurement area Pa of the test object P. Then, the laser light (the reflected laser light and the reference laser light) reflected on the outer surface of the measurement area Pa enters the measurement unit 30 inside the housing 40 through the opening 43a.

[0030] 1, the gripping unit 50 is gripped by an inspection operator. The gripping unit 50 is connected to an axis portion 61 (see FIG. 3) of a wheel unit 60 described later, and transmits an operating force for moving the irradiation unit 20 and the measurement unit 30 by the inspection operator to the housing 40.

[0031] In the first embodiment, the wheel unit 60 is configured to move the housing 40 in the Y direction along the outer surface of the test object P. Specifically, the wheel unit 60 includes two different (a pair of) wheel units 60a and 60b. The wheel unit 60a is connected to the X1 direction side of the housing 40, and the wheel unit 60b is connected to the X2 direction side. That is, the measurement unit 30 is disposed between the two different wheel units 60a and 60b. In the first embodiment, the wheel unit 60 is configured to rotate while abutting against the outer surface of the test object P in a state in which the housing 40 is fixed so as to be spaced apart from and facing the outer surface of the test object P. In other words, even when the wheel unit 60 rotates, the relative positions of the irradiation unit 20 and the measurement unit 30 with respect to the test object P inside the housing 40 are not changed. In addition, the housing 40 is disposed so as not to abut against the outer surface of the test object P.

[0032] As shown in FIG. 3, the transducer 10 is disposed on the shaft portion 61 inside the wheel portion 60a on the X1 direction side. The inside of the wheel portion 60a is filled with a fluid material. The fluid material is, for example, water. Vibration caused by the transducer 10 disposed on the shaft portion 61 is propagated to the outer circumferential portion 62 of the wheel through the fluid material. The shaft portion 61 inside the wheel portion 60 is configured not to rotate even when the outer circumferential portion 62 rotates. Therefore, even when the wheel portion 60 (wheel portion 60a) rotates with the movement of the housing 40, the transducer 10 does not rotate and propagates vibrations continuously along the Z direction. In the first embodiment, the wheel portion 60 rotates about the X direction as an axis by the operating force of an inspection operator who holds the grip portion 50, thereby moving the housing 40 in the Y direction.

[0033] (Processing device configuration) 1, the processing device 102 includes a control unit 70, a display unit 80, and a signal generator 90. The processing device 102 is, for example, a tablet PC (personal computer). The processing device 102 displays a vibration state image E (see FIG. 6) for performing defect inspection based on an imaging result D captured (measured) by the defect inspection device 101.

[0034] The control unit 70 controls each part of the processing device 102. The control unit 70 also controls each part of the defect inspection device 101. The control unit 70 controls the vibration of the vibrator 10 and the imaging of interference light, which is the interfered laser light, by the image sensor 34. The control unit 70 includes, for example, a CPU (Central Processing Unit). Details of the control by the control unit 70 will be described later.

[0035] The display unit 80 displays an image based on the control by the control unit 70. Specifically, the display unit 80 displays a vibration state image E (see FIG. 6) that represents a two-dimensional distribution of the vibration state of elastic waves excited in the measurement region Pa of the inspection object P generated by the control unit 70. The display unit 80 includes a liquid crystal display, an organic EL (Electro-Luminescence) display, or the like.

[0036] The signal generator 90 outputs an alternating current for vibrating the transducer 10 under the control of the control unit 70. The alternating current from the signal generator 90 is transmitted to the transducer 10 via the cable C.

[0037] (Acquisition of imaging results) As shown in FIG. 4, in the first embodiment, the control unit 70 sequentially obtains linear imaging results D by the measurement unit 30 at each of a plurality of measurement positions (P1, P2, P3, . . .) in the measurement area Pa as the wheel unit 60 moves along the outer surface of the housing 40. The imaging results D are one-dimensional images showing the intensity of the interference light by pixel values ​​(brightness values). Specifically, in the first embodiment, the measurement unit 30 performs linear imaging (measurement) at each of a plurality of measurement positions (P1, P2, P3, . . .) in the measurement area Pa while being moved in the Y direction by the inspection operator. That is, the measurement unit 30 scans the measurement area Pa with an imaging element (image sensor 34) arranged one-dimensionally in a line extending in the X direction, and performs two-dimensional measurement (imaging) of the interference light over the entire measurement area Pa along the XY plane. In FIG. 4, the difference (shade) in pixel values ​​(brightness values) is shown by the difference in hatching.

[0038] In the first embodiment, the measurement unit 30 performs continuous linear imaging (measurement) multiple times (twice) at one measurement position (for example, P1) among a plurality of measurement positions (P1, P2, P3, ...) that are changed with the movement of the wheel unit 60. That is, the measurement unit 30 is moved in the Y direction by the rotation of the wheel unit 60. At this time, the measurement unit 30 performs imaging multiple times (twice) at the measurement position P1, and then the measurement position is changed from P1 to P2, and performs imaging multiple times (twice) at the next measurement position P2. For example, one measurement position has a width of 0.1 mm in the Y direction. That is, the measurement unit 30 performs imaging (measurement) multiple times (twice) as the measurement position is changed every time it is moved 0.1 mm in the Y direction. The control unit 70 obtains information indicating that the measurement position has been changed by obtaining the rotation angle of the wheel unit 60 based on information from an angle sensor such as an encoder (not shown) provided on the wheel unit 60. Furthermore, even when imaging (measurement) is performed continuously while moving the measurement unit 30 by continuously moving the wheel unit 60, if the amount of movement of the measurement unit 30 between multiple imaging (measurements) is sufficiently small compared to the width of one measurement position P1, it can be considered as multiple imaging (measurements) at the same measurement position.

[0039] Specifically, in the first embodiment, the control unit 70 obtains, at each of the multiple measurement positions, a line-shaped imaging result D in a state in which elastic waves are excited, and a line-shaped imaging result D in a state in which elastic waves are not excited. That is, the measurement unit 30 performs a first imaging at one of the multiple measurement positions with the transducer 10 vibrating, and then performs a second imaging with the transducer 10 stopped vibrating.

[0040] 5, in the first embodiment, the exposure time for one image capture by the image sensor 34 is longer than the period T of the vibration of the vibrator 10. Therefore, the intensity of the captured (measured) interference light is an integrated value of the interference light over a time longer than the period T of the vibrator 10.

[0041] (Generation of vibration state image by control unit) 6, the control unit 70 is configured to acquire a two-dimensional distribution of vibration states for defect inspection in the measurement area Pa based on the sequentially acquired line-shaped imaging results D. The control unit 70 is then configured to generate a vibration state image E that allows the two-dimensional distribution of the vibration states in the measurement area Pa to be visually recognized based on the acquired two-dimensional distribution of the vibration states.

[0042] For example, the control unit 70 acquires an intensity (brightness value) I1 of interference light as the imaging result D measured at one measurement position P1 among the multiple measurement positions while the transducer 10 is vibrating. Then, at the measurement position P1, the control unit 70 acquires an intensity (brightness value) I2 of interference light as the imaging result D measured at a state where the transducer 10 is stopped. Then, the control unit 70 acquires a pixel value I0 for generating a vibration state image E by calculation based on the two acquired intensities (brightness values) I1 and I2 of interference light, as shown in formula (1). I0 = |I1 - I2| (1) That is, the pixel value I0 for generating the vibration state image E is the absolute value of the difference between the intensities I1 and I2 of the two obtained interference lights.

[0043] The control unit 70 acquires a linear vibration state (distribution of pixel values ​​I0) at the measurement position P1 by acquiring a pixel value I0 based on the intensities (brightness values) I1 and I2 of two interference lights acquired by all the imaging elements of the image sensor 34 at the measurement position P1. Then, the control unit 70 changes the measurement position from P1 to P2, P3, ..., and acquires linear vibration states at each of the multiple measurement positions throughout the entire measurement area Pa in accordance with the movement of the wheel unit 60. Based on the linear vibration states (distribution of pixel values ​​I0) at the multiple measurement positions acquired, the control unit 70 generates a vibration state image E showing a two-dimensional distribution of the vibration state in the measurement area Pa. The control unit 70 generates a vibration state image E showing the two-dimensional distribution of the vibration state so that it can be visually recognized by expressing the magnitude of the pixel value I0 by different colors (red for large values ​​and blue for small values), for example. In FIG. 6, the color differences are expressed by different hatching.

[0044] Furthermore, the control unit 70 causes the generated vibration state image E to be displayed on the display unit 80. The inspection operator visually checks the vibration state image E displayed on the display unit 80 to recognize the position of the defect (defective portion Q) based on the two-dimensional distribution of the vibration state in the measurement area Pa of the inspection object P. For example, the area Ea of the vibration state image E in Fig. 6 is an area where the pixel value I0 is relatively large, and is an area that approximately indicates the position of the defect (defective portion Q).

[0045] After measuring (imaging) the entire measurement area Pa, a vibration state image E may be generated and displayed based on an input operation to an operation unit not shown, or vibration state images E may be generated and displayed sequentially in real time for each measurement position while measuring (imaging) as the measurement unit 30 (housing 40) moves.

[0046] (Regarding the defect inspection method according to the first embodiment) Next, the defect inspection method according to the first embodiment will be described with reference to Fig. 7. The defect inspection method is performed by the processing device 102 while an inspection operator applies an operating force to the gripping part 50 to cause the wheel part 60 to rotate (turn) and move the housing 40.

[0047] First, in step 501, an elastic wave is excited in the test object P. Specifically, an AC signal for exciting an elastic wave is output to the transducer 10 from the signal generator 90.

[0048] Next, in step 502, a line image is captured at one of the multiple measurement positions (P1, P2, P3, ...) in the measurement area Pa on the outer surface of the object to be inspected P in a state in which elastic waves are excited, and the imaging result D is measured.

[0049] Next, in step 503, the operation of the transducer 10 is stopped, and the elastic waves excited in the test object P are stopped.

[0050] Next, in step 504, a line image is captured at one measurement position on the outer surface of the inspection object P in a state where no elastic waves are excited, and an imaging result D is measured.

[0051] Next, in step 505, it is determined whether or not the change of the measurement position has been completed. If it is determined that the change of the measurement position has been completed, the process proceeds to step 507. If it is not determined that the change of the measurement position has been completed, the process proceeds to step 506.

[0052] In step 506, the wheel unit 60 is moved (rotated) by the inspection operator, and information indicating that the measurement position has been changed is obtained. That is, information indicating that the measurement position has been changed is obtained based on angle information from the encoder provided on the wheel unit 60. Then, at the measurement position after the change (movement), linear imaging (measurement) is started, and the process returns to step 501. Note that, until it is determined in step 505 that the change of the measurement position has been completed, steps 501 to 504 are repeated while the measurement position is sequentially changed (moved). That is, at each of a plurality of measurement positions in the measurement area Pa of the outer surface of the inspection object P in both a state in which elastic waves are excited and a state in which elastic waves are not excited, linear imaging results D are sequentially obtained by imaging and measuring in a line while moving the measurement position.

[0053] In step 507, when it is determined that the change of the measurement position has been completed, a two-dimensional distribution of the vibration state for defect inspection in the measurement area Pa is acquired based on the line-shaped imaging results D acquired sequentially at each of the acquired measurement positions.

[0054] Next, in step 508, a vibration state image E is generated based on the acquired two-dimensional distribution of the vibration states.

[0055] Next, in step 509, the generated vibration state image E is displayed on the display unit 80.

[0056] [Effects of the first embodiment] In the first embodiment, the following effects can be obtained.

[0057] According to the defect inspection system 100 of the first embodiment, the control unit 70 is configured to sequentially obtain linear imaging results D by the measurement unit 30 at each of a plurality of measurement positions (P1, P2, P3, ...) of the measurement area Pa as the wheel unit 60 (moving mechanism) moves along the outer surface of the housing 40 (main housing), and to obtain a two-dimensional distribution of vibration conditions for defect inspection in the measurement area Pa based on the sequentially obtained linear imaging results D. As a result, the measurement unit 30 can be moved along the outer surface of the measurement area Pa of the inspection target P by moving the housing 40 in which the measurement unit 30 is disposed by the wheel unit 60. Therefore, unlike a case in which the measurement unit 30 is lifted up one by one and installed at a different installation position without the wheel unit 60, the imaging results D imaged in a line shape at each of the plurality of measurement positions in the measurement area Pa can be easily obtained without adjusting the installation position and measurement field of the measurement unit 30. Therefore, the imaging results D over the entire measurement area Pa can be easily obtained by combining the linear imaging results D imaged at each of the plurality of measurement positions. As a result, even when measuring an inspection object P having a relatively large area, an increase in the workload of the inspection operator can be suppressed.

[0058] In the first embodiment, further advantages can be obtained by configuring as follows.

[0059] That is, in the first embodiment, the moving mechanism includes a wheel unit 60 that rotates while abutting against the outer surface of the test object P in a state where the housing 40 (main body housing unit) is fixed so as to be spaced from and facing the outer surface of the test object P, and the transducer 10 (excitation unit) is arranged inside the wheel unit 60 and configured to excite an elastic wave in the test object P by propagating vibrations through the wheel unit 60. With this configuration, the wheel unit 60 that abuts against the outer surface of the test object P rotates, and unlike the case where the measurement position is changed by lifting it up one by one, the housing 40 can be easily moved in a state facing the test object P. Therefore, by rotating the wheel unit 60, it is possible to more easily perform measurement while changing multiple measurement positions (P1, P2, P3, . . .) in the measurement area Pa. As a result, it is possible to more easily obtain the imaging result D over the entire measurement area Pa, and therefore it is possible to more effectively suppress an increase in the workload of the inspection operator.

[0060] In the first embodiment, the measuring section 30 is further provided with an irradiation section 20 that irradiates a laser beam onto a measuring area Pa in a state where an elastic wave is excited by the transducer 10 (excitation section), and is configured to cause a reflected laser beam, which is a laser beam irradiated by the irradiation section 20 and reflected at the measuring area Pa, to interfere with a reference laser beam irradiated by the irradiation section 20, and to image and measure the interference light caused by the interference of the reflected laser beam with the reference laser beam in a line shape, and the control section 70 is configured to acquire a two-dimensional distribution of the vibration state in the measuring area Pa based on the imaging result D indicating the intensity of the interference light imaged and measured in a line shape by the measuring section 30. Here, when inspecting defects in the inspection object P by ultrasonic inspection using an ultrasonic array, the ultrasonic waves output from the ultrasonic array generate large reflected waves at the interface (outer surface) of the inspection object P. Due to these reflected waves, the surface and the surface layer near the surface become dead zones in ultrasonic inspection, making it difficult to detect defects. In contrast, in the first embodiment, the control unit 70 is configured to obtain a two-dimensional distribution of the vibration state in the measurement area Pa based on the imaging result D indicating the intensity of the interference light captured in a line shape and measured by the measurement unit 30. With this configuration, a two-dimensional distribution of the vibration state of the elastic wave in the measurement area Pa can be obtained based on the intensity of the interference light caused by interfering with the laser light, so that a two-dimensional distribution of the vibration state for defect inspection can be obtained that can detect defects occurring on the surface and the surface layer of the outer surface of the measurement area Pa while suppressing the influence of the reflected wave generated at the interface (outer surface). Therefore, by capturing (measuring) the interference light, a two-dimensional distribution of the vibration state for defect inspection can be obtained more effectively.

[0061] In the first embodiment, the reference laser light includes a laser light reflected at a position different from the reflection position of the reflected laser light in the measurement area Pa, and the measurement unit 30 is configured to capture and measure the interference light caused by the interference between the reflected laser light and the reference laser light reflected at different positions in the measurement area Pa in a line shape. With this configuration, since the reference laser light is a laser light reflected in the measurement area Pa like the reflected laser light, the difference between the optical path of the reflected laser light and the optical path of the reference laser light can be reduced. Therefore, it is possible to suppress a decrease in detection accuracy due to environmental disturbance caused by a large difference between the optical path of the reflected laser light and the optical path of the reference laser light. As a result, it is possible to accurately obtain a two-dimensional distribution of the vibration state for defect inspection by capturing an image of the interference light caused by the interference between the reflected laser light and the reference laser light, whose optical path difference is small, in a line shape.

[0062] In the first embodiment, the control unit 70 is configured to acquire a line-shaped vibration state at each of the multiple measurement positions by acquiring a line-shaped imaging result D in a state where elastic waves are excited and a line-shaped imaging result D in a state where elastic waves are not excited at each of the multiple measurement positions. Here, when acquiring a vibration state based on the intensity of the interference light, it is considered to perform multiple measurements by shifting the phase of the interference light. In this case, in order to approximately measure the vibration state, it is necessary to perform at least three or more measurements while shifting the phase of the interference light. In contrast, in the first embodiment, the control unit 70 is configured to acquire a line-shaped vibration state at each of the multiple measurement positions by acquiring a line-shaped imaging result D in a state where elastic waves are excited and a line-shaped imaging result D in a state where elastic waves are not excited at each of the multiple measurement positions. With this configuration, it is possible to acquire a vibration state by performing two measurements at each of the multiple measurement positions. Therefore, the number of measurements at each measurement position can be reduced compared to the case where the phase of the interference light is shifted and measurements are performed multiple times. As a result, when measurements are taken while moving between multiple measurement positions, the measurement time at one measurement position can be shortened, thereby shortening the measurement time required to measure the entire measurement area Pa.

[0063] In the first embodiment, the housing 40 (main housing) shields the laser light by surrounding the irradiation unit 20 and the measurement unit 30. With this configuration, the housing 40 (shielding unit) can shield the laser light leaking to the outside of the device (defect inspection device 101), so even when the output of the laser light is increased, it is possible to suppress the leakage of high-output laser light to the outside of the device. Therefore, it is possible to perform measurement using high-output laser light without affecting the outside of the device. In addition, since the measurement unit 30 arranged inside the housing 40 is shielded from the outside by the housing 40, it is possible to suppress the intrusion of environmental light (disturbance light) from the outside into the housing 40. Therefore, it is possible to suppress the deterioration of the accuracy of the measurement by the measurement unit 30 due to the environmental light (disturbance light).

[0064] In the first embodiment, the irradiation unit 20 is configured to irradiate the measurement area Pa with planar sheet light obtained by diffusing the laser light along the direction (X direction) in which the imaging elements of the measurement unit 30 are arranged in a line. With this configuration, the laser light from the irradiation unit 20 can be diffused so as to correspond to the linear arrangement of the imaging elements for the measurement unit 30 to perform the measurement. Therefore, it is possible to prevent the illumination light amount of the irradiation unit 20 from becoming larger than necessary relative to the light reception amount of the measurement unit 30. As a result, it is possible to prevent the irradiation unit 20 from irradiating the laser light more than necessary.

[0065] Moreover, in the first embodiment, the inspection apparatus further includes a gripping unit 50 that is gripped by an inspection operator, and the wheel unit 60 (moving mechanism) is configured to move the housing 40 (main housing unit) by the operating force of the inspection operator gripping the gripping unit 50. With this configuration, the inspection operator can easily transmit the operating force of the inspection operator for moving the housing 40 to the housing 40 by gripping the gripping unit 50. Therefore, the inspection operator can easily move the housing 40 by gripping the gripping unit 50.

[0066] Moreover, in the first embodiment, the apparatus further includes a display unit 80 that displays an image based on the control of the control unit 70, and the control unit 70 is configured to generate a vibration state image E that allows visual recognition of the two-dimensional distribution of the vibration state in the measurement area Pa based on the acquired two-dimensional distribution of the vibration state, and display the vibration state image E on the display unit 80. With this configuration, the inspection operator can easily recognize the two-dimensional distribution of the vibration state in the measurement area Pa by visually checking the vibration state image E displayed on the display unit 80. Therefore, based on the vibration state image E displayed on the display unit 80, it is possible to easily recognize a portion where the vibration state is discontinuous as a defect.

[0067] In the first embodiment, the wheel unit 60 (moving mechanism) includes two different wheel units 60a and 60b that rotate while abutting against the outer surface of the test object P in a state where the housing 40 (main housing unit) is fixed so as to be spaced apart from and facing the outer surface of the test object P, and the measurement unit 30 is disposed between the two different wheel units 60a and 60b. With this configuration, the measurement unit 30 is disposed between the two different wheel units 60a and 60b, so that the measurement unit 30 can be moved in a stable state by the two different wheel units 60a and 60b, compared to the case where there is only one wheel unit 60. Therefore, stable measurement can be performed while moving the measurement unit 30, so that when measuring (imaging) while moving the measurement unit 30 (housing 40) to measure a test object P with a relatively large area, measurement can be performed with high accuracy through stable measurement.

[0068] (Effects of the defect inspection method according to the first embodiment) The defect inspection method of the first embodiment can provide the following effects.

[0069] In the defect inspection method of the first embodiment, as described above, at each of a plurality of measurement positions in the measurement area Pa of the outer surface of the inspection object P in a state where an elastic wave is excited, a line-shaped image result D is sequentially acquired by imaging and measuring in a line shape while moving the measurement position. Then, based on the sequentially acquired line-shaped image results D, a two-dimensional distribution of the vibration state for defect inspection in the measurement area Pa is acquired. As a result, since the line-shaped image results D can be sequentially acquired by imaging and measuring in a line shape while moving the measurement position at each of the plurality of measurement positions, unlike the case where the measurement unit 30 that performs the measurement is lifted one by one and moved to another measurement position without having a wheel unit 60 for moving the measurement position, the image results D imaged in a line shape at each of the plurality of measurement positions in the measurement area Pa can be easily acquired without adjusting the measurement position and the measurement field of view. Therefore, by combining the line-shaped image results D measured at each of the plurality of measurement positions, the image results D over the entire measurement area Pa can be easily acquired. As a result, it is possible to provide a defect inspection method that can suppress an increase in the workload of the inspection operator even when measuring an inspection object P with a relatively large area.

[0070] [Second embodiment] Next, the configuration of a defect inspection system 200 according to a second embodiment of the present invention will be described with reference to Fig. 8 to Fig. 10. Unlike the first embodiment described above which is configured to obtain two imaging results D at one measurement position, this second embodiment is configured to obtain 32 imaging results D at one measurement position. Note that the same components as those in the first embodiment are shown with the same reference numerals in the drawings, and their description will be omitted.

[0071] 8, the defect inspection system 200 according to the second embodiment includes a defect inspection apparatus 201 and a processing apparatus 202. The defect inspection apparatus 201 includes a measurement unit 230. The processing apparatus 202 includes a control unit 270.

[0072] 9, the measurement unit 230, like the first embodiment, causes interference between laser beams reflected at two different points in the measurement area Pa in which an elastic wave is excited by the transducer 10. In the second embodiment, the measurement unit 230 includes an image sensor 234 and a phase shifter 235.

[0073] The phase shifter 235 is disposed between the beam splitter 31 and the first reflecting mirror 32a, and changes (shifts) the phase of the transmitting laser light (straight line S1 in FIG. 9) under the control of the control unit 270. That is, the phase shifter 235 changes the phase difference between the two laser lights to be interfered with. In the second embodiment, the measurement unit 230 operates the phase shifter 235 to change the phase difference between the two laser lights to be interfered with, while measuring (imaging) the interference light with the image sensor 234.

[0074] 10, in the second embodiment, the measuring unit 230 that captures and measures a line-shaped image is configured to perform multiple measurements (image capture) at the same measurement position among the multiple measurement positions in a time shorter than the period T of the elastic wave excited by the transducer 10. That is, unlike the first embodiment, the image sensor 234 of the measuring unit 230 has an exposure time shorter than the period T of the elastic wave. For example, when the period T of the transducer 10 is 0.08 milliseconds, the measuring unit 230 (image sensor 234) captures an image every 0.01 milliseconds (every eighth of the period T).

[0075] The control unit 270 controls each unit of the defect inspection device 201 and the processing device 202, similarly to the control unit 70 according to the first embodiment. Moreover, the control unit 270 acquires a line-shaped vibration state from the line-shaped imaging results D at each of the multiple measurement positions (P1, P2, P3, . . .) over the entire measurement area Pa in association with the movement of the wheel unit 60. Then, based on the acquired line-shaped vibration state, the control unit 270 generates a vibration state image E and causes the display unit 80 to display it.

[0076] (Generation of Vibration State Image According to Second Embodiment) In the second embodiment, the control unit 270 is configured to acquire a two-dimensional distribution of the vibration state in the measurement region Pa by multiple measurements at the same measurement position in a time shorter than the period T of the elastic wave by the measurement unit 230 that captures and measures in a line shape. Specifically, the control unit 270 captures 32 images at one measurement position (for example, P1) among the multiple measurement positions (P1, P2, P3, ...) while changing the phase difference between two laser lights, and acquires the imaging result D. At one measurement position, the measurement unit 230 changes the phase shift amount by λ / 4, for example, and captures eight images at timing k (k=0 to 7) at which the phase of the elastic wave differs by T / 8 every 0.01 milliseconds at each phase shift amount (0, λ / 4, λ / 2, 3λ / 4). Here, λ is the wavelength of the laser light.

[0077] Then, the control unit 270 calculates the luminance value I of each pixel of the four imaging results D, which have the same timing k (k=0 to 7) of the phase of the elastic wave and differ in the amount of phase shift of the laser light by λ / 4. k0 ~I k3 From equation (2), the optical phase (phase difference between the two optical paths when the phase shift is zero) Φ k Request. Φ k =-arctan{(I k3 -I k1 ) / (I k2 -I k0 )}···(2) In addition, the control unit 270 controls the optical phase Φ k The approximation coefficients X, φ, and Z in equation (3) are calculated by performing a sine wave approximation on Φ k =Xcos(φ+kπ / 4)+Z=Yexp(kπ / 4)+Z...(3) Here, k is an integer from 0 to 7. Furthermore, Y is a complex amplitude and is expressed as shown in formula (4). Y=Xexp(iφ): complex amplitude (4) Furthermore, the control unit 270 obtains a vibration state indicating an optical phase change at each phase time ξ (0≦ξ<2π) of the vibration of the elastic wave from an approximation obtained by removing the constant term Z from equation (3). The control unit 270 obtains a linear vibration state at one measurement position by performing the same process on all the linear pixels at one measurement position.

[0078] The control unit 270 acquires a line-shaped vibration state at each of a plurality of measurement positions over the entire measurement area Pa in accordance with the movement of the wheel unit 60. Then, the control unit 270 acquires a two-dimensional distribution of the vibration state based on the acquired line-shaped vibration state. The control unit 270 generates a vibration state image E that displays the acquired two-dimensional distribution of the vibration state (distribution of approximated optical phase change) in different colors, for example, as in the first embodiment.

[0079] Other configurations in the second embodiment are similar to those in the first embodiment.

[0080] [Effects of the second embodiment] In the second embodiment, the following effects can be obtained.

[0081] In the second embodiment, as described above, the measuring unit 230 that performs measurement by imaging in a line shape is configured to perform multiple measurements at the same measurement position among the multiple measurement positions (P1, P2, P3, ...) in a time shorter than the period T of the elastic wave excited by the transducer 10 (excitation unit), and the control unit 270 is configured to acquire a two-dimensional distribution of the vibration state in the measurement area Pa by multiple measurements at the same measurement position in a time shorter than the period T of the elastic wave by the measuring unit 230 that performs measurement by imaging in a line shape. Here, when the interval between measurements by the measuring unit 230 is longer than the period T of the elastic wave, it is necessary to perform imaging (measurement) while acquiring the phase of the elastic wave at the timing of imaging. Then, it is necessary to calculate the vibration state of the elastic wave based on the acquired imaging result D and the phase of the elastic wave. In contrast, in the second embodiment, the measuring unit 230 that performs measurement by imaging in a line shape is configured to perform multiple measurements at the same measurement position in a time shorter than the period T of the elastic wave. With this configuration, multiple imaging results D can be obtained during one elastic wave period T, so that the vibration state of the elastic wave can be easily obtained (calculated) based on the multiple obtained imaging results D without obtaining (controlling) the phase of the elastic wave. Therefore, it is possible to suppress an increase in the processing load for controlling the timing of imaging and the phase of the elastic wave together. Other effects of the second embodiment are similar to those of the first embodiment.

[0082] [Third embodiment] Next, the configuration of a defect inspection system 300 according to a third embodiment of the present invention will be described with reference to Fig. 11 to Fig. 13. Unlike the second embodiment described above which is configured to perform imaging multiple times in a time shorter than the period T of the elastic wave, the third embodiment is configured to perform imaging while performing strobe irradiation by the irradiation unit 320 in accordance with the phase of the elastic wave. Note that the same components as those in the second embodiment are shown with the same reference numerals in the drawings, and their description will be omitted.

[0083] 11, a defect inspection system 300 in the third embodiment includes a defect inspection apparatus 301 and a processing apparatus 302. The defect inspection apparatus 301 includes an irradiation unit 320 and a measurement unit 330. The processing apparatus 302 includes a control unit 370.

[0084] The irradiation unit 320 irradiates the laser light in the same manner as in the first and second embodiments. In the third embodiment, the irradiation unit 320 is configured to irradiate the laser light by strobe lighting synchronized with a predetermined phase of the vibration of the vibrator 10 based on an AC current from a signal generator 90.

[0085] As shown in Fig. 12, the measurement unit 330 causes the laser light reflected at two different points in the measurement area Pa in which the elastic wave is excited by the transducer 10 to interfere with each other, as in the first and second embodiments. The measurement unit 330 also includes an image sensor 34 and a phase shifter 235. The measurement unit 330 according to the third embodiment performs imaging using the image sensor 34 with an exposure time greater than the vibration period T of the elastic wave, as in the first embodiment. The measurement unit 330 also measures (images) the interference light while changing the phase difference between the two interfering laser light by operating the phase shifter 235, as in the second embodiment.

[0086] The control unit 370 controls each unit of the defect inspection device 301 and the processing device 302, similarly to the control unit 70 (270) according to the first and second embodiments. Furthermore, the control unit 370 acquires a line-shaped vibration state from the line-shaped imaging results D at each of the multiple measurement positions over the entire measurement area Pa in association with the movement of the wheel unit 60. Then, based on the acquired line-shaped vibration state, the control unit 370 generates a vibration state image E and causes the display unit 80 to display it.

[0087] In the third embodiment, the control unit 370 is configured to control the phase of the elastic wave and the timing of measurement by the measurement unit 330, thereby acquiring the phase of the elastic wave at the timing when the imaging result D is acquired, and to acquire a two-dimensional distribution of the vibration state in the measurement area Pa based on the acquired phase of the elastic wave and the imaging result D.

[0088] 13, specifically, the control unit 370 controls the signal generator 90 to control the phase and frequency of the vibration of the transducer 10. The control unit 370 also controls the signal generator 90 to cause the irradiation unit 320 to irradiate laser light in synchronization with a predetermined phase of the vibration of the transducer 10. For example, the measurement unit 330 changes the amount of phase shift by λ / 4 at each of timings k (k=0 to 7) at which the phases of the elastic waves produced by the transducer 10 differ by T / 8, and irradiates the laser light at each phase shift amount (0, λ / 4, λ / 2, 3λ / 4) to perform imaging.

[0089] The control unit 370 acquires the phase of the elastic wave at the timing when the imaging result D is acquired, and acquires the luminance value of each pixel of the four imaging results D having the same timing k (k=0 to 7) of the phase of the elastic wave and different amounts of phase shift of the laser light by λ / 4, based on the acquired phase of the elastic wave and the imaging result D. The control unit 370 acquires a vibration state indicating an optical phase change from the acquired luminance value by a control process similar to that of the control unit 270 according to the second embodiment, and generates a vibration state image E displaying a two-dimensional distribution of the acquired vibration state (distribution of approximated optical phase change).

[0090] Other configurations in the third embodiment are similar to those in the second embodiment.

[0091] [Effects of the third embodiment] In the third embodiment, the following effects can be obtained.

[0092] In the third embodiment, as described above, the control unit 370 is configured to control the phase of the elastic wave and the timing of the measurement by the measurement unit 330 to obtain the phase of the elastic wave at the timing when the imaging result D is obtained, and to obtain a two-dimensional distribution of the vibration state in the measurement area Pa based on the phase of the acquired elastic wave and the imaging result D. With this configuration, even if the interval between measurements by the measurement unit 330 is longer than the period T of the elastic wave, the vibration state of the elastic wave can be obtained from the imaging result D at each phase of the elastic wave based on the phase of the elastic wave at the timing when the imaging result D is obtained. Therefore, even if the interval between measurements by the measurement unit 330 is longer than the period T of the elastic wave, the vibration state of the elastic wave can be effectively obtained while changing the measurement position by the wheel unit 60. Note that other effects of the third embodiment are similar to those of the first and second embodiments.

[0093] (Modification) The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is indicated by the claims, not by the description of the embodiments above, and further includes all modifications (variations) within the meaning and scope of the claims.

[0094] For example, in the above first to third embodiments, the vibration state image E that allows visual recognition of the two-dimensional distribution of the vibration state in the measurement area Pa is displayed on the display unit 80, but the present invention is not limited to this. In the present invention, as in the processing device 402 according to the modified example shown in FIG. 14, a defect image F that allows identification of a defect (defective portion Q) based on the acquired two-dimensional distribution of the vibration state may be generated, and the generated defect image F may be displayed on the display unit 480. That is, the defective portion Q (defect) in the measurement area Pa of the inspection object P may be detected (extracted) by image processing. Specifically, the control unit of the processing device 402 detects a discontinuous area of ​​the vibration state as a defect (defective portion Q) of the inspection object P based on the acquired two-dimensional distribution of the vibration state. Then, a defect image F that allows identification of the area detected as a defect is generated. For example, a defect image F that shows the shape of the defect by a contour line surrounding the detected area may be generated. Note that the vibration state image E showing the two-dimensional distribution of the vibration state and the generated defect image F may be displayed side by side on the display unit 480. Furthermore, the vibration state image E and the defect image F may be displayed on the display unit 480 in a superimposed manner.

[0095] The control unit of the processing device 402 may be configured to specify the type of defect, such as peeling of the coating film or a crack, based on the area or shape of the region of the detected defect (defective portion Q). In this case, defect type information Fa (see FIG. 14) that allows the type of defect to be identified may be displayed on the display unit 480 together with the defect image F. The defect image F may be generated so that the type of defect can be identified by color-coding the defect according to its type.

[0096] In the above first to third embodiments, an example was shown in which the moving mechanism includes the wheel unit 60 that rotates while abutting against the outer surface of the test object P in a state in which the housing 40 (main housing unit) is fixed so as to be spaced apart from and facing the outer surface of the test object P, but the present invention is not limited to this. In the present invention, the moving mechanism may be configured with a member having a smooth surface, and the housing 40 may be configured to move while sliding on the outer surface of the test object P.

[0097] In the above first to third embodiments, the vibrator 10 (excitation unit) is disposed on the shaft portion 61 of the wheel portion 60a, but the present invention is not limited to this. For example, the vibrator 10 may be disposed on a portion inside the wheel portion 60a other than the shaft portion 61. That is, the vibrator 10 may be provided so as to abut on the inside of the outer circumferential portion 62. The vibrator 10 may be provided on the outside of the wheel portion 60a, rather than on the inside. The vibrator 10 may be disposed on the wheel portion 60b, rather than on the wheel portion 60a.

[0098] In the above first to third embodiments, the measuring unit 30 (230, 330) is configured to capture and measure the interference light caused by interfering laser light in a line shape, but the present invention is not limited to this. For example, instead of the laser interferometry using the interference light, the vibration state (two-dimensional distribution of the vibration state) on the outer surface may be obtained by an optical measurement method such as a digital image correlation method or a moire sampling method.

[0099] In the second and third embodiments, the phase shift amount is changed and imaging is performed at different timings when the phase of the elastic wave is different for each phase shift amount, but the present invention is not limited to this. For example, the vibration state (two-dimensional distribution of the vibration state) may be approximately acquired by performing imaging multiple times at different timings when the phase of the elastic wave is different without performing phase shift.

[0100] In the above first to third embodiments, the housing 40 (main housing) shields the laser light by surrounding the irradiation unit 20 (320) and the measurement unit 30 (230, 330), but the present invention is not limited to this. For example, the housing 40 may be configured not to shield the irradiation unit 20 (320) and the measurement unit 30 (230, 330).

[0101] In the above first to third embodiments, the irradiation unit 20 (320) is configured to irradiate the measurement area Pa with planar sheet light, which is obtained by diffusing the laser light along the direction (X direction) in which the imaging elements of the measurement unit 30 (230, 330) are arranged in a line, in a line shape, but the present invention is not limited to this. For example, the laser light irradiated from the irradiation unit 20 (320) may be irradiated by diffusing it three-dimensionally instead of in a planar (sheet-like) shape.

[0102] In the above first to third embodiments, the wheel unit 60 (moving mechanism) is configured to move the housing 40 (main housing) by the operating force of the inspection operator who holds the grip unit 50, but the present invention is not limited to this. For example, the moving mechanism may include a drive unit such as a motor, and the drive unit of the moving mechanism may be operated under the control of the control unit 70 (270, 370) to move the housing 40.

[0103] In the above first to third embodiments, the control unit 70 (270, 370) is configured to display the vibration state image E on the display unit 80 of the processing device 102 (202, 302) which is a tablet PC, but the present invention is not limited to this. For example, the generated vibration state image E may be displayed on a wearable device such as smart glasses.

[0104] In the above first to third embodiments, the measurement units 30 (230, 330) are disposed between two different wheel units 60 (60a and 60b), but the present invention is not limited to this. For example, the measurement units 30 (230, 330) may be disposed between three wheels. Furthermore, the wheel unit 60 may be constituted by one wheel.

[0105] In the above first to third embodiments, an example has been shown in which a vibration state image E is generated by the control unit 70 (270, 370) of the processing device 102 (202, 302) based on the imaging result D acquired by the defect inspection device 101 (201, 301), and the generated vibration state image E is displayed on the display unit 80 of the processing device 102 (202, 302), but the present invention is not limited to this. For example, the control unit 70 (270, 370) and the display unit 80 may be integrally provided in the defect inspection device 101 (201, 301).

[0106] In the above first to third embodiments, the number of pixels of the linear imaging result D by the measuring unit 30 (230, 330) is 1×1024, but the present invention is not limited to this. For example, the number of pixels of the imaging result D may be 64×1024. That is, the imaging element included in the measuring unit 30 (230, 330) may be configured to measure (image) the imaging result D having a plurality of pixels in the width direction.

[0107] In the above first to third embodiments, the laser light is irradiated in a line shape along the direction in which the shaft portion 61 of the wheel unit 60 extends (X direction), and the measurement area Pa of the outer surface of the object P to be inspected is imaged and measured in a line shape along the direction in which the shaft portion 61 extends (X direction), but the present invention is not limited to this. For example, the area to be imaged in a line shape may be imaged in a line shape extending along a direction perpendicular to the shaft portion 61 (Y direction). Also, the area may be imaged in a line shape extending in a direction inclined (diagonal) from a direction perpendicular to the direction of movement (Y direction).

[0108] In the above first to third embodiments, the laser light reflected at two different positions (positions Pa1 and Pa2) in the Y direction (movement direction) of the measurement area Pa is used as the reflected laser light and the reference laser light, and the reflected laser light and the reference laser light are made to interfere with each other by laser interference, but the present invention is not limited to this. For example, the direction (shear direction) in which the positions Pa1 and Pa2 move apart may be a direction parallel to the shaft portion 61 of the wheel part 60 (X direction) or a direction obliquely shifted from the direction parallel to the shaft portion 61.

[0109] [Aspects] It will be appreciated by those skilled in the art that the exemplary embodiments described above are examples of the following aspects.

[0110] (Item 1) an excitation unit that excites an elastic wave in the object to be inspected; a measurement unit including imaging elements arranged in a line and configured to image and measure a measurement area of ​​the outer surface of the object to be inspected in a line shape in a state in which the elastic waves are excited by the excitation unit; a main body housing in which the measurement unit is disposed; a moving mechanism for disposing the main body housing so as to be movable along the outer surface of the inspection object; a control unit configured to sequentially acquire line-shaped imaging results by the measurement unit at each of a plurality of measurement positions in the measurement area as the moving mechanism moves along the outer surface of the main body housing, and to acquire a two-dimensional distribution of vibration conditions for defect inspection in the measurement area based on the sequentially acquired line-shaped imaging results.

[0111] (Item 2) the moving mechanism includes a wheel unit that rotates while contacting the outer surface of the inspection object in a state in which the main body housing unit is fixed so as to be spaced apart from and facing the outer surface of the inspection object, 2. The defect inspection system of claim 1, wherein the excitation unit is disposed inside the wheel unit and configured to excite the elastic waves in the object to be inspected by propagating vibrations through the wheel unit.

[0112] (Item 3) The measurement area may further include an irradiation unit that irradiates the measurement area with a laser beam in a state in which the elastic wave is excited by the excitation unit. the measurement unit is configured to cause interference between a reflected laser light, which is the laser light irradiated by the irradiation unit and reflected at the measurement region, and a reference laser light irradiated by the irradiation unit, and to capture and measure interference light, which is caused by interference between the reflected laser light and the reference laser light, in a line shape; 3. The defect inspection system according to claim 1, wherein the control unit is configured to acquire the two-dimensional distribution of the vibration state in the measurement area based on the imaging result indicating the intensity of the interference light captured and measured in a line shape by the measurement unit.

[0113] (Item 4) the reference laser light includes the laser light reflected at a position in the measurement area different from the reflection position of the reflected laser light, 4. The defect inspection system according to item 3, wherein the measurement unit is configured to capture and measure a line-shaped image of interference light produced by interfering between the reflected laser light and the reference laser light reflected at different positions in the measurement area.

[0114] (Item 5) 5. The defect inspection system of claim 3, wherein the control unit is configured to acquire a line-shaped vibration state at each of the plurality of measurement positions by acquiring a line-shaped imaging result in a state in which the elastic wave is excited and a line-shaped imaging result in a state in which the elastic wave is not excited at each of the plurality of measurement positions.

[0115] (Item 6) the measurement unit that captures and measures in a line shape is configured to perform a plurality of measurements at the same measurement position among the plurality of measurement positions in a time shorter than a period of the elastic wave excited by the excitation unit, 5. The defect inspection system of claim 3, wherein the control unit is configured to acquire the two-dimensional distribution of the vibration state in the measurement area by measuring the same measurement position multiple times in a time shorter than the period of the elastic wave by the measurement unit, which captures and measures in a line shape.

[0116] (Item 7) The control unit is configured to control the phase of the elastic wave and the timing of measurement by the measurement unit to acquire the phase of the elastic wave at the timing when the imaging result is acquired, and to acquire the two-dimensional distribution of the vibration state in the measurement area based on the acquired phase of the elastic wave and the imaging result.

[0117] (Item 8) 8. The defect inspection system according to any one of items 3 to 7, wherein the main body housing includes a shielding section that shields the laser light by surrounding the irradiation section and the measurement section.

[0118] (Item 9) 9. The defect inspection system according to any one of items 3 to 8, wherein the irradiation unit is configured to irradiate the measurement area in a line with a planar sheet light obtained by diffusing the laser light along a direction in which the imaging elements of the measurement unit are arranged in a line.

[0119] (Item 10) The inspection apparatus further includes a gripping portion that is gripped by an inspection operator, 10. The defect inspection system according to any one of claims 1 to 9, wherein the moving mechanism is configured to move the main body housing by an operating force applied by the inspection operator holding the gripping portion.

[0120] (Item 11) A display unit that displays an image based on the control by the control unit is further provided. The defect inspection system described in any one of items 1 to 10, wherein the control unit is configured to generate a vibration state image that allows the two-dimensional distribution of the vibration state in the measurement area to be visually recognized based on the acquired two-dimensional distribution of the vibration state, and display the image on the display unit.

[0121] (Item 12) the moving mechanism includes two different wheel units that rotate while contacting the outer surface of the inspection object in a state in which the main body housing unit is fixed so as to be spaced apart from and facing the outer surface of the inspection object, 12. The defect inspection system according to any one of claims 1 to 11, wherein the measurement unit is disposed between each of two different wheel units.

[0122] (Item 13) an excitation unit that excites an elastic wave in the object to be inspected; a measurement unit including imaging elements arranged in a line and configured to image and measure a measurement area of ​​the outer surface of the object to be inspected in a line shape in a state in which the elastic waves are excited by the excitation unit; a main body housing in which the measurement unit is disposed; a moving mechanism that positions the main body housing so that it can move along the outer surface of the object to be inspected.

[0123] (Item 14) Exciting an elastic wave in an object to be inspected; a step of sequentially acquiring line-shaped imaging results by imaging and measuring a line-shaped image while moving a plurality of measurement positions in a measurement region on the outer surface of the test object in a state in which the elastic wave is excited; acquiring a two-dimensional distribution of vibration conditions for defect inspection in the measurement area based on the sequentially acquired line-shaped imaging results. [Explanation of symbols]

[0124] 10. Transducer (excitation part) 20, 320 Irradiation unit 30, 230, 330 measurement section 40 Housing (main housing, shielding part) 50 Gripping part 60, 60a, 60b Wheel section (moving mechanism) 70, 270, 370 Control section 80, 480 display section 100, 200, 300 Defect Inspection System 101, 201, 301 Defect inspection equipment

Claims

1. an excitation unit that excites an elastic wave in the object to be inspected; a measurement unit including imaging elements arranged in a line and configured to image and measure a measurement area of ​​the outer surface of the object to be inspected in a line shape in a state in which the elastic waves are excited by the excitation unit; a main body housing in which the measurement unit is disposed; a moving mechanism for disposing the main body housing so as to be movable along the outer surface of the inspection object; a control unit configured to sequentially obtain linear imaging results by the measurement unit at each of a plurality of measurement positions in the measurement area as the moving mechanism moves along the outer surface of the main body housing, and to obtain a two-dimensional distribution of vibration conditions for defect inspection in the measurement area based on the sequentially obtained linear imaging results; The moving mechanism is configured to come into contact with the outer surface of the inspection object, A defect inspection system, wherein the excitation unit is disposed inside the moving mechanism.

2. the moving mechanism includes a wheel unit that rotates while contacting the outer surface of the inspection object in a state in which the main body housing unit is fixed so as to be spaced apart from and facing the outer surface of the inspection object, The defect inspection system of claim 1 , wherein the excitation unit is disposed inside the wheel unit and configured to excite the elastic waves in the object to be inspected by propagating vibrations through the wheel unit.

3. The wheel portion includes a pair of wheel portions that are different from each other, The defect inspection system according to claim 2 , wherein the main body housing is disposed between the pair of wheel units.

4. The measurement area may further include an irradiation unit that irradiates the measurement area with a laser beam in a state in which the elastic wave is excited by the excitation unit. the measurement unit is configured to cause interference between a reflected laser light, which is the laser light irradiated by the irradiation unit and reflected at the measurement region, and a reference laser light irradiated by the irradiation unit, and to capture and measure interference light, which is caused by interference between the reflected laser light and the reference laser light, in a line shape; 2. The defect inspection system of claim 1, wherein the control unit is configured to acquire the two-dimensional distribution of the vibration state in the measurement area based on the imaging result indicating the intensity of the interference light captured in a line shape and measured by the measurement unit.

5. the reference laser light includes the laser light reflected at a position in the measurement area different from the reflection position of the reflected laser light, 5. The defect inspection system according to claim 4, wherein the measurement unit is configured to image and measure the interference light generated by interfering between the reflected laser light and the reference laser light reflected at different positions in the measurement area in a line shape.

6. The defect inspection system of claim 4, wherein the control unit is configured to acquire the line-shaped vibration state at each of the plurality of measurement positions by acquiring the line-shaped imaging result in a state in which the elastic wave is excited and the line-shaped imaging result in a state in which the elastic wave is not excited at each of the plurality of measurement positions.

7. the measurement unit that captures and measures in a line shape is configured to perform a plurality of measurements at the same measurement position among the plurality of measurement positions in a time shorter than a period of the elastic wave excited by the excitation unit, The defect inspection system of claim 4, wherein the control unit is configured to acquire the two-dimensional distribution of the vibration state in the measurement area by measuring the same measurement position multiple times in a time shorter than the period of the elastic wave by the measurement unit, which captures and measures in a line shape.

8. The defect inspection system of claim 4, wherein the control unit is configured to acquire the phase of the elastic wave at the timing when the imaging result is acquired by controlling the phase of the elastic wave and the timing of measurement by the measurement unit, and to acquire the two-dimensional distribution of the vibration state in the measurement area based on the acquired phase of the elastic wave and the imaging result.

9. The defect inspection system according to claim 4 , wherein the main body housing includes a shielding section that shields the laser light by surrounding the irradiation section and the measurement section.

10. 5. The defect inspection system of claim 4, wherein the irradiation unit is configured to irradiate the measurement area in a line shape with a planar sheet light obtained by diffusing the laser light along a direction in which the imaging elements of the measurement unit are arranged in a line shape.

11. The inspection apparatus further includes a gripping portion that is gripped by an inspection operator, The defect inspection system according to claim 1 , wherein the moving mechanism is configured to move the main body housing by an operating force applied by the inspection operator holding the grip portion.

12. A display unit that displays an image based on the control by the control unit is further provided. The defect inspection system of claim 1, wherein the control unit is configured to generate a vibration state image that allows the two-dimensional distribution of the vibration state in the measurement area to be visually recognized based on the acquired two-dimensional distribution of the vibration state, and display the image on the display unit.

13. the moving mechanism includes two different wheel units that rotate while contacting the outer surface of the inspection object in a state in which the main body housing unit is fixed so as to be spaced apart from and facing the outer surface of the inspection object, The defect inspection system of claim 1 , wherein the measurement portion is disposed between each of two different wheel portions.

14. an excitation unit that excites an elastic wave in the object to be inspected; a measurement unit including imaging elements arranged in a line and configured to image and measure a measurement area of ​​the outer surface of the object to be inspected in a line shape in a state in which the elastic waves are excited by the excitation unit; a main body housing in which the measurement unit is disposed; a moving mechanism that disposes the main body housing so as to be movable along the outer surface of the inspection object, The moving mechanism is configured to come into contact with the outer surface of the inspection object, A defect inspection device, wherein the excitation unit is disposed inside the moving mechanism.

15. Exciting an elastic wave in an object to be inspected; a step of sequentially obtaining linear imaging results by imaging and measuring a line at each of a plurality of measurement positions in a measurement region on the outer surface of the test object in a state in which the elastic wave is excited, while moving the measurement positions by a moving mechanism configured to abut against the outer surface of the test object; acquiring a two-dimensional distribution of vibration conditions for defect inspection in the measurement area based on the line-shaped imaging results acquired sequentially, A defect inspection method, wherein the step of exciting elastic waves in the object to be inspected includes a step of exciting the elastic waves in the object to be inspected by an excitation unit arranged inside the moving mechanism.

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