Defect inspection apparatus

Abstract

A defect inspection apparatus is provided. The defect inspection apparatus generates an image representing displacement at a measurement region of an inspection object, i.e., a surface layer inspection image, based on an intensity pattern of laser light that has undergone interference. Also, the defect inspection apparatus generates an image of an outer surface of the measurement region, i.e., an appearance inspection image, based on an intensity pattern of incoherent light.

Description

Technical Field

[0001] This invention relates to a defect inspection device. Background Technology

[0002] Previously, a defect inspection device using laser interferometry was known. Such a defect inspection device was disclosed, for example, in Japanese Patent Application Publication No. 2007-024674.

[0003] Japanese Patent Application Publication No. 2007-024674 discloses a surface inspection apparatus that heats the object to be inspected and measures the displacement of the object's surface using laser interferometry to evaluate defects in the object. The surface inspection apparatus described in Japanese Patent Application Publication No. 2007-024674 locally heats the surface of the object to be inspected, causing thermal deformation. When defects such as cracks or peeling exist on the object, the thermal deformation at these defects increases, resulting in displacement on the surface of the object. Furthermore, the surface inspection apparatus described in Japanese Patent Application Publication No. 2007-024674 is configured to evaluate defects in the object by measuring the resulting displacement using laser interferometry.

[0004] In addition to surface defect inspection, visual inspection is sometimes performed. In surface defect inspection, cracks and peeling occurring inside the object (surface and outer layer) are checked by measuring surface displacement using laser interferometry. In visual inspection, depending on the object being inspected, dirt, deposits, and minor irregularities on the outer surface are examined. Therefore, although not explicitly described in Japanese Patent Application Publication No. 2007-024674, it is considered to use the surface defect inspection apparatus using laser interferometry described in Japanese Patent Application Publication No. 2007-024674 for visual inspection of the object. However, when visual inspection is performed using the aforementioned conventional surface inspection apparatus, the image of the object being inspected, captured by laser irradiation, contains bright and dark spots (streaks) caused by laser interference. These streaks significantly degrade image quality during visual inspection, making it difficult to perform visual inspection using images captured by laser irradiation that contain streaks. Therefore, there is a problem that it is difficult to use a single device to perform both surface defect inspection and appearance inspection of the object being inspected using laser interferometry. Summary of the Invention

[0005] The present invention was made to solve the problems described above. One object of the present invention is to provide a defect inspection device that can perform both surface defect inspection and appearance inspection using laser interferometry.

[0006] To achieve the above objectives, one aspect of the defect inspection apparatus of the present invention includes: a displacement unit that displaces a measurement area of ​​the object to be inspected; a first irradiation unit that irradiates the measurement area with laser light; a second irradiation unit that irradiates the measurement area with incoherent light; a control unit that controls the irradiation by the first and second irradiation units; an interference unit that interferes with the laser light reflected at the measurement area using laser interferometry; and an imaging unit that captures images of the interfering laser light and the incoherent light reflected at the measurement area. The defect inspection apparatus is configured to generate an image representing the displacement at the measurement area of ​​the object to be inspected, i.e., a surface inspection image, based on the intensity pattern of the interfering laser light captured by the imaging unit, and to generate an image of the outer surface of the measurement area, i.e., an appearance inspection image, based on the intensity pattern of the incoherent light captured by the imaging unit. Furthermore, "incoherent light" refers to light with inconsistent amplitude and phase, and is light with properties that make interference difficult to observe.

[0007] The defect inspection apparatus described above includes: a first irradiation unit that irradiates a measurement area with laser light; and a second irradiation unit that irradiates the measurement area with incoherent light. Furthermore, based on the intensity pattern of the interfering laser light captured by the imaging unit, an image representing the displacement at the measurement area of ​​the object under inspection, i.e., a surface inspection image, is generated; and based on the intensity pattern of the incoherent light captured by the imaging unit, an image of the outer surface of the measurement area, i.e., an appearance inspection image, is generated. Thus, surface defect inspection can be performed using laser interferometry, and appearance inspection can be performed using an image captured by irradiating incoherent light without any streaks. As a result, both surface defect inspection and appearance inspection using laser interferometry can be performed using a single apparatus. Attached Figure Description

[0008] Figure 1 This is a diagram illustrating the structure of the defect inspection device according to the first embodiment.

[0009] Figure 2 This is a diagram used to illustrate the surface inspection image of the first embodiment.

[0010] Figure 3 This is a diagram used to illustrate the appearance inspection of the first embodiment.

[0011] Figure 4 This is a diagram used to illustrate the extracted image in the first embodiment.

[0012] Figure 5 This is a diagram illustrating an appearance inspection image superimposed on an extracted image, used to explain the first embodiment.

[0013] Figure 6 This is a diagram illustrating the display of the display unit in the first embodiment.

[0014] Figure 7 This is a flowchart for explaining the control unit of the first embodiment.

[0015] Figure 8 This is a diagram illustrating the structure of the defect inspection device according to the second embodiment.

[0016] Figure 9 This is a diagram illustrating the structure of the defect inspection device according to the third embodiment.

[0017] Figure 10 This is a diagram illustrating the structure of the defect inspection device according to the fourth embodiment.

[0018] Figure 11 This is a diagram illustrating the operation of the second reflector in the fourth embodiment.

[0019] Figure 12 This is a diagram illustrating the structure of the defect inspection device according to the fifth embodiment.

[0020] Figure 13A This is a diagram used to illustrate the appearance inspection image of the fifth embodiment, showing the image before image processing.

[0021] Figure 13B This is a diagram used to illustrate the appearance inspection image of the fifth embodiment, and it shows the image after image processing.

[0022] Figure 14 This is a diagram illustrating the structure of the defect inspection device according to the sixth embodiment.

[0023] Figure 15 This is a diagram illustrating the structure of the defect inspection device according to the seventh embodiment. Detailed Implementation

[0024] Hereinafter, embodiments embodying the present invention will be described with reference to the accompanying drawings.

[0025] [First Implementation Method]

[0026] (Structure of the defect inspection device)

[0027] Reference Figure 1 The overall structure of the defect inspection device 100 according to the first embodiment of the present invention will be described.

[0028] like Figure 1As shown, the defect inspection device 100 of the first embodiment includes an oscillator 1, a first irradiation unit 2, a second irradiation unit 3, a speckle shear interferometer 4, a control unit 5, a signal generator 6, and a display unit 7. Furthermore, the oscillator 1 is an example of the "displacement unit" of the present invention, and the speckle shear interferometer 4 is an example of the "interference unit" of the present invention.

[0029] The oscillator 1 and the first irradiation unit 2 are connected to the signal generator 6 via cables.

[0030] The oscillator 1 displaces the measurement area Pa of the object under inspection P. Specifically, the oscillator 1 excites an elastic wave in the measurement area Pa. That is, the oscillator 1 is configured to contact the object under inspection P, converting the AC signal from the signal generator 6 into mechanical vibration, thereby exciting an elastic wave in the measurement area Pa.

[0031] The first irradiation unit 2 irradiates the measurement area Pa with laser L1. The first irradiation unit 2 includes a laser source (not shown). The laser L1 irradiated from the laser source is diffusely irradiated onto the entire measurement area Pa of the surface of the object P through the first illumination lens 21. In addition, the first irradiation unit 2 irradiates the laser L1 at a predetermined time based on an electrical signal from the signal generator 6. That is, the first irradiation unit 2 irradiates the object P with laser L1 in accordance with the elastic wave generated by the oscillator 1. The laser source is, for example, a laser diode, used to irradiate the object P with laser L1 (near-infrared light) with a wavelength of 785 nm.

[0032] The second irradiation unit 3 irradiates incoherent light, i.e., incoherent light L2, onto the measurement area Pa. In this embodiment, the second irradiation unit 3 irradiates incoherent light L2, which includes light having a wavelength equal to that of the laser L1 irradiated by the first irradiation unit 2 (a wavelength of 785 nm). That is, the incoherent light L2 includes light with the same wavelength range as the laser L1. Furthermore, the incoherent light L2 irradiated from the second irradiation unit 3 is diffusely irradiated onto the entire measurement area Pa of the surface of the object being inspected, P, through the second illumination lens 31. The second irradiation unit 3 is, for example, an LED (Light Emitting Diode), and is configured with a center wavelength in the range of 780 nm or more and 800 nm or less.

[0033] The speckle shearing interferometer 4 is configured to interfere with the laser L1 reflected at the measurement region Pa using laser interferometry. The speckle shearing interferometer 4 is configured to measure the displacement at the measurement region Pa of the object under inspection P using a method (shearing interferometry) that interferes with the laser L1 reflected at two distinct points in the measurement region Pa excited by the oscillator 1. Furthermore, the speckle shearing interferometer 4 includes a beam splitter 41, a phase shifter 42, a first reflecting mirror 43a, a second reflecting mirror 43b, a condenser lens 44, and a bandpass filter 45, which are optical components arranged in the optical path of the laser L1. Additionally, the speckle shearing interferometer 4 includes an image sensor 46 and a light shield 47. Furthermore, the image sensor 46 is an example of the "camera unit" of the present invention, and the bandpass filter 45 is an example of the "optical filter" of the present invention. Furthermore, the light shield 47 is an example of the "shielding unit" of the present invention.

[0034] Beam splitter 41 includes a semi-transparent, semi-reflective mirror. Beam splitter 41 is positioned at the point where the reflected laser L1 and incoherent light L2 from the measurement area Pa of the object being inspected P are to be incident. Furthermore, beam splitter 41 causes the incident laser L1 and incoherent light L2 to... Figure 1 The light path, as shown by the solid line S1, is reflected towards the phase shifter 42, and the incident laser L1 and the incoherent light L2 are reflected as... Figure 1 The light path, as shown by the dashed line S2, passes through to the second reflecting mirror 43b. Additionally, the beam splitter 41 allows the laser L1 and incoherent light L2 incident by the first reflecting mirror 43a to pass through as... Figure 1 The light path, as shown by the solid line S1, passes through the condenser lens 44, and the laser L1 and incoherent light L2 reflected by the second mirror 43b are as follows: Figure 1 As shown by the dashed line S2, it reflects towards the condenser lens 44.

[0035] The first reflector 43a is positioned at a 45-degree angle relative to the reflecting surface of the beam splitter 41 in the optical path of the laser L1 and the incoherent light L2 reflected by the beam splitter 41. The first reflector 43a causes the laser L1 and the incoherent light L2 reflected by the beam splitter 41 to reflect towards the beam splitter 41.

[0036] The second reflector 43b is positioned at a slightly tilted angle of 45 degrees relative to the reflecting surface of the beam splitter 41 in the optical path of the laser L1 and the incoherent light L2 that are to pass through the beam splitter 41. The second reflector 43b reflects the laser L1 and the incoherent light L2 that are incident through the beam splitter 41 toward the beam splitter 41 side.

[0037] Phase shifter 42 is disposed between beam splitter 41 and first reflector 43a, and is controlled by control unit 5 to change (shift) the phase of the laser L1 to be transmitted. Specifically, phase shifter 42 is configured to change the optical path length of the laser L1 to be transmitted.

[0038] Image sensor 46 has multiple detection elements, configured to detect laser L1 and incoherent light L2 that are reflected by first mirror 43a after being reflected by beam splitter 41 and then transmitted through beam splitter 41. Figure 1 The straight line S1 in the beam splitter 41 and the laser L1 and incoherent light L2 reflected by the second mirror 43b and then reflected by the beam splitter 41 after passing through the beam splitter 41. Figure 1 The image sensor 46 includes, for example, a CMOS image sensor or a CCD image sensor, in the optical path of the dashed line S2.

[0039] A focusing lens 44 is positioned between the beam splitter 41 and the image sensor 46, allowing the laser L1 and incoherent light L2 passing through the beam splitter 41 to pass through. Figure 1 The straight line S1 in the beam splitter 41 and the laser L1 and incoherent light L2 reflected by the beam splitter 41 Figure 1 The dashed lines S2 in the middle converge.

[0040] A bandpass filter 45 is disposed between the condenser lens 44 and the image sensor 46. Furthermore, the bandpass filter 45 allows light of a predetermined wavelength to pass through. Moreover, the bandpass filter 45 is configured to block (attenuate) light of wavelengths other than the predetermined wavelength. The bandpass filter 45 may include, for example, a dielectric multilayer film, and has a center wavelength configured to be 785 nm. That is, the bandpass filter 45 is configured to allow light contained in laser L1 and light contained in incoherent light L2 to pass through.

[0041] The light shield 47 blocks either of the two distinct optical paths through which the laser L1 and the incoherent light L2, reflected at two different points, should pass. Specifically, the light shield 47 is configured to switch between two states under the control of the control unit 5 (described later): blocking the optical path between the beam splitter 41 and the second reflector 43b. Figure 1 The state of the dashed line S2 in the middle ( Figure 1 (solid line), and the state of the optical path between the open beam splitter 41 and the second reflector 43b ( Figure 1 (dashed line).

[0042] In the speckle shear interferometer 4 using shear interference, for example, the laser L1 reflected at position Pa1 on the surface of the measurement region Pa and at the first reflecting mirror 43a ( Figure 1 The straight line S1) and the laser L1 reflected from position Pa2 on the surface of the measurement area Pa and the second reflector 43b Figure 1The dashed lines S2 in the image sensor 46 interfere with each other and are incident on the same location. Positions Pa1 and Pa2 are positions separated by a small distance from each other. Lasers L1 reflected from different positions in various regions of the measurement area Pa are guided by the speckle shear interferometer 4 and are incident on the image sensor 46 respectively.

[0043] In this embodiment, a portion of the optical path of laser L1 and a portion of the optical path of incoherent light L2 are shared, and a shared optical component is used for image capture by image sensor 46. That is, the incoherent light L2, illuminated by the second irradiation unit 3, is captured by image sensor 46 after passing through an optical component disposed on the optical path of laser L1 illuminated by the first irradiation unit 2. In other words, a shared optical component is disposed on the optical paths of laser L1 and incoherent light L2.

[0044] Furthermore, the image sensor 46 captures images of the interfering laser L1 and the incoherent light L2 reflected at the measurement area Pa. In other words, the interfering laser L1 and the incoherent light L2 reflected at the measurement area Pa are captured by a shared image sensor 46. Additionally, the interfering laser L1 and the incoherent light L2 reflected at the measurement area Pa contain light with wavelengths capable of passing through a shared bandpass filter 45.

[0045] The control unit 5 controls the irradiation of the first irradiation unit 2 and the second irradiation unit 3. Furthermore, the control unit 5 is configured to generate an image representing the displacement at the measurement area Pa of the inspection object P, i.e., a surface inspection image D1 (refer to...), based on the intensity pattern of the interfering laser L1 captured by the image sensor 46. Figure 2 And based on the intensity pattern of the incoherent light L2 captured by the image sensor 46, an image of the outer surface of the measurement area Pa, namely the visual inspection image D2 (refer to...), is generated. Figure 3 Furthermore, the control measures performed by the control unit 5 related to the generation of surface inspection image D1 and appearance inspection image D2 will be described later.

[0046] Furthermore, the control unit 5 is configured such that the timing for the image sensor 46 to capture the laser L1 by irradiating the first irradiation unit 2 with the laser L1 is different from the timing for the image sensor 46 to capture the incoherent light L2 by irradiating the second irradiation unit 3 with the incoherent light L2. Moreover, the control unit 5 is configured such that, while the oscillator 1 is stopped, the second irradiation unit 3 irradiates the incoherent light L2, thereby causing the image sensor 46 to capture the incoherent light L2. Furthermore, the control unit 5 is configured such that, while the light shield 47 blocks the two different light paths (…),… Figure 1 One of the optical paths (straight line S1 and dashed line S2) in the image. Figure 1 In the state of dashed line S2), another optical path is used ( Figure 1 The straight line S1 in the image sensor 46 illuminates the incoherent light L2 through the second irradiation unit 3, thereby enabling the image sensor 46 to capture the incoherent light L2.

[0047] The signal generator 6 emits a signal for the control unit 5 to control the vibration of the oscillator 1 and the timing of the irradiation of the laser L1 of the first irradiation unit 2.

[0048] Display unit 7 displays surface inspection image D1 and appearance inspection image D2 generated by control unit 5. Display unit 7 includes liquid crystal display, organic EL display, etc.

[0049] The inspection object P is a coated steel sheet obtained by applying a coating film to a steel plate. The defective area Q is a defective area within the measurement area Pa that occurs internally (on the surface and outer layer), including cracks, peeling, etc. Additionally, the defective area R is a defective area within the measurement area Pa that occurs on the outer surface, including dirt, deposits, and minor irregularities adhering to the outer surface.

[0050] (Controls regarding the generation of images for surface inspection)

[0051] like Figure 2 As shown, the surface inspection image D1 is configured to visually identify the location of the defect Q in the measurement area Pa, which is determined to be internally generated. Figure 2 The positions Pb1 and Pb2). That is, the surface inspection image D1 is an image that visually shows the vibration state of the inspection object P excited by the oscillator 1, and is configured to visually identify the location of the defective part Q generated inside by the discontinuous area of ​​vibration state.

[0052] The control unit 5 uses an actuator (not shown) to activate the phase shifter 42 located within the speckle shear interferometer 4, thereby changing the phase of the laser L1 to be transmitted. As a result, the laser L1 reflected at position Pa1 (… Figure 1 The solid line S1 in the image and the laser L1 reflected at position Pa2 ( Figure 1 The phase difference change is represented by the dashed line S2 in the image sensor 46. The detection elements of the image sensor 46 detect the intensity of the interference light after the two lasers L1 interfere.

[0053] The control unit 5 controls the vibration of the oscillator 1 and the timing of the laser L1 irradiation of the first irradiation unit 2 via the signal generator 6. While changing the phase shift, it captures multiple interference images D0 (not shown). The phase shift changes by λ / 4 each time. At each phase shift (0, λ / 4, λ / 2, 3λ / 4), a total of 37 interference images D0 are captured. These include 32 interference images D0 captured at laser irradiation timing j (j=0~7) and 5 interference images D0 before and after each phase shift (0, λ / 4, λ / 2, 3λ / 4) when the laser is extinguished. Furthermore, λ is the wavelength of the laser L1.

[0054] The control unit 5 processes the detection signal detected based on the intensity pattern of the interfering laser L1 captured by the image sensor 46 according to the following process, and acquires a surface inspection image D1 representing the state of vibration.

[0055] The control unit 5 calculates the brightness value I of four interference images D0 (each with the same timing j (j=0~7) of the irradiating laser L1 but with a phase shift difference of λ / 4. j0 ~I j3 And the optical phase (the phase difference between the two optical paths when the phase offset is zero) Φ is obtained by equation (1). j .

[0056] Φ j =-arctan{(I j3 -I j1 ) / (I j2 -I j0 )}···(1)

[0057] In addition, the control unit 5 uses the least squares method to control the light phase Φ j The approximation is performed using a sine wave to obtain the approximation coefficients A, θ, and C in equation (2).

[0058] Φ j =Acos(θ+jπ / 4)+C=Bexp(jπ / 4) +C···(2)

[0059] Where B is a complex amplitude, as expressed in equation (3).

[0060] B=Aexp(iθ): Complex amplitude···(3)

[0061] Furthermore, the control unit 5 constructs and outputs motion images (30 to 60 frames) showing the optical phase changes at each phase moment ξ (0 ≤ ξ < 2π) of the vibration, based on an approximation obtained by removing the constant term C from equation (2). In addition, during the above process, a spatial filter is appropriately applied to the complex amplitude B to remove noise. Furthermore, the steps for phase shift and timing of the irradiated laser L1 are not limited to this. In this case, the calculation formula is different from equations (1) to (3) described above.

[0062] Control unit 5 applies a spatial filter to detect discontinuous areas of vibration state based on the aforementioned motion image, identifying these as defective areas Q generated inside the inspection object P. Then, it displays a surface inspection image D1, including extracted images D1a and D1b, which are images obtained by extracting the detected areas. Here, when the shape of the inspection object P itself includes unevenness, discontinuities in vibration state may sometimes occur at the boundaries between planar and uneven portions. Therefore, control unit 5 can also be configured to detect internally generated defective areas Q based on the shape information of the inspection object P to avoid detecting them as defects.

[0063] (Controls for generating images for visual inspection)

[0064] like Figure 3 As shown, the image D2 used for visual inspection is configured to identify the location of the defective part R on the outer surface within the measurement area Pa, which is determined to be generated on the outer surface. Figure 3 The location Pb3). That is, the image D2 for visual inspection is configured such that: the location of the defective part R on the outer surface can be determined by image processing of the image captured by irradiating the outer surface of the measurement area Pa with incoherent light L2, and the determined location can be visually identified ( Figure 3 The location is Pb3). In addition, the measurement area Pa in the surface inspection image D1 and the measurement area Pa in the appearance inspection image D2 are approximately the same area.

[0065] The control unit 5 generates an image from the detection signal detected based on the intensity pattern of the incoherent light L2 captured by the image sensor 46, and performs image processing on the generated image. For example, it is configured to determine the location of the defective part R on the outer surface based on the difference in brightness values ​​between pixels. Then, the control unit 5 displays an appearance inspection image D2 including an image D2a, which highlights the location of the defective part R.

[0066] (Controls related to the display of the display unit)

[0067] The control unit 5 controls the display unit 7 to show the surface inspection image D1 and the appearance inspection image D2. Additionally, as... Figure 4 and Figure 5 As shown, the control unit 5 overlays an image that emphasizes the location of the defective part Q identified as being generated internally in the measurement area Pa onto the visual inspection image D2 and displays it on the display unit 7. That is, for the location of the defective part Q generated internally, the extracted images D1a and D1b, which are images of the extracted contours, are overlaid onto the visual inspection image D2 and displayed on the display unit 7.

[0068] In addition, such as Figure 6 As shown, the control unit 5 controls the display unit 7 to display the surface inspection image D1 and the appearance inspection image D2 side by side.

[0069] The control unit 5 is configured to generate position information E related to the positions of defective parts Q determined to be internally generated and defective parts R determined to be generated on the outer surface within the measurement area Pa. Specifically, as... Figure 6 As shown, the control unit 5 displays the surface inspection image D1, the appearance inspection image D2, and the position information E together on the display unit 7. Furthermore, in order to distinguish between internally generated defective parts Q and externally generated defective parts R, each defective part is displayed using a color corresponding to it. That is, the control unit 5 is configured to output reports related to the internally generated defective parts Q and the externally generated defective parts R.

[0070] (Control processing performed by the defect inspection device 100 of the first embodiment)

[0071] Next, refer to Figure 7 The control process related to surface defect inspection and appearance inspection performed by the defect inspection apparatus 100 of the first embodiment will be described. The control related to surface defect inspection and appearance inspection performed by the defect inspection apparatus 100 is executed by the control unit 5.

[0072] First, in step 101, vibration is applied from the oscillator 1 to the object under inspection P. This excites an elastic wave in the measurement region Pa of the object under inspection P.

[0073] Next, in step 102, laser L1 is irradiated onto the measurement area Pa from the first irradiation unit 2.

[0074] Next, in step 103, interference data is acquired while the offset of the phase shifter 42 is changed. That is, multiple interference images D0 that cause interference due to different phases are acquired. Thus, the phase shifter 42 of the speckle shear interferometer 4 is operated by changing the phase of the laser L1 by λ / 4 each time, and the intensity of the interference light of the laser L1 at each phase is detected (captured) by the image sensor 46.

[0075] Next, in step 104, the vibration applied from the oscillator 1 to the object being inspected P is stopped. Additionally, the irradiation of laser L1 by the first irradiation unit 2 is stopped. Furthermore, a portion of the optical path of laser L1 is blocked by activating the light shield 47. Figure 1 (S1 in the solid line).

[0076] Next, in step 105, incoherent light L2 is irradiated onto the measurement area Pa from the second irradiation unit 3.

[0077] Next, in step 106, the image sensor 46 detects (captures) the incoherent light L2. That is, the timing of capturing the laser L1 by the image sensor 46 when the laser L1 is irradiated from the first irradiation unit 2 is different from the timing of capturing the incoherent light L2 by the image sensor 46 when the incoherent light L2 is irradiated from the second irradiation unit 3. Furthermore, when the oscillator 1 is stopped, the incoherent light L2 is captured by the image sensor 46 when the incoherent light L2 is irradiated from the second irradiation unit 3. Moreover, the light shield 47 blocks the two different light paths (…). Figure 1 One of the optical paths (straight line S1 and dashed line S2) in the image. Figure 1 In the state of dashed line S2), another optical path is used ( Figure 1 The straight line S1 in the image is illuminated by the second irradiation unit 3 with incoherent light L2, and the incoherent light L2 is captured by the image sensor 46.

[0078] Next, in step 107, the discontinuous parts of the vibration of the object P in the measurement area Pa are extracted based on multiple interference images D0 (not shown) to generate a surface inspection image D1 that visually shows the vibration state of the object P.

[0079] Next, in step 108, an image D2 for visual inspection is generated based on the intensity pattern of the captured incoherent light L2 (refer to...). Figure 3 ).

[0080] Next, in step 109, images of the contours of the discontinuous parts of the vibration are generated, namely extracted images D1a and D1b.

[0081] Next, in step 110, the surface inspection image D1, the appearance inspection image D2, and the position information E are displayed on the display unit 7. Then, the surface defect inspection and appearance inspection processes are terminated by inputting an end instruction from the operator.

[0082] Furthermore, regarding the processes of capturing incoherent light L2 and generating an appearance inspection image D2 in steps 104-106 and 108, as well as the processes of generating a surface inspection image D1 and generating extracted images D1a (and D1b) in steps 107 and 109, any of these processes can be performed in any order.

[0083] (Effects of the first implementation method)

[0084] In the first embodiment, the following effects can be obtained.

[0085] As described above, the defect inspection apparatus 100 of the first embodiment includes: an oscillator 1 (displacement unit) that displaces the measurement area Pa of the inspection object P; a first irradiation unit 2 that irradiates the measurement area Pa with laser L1; a second irradiation unit 3 that irradiates the measurement area Pa with incoherent light, i.e., incoherent light L2; a control unit 5 that controls the irradiation of the first irradiation unit 2 and the second irradiation unit 3; a speckle shear interferometer 4 (interference unit) that interferes with the laser L1 reflected at the measurement area Pa using laser interferometry; and an image sensor 46 (image capture unit) that captures images of the interfering laser L1 and the incoherent light L2 reflected at the measurement area Pa. The defect inspection apparatus 100 is configured to generate an image representing the displacement of the measurement area Pa of the inspection object P, i.e., a surface inspection image D1, based on the intensity pattern of the interfering laser L1 captured by the image sensor 46, and to generate an image of the outer surface of the measurement area Pa, i.e., an appearance inspection image D2, based on the intensity pattern of the incoherent light L2 captured by the image sensor 46. Furthermore, in the defect inspection apparatus 100 of the first embodiment, according to the above structure, a first irradiation unit 2 and a second irradiation unit 3 are provided. The first irradiation unit 2 irradiates a laser L1 onto the measurement area Pa, and the second irradiation unit 3 irradiates incoherent light, i.e., incoherent light L2, onto the measurement area Pa. Additionally, based on the intensity pattern of the interfering laser L1 captured by the image sensor 46, an image representing the displacement at the measurement area Pa of the inspection object P, i.e., a surface inspection image D1, is generated. Furthermore, based on the intensity pattern of the incoherent light L2 captured by the image sensor 46, an image of the outer surface of the measurement area Pa, i.e., an appearance inspection image D2, is generated. Thus, surface defect inspection can be performed using laser interferometry, and appearance inspection can be performed using an image captured by irradiating incoherent light L2 without any spots. As a result, both surface defect inspection and appearance inspection using laser interferometry can be performed using a single apparatus.

[0086] Furthermore, in the first embodiment, further effects can be obtained by configuring it as follows.

[0087] That is, in the first embodiment, the speckle shearing interferometer 4 (interference section) includes a common optical component disposed on the optical path of the laser L1 and the incoherent light L2. If configured in this way, it is not necessary to separately provide optical components for the laser L1 and optical components for the incoherent light L2 in the speckle shearing interferometer 4. As a result, even when surface defect inspection and appearance inspection are performed simultaneously using a single device, the increase in the number of components can be suppressed.

[0088] Furthermore, in the first embodiment, the second irradiation unit 3 is configured to irradiate incoherent light L2, which contains light having a wavelength equal to that of the laser L1 irradiated by the first irradiation unit 2. If configured in this way, since the incoherent light L2 contains a wavelength equal to that of the laser L1, even when the speckle shearing interferometer 4 is configured to perform laser interference with high precision based on the wavelength of the laser L1, it is possible to capture the incoherent light L2 using common optical components (bandpass filters, etc.). As a result, even when surface defect inspection and appearance inspection are performed simultaneously using a single device, the increase in the number of components can be suppressed without reducing the accuracy of laser interference.

[0089] Furthermore, in the first embodiment, the laser interferometry is a method of interfering laser L1 reflected at two different points in the measurement area Pa (shearing interferometry), and the optical path of laser L1 is configured to be shared by a portion of the optical path of incoherent light L2. With this configuration, shared optical components can be easily used in the shared portion of the optical path. As a result, even when performing surface defect inspection and appearance inspection simultaneously using a single device, it is easier to suppress the increase in the number of components.

[0090] Furthermore, in the first embodiment, a light shield 47 (shielding part) is also provided, which shields either of the two different optical paths through which the laser L1 reflected at two different points passes. The control unit 5 is configured such that, with the light shield 47 shielding either of the two optical paths, the second irradiation unit 3 is irradiated with incoherent light L2 using the other optical path, thereby causing the image sensor 46 (image capturing unit) to capture the incoherent light L2. Here, we consider the case where the second irradiation unit 3 is irradiated with incoherent light L2 using the two optical paths through which the laser L1 reflected at two different points passes. In this case, since the incoherent light L2 reflected at two different points is imaged and captured by the image sensor 46, the captured visual inspection image D2 is considered to be doubly distorted and thus a degraded image. Considering this, the control unit 5 is configured as described in the first embodiment to shield either optical path using the light shield 47. Therefore, since the incoherent light L2 reflected at a single point in the measurement area Pa is imaged, the visual inspection image D2 does not become doubly distorted, and a clear image can be formed. As a result, even when laser interference is performed using a method that uses laser L1 interference reflected at two different points in the measurement area Pa (shearing interference), image quality degradation of the visual inspection image D2 can be suppressed.

[0091] Furthermore, in the first embodiment, the control unit 5 is configured such that the timing of the image sensor 46 (camera unit) capturing the laser L1 by irradiating the first irradiation unit 2 with the laser L1 is different from the timing of the image sensor 46 capturing the incoherent light L2 by irradiating the second irradiation unit 3 with the incoherent light L2. Here, when the timing of the image sensor 46 capturing the laser L1 by irradiating the first irradiation unit 2 with the timing of the image sensor 46 capturing the incoherent light L2 by irradiating the second irradiation unit 3 is performed simultaneously, it is assumed that the incoherent light L2 acts as interference light when the laser L1 interferes, causing the surface inspection image D1 to become less clear. Additionally, in the appearance inspection image D2 generated by capturing the incoherent light L2 by the image sensor 46, speckles caused by the laser L1 are produced, therefore the appearance inspection image D2 is also considered less clear. With this in mind, if configured as described in the first embodiment above, even when performing surface defect inspection and appearance inspection simultaneously using a single device, it is possible to prevent both the surface inspection image D1 and the appearance inspection image D2 from becoming less sharp. As a result, both surface defect inspection based on laser interferometry and appearance inspection based on incoherent light L2 can be performed with high precision.

[0092] Furthermore, in the first embodiment, the control unit 5 is configured such that, while the oscillator 1 (displacement unit) is stopped, the second irradiation unit 3 irradiates incoherent light L2, thereby causing the image sensor 46 (image capture unit) to capture the incoherent light L2. With this configuration, it is possible to suppress the blurring of the visual inspection image D2 caused by the vibration of the inspection object P due to the oscillator 1.

[0093] Furthermore, in the first embodiment, a display unit 7 for displaying images is also included, and the control unit 5 is configured to control the display unit 7 to display a surface inspection image D1 and an appearance inspection image D2. The surface inspection image D1 is configured to visually identify the location of a defective part Q identified as internally generated within the measurement area Pa, and the appearance inspection image D2 is configured to visually identify the location of a defective part R identified as externally generated within the measurement area Pa. With this configuration, the operator can visually identify the locations of both the defective parts Q (identified as internally generated) and R (identified as externally generated) within the measurement area Pa of the inspection object P. As a result, the operator can more easily visually identify the results of both surface defect inspection and appearance inspection simultaneously.

[0094] Furthermore, in the first embodiment, the control unit 5 is configured to perform the following control: superimpose the extracted images D1a and D1b onto the appearance inspection image D2 and display them on the display unit 7. These extracted images D1a and D1b are images that emphasize the positions of the defects Q identified as internally generated within the measurement area Pa. With this configuration, the operator can visually identify the positions of the defects Q identified as internally generated within the measurement area Pa of the inspection object P together with an image showing the appearance of the inspection object P. As a result, based on the display on the display unit 7, the operator can identify the positions of internally generated defects Q on the appearance image that are difficult to determine solely by visually recognizing the appearance of the inspection object P, thus making it easier to identify defect locations.

[0095] Furthermore, in the first embodiment, the control unit 5 is configured to control the display unit 7 to display the surface inspection image D1 and the appearance inspection image D2 side by side. With this configuration, the operator can easily visually identify the surface inspection image D1 and the appearance inspection image D2 while comparing them.

[0096] Furthermore, in the first embodiment, the control unit 5 is configured to capture images of the interfering laser L1 and the incoherent light L2 reflected at the measurement area Pa using a shared image sensor 46 (camera unit). Here, if images of the interfering laser L1 and the incoherent light L2 reflected at the measurement area Pa are captured using different image sensors 46, it is considered necessary to adjust each image sensor 46 separately. If, as in the above embodiment, the image is captured using a shared image sensor 46, only one image sensor 46 needs adjustment, thus reducing the workload of the operator. Additionally, compared to the case where different image sensors 46 are used, the increase in the number of components can be suppressed. Furthermore, since the image is captured using a shared image sensor 46, the surface inspection image D1 and the appearance inspection image D2 can be easily configured as images within the same field of view. As a result, the operator does not need to compare the location of the defective part Q determined to be internal with the location of the defective part R determined to be external, thus reducing the operator's workload.

[0097] Furthermore, in the first embodiment, the speckle shear interferometer 4 (interference section) is configured to include a common optical component disposed on the optical path of the laser L1 and the incoherent light L2. The optical component has a bandpass filter 45 (optical filter) that allows light of a predetermined wavelength to pass through. The interfering laser L1 and the incoherent light L2 reflected at the measurement region Pa have wavelengths that can pass through the common bandpass filter 45, and are captured by a common image sensor 46. With this configuration, imaging of the laser L1 and the incoherent light L2 can be performed using the common optical filter. As a result, even when surface defect inspection and visual inspection are performed simultaneously using a single device, the increase in the number of components can be suppressed.

[0098] [Second Implementation]

[0099] Reference Figure 8 The structure of the defect inspection apparatus 200 according to the second embodiment will be described. This second embodiment differs from the first embodiment, which is configured such that the center wavelength of the incoherent light L2 is close to the wavelength of the laser L1, i.e., 780nm to 800nm, so that the laser L1 and incoherent light L2 are captured using shared optical components. In this second embodiment, the incoherent light L202 is configured to be light containing wavelengths of the three primary colors (red, green, and blue). Furthermore, in the figures, parts of the same structure as those in the first embodiment are illustrated using the same reference numerals, and descriptions are omitted.

[0100] (Structure of the defect inspection device in the second embodiment)

[0101] like Figure 8 As shown, the defect inspection apparatus 200 of the second embodiment of the present invention includes a second illumination unit 203, a speckle shearing interferometer 204, and a control unit 205. Furthermore, the speckle shearing interferometer 204 includes a bandpass filter 245 and an image sensor 246.

[0102] The second irradiation unit 203 irradiates the measurement area Pa with incoherent light, namely incoherent light L202. The incoherent light L202 is configured to include light with a red wavelength, light with a green wavelength, and light with a blue wavelength. Specifically, the second irradiation unit 203 is configured to irradiate three types of incoherent light: L202r, L202g, and L202b. L202r contains light with a red wavelength. L202g contains light with a green wavelength. L202b contains light with a blue wavelength. The second irradiation unit 203 can be configured to have one light source that irradiates light with each of the three wavelengths, or it can be configured to have three light sources that irradiate light with each of the three wavelengths.

[0103] A bandpass filter 245 is disposed between the condenser lens 44 and the image sensor 246. Furthermore, the bandpass filter 245 allows light with multiple specific wavelengths to pass through. Moreover, the bandpass filter 245 is configured to block (attenuate) light without a specified wavelength. The bandpass filter 245 may include, for example, a dielectric multilayer film. That is, the bandpass filter 245 is configured to allow light with four specific wavelengths—the wavelength of the light contained in laser L1, the red wavelength, the green wavelength, and the blue wavelength—to pass through.

[0104] The image sensor 246 is configured to detect laser L1 and incoherent light L202. That is, it is configured to detect light with a wavelength of 785 nm, light with a red wavelength, light with a green wavelength, and light with a blue wavelength, respectively.

[0105] The control unit 205 controls the irradiation of the first irradiation unit 2 and the second irradiation unit 203. That is, the control unit 205 controls the first irradiation unit 2 to irradiate the laser L1. In addition, the control unit 205 controls the second irradiation unit 203 to switch between irradiating incoherent light L202r, incoherent light L202g, and incoherent light L202b.

[0106] The control unit 205 generates a surface inspection image D1 based on the intensity pattern of the laser L1 detected by the image sensor 246. Furthermore, the control unit 205 generates three monochrome images for appearance inspection based on the intensity patterns of the red wavelength light contained in the incoherent light L202r, the green wavelength light contained in the incoherent light L202g, and the blue wavelength light contained in the incoherent light L202b. Moreover, the control unit 205 is configured to generate a color image for appearance inspection, D202, based on the generated three monochrome images for appearance inspection.

[0107] Furthermore, the other structures of the second embodiment are the same as those of the first embodiment.

[0108] (Effects of the second implementation method)

[0109] In the second embodiment, the following effects can be obtained.

[0110] In the second embodiment, as described above, the incoherent light L202 includes light with a red wavelength, light with a green wavelength, and light with a blue wavelength. If configured in this way, an image D202 for visual inspection can be acquired in the form of a color image. As a result, in addition to using brightness information for visual inspection, hue information can also be used for visual inspection, thus further improving the accuracy of visual inspection.

[0111] Furthermore, the other effects of the second embodiment are the same as those of the first embodiment described above.

[0112] [Third Implementation Method]

[0113] Reference Figure 9 The structure of the defect inspection device 300 according to the third embodiment will be described. This third embodiment differs from the first and second embodiments, which are configured to capture images of the laser L1 and the incoherent light L2 and L202 using shared image sensors 46 and 246. This third embodiment is configured to include two distinct image sensors (camera units), a first image sensor 346a and a second image sensor 346b, and capture images of the laser L1 and the incoherent light L202 using these two separate image sensors. Furthermore, in the figures, parts of the structure identical to those in the first and second embodiments are illustrated using the same reference numerals, and their descriptions are omitted.

[0114] (Structure of the defect inspection device in the third embodiment)

[0115] like Figure 9As shown, the defect inspection apparatus 300 of the third embodiment of the present invention includes a speckle shearing interferometer 304 and a control unit 305. Furthermore, the speckle shearing interferometer 304 includes a first bandpass filter 345a, a second bandpass filter 345b, a first image sensor 346a, a second image sensor 346b, a first beam splitter 341, and a second beam splitter 348.

[0116] A first bandpass filter 345a is disposed between the first image sensor 346a and the second beam splitter 348. Furthermore, the first bandpass filter 345a allows light of a specific wavelength to pass through. Moreover, the first bandpass filter 345a is configured to block (attenuate) light of wavelengths other than the specified wavelength. The first bandpass filter 345a may include, for example, a dielectric multilayer film, with a center wavelength configured to be 785 nm. That is, the first bandpass filter 345a is configured to allow light of the wavelength of laser L1 to pass through.

[0117] The second bandpass filter 345b is disposed between the second image sensor 346b and the second beam splitter 348. Furthermore, the second bandpass filter 345b allows light with multiple specific wavelengths to pass through. Moreover, the second bandpass filter 345b is configured to block (attenuate) light without a specified wavelength. The second bandpass filter 345b may include, for example, a dielectric multilayer film. That is, the second bandpass filter 345b is configured to allow light with three specific wavelengths—red, green, and blue—to pass through.

[0118] The first image sensor 346a is configured to detect laser L1. That is, it is configured to detect light with a wavelength of 785 nm.

[0119] The second image sensor 346b is configured to detect incoherent light L202. That is, it is configured to detect light with a red wavelength, light with a green wavelength, and light with a blue wavelength, respectively.

[0120] The first beam splitter 341 is configured in the same way as the beam splitter 41 in the first embodiment and the second embodiment.

[0121] The second beam splitter 348 includes a semi-transparent and semi-reflective mirror. The second beam splitter 348 is positioned at the point where the laser L1 and incoherent light L202, which have passed through the condenser lens 44, are to be incident. Furthermore, the second beam splitter 348 allows the incident laser L1 and incoherent light L202 to pass through towards the first image sensor 346a side and reflect towards the second image sensor 346b side.

[0122] The control unit 305 generates a surface inspection image D1 based on the intensity pattern of the laser L1 detected by the first image sensor 346a. Furthermore, the control unit 305 generates three monochrome images for appearance inspection based on the intensity patterns of red, green, and blue wavelengths of light contained in the incoherent light L202 detected by the second image sensor 346b. Moreover, the control unit 305 is configured to generate a color image for appearance inspection, D302, based on the generated three monochrome images for appearance inspection.

[0123] Furthermore, the other structures of the third embodiment are the same as those of the first and second embodiments.

[0124] (Effects of the third implementation method)

[0125] In the third embodiment, the following effects can be obtained.

[0126] In the third embodiment, as described above, the imaging unit is configured to include a first image sensor 346a (first imaging unit) and a second image sensor 346b (second imaging unit). The first image sensor 346a is used to capture laser light L1, and the second image sensor 346b is disposed separately from the first image sensor 346a and is used to capture incoherent light L2. With this configuration, the structure of the first image sensor 346a can be adapted to capture laser light L1, and the structure of the second image sensor 346b can be adapted to capture incoherent light L202. That is, the first image sensor 346a can be configured to capture light at a wavelength suitable for laser interferometry, and the second image sensor 346b can be configured to capture light at a wavelength suitable for visual inspection. Therefore, higher precision surface defect inspection can be performed based on the surface inspection image D1, and higher precision visual inspection can be performed based on the visual inspection image D302.

[0127] Furthermore, the other effects of the third embodiment are the same as those of the first and second embodiments described above.

[0128] [Fourth Implementation Method]

[0129] Reference Figure 10 and Figure 11The structure of the defect inspection apparatus 400 according to the fourth embodiment will be described. This fourth embodiment differs from the first embodiment. In the first embodiment, with the light shield 47 blocking either of two different optical paths, the second irradiation unit irradiates incoherent light L2 using the other optical path, thereby causing the image sensor 46 (camera unit) to capture the incoherent light L2. In this fourth embodiment, the light shield 47 is not used, and the angle of the second reflector 443b is adjusted to a 45-degree angle relative to the reflecting surface of the beam splitter 41, and the incoherent light L2 is captured. Furthermore, in the figures, parts of the same structure as in the first embodiment are illustrated using the same reference numerals, and descriptions are omitted.

[0130] (Structure of the defect inspection device according to the fourth embodiment)

[0131] like Figure 10 As shown, the defect inspection apparatus 400 of the fourth embodiment of the present invention includes a speckle shearing interferometer 404 and a control unit 405. Furthermore, the speckle shearing interferometer 404 includes a second reflector 443b disposed in the optical path through which the laser L1 will pass.

[0132] The second reflector 443b is positioned at a slightly angled 45 degrees relative to the reflecting surface of the beam splitter 41 in the optical path of the laser L1 and the incoherent light L2 that are to pass through the beam splitter 41. The second reflector 43b reflects the incident laser L1 that has passed through the beam splitter 41 toward the beam splitter 41. Furthermore, the second reflector 443b is configured to change its position (angle) relative to the beam splitter 41. Specifically, the second reflector 443b is configured to change its position (angle) to a 45-degree angle relative to the reflecting surface of the beam splitter 41.

[0133] The control unit 405 is configured to change the position (angle) of the second reflector 443b. That is, the control unit 405 is configured to illuminate incoherent light L2 when either of the two different optical paths through which the laser L1 reflected at two different points is changed by changing the position (angle) of the second reflector 443b, thereby causing the image sensor 46 to capture the incoherent light L2.

[0134] With the second reflector 443b positioned at a slightly tilted angle of 45 degrees relative to the reflecting surface of the beam splitter 41, the control unit 405 irradiates the first irradiation unit 2 with laser L1. Then, based on the intensity pattern of the interfering laser L1 captured by the image sensor 46, the control unit 405 generates a surface inspection image D1. That is, the control unit 405 performs inspection on two distinct points (e.g., on the surface of the measurement area Pa) that are not identical to each other. Figure 10The laser L1 reflected at positions Pa1 and Pa2 is interfered with and captured by the image sensor 46 to generate an image D for surface inspection.

[0135] In addition, such as Figure 11 As shown, the control unit 405, while changing the position (angle) of the second reflector 443b to configure it at a 45-degree angle relative to the reflecting surface of the beam splitter 41, causes the second irradiation unit 3 to irradiate incoherent light L2. Then, the control unit 405 generates an image D2 for visual inspection based on the intensity pattern of the incoherent light L2 captured by the image sensor 46. That is, the control unit 405 controls the image sensor 46 to capture the incoherent light L2 reflected at a point (e.g., position Pa1) in the measurement area Pa to generate the image D2 for visual inspection.

[0136] Furthermore, the other structures of the fourth embodiment are the same as those of the first embodiment.

[0137] (Effects of the fourth implementation method)

[0138] In the fourth embodiment, the following effects can be obtained.

[0139] In the fourth embodiment, as described above, a second reflector 443b (reflector member) is also provided on the optical path through which the laser L1 passes. The control unit 405 is configured such that, when the position (angle) of the second reflector 443b is changed, either of the two different optical paths through which the laser L1, reflected at two different points (Pa1 and Pa2), passes is altered, incoherent light L2 is irradiated, thereby causing the image sensor 46 (image capture unit) to capture the incoherent light L2. Here, we consider the case where the second irradiation unit irradiates the incoherent light L2 using the two optical paths through which the laser L1, reflected at two different points, passes. In this case, the incoherent light L2 reflected at two different points is imaged and captured by the image sensor 46, resulting in a double-distorted and degraded image D2 for visual inspection. Considering this, as in the fourth embodiment described above, the position (angle) of the second reflector 443b is changed so that the optical path is single. Therefore, the incoherent light L2 reflected at a single point in the measurement area Pa is imaged, so the visual inspection image D2 will not become a distorted image and can be transformed into a clear image. Furthermore, compared to blocking the light path with a light shield or the like, the increase in the number of components can be suppressed. As a result, even when using laser interference with a method that interferes with lasers L1 reflected at two different points in the measurement area Pa (shearing interference method), it is easier to suppress the image quality degradation of the visual inspection image D2.

[0140] Furthermore, the other effects of the fourth embodiment are the same as those of the first embodiment described above.

[0141] [Fifth Implementation Method]

[0142] Reference Figure 12 , Figure 13A as well as Figure 13B The structure of the defect inspection apparatus 500 according to the fifth embodiment will be described. This fifth embodiment differs from the first embodiment, which is configured such that, with the light shield 47 blocking either of two different light paths, the second irradiation unit irradiates incoherent light L2 using the other light path, thereby causing the image sensor 46 (camera unit) to capture the incoherent light L2. This fifth embodiment is configured to capture the incoherent light L2 reflected at two different points in the measurement area Pa, and to perform image processing on the appearance inspection image D502a generated based on the intensity pattern of the captured incoherent light L2. Furthermore, in the figures, parts of the same structure as those in the first embodiment are illustrated using the same reference numerals, and descriptions are omitted.

[0143] (Structure of the defect inspection device in the fifth embodiment)

[0144] like Figure 12 As shown, the defect inspection device 500 of the fifth embodiment of the present invention includes a speckle shear interferometer 504 and a control unit 505.

[0145] The speckle shearing interferometer 504 interferes with laser light L1 reflected from two distinct points (e.g., positions Pa1 and Pa2) within the measurement region Pa using laser interferometry. Then, the speckle shearing interferometer 504 images the interfered laser L1 in the image sensor 46. Additionally, the speckle shearing interferometer 504 images incoherent light L2 reflected from two distinct points (e.g., positions Pa1 and Pa2) within the measurement region Pa using the image sensor 46.

[0146] The control unit 505 controls the irradiation of the first irradiation unit 2 and the second irradiation unit 3. In addition, the control unit 505 is configured to generate a surface inspection image D1 based on the intensity pattern of the interfering laser L1 captured by the image sensor 46.

[0147] Furthermore, the control unit 505 is configured to generate an appearance inspection image D502a based on the intensity pattern of incoherent light L2 reflected at two different points in the measurement area Pa. Here, since the appearance inspection image D502a is generated based on the intensity pattern of incoherent light L2 reflected at two different points in the measurement area Pa, it is an image with distortion. Specifically, the incoherent light L2 reflected at two locations slightly separated from each other in the measurement area Pa is imaged in one element of the image sensor 46, therefore, as... Figure 13A As shown, the generated visual inspection image D502a is a distorted image with ghosting. Furthermore, "distortion" here refers to the lack of sharpness in the visual inspection image D502a produced in order to image the incoherent light L2 reflected at two points. In other words, "distortion" here refers to the lack of sharpness and clarity, such as image distortion, blurring, and ghosting.

[0148] The control unit 505 is configured to generate a distortion-free appearance inspection image D502b by performing image processing on the generated, distorted appearance inspection image D502a to reduce distortion (see reference). Figure 13B Regarding image processing, for example, deconvolution is performed. Deconvolution is a process used to eliminate distortion and blur in an image. Specifically, the point spread function (PSF) of the optical system is obtained in advance, and the PSF is removed from the distorted appearance inspection image D502a by performing deconvolution on the generated image, thereby eliminating distortion (ghosting).

[0149] Furthermore, the other structures of the fifth embodiment are the same as those of the first embodiment.

[0150] (Effects of the fifth implementation method)

[0151] In the fifth embodiment, the following effects can be obtained.

[0152] In the fifth embodiment, as described above, the control unit 505 is configured to perform image processing to reduce distortion on the appearance inspection image D502a, which is generated based on the intensity pattern of incoherent light L2 reflected at two different points and thus contains distortion. Therefore, the control unit 505 can acquire the appearance inspection image D502b obtained after the distortion reduction image processing. Furthermore, since it is not necessary to newly install components for changing the optical path in order to suppress distortion in the appearance inspection image D502b, the increase in the number of components can be suppressed.

[0153] Furthermore, the other effects of the fifth embodiment are the same as those of the first embodiment described above.

[0154] [Sixth Implementation Method]

[0155] Reference Figure 14 The structure of the defect inspection apparatus 600 according to the sixth embodiment will be described. This sixth embodiment differs from the first embodiment, which is configured such that, with the light shield 47 blocking either of two different optical paths, the second irradiation unit irradiates incoherent light L2 using the other optical path, thereby causing the image sensor 46 (camera unit) to capture the incoherent light L2. The sixth embodiment is configured such that each of the two different optical paths includes a bandpass filter (first bandpass filter 645a and second bandpass filter 645b) that allows a specific wavelength to pass through. Furthermore, in the figures, parts with the same structure as those in the first embodiment are illustrated using the same reference numerals, and their descriptions are omitted.

[0156] (Structure of the defect inspection device according to the sixth embodiment)

[0157] like Figure 14 As shown, the defect inspection apparatus 600 of the sixth embodiment of the present invention includes a second irradiation unit 603, a speckle shear interferometer 604, and a control unit 605.

[0158] The second irradiation unit 603 irradiates the measurement area Pa with incoherent light, namely incoherent light L602. The incoherent light L602 is configured to have a wavelength different from that of the laser L1 irradiated by the first irradiation unit 2.

[0159] The speckle shear interferometer 604 is configured such that one of the two distinct optical paths through which the laser L1 and incoherent light L602 reflected from two different points (e.g., positions Pa1 and Pa2) in the measurement region Pa commonly pass includes a first bandpass filter 645a that allows light of a predetermined wavelength to pass through, and the other of the two distinct optical paths includes a second bandpass filter 645b that allows light of a predetermined wavelength to pass through. Furthermore, the first bandpass filter 645a is an example of the "first optical filter" of the present invention. Additionally, the second bandpass filter 645b is an example of the "second optical filter" of the present invention.

[0160] A first bandpass filter 645a is disposed between the beam splitter 41 and the phase shifter 42. Furthermore, the first bandpass filter 645a allows light of a predetermined wavelength to pass through. Moreover, the first bandpass filter 645a is configured to block (attenuate) light of wavelengths other than the predetermined wavelength. The first bandpass filter 645a includes, for example, a dielectric multilayer film. Furthermore, the first bandpass filter 645a is configured to allow light of the wavelength of laser L1 to pass through. Additionally, the first bandpass filter 645a is configured to block (attenuate) light of the wavelength of incoherent light L602.

[0161] The second bandpass filter 645b is disposed between the beam splitter 41 and the second reflector 43b. Furthermore, the second bandpass filter 645b allows light of a predetermined wavelength to pass through. Moreover, the second bandpass filter 645b is configured to block (attenuate) light of wavelengths other than the predetermined wavelength. The second bandpass filter 645b may include, for example, a dielectric multilayer film. Furthermore, the second bandpass filter 645b is configured to allow both light of the wavelength of laser light L1 and light of the wavelength of incoherent light L602 to pass through.

[0162] The control unit 605 controls the irradiation of the incoherent light L602 by the second irradiation unit 603. Furthermore, the control unit 605 generates an image D2 for visual inspection based on the intensity pattern of the incoherent light L602 captured by the image sensor 46. The control unit 605 is configured such that the timing of the image sensor 46 capturing the laser L1 by irradiating the first irradiation unit 2 is different from the timing of the image sensor 46 capturing the incoherent light L602 by irradiating the incoherent light L602 by the second irradiation unit 603. Moreover, the control unit 605 is configured such that, while the oscillator 1 is stopped, the second irradiation unit 603 irradiates the incoherent light L602, thereby causing the image sensor 46 to capture the incoherent light L602.

[0163] Furthermore, the other structures of the sixth embodiment are the same as those of the first embodiment.

[0164] (Effects of the sixth implementation method)

[0165] In the sixth embodiment, the following effects can be obtained.

[0166] In the sixth embodiment, as described above, the speckle shearing interferometer 604 is configured such that one of the two distinct optical paths through which the laser L1 and incoherent light L602 reflected at two different points pass together includes a first bandpass filter 645a (first optical filter) that allows light of a predetermined wavelength to pass through, and the other of the two distinct optical paths includes a second bandpass filter 645b (second optical filter) that allows light of a predetermined wavelength to pass through. Furthermore, the first bandpass filter 645a is configured to allow the laser L1 to pass through and attenuate the incoherent light L602, while the second bandpass filter 645b is configured to allow both the laser L1 and the incoherent light L602 to pass through. Thus, the incoherent light L602 reflected at a point in the measurement area Pa is imaged, and therefore the visual inspection image D2 is not a distorted image, but a clear image. Furthermore, by configuring the first bandpass filter 645a and the second bandpass filter 645b in the optical path, it is unnecessary to perform the following controls: to operate the components constituting the speckle shearing interferometer 604 to change the optical path or perform shielding, etc. As a result, even when using laser interference with a method that interferes with laser L1 reflected at two different points in the measurement region Pa (shearing interferometry), it is possible to suppress the increase in processing burden for further suppressing image quality degradation of the visual inspection image D2.

[0167] Furthermore, the other effects of the sixth embodiment are the same as those of the first embodiment described above.

[0168] [Seventh Implementation Method]

[0169] Reference Figure 15 The structure of the defect inspection apparatus 700 according to the seventh embodiment will be described. This seventh embodiment differs from the first embodiment, which is configured to include a first irradiation unit 2 that irradiates a laser L1 and a second irradiation unit 3 that irradiates incoherent light L2. This seventh embodiment is configured to include a first irradiation unit 2 that irradiates a laser L1 and a second irradiation unit 703 that irradiates incoherent light L702 by reducing the coherence of the irradiated laser L1. Furthermore, in the figures, parts with the same structure as those in the first embodiment are illustrated using the same reference numerals, and descriptions are omitted.

[0170] (Structure of the defect inspection device according to the seventh embodiment)

[0171] like Figure 15 As shown, the defect inspection apparatus 700 of the seventh embodiment of the present invention includes a second irradiation unit 703 and a control unit 705.

[0172] The second irradiation unit 703 is configured to irradiate the measurement region Pa with incoherent light, i.e., incoherent light L702, by reducing the coherence of the laser L1 irradiated by the first irradiation unit 2. The second irradiation unit 703 includes, for example, a speckle reducer 703a. The speckle reducer 703a reduces the interference (coherence) of the laser L1 by causing the laser L1 to diffuse.

[0173] The control unit 705 controls the irradiation of the first irradiation unit 2 and the second irradiation unit 703. Specifically, the control unit 705 controls the irradiation of laser L1 by the first irradiation unit 2, and by controlling the operation of the second irradiation unit 703, reduces the coherence of the laser L1 irradiated by the first irradiation unit 2, thereby irradiating incoherent light L702. Furthermore, the control unit 705 is configured such that the timing of the image sensor 46 capturing the laser L1 by irradiating it by the first irradiation unit 2 is different from the timing of the image sensor 46 capturing the incoherent light L702 by irradiating it by the second irradiation unit 703. Additionally, the control unit 705 is configured to generate a surface inspection image D1 based on the intensity pattern of the interfering laser L1 captured by the image sensor 46, and to generate an appearance inspection image D2 based on the intensity pattern of the incoherent light L702 captured by the image sensor 46.

[0174] Furthermore, the other structures of the seventh embodiment are the same as those of the first embodiment.

[0175] (Effects of the seventh implementation method)

[0176] In the seventh embodiment, the following effects can be obtained.

[0177] In the seventh embodiment, as described above, the second irradiation unit 703 is configured to irradiate incoherent light L702 by reducing the coherence of the laser L1 irradiated by the first irradiation unit 2. Therefore, laser L1 and incoherent light L702 can be irradiated using a single light source, thus suppressing the increase in the number of components compared to having two light sources (irradiation units). Furthermore, by diffusing laser L1 to irradiate as incoherent light L702, the wavelengths of laser L1 and incoherent light L702 are approximately equal. As a result, components such as bandpass filters can be made identical, thus suppressing the increase in the number of components.

[0178] Furthermore, the other effects of the seventh embodiment are the same as those of the first embodiment described above.

[0179] [Variation Example]

[0180] Furthermore, the embodiments disclosed herein should be considered illustrative in all respects and not restrictive. The scope of the invention is shown by the patent claims, not by the description of the above embodiments, and includes all modifications (variations) with the same meaning and scope as the patent claims.

[0181] For example, the first to seventh embodiments described above illustrate the following: As a displacement unit that displaces the measurement area of ​​the object being inspected, an oscillator that is in contact with the object being inspected and excites elastic waves in the measurement area through mechanical vibration is used; however, the present invention is not limited to this. For example, a powerful loudspeaker positioned in a location not in contact with the object being inspected can also be used to excite elastic waves. Alternatively, a pulsed high-frequency source can be used as the displacement unit, and the measurement area can be displaced by applying heat to the object being inspected. Furthermore, a pulsed laser can also be configured as the displacement unit.

[0182] Furthermore, examples have been shown in the first to seventh embodiments above, where a speckle shear interferometry is used as a laser interferometry method, but the present invention is not limited thereto. In the present invention, other optical interferometers may also be used to construct the interferometer section.

[0183] Furthermore, while the first to seventh embodiments described above illustrate examples of images such as surface inspection images and appearance inspection images generated by the control unit, the present invention is not limited thereto. For example, the images may also be generated using an external image processing unit such as a GPU (Graphics Processing Unit).

[0184] Furthermore, the first to seventh embodiments described above illustrate an example where, during image processing for generating images for visual inspection, the location of defects on the outer surface is determined based on the difference in brightness values ​​between pixels; however, the present invention is not limited to this. Alternatively, after obtaining an average of brightness values ​​from multiple images, regions with values ​​differing from the average by a predetermined threshold can be identified as locations of defects on the outer surface. Furthermore, machine learning can be used to perform this determination using a method called an autoencoder.

[0185] Furthermore, in the first to third and seventh embodiments described above, the light shield is shown to be configured to block the optical path between the beam splitter and the second reflector. Figure 1 The example shown is the dashed line S2, but the invention is not limited thereto. For example, it can also be configured as the optical path between the beam splitter and the first reflector (…). Figure 1 (S1 in the solid line).

[0186] Furthermore, in the first to seventh embodiments described above, the following example is shown: after laser irradiation by the first irradiation unit and laser imaging (detection) by the imaging unit, incoherent light irradiation is performed by the second irradiation unit, but the present invention is not limited thereto. For example, it may be configured to irradiate incoherent light before irradiating the laser. Alternatively, it may be configured to irradiate incoherent light midway through a period of multiple laser irradiations.

[0187] Furthermore, in the first to seventh embodiments described above, examples of image sensors (camera units) using CMOS image sensors and CCD image sensors were shown, but the present invention is not limited thereto. For example, linear sensors or ultra-high-speed scanning cameras may also be used.

[0188] Furthermore, the first to seventh embodiments described above show examples of speckle shear interferometers (interference sections) including shared optical components arranged in the optical paths of laser and incoherent light, but the present invention is not limited thereto. For example, different optical components may be used for imaging laser and incoherent light.

[0189] Furthermore, in the first to fifth and seventh embodiments described above, an example was shown where the second irradiation unit was configured to irradiate incoherent light containing light having a wavelength equal to that of the laser irradiated by the first irradiation unit; however, the present invention is not limited thereto. For example, the second irradiation unit may also be configured to irradiate incoherent light containing light that does not contain the wavelength of the laser irradiated by the first irradiation unit.

[0190] Furthermore, the first to seventh embodiments described above illustrate the following example: Laser interferometry is a method of interfering laser light reflected at two different points in the measurement area, configured such that a portion of the laser's optical path and a portion of the incoherent light's optical path are shared; however, the present invention is not limited to this. For example, it may also be configured to measure the displacement of the surface of the measurement area by interfering light reflected at a single point in the measurement area.

[0191] Furthermore, examples are shown in the first to third and seventh embodiments described above, where a light shield is also provided to block one of the two different optical paths through which the laser reflected at two different points will pass. The control unit is configured to use another optical path to irradiate the second irradiation unit with incoherent light while the light shield blocks one of the two optical paths, thereby causing the imaging unit (image sensor) to capture the incoherent light. However, the present invention is not limited to this. For example, when capturing incoherent light, it may be configured such that no shielding part (light shield) is provided, and neither of the two optical paths through which the laser reflected at two different points in the measurement area will be imaged in the imaging unit (image sensor). That is, it may also be configured such that no shielding part is provided, and either of the two different optical paths will not be imaged in the imaging unit by changing the position of the optical components (e.g., mirrors) included in the speckle shear interferometer.

[0192] Furthermore, the fourth embodiment described above illustrates an example where a reflector component is also provided on the optical path through which the laser beam will pass. The control unit is configured to irradiate incoherent light when, by changing the position of the reflector component, one of the two different optical paths through which the laser beam reflected at two different points passes is altered, thereby causing the imaging unit to capture the incoherent light. However, the present invention is not limited to this. For example, it is also possible to cause the imaging unit to capture incoherent light when, by changing the positions of both the first and second reflectors, both of the two different optical paths are altered.

[0193] Furthermore, the fifth embodiment described above illustrates an example where the camera unit is configured to capture incoherent light reflected at two distinct points, and the control unit is configured to perform image processing to reduce distortion on an image for appearance inspection generated based on the intensity pattern of the incoherent light reflected at the two distinct points, although the present invention is not limited thereto. For example, it may be configured to extract and display locations identified as defective during appearance inspection without performing image processing to reduce distortion.

[0194] Furthermore, the sixth embodiment described above illustrates an example where a speckle shearing interferometer (interference section) includes a first bandpass filter (first optical filter) on one of two distinct optical paths through which laser light and incoherent light reflected from two different points pass, and a second bandpass filter (second optical filter) on the other of the two distinct optical paths, also allowing light of a predetermined wavelength to pass through. The first bandpass filter is configured to attenuate incoherent light while allowing laser light to pass through, and the second bandpass filter is configured to allow both laser light and incoherent light to pass through. However, the present invention is not limited to this. For example, the speckle shearing interferometer may also be configured such that the first bandpass filter is included on one of the two distinct optical paths, while the second bandpass filter is not included on the other of the two distinct optical paths.

[0195] Furthermore, the fourth to sixth embodiments described above show an example of incoherent light L2 being irradiated by the second irradiation unit 3, but the present invention is not limited thereto. For example, it may be configured such that a second irradiation unit 203 is used instead of the second irradiation unit 3, thereby irradiating light containing wavelengths of the three primary colors (red, green, and blue), i.e., incoherent light L202.

[0196] Furthermore, in the first to seventh embodiments described above, the following example is shown: the control unit is configured such that the timing for the image sensor (camera unit) to capture laser light by irradiating the first irradiation unit with laser light is different from the timing for the image sensor to capture incoherent light by irradiating the second irradiation unit with incoherent light, but the present invention is not limited thereto. For example, the timing for capturing laser light and the timing for capturing incoherent light may also be performed simultaneously.

[0197] Furthermore, in the first to seventh embodiments described above, the following example is shown: the control unit is configured such that, while the operation of the oscillator (displacement unit) is stopped, the second irradiation unit irradiates incoherent light, thereby causing the image sensor (camera unit) to capture the incoherent light. However, the present invention is not limited to this. For example, incoherent light may be irradiated without stopping the operation of the oscillator.

[0198] Furthermore, examples were shown in the first to seventh embodiments described above, including a display unit that displays images, and a control unit configured to control the display unit to display both a surface inspection image and an appearance inspection image. The surface inspection image is configured to visually identify the location of a defective part determined to be internally generated within the measurement area, and the appearance inspection image is configured to visually identify the location of a defective part determined to be externally generated within the measurement area. However, the present invention is not limited to this. For example, it may be configured such that a display unit without an image display is used, and the generated image is output to the outside in data form.

[0199] Furthermore, in the first to seventh embodiments described above, the control unit is configured to overlay the extracted image onto the visual inspection image and display it on the display unit. The extracted image is an image that emphasizes the location of a defective part identified as internally generated within the measurement area; however, the present invention is not limited to this. For example, the extracted image and the visual inspection image may also be configured to be displayed side-by-side.

[0200] Furthermore, while the first to seventh embodiments described above illustrate examples of the control unit controlling the display unit to show surface inspection images and appearance inspection images side-by-side on the display unit, the present invention is not limited thereto. For example, the surface inspection image may be superimposed on the appearance inspection image in a semi-transparent state for display.

[0201] Furthermore, the first to third embodiments described above illustrate the following example: the speckle shear interferometer 4 (interference section) includes a common optical component disposed on the optical path of the laser L1 and the incoherent light L2. The optical component has a bandpass filter 45 (optical filter) that allows light with a predetermined wavelength to pass through. The defect inspection device is configured such that the interfering laser L1 and the incoherent light L2 reflected at the measurement area Pa have wavelengths capable of passing through the common bandpass filter 45, and are captured by a common image sensor 46. However, the present invention is not limited to this. For example, it may be configured to have multiple bandpass filters, and the bandpass filters on the optical path may be switched according to the wavelengths of the laser L1 and the incoherent light L2 and L202 respectively, so that the corresponding wavelengths pass through.

[0202] Furthermore, the third embodiment described above illustrates an example where the imaging unit is configured to include a first image sensor (first imaging unit) for capturing laser light and a second image sensor (second imaging unit) disposed separately from the first image sensor for capturing incoherent light, and the second illumination unit is configured to illuminate incoherent light containing light having a red wavelength, light having a green wavelength, and light having a blue wavelength; however, the present invention is not limited thereto. For example, the imaging unit may be configured to illuminate incoherent light containing wavelengths close to those of a laser, and the laser light and incoherent light may be captured separately by two separately disposed imaging units (first image sensor and second image sensor).

[0203] Furthermore, examples are shown in the second and third embodiments described above, where the second irradiation unit is configured to irradiate incoherent light having a red wavelength, incoherent light having a green wavelength, and incoherent light having a blue wavelength, respectively. However, the present invention is not limited to this. For example, the second irradiation unit may also be configured to irradiate white light, which is an incoherent light, and this white light includes light having a red wavelength, light having a blue wavelength, and light having a green wavelength. In addition, in this case, the image sensor may be configured to have a color filter to acquire a color image, or the image sensor may be configured to have a monochrome sensor, thereby switching between using bandpass filters that allow red, green, and blue wavelengths to pass through.

[0204] Furthermore, the examples shown in the first to seventh embodiments above illustrate lasers containing light (near-infrared light) with a wavelength of 785 nm, but the present invention is not limited thereto. For example, it may also be configured to contain visible light with a wavelength of 633 nm.

[0205] [Way]

[0206] Those skilled in the art should understand that the above exemplary embodiments are specific examples of the following methods.

[0207] (Project 1)

[0208] A defect inspection device, comprising:

[0209] The displacement section causes the measurement area of ​​the object being inspected to shift.

[0210] A first irradiation unit irradiates the measurement area with laser light;

[0211] The second irradiation unit irradiates the measurement area with incoherent light, i.e., incoherent light;

[0212] A control unit that controls the irradiation of the first irradiation unit and the second irradiation unit;

[0213] Interference section, which interferes with the laser reflected at the measurement area by laser interferometry; and

[0214] The camera unit captures images of the interfering laser light and the incoherent light reflected at the measurement area.

[0215] The defect inspection device is configured to generate an image representing the displacement at the measurement area of ​​the object to be inspected, i.e., a surface inspection image, based on the intensity pattern of the interfering laser captured by the camera unit, and to generate an image of the outer surface of the measurement area, i.e., an appearance inspection image, based on the intensity pattern of the incoherent light captured by the camera unit.

[0216] (Project 2)

[0217] According to the defect inspection device described in Project 1, wherein...

[0218] The interference section includes a common optical component disposed in the optical paths of the laser and the incoherent light.

[0219] (Project 3)

[0220] According to the defect inspection device described in Project 1 or 2, wherein,

[0221] The second irradiation unit is configured to irradiate the incoherent light, which includes light having a wavelength equal to that of the laser irradiated by the first irradiation unit.

[0222] (Project 4)

[0223] According to any one of items 1 to 3, the defect inspection device, wherein,

[0224] The laser interferometry method is a method of interfering the laser reflected at two distinct points in the measurement area.

[0225] The defect inspection device is configured such that a portion of the optical path of the laser and a portion of the optical path of the incoherent light are shared.

[0226] (Project 5)

[0227] According to the defect inspection device described in Project 4, wherein...

[0228] It also includes a shielding part that shields either of the two distinct optical paths through which the laser light reflected at the two distinct points passes.

[0229] The control unit is configured such that, while the shielding unit shields either of the two optical paths, the second irradiation unit is used to irradiate the incoherent light using the other optical path, thereby causing the imaging unit to capture the incoherent light.

[0230] (Project 6)

[0231] According to the defect inspection device described in Project 4, wherein...

[0232] It also includes a reflector component, which is disposed in the optical path through which the laser beam will pass.

[0233] The control unit is configured to illuminate the incoherent light while the position of the reflector component is changed, thereby altering one of the two different optical paths through which the laser reflected at the two different points passes, and thus causing the camera unit to capture the incoherent light.

[0234] (Project 7)

[0235] According to the defect inspection device described in Project 4, wherein...

[0236] The camera unit is configured to capture images of the incoherent light reflected at the two distinct points.

[0237] The control unit is configured to perform image processing on an appearance inspection image generated based on an intensity pattern of the incoherent light reflected at the two distinct points, which contains distortion, to reduce the distortion.

[0238] (Project 8)

[0239] According to the defect inspection device described in Project 4, wherein...

[0240] The interference section is configured such that: one of the two distinct optical paths through which the laser light reflected from the two distinct points and the incoherent light pass together includes a first optical filter for allowing light of a predetermined wavelength to pass through; and the other of the two distinct optical paths includes a second optical filter for allowing light of a predetermined wavelength to pass through.

[0241] The first optical filter is configured to allow the laser light to pass through and to attenuate the incoherent light.

[0242] The second optical filter is configured to allow the laser and the incoherent light to pass through.

[0243] (Project 9)

[0244] According to any one of items 1 to 8, the defect inspection device, wherein,

[0245] The control unit is configured such that the timing for the camera unit to capture the laser by irradiating the laser with the first irradiation unit is different from the timing for the camera unit to capture the incoherent light by irradiating the incoherent light with the second irradiation unit.

[0246] (Project 10)

[0247] According to the defect inspection device described in Project 9, wherein...

[0248] The control unit is configured such that, while the movement of the displacement unit is stopped, the second irradiation unit irradiates the incoherent light, thereby causing the imaging unit to capture the incoherent light.

[0249] (Project 11)

[0250] The defect inspection device according to any one of items 1 to 10, wherein,

[0251] It also has a display unit for displaying images.

[0252] The control unit is configured to perform the following control: to cause the display unit to display the surface inspection image, and to cause the display unit to display the appearance inspection image, wherein the surface inspection image is configured to visually identify the location of the defective part determined to be generated internally in the measurement area, and the appearance inspection image is configured to visually identify the location of the defective part determined to be generated on the outer surface in the measurement area.

[0253] (Project 12)

[0254] According to the defect inspection device described in Project 11, wherein...

[0255] The control unit is configured to perform the following control: superimpose an image that emphasizes the location of the defective part identified as being generated internally in the measurement area onto the visual inspection image and display it on the display unit.

[0256] (Project 13)

[0257] According to the defect inspection device described in item 11 or 12, wherein,

[0258] The control unit is configured to perform the following control: to display the surface inspection image and the appearance inspection image side by side on the display unit.

[0259] (Project 14)

[0260] The defect inspection device according to any one of items 1 to 13, wherein,

[0261] The control unit is configured such that the shared camera unit captures images of the interfering laser light and the incoherent light reflected at the measurement area.

[0262] (Project 15)

[0263] According to the defect inspection device described in Project 14, wherein...

[0264] The interference section includes a common optical component disposed on the optical paths of the laser and the incoherent light.

[0265] The optical component has an optical filter that allows light of a specified wavelength to pass through.

[0266] The defect inspection device is configured such that the laser that has interfered and the incoherent light reflected at the measurement area have wavelengths that can pass through the shared optical filter and are captured by the shared camera unit.

[0267] (Project 16)

[0268] The defect inspection device according to any one of items 1 to 13, wherein,

[0269] The camera unit is configured to include a first camera unit and a second camera unit, wherein the first camera unit is used to capture the laser, and the second camera unit is disposed separately from the first camera unit and is used to capture the incoherent light.

[0270] (Project 17)

[0271] The defect inspection device according to any one of items 1 to 16, wherein,

[0272] The defect inspection device is configured such that the incoherent light includes light with a red wavelength, light with a green wavelength, and light with a blue wavelength.

[0273] (Project 18)

[0274] The defect inspection device according to any one of items 1 to 17, wherein,

[0275] The second irradiation unit is configured to irradiate the incoherent light by reducing the coherence of the laser light irradiated by the first irradiation unit.

Claims

1. A defect inspection device, comprising: The displacement section causes the measurement area of ​​the object being inspected to shift. A first irradiation unit irradiates the measurement area with laser light; The second irradiation unit irradiates the measurement area with incoherent light, i.e., incoherent light; A control unit that controls the irradiation of the first irradiation unit and the second irradiation unit; An interferometer section, which uses laser interferometry to cause the laser reflected at the measurement area to interfere; as well as The camera unit captures images of the interfering laser light and the incoherent light reflected at the measurement area. The displacement portion is configured to excite an elastic wave within the measurement region. The defect inspection apparatus is configured such that, when the second irradiation unit does not irradiate the incoherent light but the first irradiation unit irradiates the laser in correspondence with the elastic wave excited by the displacement unit, an image representing the displacement excited by the displacement unit at the measurement area of ​​the object under inspection, i.e., a surface inspection image, is generated based on the intensity pattern of the laser that has interfered, captured by the imaging unit. Furthermore, when the displacement unit stops exciting the elastic wave and the laser is no longer irradiated by the first irradiation unit, and the second irradiation unit irradiates the incoherent light, an image of the outer surface of the measurement area, i.e., an appearance inspection image, is generated based on the intensity pattern of the incoherent light captured by the imaging unit. The laser interferometry method is a method of interfering the laser reflected at two distinct points in the measurement area. The defect inspection device is configured such that a portion of the laser's optical path and a portion of the incoherent light's optical path are shared. The defect inspection device also includes a shielding part that shields either of the two different optical paths through which the laser reflected at the two different points passes. The control unit is configured such that, while the shielding unit shields either of the two optical paths, the second irradiation unit is used to irradiate the incoherent light using the other optical path, thereby causing the imaging unit to capture the incoherent light.

2. A defect inspection device, comprising: The displacement section causes the measurement area of ​​the object being inspected to shift. A first irradiation unit irradiates the measurement area with laser light; The second irradiation unit irradiates the measurement area with incoherent light, i.e., incoherent light; A control unit that controls the irradiation of the first irradiation unit and the second irradiation unit; An interferometer section, which uses laser interferometry to cause the laser reflected at the measurement area to interfere; as well as The camera unit captures images of the interfering laser light and the incoherent light reflected at the measurement area. The displacement portion is configured to excite an elastic wave within the measurement region. The defect inspection apparatus is configured such that, when the second irradiation unit does not irradiate the incoherent light but the first irradiation unit irradiates the laser in correspondence with the elastic wave excited by the displacement unit, an image representing the displacement excited by the displacement unit at the measurement area of ​​the object under inspection, i.e., a surface inspection image, is generated based on the intensity pattern of the laser that has interfered, captured by the imaging unit. Furthermore, when the displacement unit stops exciting the elastic wave and the laser is no longer irradiated by the first irradiation unit, and the second irradiation unit irradiates the incoherent light, an image of the outer surface of the measurement area, i.e., an appearance inspection image, is generated based on the intensity pattern of the incoherent light captured by the imaging unit. The laser interferometry method is a method of interfering the laser reflected at two distinct points in the measurement area. The defect inspection device is configured such that a portion of the laser's optical path and a portion of the incoherent light's optical path are shared. The defect inspection device also includes a reflector component, which is disposed in the optical path through which the laser beam will pass. The control unit is configured to illuminate the incoherent light while the position of the reflector component is changed, thereby altering one of the two different optical paths through which the laser reflected at the two different points passes, and thus causing the camera unit to capture the incoherent light.

3. A defect inspection device, comprising: The displacement section causes the measurement area of ​​the object being inspected to shift. A first irradiation unit irradiates the measurement area with laser light; The second irradiation unit irradiates the measurement area with incoherent light, i.e., incoherent light; A control unit that controls the irradiation of the first irradiation unit and the second irradiation unit; An interferometer section, which uses laser interferometry to cause the laser reflected at the measurement area to interfere; as well as The camera unit captures images of the interfering laser light and the incoherent light reflected at the measurement area. The displacement portion is configured to excite an elastic wave within the measurement region. The defect inspection apparatus is configured such that, when the second irradiation unit does not irradiate the incoherent light but the first irradiation unit irradiates the laser in correspondence with the elastic wave excited by the displacement unit, an image representing the displacement excited by the displacement unit at the measurement area of ​​the object under inspection, i.e., a surface inspection image, is generated based on the intensity pattern of the laser that has interfered, captured by the imaging unit. Furthermore, when the displacement unit stops exciting the elastic wave and the laser is no longer irradiated by the first irradiation unit, and the second irradiation unit irradiates the incoherent light, an image of the outer surface of the measurement area, i.e., an appearance inspection image, is generated based on the intensity pattern of the incoherent light captured by the imaging unit. The laser interferometry method is a method of interfering the laser reflected at two distinct points in the measurement area. The defect inspection device is configured such that a portion of the laser's optical path and a portion of the incoherent light's optical path are shared. The interference section is configured such that: one of the two distinct optical paths through which the laser light reflected from the two distinct points and the incoherent light pass together includes a first optical filter for allowing light of a predetermined wavelength to pass through; and the other of the two distinct optical paths includes a second optical filter for allowing light of a predetermined wavelength to pass through. The first optical filter is configured to allow the laser light to pass through and to attenuate the incoherent light. The second optical filter is configured to allow the laser and the incoherent light to pass through.

4. The defect inspection device according to any one of claims 1 to 3, characterized in that, The interference section includes a common optical component disposed in the optical paths of the laser and the incoherent light.

5. The defect inspection device according to any one of claims 1 to 3, characterized in that, The second irradiation unit is configured to irradiate the incoherent light, which includes light having a wavelength equal to that of the laser irradiated by the first irradiation unit.

6. The defect inspection apparatus according to any one of claims 1 to 3, characterized in that, The camera unit is configured to capture images of the incoherent light reflected at the two distinct points. The control unit is configured to perform image processing on an appearance inspection image generated based on an intensity pattern of the incoherent light reflected at the two distinct points, which contains distortion, to reduce the distortion.

7. The defect inspection device according to any one of claims 1 to 3, characterized in that, The control unit is configured such that the timing for the camera unit to capture the laser by irradiating the laser with the first irradiation unit is different from the timing for the camera unit to capture the incoherent light by irradiating the incoherent light with the second irradiation unit.

8. The defect inspection device according to claim 7, characterized in that, The control unit is configured such that, while the movement of the displacement unit is stopped, the second irradiation unit irradiates the incoherent light, thereby causing the imaging unit to capture the incoherent light.

9. The defect inspection apparatus according to any one of claims 1 to 3, characterized in that, It also has a display unit for displaying images. The control unit is configured to perform the following control: to display the surface inspection image on the display unit, and to display the appearance inspection image on the display unit, wherein the surface inspection image is configured to visually identify the location of a defective part in the measurement area that is determined to be generated internally, and the appearance inspection image is configured to visually identify the location of a defective part in the measurement area that is determined to be generated on the outer surface.

10. The defect inspection device according to claim 9, characterized in that, The control unit is configured to perform the following control: superimpose an image that emphasizes the location of a defective part identified as being generated internally in the measurement area onto the visual inspection image and display it on the display unit.

11. The defect inspection device according to claim 9, characterized in that, The control unit is configured to perform the following control: to display the surface inspection image and the appearance inspection image side by side on the display unit.

12. The defect inspection apparatus according to any one of claims 1 to 3, characterized in that, The control unit is configured such that the shared camera unit captures images of the interfering laser light and the incoherent light reflected at the measurement area.

13. The defect inspection device according to claim 12, characterized in that, The interference section includes a common optical component disposed on the optical paths of the laser and the incoherent light. The optical component has an optical filter that allows light of a specified wavelength to pass through. The defect inspection device is configured such that the laser that has interfered and the incoherent light reflected at the measurement area have wavelengths that can pass through the shared optical filter and are captured by the shared camera unit.

14. The defect inspection apparatus according to any one of claims 1 to 3, characterized in that, The camera unit is configured to include a first camera unit and a second camera unit, wherein the first camera unit is used to capture the laser, and the second camera unit is disposed separately from the first camera unit and is used to capture the incoherent light.

15. The defect inspection apparatus according to any one of claims 1 to 3, characterized in that, The defect inspection device is configured such that the incoherent light includes light with a red wavelength, light with a green wavelength, and light with a blue wavelength.

16. The defect inspection apparatus according to any one of claims 1 to 3, characterized in that, The second irradiation unit is configured to irradiate the incoherent light by reducing the coherence of the laser light irradiated by the first irradiation unit.

Images