JP2019056669A - Inspection device and inspection method - Google Patents

Abstract

To enable an inspection of convex-shape or concave-shape defects extending in a movement direction of an inspection object without complicating a structure of an illumination unit.SOLUTION: An inspection device 1 is configured to photograph a linear area 92 on an inspection surface as illuminating the linear area thereon, and moves on the linear area 92 to thereby acquire an image on the inspection surface. An illumination unit 21 has: a light source unit 31; an illumination optical system 32; and an auxiliary optical element 33. The auxiliary optical element 33 is configured to: incline one part of light from the light source unit 31 with respect to a virtual surface 81 serving as a vertical surface relative to a lateral direction where the linear area 92 extends and including a photographing optical axis; and guide the one part thereof to an intersection area including a position where the linear area 92 goes across the virtual surface 81. Thus, without complicating a structure of the illumination unit 21, a convex shape or concave shape defect extending in a movement direction of an inspection object in the intersection area can be shown up in the image, which in turn the defect can be detected.SELECTED DRAWING: Figure 7

Description

  The present invention relates to an inspection apparatus and an inspection method for inspecting the appearance of an inspection surface.

  Conventionally, a linear area on an inspection surface of an object is illuminated with linear illumination light, and imaging of the linear area is repeated while moving the object with respect to the illumination unit and the imaging unit. Inspection apparatuses that acquire images of these are used in various fields. When acquiring an image using such an inspection apparatus, the shadow of a convex part and a recessed part does not appear easily in the horizontal direction where linear illumination light extends. For this reason, there is a possibility that a hook-shaped convex portion or a groove-shaped concave portion extending in the moving direction of the object is not detected as a defect.

  Therefore, in Patent Document 1, a plurality of pseudo parallel lights having different inclination directions are used as illumination light. Further, Patent Document 1 also shows that a plurality of pseudo-parallel lights are switched to irradiate the inspection surface.

JP-A-2015-105904

  By the way, when using several pseudo-parallel light, it is necessary to change the structure of an illumination part significantly from the conventional one. In addition, the illumination unit is increased in size and complexity. When imaging is performed while alternately irradiating a plurality of pseudo-parallel light beams, the moving speed of the inspection target or the resolution of the image depends on the blinking speed of the pseudo-parallel light beams. For this reason, it is difficult to increase the imaging speed and the resolution of the image.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has an object to detect a convex or concave defect extending in the moving direction of the inspection surface to be inspected without complicating the structure of the illumination unit. Yes.

  Invention of Claim 1 is an inspection apparatus, Comprising: The support part which supports the target object which has a test surface used as test object, The illumination part which illuminates the linear area | region on the said test | inspection surface, The said linear The support unit is moved relative to the illuminating unit and the imaging unit in a moving direction perpendicular to a lateral direction in which the linear region extends parallel to the inspection surface and the linear region extends. A moving mechanism, and an imaging optical axis of the imaging unit is perpendicular to the lateral direction, and the illumination unit transmits a light source unit and light emitted from the light source unit to the lateral direction. An illumination optical system that is a vertical surface and converts the light into linear light having directivity in a direction parallel to a virtual surface including the imaging optical axis, and guides the linear light from the light source unit to the linear region Is arranged on the optical path leading to the part, and a part of the light from the light source part is inclined with respect to the virtual plane While, among the linear region, and a supplementary optical element and the linear region and the imaginary plane is guided to the intersection region including a position intersecting.

  Invention of Claim 2 is an inspection apparatus of Claim 1, Comprising: In the area | region which left | separated to the said horizontal direction from the said intersection area | region among the said linear area | regions, the said illumination light is parallel to the said virtual surface. Directivity in various directions.

  Invention of Claim 3 is an inspection apparatus of Claim 2, Comprising: The quantity of the illumination light inclined with respect to the said virtual surface between the said crossing area | region and the said area | region separated in the horizontal direction Gradually changes.

  A fourth aspect of the present invention is the inspection apparatus according to the third aspect, wherein the auxiliary optical element changes a light propagation direction by refraction, and a width of a light beam cross section at a position where the auxiliary optical element is disposed. The amount of the illumination light inclined with respect to the imaginary plane gradually changes due to a gradual change in the existence ratio of the auxiliary optical element with respect to the position in the lateral direction.

  Invention of Claim 5 is an inspection apparatus of Claim 2, Comprising: The inclination of the illumination light inclined with respect to the said virtual surface between the said crossing area | region and the said area | region separated in the horizontal direction The angle changes gradually.

  The invention according to claim 6 is an inspection method, in which a) an object having an inspection surface to be inspected is moved relative to the illumination unit and the imaging unit in a moving direction parallel to the inspection surface. A step of moving, b) a step of illuminating a linear region perpendicular to the moving direction on the inspection surface by the illumination unit in parallel with the step of a), and c) the step of a) In parallel, the imaging unit repeatedly captures the linear region to acquire an image of the inspection surface, and the imaging optical axis of the imaging unit has a lateral direction in which the linear region extends. In the step b), the illumination unit causes the light emitted from the light source unit to emit light emitted from the light source unit and is parallel to a virtual plane that is perpendicular to the lateral direction and includes the imaging optical axis. Led to the linear region while converting to linear light having directivity in the direction, While a portion of the light from the source unit is inclined relative to the imaginary plane, of the linear region, and the linear region and the imaginary plane is guided to the intersection region including a position intersecting.

  According to the present invention, a convex or concave defect extending in the moving direction of an inspection object can be detected without complicating the structure of the illumination unit.

It is a figure which shows the structure of an inspection apparatus. It is a top view which shows the arrangement | positioning relationship of an illumination part, an imaging part, and a board | substrate. It is a figure which shows the structure of a computer. It is a block diagram which shows the function structure of an inspection apparatus. It is a figure which shows the flow of operation | movement of an inspection apparatus. It is a figure which shows the internal structure of an illumination part. It is a figure which shows the internal structure of an illumination part. It is a figure which shows the light quantity distribution in an auxiliary optical element and a linear area | region. It is a figure which shows the relationship between the illumination direction in an adjacent area | region, and an imaging direction. It is a figure which shows the relationship between the illumination direction in an intersection area | region when an auxiliary optical element does not exist, and an imaging direction. It is a figure which shows the relationship between the illumination direction in an intersection area | region in case an auxiliary optical element exists, and an imaging direction. It is a figure which shows the other example of an auxiliary optical element.

  FIG. 1 is a diagram showing a configuration of an inspection apparatus 1 according to an embodiment of the present invention. The inspection apparatus 1 is an apparatus that inspects the appearance of an object using an optical method. In the present embodiment, the object is the substrate 9, and the inspection apparatus 1 detects convex portions and concave portions present in the metal thin film included in the substrate 9 as defects. The substrate 9 is used for manufacturing a printed wiring board, for example.

  The upper surface of the substrate 9 is an inspection surface 91 to be inspected. The inspection apparatus 1 includes an apparatus main body 2 that captures an image of the inspection surface 91, and a computer 5 that controls the overall operation of the inspection apparatus 1 and implements various functions described below. The apparatus main body 2 includes an illumination unit 21, an imaging unit 22, a support unit 23 that supports the substrate 9, and a moving mechanism 24 that moves the support unit 23. FIG. 2 is a plan view showing the positional relationship among the illumination unit 21, the imaging unit 22, and the substrate 9. The left-right direction in FIG. 1 corresponds to the up-down direction in FIG.

  The illumination unit 21 is long in the horizontal direction, which is the left-right direction in FIG. The illumination unit 21 illuminates a linear region 92 extending in the lateral direction on the inspection surface 91. The linear region 92 is a region captured by the imaging unit 22 having a line sensor. Although the region irradiated with the illumination light may coincide with the linear region 92, the illumination light is usually irradiated onto a linear region wider than the linear region 92. The illumination light emitted from the illumination unit 21 is pseudo parallel light. That is, as shown in FIG. 2, assuming a virtual surface 81 that is perpendicular to the horizontal direction and includes the imaging optical axis 221 of the imaging unit 22, the illumination light is emitted from the illumination unit 21 in parallel to the virtual surface 81. The light has a large amount of component toward the linear region 92.

  As described above, the imaging unit 22 includes a line sensor that is an imaging device and an imaging optical system. The imaging unit 22 images the linear region 92 via the imaging optical system. The imaging device is not limited to a line sensor. For example, the imaging unit 22 may have a two-dimensional sensor, and the linear region 92 may be imaged using a part thereof. The imaging optical axis 221 of the imaging unit 22 is perpendicular to the horizontal direction in which the linear region 92 extends. The imaging optical axis 221 is inclined with respect to the normal line of the inspection surface 91.

  As shown in FIG. 1, in the present embodiment, the support portion 23 is a stage. As long as the support part 23 can support the board | substrate 9, various structures are employable. For example, the support part 23 may have a structure for gripping the outer edge of the substrate 9.

  The moving mechanism 24 includes a ball screw, a guide rail, a motor, and the like. When the moving mechanism 24 moves the support unit 23, the substrate 9 having the inspection surface 91 moves relative to the illumination unit 21 and the imaging unit 22 in a movement direction parallel to the inspection surface 91. The moving direction is perpendicular to the lateral direction, as indicated by the arrow labeled 82 in FIGS. As the substrate 9 moves, the illumination area and the linear area 92 move relative to the inspection surface 91. Thereby, the linear region 92 which is an imaging region scans the inspection surface 91. In addition, the support part 23 should just move relatively with respect to the illumination part 21 and the imaging part 22, and the illumination part 21 and the imaging part 22 may move with respect to the support part 23. FIG.

  The computer 5 controls the illumination unit 21, the imaging unit 22, and the moving mechanism 24. In parallel with the movement of the substrate 9, illumination light is irradiated from the illumination unit 21 to the inspection surface 91, and the imaging unit 22 repeatedly images the linear region 92. Thereby, an image of the inspection surface 91 is acquired and stored in the computer 5.

  FIG. 3 is a diagram illustrating the configuration of the computer 5. The computer 5 has a general computer system configuration including a CPU 51 that performs various arithmetic processes, a ROM 52 that stores basic programs, and a RAM 53 that stores various information. The computer 5 includes a fixed disk 54 that stores information, a display 55 that displays various types of information such as images, and a keyboard 56a and a mouse 56b (hereinafter, referred to as an “input unit 56”) that receive input from an operator. ), A reading device 57 that reads information from a computer-readable recording medium 8 such as an optical disk, a magnetic disk, or a magneto-optical disk, and a communication unit 58 that transmits and receives signals between other configurations of the inspection device 1 Further included.

  In the computer 5, the program 80 is read from the recording medium 8 via the reading device 57 in advance and stored in the fixed disk 54. The CPU 51 executes arithmetic processing according to the program 80 while using the RAM 53 and the fixed disk 54.

  FIG. 4 is a block diagram showing a functional configuration of the inspection apparatus 1. In FIG. 4, the functional configuration realized by the CPU 51, ROM 52, RAM 53, fixed disk 54, dedicated control circuit, and the like of the computer 5 is surrounded by a broken-line rectangle denoted by reference numeral 5. The computer 5 includes an imaging control unit 41, a shading correction unit 42, an image processing unit 43, and an inspection unit 44. Although not shown, an overall control unit that controls the operation of each functional configuration is also realized by the computer 5. In addition, these functions may be constructed by a dedicated electric circuit, or a dedicated electric circuit may be partially used.

  FIG. 5 is a diagram showing a flow of operation of the inspection apparatus 1. If the board | substrate 9 is supported by the support part 23, emission of illumination light will be started from the illumination part 21 by control of the imaging control part 41, and the movement of the support part 23 will be started (step S11, S12). As described above, the imaging unit 22 repeats imaging of the linear region 92. As the linear region 92 moves from one end portion of the substrate 9 toward the other end portion, an image of the inspection surface 91 is acquired (step S13). Thereafter, the movement of the support part 23 is stopped, and the emission of illumination light from the illumination part 21 is also stopped (steps S14 and S15). If the illumination light is emitted, the support unit 23 is moved, and the imaging is performed in parallel, the illumination light emission, the support unit 23 is moved, and the imaging timing may be appropriately changed.

  When the image of the inspection surface 91 is acquired, the shading correction unit 42 performs shading correction on the image (step S16). In the shading correction, variations in illumination light intensity and line sensor sensitivity are corrected. The coefficient used for correction is obtained in advance from an image obtained by imaging an inspection surface having no defect. As will be described later, in this embodiment, the change in the amount of illumination light in the horizontal direction is large, but this change in the amount of light is also removed by shading correction. In the following description, the difference in the amount of light at different positions in the lateral direction and the variation in the amount of light in the lateral direction accurately mean the difference or variation in “amount of light per unit length in the lateral direction”.

  The image processing unit 43 performs various image processing on the corrected image (step S17). Precisely, arithmetic processing is performed on the image data. As the correction, for example, brightness correction, contrast correction, binarization, and the like are performed. The inspection unit 44 determines the presence or absence of a defect based on the corrected image (step S18).

  6 and 7 are diagrams showing the internal structure of the illumination unit 21. FIG. 6 and 7, the illumination unit 21 is shown so that the traveling direction of light is downward. Actually, the traveling direction of the light is inclined with respect to the inspection surface 91 as shown in FIG. 6 shows the illumination unit 21 viewed from the lateral direction, and FIG. 7 shows the illumination unit 21 viewed from the lateral direction and the direction perpendicular to the traveling direction of the illumination light. The horizontal direction in FIG. 7 is the horizontal direction.

  The illumination unit 21 includes a light source unit 31, an illumination optical system 32, and an auxiliary optical element 33. Light from the light source unit 31 is guided to the inspection surface 91 via the illumination optical system 32 and the auxiliary optical element 33. In FIG. 6, the approximate state of light divergence and convergence is indicated by broken lines.

  The light source unit 31 includes a plurality of LED elements 311. The plurality of LED elements 311 are arranged in the horizontal direction at equal intervals. Actually, a large number of LED elements 311 are arranged. The light source of the light source part 31 is not limited to LED.

  The illumination optical system 32 includes a diffusion plate 321, a Fresnel lens 322, a honeycomb structure 323, and a Fresnel lens 324 in order from the light source unit 31 toward the linear region 92. The two Fresnel lenses 322 and 324 are linear Fresnel lenses that are long in the lateral direction. Although various types of diffuser plates 321 can be used, LSD (Light Shaping Diffusers) is used in the present embodiment. The two Fresnel lenses 322 and 324 have positive power in the left-right direction in FIG. 6, that is, in the direction from the light source unit 31 toward the linear region 92 and the direction perpendicular to the lateral direction. In FIG. 6, the Fresnel lens is indicated by a rectangle. The honeycomb structure 323 has a honeycomb structure in which a cross section perpendicular to the light traveling direction has a large number of hexagons. Each hexagonal space extends linearly from the Fresnel lens 322 toward the Fresnel lens 324. The honeycomb structure 323 has a large number of hexagonal openings on the top and bottom.

  Light from the light source unit 31 is diffused by the diffusion plate 321. Thereby, the fluctuation | variation of the light quantity in a horizontal direction is reduced. The spread of light from the diffusion plate 321 in the left-right direction in FIG. 6 is suppressed by the Fresnel lens 322. The light is further guided into the honeycomb structure 323. The honeycomb structure 323 blocks scattered light, and light substantially parallel to the direction in which the through holes of the honeycomb structure 323 extend is led out from the honeycomb structure 323. Thereby, substantially parallel light parallel to the virtual surface 81 (see FIG. 2) and perpendicular to the lateral direction is obtained. In FIG. 7, the position of the virtual surface 81 is indicated by a two-dot chain line. The Fresnel lens 324 converges light in the left-right direction of FIG. As a result, linear light that illuminates the linear region 92 having a linear cross section is obtained.

  As described above, the illumination optical system 32 guides the light emitted from the light source unit 31 to the linear region 92 while converting it into linear light having directivity in a direction parallel to the virtual surface 81. The directivity here refers to a state in which the amount of light incident on a certain position on the linear region 92 is the largest in a specific direction and decreases as the distance from the direction increases. This direction can be regarded as the traveling direction of light incident on this position. More specifically, the illumination optical system 32 converts the light emitted from the light source unit 31 into light that travels in a direction parallel to the virtual surface 81 and perpendicular to the lateral direction. Hereinafter, a direction parallel to the virtual surface 81 and directed from the illumination optical system 32 toward the linear region 92 is referred to as an “illumination optical axis direction”. Since the illumination optical system 32 is long in the lateral direction, the illumination optical axis extending in the illumination optical axis direction from the light source unit 31 is planar. In FIG. 6, reference numeral 211 is attached to the illumination optical axis.

  The auxiliary optical element 33 is disposed between the illumination optical system 32 and the inspection surface 91. The auxiliary optical element 33 may be disposed between the honeycomb structure 323 and the Fresnel lens 324. Depending on the structure of the illumination optical system 32, the auxiliary optical element 33 may be disposed at another position on the optical path from the light source unit 31 to the linear region 92. As shown in FIG. 7, the auxiliary optical element 33 is a prism plate having a large number of prisms. Since the auxiliary optical element 33 changes the propagation direction of light by refraction, the light incident on the auxiliary optical element 33 is uniform toward the left side of FIG. 7 as indicated by an arrow 84 in FIG. And is led to the linear region 92. That is, the vector of the traveling direction of the light transmitted through the auxiliary optical element 33 has a lateral component.

  The upper part of FIG. 8 shows the auxiliary optical element 33 viewed along the illumination optical axis 211. The external shape of the auxiliary optical element 33 is a parallelogram. In FIG. 8, the cross section 85 of illumination light is shown by the broken line. At the position where the auxiliary optical element 33 is disposed, the illumination light has a certain width. The middle two-dot chain line indicates the position of the virtual surface 81 in the horizontal direction. The auxiliary optical element 33 is a parallelogram having two sides facing in the horizontal direction. For this reason, at the position where the auxiliary optical element 33 exists, the amount of light incident on the auxiliary optical element 33 (per unit length in the lateral direction) gradually increases and then decreases gradually from left to right. Therefore, the amount of inclined light indicated by reference numeral 84 in FIG. 7 also gradually increases and then gradually decreases from left to right. A polygonal line 86 in the middle of FIG. 8 indicates an increase or decrease in the amount of tilted light. The middle horizontal axis indicates the horizontal position corresponding to the upper stage, and the vertical axis indicates the amount of light.

  The auxiliary optical element 33 is arranged so as to be shifted from the virtual surface 81 in the lateral direction so that the maximum position of the light amount of the inclined light substantially coincides with the position of the virtual surface 81. Accordingly, a large amount of light that is inclined with respect to the virtual plane 81 is incident on a region of the linear region 92 in a range indicated by reference numeral 861 in the middle stage of FIG. A large amount of light parallel to the illumination optical axis 211 and the imaginary plane 81 is incident on the area of the linear area 92 that is designated by reference numeral 862. Since the illumination light is not perfect parallel light, the light parallel to the virtual surface 81 is exactly pseudo-parallel light approximately parallel to the virtual surface 81.

  Of the linear region 92, the region in the range denoted by reference numeral 861 includes a position where the linear region 92 and the virtual surface 81 intersect with each other, and is hereinafter referred to as “intersection region 861”. The area in the range indicated by reference numeral 862 in the linear area 92 is hereinafter referred to as “adjacent area 862”.

  The boundary between the intersection area 861 and the adjacent area 862 does not need to be strictly determined. A region where the inclined light is incident to some extent is appropriately determined as a crossing region 861. As will be described later, the horizontal length of the intersecting region 861 is appropriately set within a range in which a defect extending in the vertical direction, that is, in the moving direction of the inspection surface 91 can be detected in the vicinity of the virtual surface 81. Therefore, the intersection region 861 may be short. Illumination light inclined with respect to the virtual surface 81 is incident at least at a position where the linear region 92 and the virtual surface 81 intersect.

  Since the illumination light converges in a direction parallel to the virtual plane 81 and perpendicular to the illumination optical axis direction as it goes from the auxiliary optical element 33 toward the linear region 92, the auxiliary optical element 33 is made a parallelogram. Thus, the amount of illumination light inclined with respect to the virtual surface 81 gradually changes between the intersecting region 861 and the adjacent region 862.

  A lower broken line 87 in FIG. 8 indicates the light amount distribution of the illumination light in the linear region 92. Since the auxiliary optical element 33 blocks light that enters the linear region 92 straight from the illumination optical system 32, the light amount distribution in the linear region 92 changes in a complicated manner as indicated by the broken line 87. However, as described above, since the shading correction unit 42 in FIG. 4 corrects the influence of the light amount distribution, there is no problem in acquiring an image. Further, since the auxiliary optical element 33 gradually changes the amount of inclined light between the intersecting region 861 and the adjacent region 862, the amount of illumination light in the linear region 92 is prevented from changing discontinuously. Since the boundary between the intersecting region 861 and the adjacent region 862 is not strictly defined, in general terms, at least between the intersecting region 861 and the region laterally separated from the intersecting region 861 By gradually changing the amount of illumination light inclined with respect to the surface 81, the amount of illumination light in the linear region 92 is prevented from changing discontinuously.

  FIG. 9 is a diagram illustrating the relationship between the illumination direction and the imaging direction in the adjacent region 862, and shows a state viewed along the movement direction of the substrate 9. It is assumed that a groove-like defect 93 extending in the moving direction of the substrate 9 exists on the inspection surface 91. As indicated by reference numeral 931, the illumination light is incident on the inspection surface 91 perpendicularly when viewed from the moving direction. As indicated by reference numeral 932, the imaging direction is inclined with respect to the normal direction of the inspection surface 91 when viewed from the movement direction. In this case, the region indicated by reference numeral 933 appears as a dark region in the image, and a defect can be detected. That is, since the illumination direction and the imaging direction are different when viewed from the movement direction, it is possible to detect a convex or concave defect extending in the movement direction. The defect is, for example, a defect of a metal thin film.

  On the other hand, if it is assumed that the auxiliary optical element 33 is not present, the illumination direction 931 and the imaging direction 932 are parallel to each other in the intersection area 861 near the virtual plane 81 as seen from the moving direction as shown in FIG. Become. As a result, the defect 93 is unlikely to appear as light and dark in the image and may not be detected as a defect.

  On the other hand, when the auxiliary optical element 33 is present, the illumination direction 931 is inclined with respect to the imaging direction 932 as shown in FIG. 11, so that the region indicated by reference numeral 934 appears as a dark region in the image. The defect 93 can be detected. That is, since the illumination direction 931 and the imaging direction 932 are different when viewed from the moving direction, a convex or concave defect extending in the moving direction can be detected.

  Note that when viewed from the lateral direction, the illumination optical axis direction and the imaging optical axis 221 are not parallel, so that a convex or concave defect extending in the lateral direction appears in the image regardless of the presence or absence of the auxiliary optical element 33. Can be detected.

  As described above, in the inspection apparatus 1, the auxiliary optical element 33 guides part of the light from the light source unit 31 to the intersecting region 861 while inclining with respect to the virtual plane 81. Thereby, it is possible to detect a convex or concave defect extending in the moving direction of the inspection surface 91 in a region close to the virtual surface 81 with only a simple design change without complicating the structure of the illumination unit 21. As a result, the defect detection of the entire imaging range is realized by one illumination optical system 32 having a simple structure. Moreover, compared with the case where the direction of illumination light is switched as in the prior art, a reduction in imaging speed and a reduction in image resolution are prevented.

  The traveling direction of the illumination light in the adjacent region 862 is not limited to the direction of the illumination optical axis, but from the viewpoint of simplifying the structure of the illumination unit 21 and preventing the accuracy of defect detection in the adjacent region 862 from being lowered. In 862, the illumination light preferably has directivity parallel to the virtual plane 81. At least in the region of the linear region 92 that is laterally separated from the intersecting region 861, the illumination light preferably has directivity parallel to the virtual surface 81.

  In FIG. 8, the external shape of the auxiliary optical element 33 is a parallelogram, but at the arrangement position of the auxiliary optical element 33, the existence ratio of the auxiliary optical element 33 with respect to the width of the beam cross section gradually depends on the position in the lateral direction. As long as it changes, the external shape of the auxiliary optical element 33 may be another shape. For example, the outer shape of the auxiliary optical element 33 that changes the light propagation direction by refraction may be a rhombus or a parallelogram whose diagonal is perpendicular to the virtual plane 81. The outline may include a curve. Even with such an auxiliary optical element 33, the amount of illumination light inclined with respect to the virtual surface 81 can be gradually changed in the lateral direction.

  FIG. 12 is a diagram illustrating another example of the auxiliary optical element, and corresponds to FIG. Constituent elements similar to those in FIG. The auxiliary optical element 33a shown in FIG. 7 has a large number of prisms arranged in the lateral direction, and the inclination angle of the refractive surface of the prism gradually changes in the lateral direction. Each refracting surface exists over the entire width of the illumination light (in the depth direction in FIG. 12). As a result, the inclination angle of the illumination light with respect to the virtual plane 81 gradually increases and then gradually decreases in the lateral direction as indicated by the arrow 84. As described above, the illumination light incident on the auxiliary optical element 33a is not completely parallel light. Therefore, the direction of the illumination light at a certain position is the relationship between the incident direction and the amount of light from the incident direction. The direction in which the amount of is maximized.

  By the auxiliary optical element 33a, the amount of illumination light tilted with respect to the virtual plane 81 in the intersection region 861 increases, and the amount of illumination light that does not tilt in the adjacent region 862 increases. Since the boundary between the intersecting region 861 and the adjacent region 862 does not need to be strictly determined, generally speaking, the region 861 and the region that is laterally separated from the intersecting region 861 due to the arrangement of the auxiliary optical element 33a. , The inclination angle of the illumination light inclined with respect to the virtual plane 81 gradually changes, and it is realized that the intersection region 861 is irradiated with the inclined illumination light.

  The auxiliary optical element 33a shown in FIG. 12 can also detect a convex or concave defect extending in the moving direction of the inspection surface 91 in a region close to the virtual surface 81 without complicating the structure of the illumination unit 21. it can. The light amount fluctuation in the lateral direction of the linear light generated by the auxiliary optical element 33 a is corrected by the shading correction unit 42.

  The configuration and operation of the inspection apparatus 1 can be variously changed.

  The object to be inspected is not limited to a substrate used for manufacturing a printed wiring board. The inspection apparatus 1 can be used to inspect various substrates that require inspection of convex or concave defects. The object is not limited to a plate shape, and may be a sheet shape or a three-dimensional object having a flat inspection surface. The inspection surface is not limited to one having a metal thin film. If the surface has a convex or concave defect, various inspection surfaces can be inspected. However, when the inspection surface has a metallic luster, the inspection apparatus 1 inspects the surface having the metallic luster because defects are less likely to appear in the image when the illumination direction and the imaging direction are parallel when viewed from the moving direction. Especially suitable for.

  The structure of the illumination unit 21 can be variously changed. Preferably, the auxiliary optical element 33 is disposed at a position where the illumination light does not converge linearly.

  Any auxiliary optical element 33 may be used as long as the direction of light can be changed. For example, the auxiliary optical element 33 may be a single prism having only one large refractive surface. Further, it may be a lens-like optical element in which the inclination of the refractive surface changes continuously. Thereby, the inclination of illumination light can be gradually changed with respect to a horizontal direction similarly to the case of FIG.

  The auxiliary optical element 33 may be a mirror. For example, a portion of the illumination light that is not used for illumination may be reflected by a mirror to guide the inclined light to the intersecting region 861. By inclining the honeycomb structure 323 partially with respect to the virtual plane 81, the inclined light may be guided to the intersecting region 861. Furthermore, you may guide the light inclined to the cross | intersection area | region 861 using various light guide members.

  When the inspection surface is wide in the horizontal direction, a plurality of combinations of the illumination unit 21 and the imaging unit 22 may be arranged in the horizontal direction.

  The configurations in the above-described embodiments and modifications may be combined as appropriate as long as they do not contradict each other.

1 Inspection device 9 Substrate (object)
DESCRIPTION OF SYMBOLS 21 Illumination part 22 Imaging part 23 Support part 24 Movement mechanism 31 Light source part 32 Illumination optical system 33,33a Auxiliary optical element 81 Virtual surface 91 Inspection surface 92 Linear area 221 Imaging optical axis 861 Intersection area 862 Adjacent area S11-S15 Step

Claims (6)

An inspection device,
A support part for supporting an object having an inspection surface to be inspected;
An illumination unit that illuminates a linear region on the inspection surface;
An imaging unit for imaging the linear region;
A moving mechanism that moves the support unit relative to the illumination unit and the imaging unit in a movement direction that is parallel to the inspection surface and perpendicular to a lateral direction in which the linear region extends;
With
The imaging optical axis of the imaging unit is perpendicular to the lateral direction,
The illumination unit is
A light source unit;
The linear region while converting the light emitted from the light source unit into linear light having directivity in a direction perpendicular to the horizontal direction and parallel to a virtual plane including the imaging optical axis An illumination optical system that leads to
The linear region and the virtual region are arranged on the optical path from the light source unit to the linear region, and the linear region and the virtual region of the linear region are tilted with respect to the virtual surface while tilting part of the light from the light source unit. An auxiliary optical element that leads to an intersecting region including a position where the surfaces intersect;
The inspection apparatus characterized by including. The inspection apparatus according to claim 1,
The inspection apparatus according to claim 1, wherein the illumination light has directivity in a direction parallel to the virtual plane in a region of the linear region separated from the intersecting region in the lateral direction. The inspection apparatus according to claim 2,
The inspection apparatus, wherein the amount of illumination light inclined with respect to the virtual plane gradually changes between the intersecting region and the region separated in the lateral direction. The inspection apparatus according to claim 3,
The auxiliary optical element changes the propagation direction of light by refraction;
The amount of illumination light that is inclined with respect to the virtual plane when the presence ratio of the auxiliary optical element with respect to the width of the beam cross section gradually changes depending on the position in the lateral direction at the arrangement position of the auxiliary optical element. Inspection apparatus characterized by gradually changing. The inspection apparatus according to claim 2,
The inspection apparatus, wherein an inclination angle of illumination light inclined with respect to the virtual plane gradually changes between the intersecting region and the region separated in the lateral direction. An inspection method,
a) moving an object having an inspection surface to be inspected relative to the illumination unit and the imaging unit in a movement direction parallel to the inspection surface;
b) illuminating a linear region perpendicular to the moving direction on the inspection surface by the illumination unit in parallel with the step a);
c) In parallel with the step a), the step of acquiring the image of the inspection surface by repeatedly imaging the linear region by the imaging unit;
With
The imaging optical axis of the imaging unit is perpendicular to the lateral direction in which the linear region extends,
In the step b), the illumination unit directs light emitted from the light source unit in a direction perpendicular to the lateral direction and parallel to a virtual plane including the imaging optical axis. The linear region and the virtual surface among the linear regions are guided to the linear region while being converted into a linear light, and a part of the light from the light source unit is inclined with respect to the virtual surface. Inspection method characterized by guiding to a crossing region including a position where the crossing points.

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