TWI691714B - Inspection device and inspection method - Google Patents

Abstract

The present invention provides an inspection device and an inspection method, wherein the inspection device photographs a linear area on an inspection surface while illuminating and moves the linear area, thereby acquiring an image of the inspection surface. The lighting section includes a light source section, an illumination optical system, and auxiliary optical elements. The auxiliary optical element guides a part of the light from the light source section to the intersection area including the position where the linear region and the virtual plane intersect while being inclined with respect to the virtual plane, and the virtual plane is perpendicular to the lateral direction where the linear region extends and includes Camera optical axis. Thereby, without complicating the structure of the illumination portion, convex or concave defects extending in the moving direction of the inspection object in the intersection area can be presented in the image, and defects can be detected.

Description

Inspection device and inspection method

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

Conventionally, the following inspection apparatuses have been used in various fields, that is, using linear illumination light to illuminate the linear region on the inspection surface of the object, and to move the object relative to the illumination unit and the imaging unit while making the linear The imaging of the area is repeated to obtain an image of the inspection surface. In the case of acquiring an image using such an inspection device, it is difficult for the shadow of the convex portion or the concave portion to appear in the lateral direction in which the linear illumination light extends. Therefore, there is a possibility that ridge-like convex portions or groove-like concave portions extending in the moving direction of the object cannot be detected as defects.

Therefore, in Patent Document 1, a plurality of simulated parallel lights with different tilt directions are used as the illumination light. Patent Document 1 also shows that a plurality of simulated parallel lights are switched and irradiated to the inspection surface. [Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2015-105904

[Problems to be solved by the invention]

When a plurality of simulated parallel lights are used, the structure of the lighting unit needs to be significantly changed compared to the existing structure. In addition, the size and complexity of the lighting unit will increase. When photographing while alternately irradiating a plurality of simulated parallel lights, the moving speed of the inspection object or the resolution of the image depends on the alternating speed of the simulated parallel lights. Therefore, it is difficult to increase the speed of imaging and increase the resolution of images.

The present invention has been accomplished in view of the above-mentioned problems, and an object of the present invention is to detect convex or concave defects extending in the moving direction of an inspection surface of an inspection object without complicating the structure of the illumination unit. [Means to solve the problem]

The invention described in claim 1 is an inspection device including: a support portion that supports an object having an inspection surface as an inspection object; an illumination portion that illuminates a linear region on the inspection surface; and an imaging portion, Photographing the linear region; and a moving mechanism that moves the support portion relative to the illumination portion and the moving portion in a moving direction parallel to the inspection plane and perpendicular to the lateral direction in which the linear region extends The imaging unit moves relatively, the imaging optical axis of the imaging unit is perpendicular to the lateral direction, the illumination unit includes: a light source unit, and an illumination optical system that converts light emitted from the light source unit into a line The linear light is guided to the linear region on one side, and the linear light has directivity in a direction parallel to a plane perpendicular to the lateral direction and including the virtual plane including the imaging optical axis; and an auxiliary optical element, It is arranged on the optical path from the light source section to the linear region, and a part of the light from the light source section is inclined to the virtual plane while including the line in the linear region The intersection area where the shape area and the virtual plane intersect is guided.

The invention described in claim 2 is the inspection device according to claim 1, wherein the illumination light is parallel to the virtual plane in the region of the linear region that is away from the intersection region in the lateral direction Is directional in the direction.

The invention described in claim 3 is the inspection device according to claim 2, wherein the illumination that is inclined with respect to the virtual plane is between the intersection area and the area that is away from the intersection area in the lateral direction The amount of light gradually changes.

The invention described in claim 4 is the inspection device according to claim 3, wherein the auxiliary optical element changes the propagation direction of light due to refraction, and the auxiliary optical element is arranged relative to the beam cross section at the arrangement position of the auxiliary optical element The existence ratio of the width gradually changes depending on the position in the lateral direction, whereby the amount of illumination light inclined with respect to the virtual plane gradually changes.

The invention described in claim 5 is the inspection device according to claim 2, wherein the illumination that is inclined relative to the virtual plane is between the intersection area and the area that is away from the intersection area in the lateral direction The tilt angle of light gradually changes.

The invention described in claim 6 is an inspection method including: a) a step of making an object having an inspection surface as an inspection object face the illumination unit and the imaging unit in a moving direction parallel to the inspection surface Moving; step b), in parallel with the step a), illuminating a linear region perpendicular to the moving direction on the inspection surface using the illumination section; and step c), a) In parallel, using the imaging unit to repeatedly image the linear region to obtain an image of the inspection surface; the imaging optical axis of the imaging unit extends relative to the linear region The horizontal direction is vertical, and in the step b), the lighting unit guides the light emitted from the light source unit to the linear region while converting it into linear light. The vertical plane and the virtual plane including the imaging optical axis are directed in a direction parallel to each other, and a part of the light from the light source part is inclined to the virtual plane while being included in the linear region The intersection area where the linear area and the virtual plane intersect is guided. [Effect of invention]

According to the present invention, it is possible to detect convex or concave defects extending in the moving direction of the inspection object without complicating the structure of the illumination portion.

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

The upper surface of the substrate 9 is an inspection surface 91 as an inspection target. The inspection apparatus 1 includes an apparatus main body 2 that photographs an inspection surface 91, and a computer 5 that controls the overall operation of the inspection apparatus 1 and realizes various functions described below. The device 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. 2 is a plan view showing the arrangement relationship of the illumination unit 21, the imaging unit 22, and the substrate 9. The horizontal direction in FIG. 1 corresponds to the vertical direction in FIG. 2.

The lighting unit 21 is long in the lateral direction in FIG. 2, that is, in the lateral direction. The illumination unit 21 illuminates the 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. The area irradiated with the illumination light may coincide with the linear area 92, but generally, the illumination light is irradiated to the linear area having a wider width than the linear area 92. The illumination light emitted from the illumination unit 21 is simulated parallel light. That is, as shown in FIG. 2, when a virtual surface 81 that is perpendicular to the horizontal direction and includes the imaging optical axis 221 of the imaging unit 22 is assumed, the illumination light is parallel to the virtual surface 81 from the illumination unit 21 toward the linear region 92 has a lot of light.

As described above, the imaging unit 22 has a line sensor as an imaging element and an imaging optical system. The imaging unit 22 images the linear region 92 via the imaging optical system. The imaging element is not limited to the line sensor. For example, the imaging unit 22 has a two-dimensional sensor, and a part of it can be used to image the linear region 92. The imaging optical axis 221 of the imaging unit 22 is perpendicular to the lateral 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 this embodiment, the support portion 23 is a stage. The support portion 23 can adopt various structures as long as it can support the substrate 9. For example, the support portion 23 may be a structure that grips the outer edge of the substrate 9.

The moving mechanism 24 includes a ball screw, a guide rail, a motor, and the like. The moving mechanism 24 moves the support portion 23, and thus the substrate 9 having the inspection surface 91 moves relative to the illumination portion 21 and the imaging portion 22 in the moving direction parallel to the inspection surface 91. In FIGS. 1 and 2, the moving direction is perpendicular to the lateral direction as indicated by the arrow with the symbol 82 attached. The movement of the substrate 9 moves the illumination area and the linear area 92 relative to the inspection surface 91. As a result, the linear area 92 as the imaging area is scanned on the inspection plane 91. In addition, the support portion 23 may be relatively moved with respect to the illumination portion 21 and the imaging portion 22, and the illumination portion 21 and the imaging portion 22 may be moved relative to the support portion 23.

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

FIG. 3 is a diagram showing the configuration of the computer 5. The computer 5 is composed of a general computer system, including a central processing unit (CPU) 51 that performs various arithmetic processing, a read-only memory (ROM) 52 that stores basic programs, and stores various information Random Access Memory (RAM) 53. The computer 5 also includes a fixed disk 54 for storing information, a display 55 for displaying various information such as images, a keyboard 56a and a mouse 56b (hereinafter collectively referred to as "input unit 56") that accept input from the operator, A reading device 57 that reads information from a computer-readable recording medium 8 such as an optical disk, magnetic disk, or optical disk, and a communication unit 58 that transmits and receives signals with other components of the inspection device 1.

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 while using the RAM 53 or the fixed disk 54 according to the program 80.

FIG. 4 is a block diagram showing the functional configuration of the inspection device 1. In FIG. 4, the functional configuration realized by the CPU 51, ROM 52, RAM 53, fixed disk 54, dedicated control circuit, etc. of the computer 5 is surrounded by a dotted rectangle with the symbol 5 attached. 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 in the drawings, the entire control unit that controls the operation of each functional configuration is also realized by the computer 5. In addition, these functions can be constructed by a dedicated circuit, or a dedicated circuit can be partially used.

FIG. 5 is a diagram showing the operation flow of the inspection device 1. When the substrate 9 is supported by the support portion 23, the illumination light is emitted from the illumination portion 21 under the control of the imaging control portion 41, and the movement of the support portion 23 is started (step S11, step S12). As described above, the imaging unit 22 repeats imaging of the linear region 92. The linear region 92 moves from one end to the other end of the substrate 9, thereby acquiring an image of the inspection surface 91 (step S13 ). Then, the movement of the support portion 23 is stopped, and the emission of the illumination light from the illumination portion 21 is also stopped (step S14, step S15). In addition, if the emission of the illumination light, the movement of the support portion 23, and the imaging are performed in parallel, the timing of the emission of the illumination light, the movement of the support portion 23, and the imaging can be appropriately changed.

When acquiring an image of the inspection surface 91, the shadow correction unit 42 performs shadow correction on the image (step S16). In shading correction, unevenness in the intensity of the illumination light or unevenness in the sensitivity of the line sensor is corrected. The coefficient used in the correction is obtained in advance from an image obtained by photographing a defect-free inspection surface. In addition, as will be described later, in the present embodiment, the change in the amount of illumination light in the horizontal direction is large, but the change in the amount of light is also removed by shading correction. In the following description, to be precise, the difference in the amount of light at different positions in the horizontal direction or the change in the amount of light in the horizontal direction refers to the difference or change in “the amount of light per unit length in the horizontal direction”.

The image processing unit 43 performs various image processing on the corrected image (step S17). To be precise, arithmetic processing is performed on the image data. Regarding the correction, for example, brightness correction, contrast correction, and binarization are performed. The inspection unit 44 determines whether there is a defect based on the corrected image (step S18).

6 and 7 are diagrams showing the internal structure of the lighting unit 21. In FIGS. 6 and 7, the illumination unit 21 is shown with the light advancing direction as the downward direction. Actually, the traveling direction of light is inclined with respect to the inspection surface 91 as shown in FIG. 1. FIG. 6 shows the illuminating unit 21 viewed from the lateral direction, and FIG. 7 shows the illuminating unit 21 viewed from a direction perpendicular to the lateral direction and the advancing direction of the illumination light. The left-right 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. The 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 outline of light divergence or focusing is indicated by broken lines.

The light source section 31 has a plurality of light emitting diode (Light Emitting Diode, LED) devices 311. The plurality of LED devices 311 are arranged in the lateral direction at equal intervals. Actually, a plurality of LED devices 311 are arranged. The light source of the light source unit 31 is not limited to the LED.

The illumination optical system 32 has a diffusion plate 321, a Fresnel lens 322, a honeycomb structure 323, and a Fresnel lens 324 in order from the light source portion 31 toward the linear region 92. Two Fresnel lenses 322, Philippine The Neel lens 324 is a linear Fresnel lens that is long in the lateral direction. Various types of diffusion plates 321 can be used, but in this embodiment, light shaping diffusers (LSD) are used. The two Fresnel lenses 322 and the Fresnel lens 324 have positive power in the left-right direction of FIG. 6, that is, in the direction perpendicular to the direction from the light source portion 31 toward the linear region 92 and the lateral direction. In FIG. 6, the Fresnel lens is represented by a rectangle. The honeycomb structure 323 has a honeycomb structure with a hexagonal cross section perpendicular to the light advancing direction. Each hexagonal space extends linearly from the Fresnel lens 322 toward the Fresnel lens 324. The honeycomb structure 323 has a plurality of hexagonal openings on the top and bottom.

The light from the light source unit 31 is diffused by the diffusion plate 321. As a result, the variation in the amount of light in the horizontal direction is reduced. The diffusion of the light from the diffusion plate 321 in the left-right direction of FIG. 6 is suppressed by the Fresnel lens 322. The light is further guided into the honeycomb structure 323. The honeycomb structure 323 shields scattered light, and emits light from the honeycomb structure 323 that is substantially parallel to the direction in which the through hole of the honeycomb structure 323 extends. Thereby, substantially parallel light that is 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 plane 81 is indicated by a two-dot chain line. The Fresnel lens 324 focuses the light in the left-right direction of FIG. 6. As a result, a linear light beam having a linear cross-section and illuminating the linear region 92 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 the direction parallel to the virtual surface 81. The directivity here refers to a state where the amount of light incident on a position on the linear region 92 is the largest in a specific direction, and decreases as it leaves the direction. This direction can be regarded as the traveling direction of the light incident on the position. More specifically, the illumination optical system 32 converts the light emitted from the light source unit 31 into light traveling in a direction parallel to the virtual plane 81 and perpendicular to the lateral direction. Hereinafter, the direction parallel to the virtual surface 81 and from the illumination optical system 32 toward the linear region 92 is referred to as the “illumination optical axis direction”. Since the illumination optical system 32 is long in the lateral direction, the illumination optical axis extending from the light source unit 31 in the illumination optical axis direction is planar. In FIG. 6, the symbol 211 is attached to the illumination optical axis.

The auxiliary optical element 33 is arranged 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. The structure of the illumination optical system 32 may be used, and the auxiliary optical element 33 may be arranged at another position on the optical path from the light source section 31 to the linear region 92. As shown in FIG. 7, the auxiliary optical element 33 is a prism plate having a plurality of prisms. Since the auxiliary optical element 33 changes the propagation direction of light by refraction, as shown by the arrow 84 in FIG. 7, the light incident on the auxiliary optical element 33 inclines uniformly toward the left side of FIG. 7 toward the linear region. 92 guide. That is, the vector of the traveling direction of the light that has passed through the auxiliary optical element 33 has a horizontal 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 the illumination light is indicated by a broken line. At the position where the auxiliary optical element 33 is arranged, the illumination light has a certain width. The two-dot chain line in the center indicates the position of the virtual plane 81 in the horizontal direction. The auxiliary optical element 33 is a parallelogram with two sides facing in the lateral direction. Therefore, at the position where the auxiliary optical element 33 is located, as the amount of light incident on the auxiliary optical element 33 (per unit length in the horizontal direction) gradually increases from left to right, it gradually decreases. Therefore, the amount of oblique light indicated by the symbol 84 in FIG. 7 also gradually decreases as it gradually increases from left to right. The broken line 86 in the middle of FIG. 8 indicates the increase or decrease in the amount of oblique light. The horizontal axis of the middle segment represents the position in the horizontal direction corresponding to the upper segment, and the vertical axis represents the amount of light.

The auxiliary optical element 33 is arranged such that the maximum position of the amount of oblique light substantially matches the position of the virtual surface 81 from the virtual surface 81 in the lateral direction. As a result, most of the light inclined with respect to the virtual surface 81 enters the region of the linear region 92 in the range where the symbol 861 is added to the middle of FIG. 8. Most of the light parallel to the illumination optical axis 211 and the virtual surface 81 enters the area of the linear area 92 in the range to which the symbol 862 is attached. In addition, the illumination light is not completely parallel light, so to be precise, the light parallel to the virtual surface 81 is pseudo parallel light substantially parallel to the virtual surface 81.

The area of the linear area 92 to which the symbol 861 is attached includes the position where the linear area 92 intersects with the virtual plane 81, and therefore is hereinafter referred to as "intersection area 861". The area of the linear area 92 to which the symbol 862 is attached is hereinafter referred to as "adjacent area 862".

The boundary between the intersection area 861 and the adjacent area 862 need not be strictly defined. The area where oblique light is incident to a certain degree can be appropriately defined as the intersection area 861. As will be described later, the length of the cross region 861 in the lateral direction is appropriately set within a range that a defect extending in the longitudinal 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 area 861 may be shorter. The illumination light inclined with respect to the virtual surface 81 enters at least the position where the linear region 92 crosses the virtual surface 81.

The illumination light is focused in a direction parallel to the virtual plane 81 and perpendicular to the direction of the illumination optical axis as it goes from the auxiliary optical element 33 toward the linear region 92. Therefore, by setting the auxiliary optical element 33 as a parallelogram, in the intersection area 861 Between the adjacent area 862, the amount of illumination light inclined with respect to the virtual surface 81 gradually changes.

The broken line 87 in the lower part of FIG. 8 shows the light quantity distribution of the illumination light in the linear region 92. Since the auxiliary optical element 33 shields light that is directly incident on the linear region 92 from the illumination optical system 32, as shown by the broken line 87, the light quantity distribution in the linear region 92 changes complicatedly. However, as already mentioned, the shading correction unit 42 of FIG. 4 corrects the influence of the light quantity distribution, so there is no problem in acquiring an image. In addition, since the auxiliary optical element 33 gradually changes the amount of oblique light between the intersection area 861 and the adjacent area 862, the amount of illumination light is prevented from changing discontinuously in the linear area 92. The boundary between the intersection area 861 and the adjacent area 862 is not strictly regulated. Therefore, if it is generally expressed, at least between the intersection area 861 and the area away from the intersection area 861 in the lateral direction, the illumination light inclined with respect to the virtual plane 81 The amount gradually changes, thereby preventing the light amount of the illumination light of the linear region 92 from changing discontinuously.

FIG. 9 is a diagram showing the relationship between the illumination direction and the imaging direction in the adjacent region 862, and shows the state viewed along the moving direction of the substrate 9. A groove-shaped defect 93 extending in the moving direction of the substrate 9 exists on the inspection surface 91. As indicated by symbol 931, the illumination light enters the inspection surface 91 vertically when viewed from the moving direction. As indicated by symbol 932, the imaging direction is inclined with respect to the normal direction of the inspection surface 91 when viewed from the moving direction. In this case, the area indicated by the symbol 933 appears as a dark area in the image, so that the defect can be detected. That is, when viewed from the moving direction, the illumination direction is different from the imaging direction, and thus it is possible to detect convex or concave defects extending in the moving direction. The defects are, for example, wrinkles of metal thin films.

On the other hand, if the auxiliary optical element 33 does not exist, the intersection area 861 near the virtual surface 81, as shown in FIG. 10, when viewed from the moving direction, the illumination direction 931 is parallel to the imaging direction 932. As a result, there is a fear that the defect 93 does not easily appear bright and dark in the image and cannot be detected as a defect.

In contrast, when the auxiliary optical element 33 is present, as shown in FIG. 11, since the illumination direction 931 is inclined with respect to the imaging direction 932, the area indicated by the symbol 934 appears as a dark area in the image and can be detected To defect 93. That is, since the illumination direction 931 and the imaging direction 932 are different when viewed from the moving direction, it is possible to detect convex or concave defects extending in the moving direction.

In addition, when viewed from the horizontal direction, since the illumination optical axis direction is not parallel to the imaging optical axis 221, convex or concave defects extending in the horizontal direction appear in the image regardless of the presence or absence of the auxiliary optical element 33. In order to be able to detect.

As described above, in the inspection device 1, the auxiliary optical element 33 guides the light from the light source unit 31 to the intersection area 861 while being inclined with respect to the virtual surface 81. Thereby, without complicating the structure of the illumination unit 21, a convex or concave defect extending in the moving direction of the inspection surface 91 can be detected in a region close to the virtual surface 81 with a simple design change. As a result, defect detection in the entire imaging range is realized with one illumination optical system 32 having a simple structure. Furthermore, compared with the case where the direction of the illumination light is switched as in the related art, the reduction in the imaging speed or the resolution of the image is prevented.

In addition, the advancing direction of the illumination light in the adjacent area 862 is not limited to the direction of the illumination optical axis, and from the viewpoint of simplifying the structure of the illumination unit 21 and preventing the accuracy of detecting defects in the adjacent area 862 from decreasing, it is preferable to illuminate the adjacent area 862 The light has directivity parallel to the virtual plane 81. It is preferable that at least the region of the linear region 92 that is away from the intersection region 861 in the lateral direction has the directivity of the illumination light parallel to the virtual plane 81.

In FIG. 8, the external shape of the auxiliary optical element 33 is a parallelogram. However, in the arrangement position of the auxiliary optical element 33, as long as the existence ratio of the auxiliary optical element 33 with respect to the width of the beam cross section gradually changes depending on the position in the lateral direction, then The external shape of the auxiliary optical element 33 may be other shapes. For example, the external shape of the auxiliary optical element 33 that changes the propagation direction of light by refraction may be a rhombus or a parallelogram whose diagonal is perpendicular to the virtual plane 81. The shape can contain curves. Even such an auxiliary optical element 33 can gradually change the amount of illumination light inclined with respect to the virtual surface 81 in the lateral direction.

FIG. 12 is a diagram showing another example of the auxiliary optical element, and corresponds to FIG. 7. The same symbols are attached to the same constituent elements as in FIG. 7. In the auxiliary optical element 33a shown in FIG. 7, a plurality of prisms are arranged in the lateral direction, and the inclination angle of the refractive surface of the prism gradually changes toward the lateral direction. Each refractive surface exists across the entire width of the illumination light (depth direction in FIG. 12). As a result, as indicated by arrow 84, the inclination angle of the illumination light with respect to the virtual surface 81 gradually increases in the lateral direction, and then gradually decreases. As already mentioned, since the illumination light incident on the auxiliary optical element 33a is not completely parallel light, the direction of the illumination light at a certain position refers to the amount of light in the relationship between the incidence direction and the amount of light from the incidence direction Great direction.

With the auxiliary optical element 33a, the amount of illumination light inclined with respect to the virtual surface 81 in the intersection area 861 increases, and the amount of illumination light not inclined in the adjacent area 862 increases. Since the boundary between the intersection area 861 and the adjacent area 862 does not need to be strictly defined, if it is generally expressed, the arrangement of the auxiliary optical element 33a is used, between the intersection area 861 and the area away from the intersection area 861 in the horizontal direction, relative to the virtual The inclination angle of the illumination light inclined by the surface 81 gradually changes, so that the inclined illumination light is irradiated to the intersection area 861.

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

The configuration and operation of the inspection device 1 can be changed in various ways.

The object to be inspected is not limited to the substrate used in the manufacture of printed wiring boards. The inspection device 1 can be used for inspection of various substrates requiring inspection of convex or concave defects. Furthermore, 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 the surface having the metal thin film. As long as the surface has convex or concave defects, various inspection surfaces can be used as inspection objects. Among them, in the case where the inspection surface has metallic luster, it is difficult for defects to appear in the image when the illumination direction is parallel to the imaging direction when viewed from the moving direction. Therefore, the inspection device 1 is particularly suitable for inspecting a surface with metallic luster.

The structure of the lighting unit 21 can be variously changed. It is preferable that the auxiliary optical element 33 is arranged at a position where the illumination light is not focused into a linear shape.

As long as the auxiliary optical element 33 can change the direction of light, any optical element can be used. For example, the auxiliary optical element 33 may be one prism having only one large refractive surface. Furthermore, it may be a lens-shaped optical element in which the inclination of the refractive surface continuously changes. Thus, as in the case of FIG. 12, the tilt of the illumination light can be gradually changed with respect to the lateral direction.

The auxiliary optical element 33 may be a mirror. For example, a reflecting mirror may be used to reflect the unused part of the illumination light, thereby guiding the oblique light to the intersection area 861. The honeycomb structure 323 may be partially inclined with respect to the virtual surface 81 to guide the inclined light toward the intersection area 861. Furthermore, various light guide members may be used to guide the inclined light toward the intersection area 861.

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-mentioned embodiment and each modification may be combined as appropriate as long as they do not contradict each other.

1‧‧‧Inspection device 2‧‧‧Main device 5‧‧‧Computer 8‧‧‧Recording medium 9‧‧‧Substrate (object) 21‧‧‧Illumination part 22‧‧‧Camera part 23‧‧‧Support part 24‧‧‧Moving mechanism 31‧‧‧Light source section 32‧‧‧Illumination optical system 33, 33a‧‧‧‧Auxiliary optical element 41‧‧‧Camera control section 42‧‧‧Shadow correction section 43‧‧‧ Image processing section 44‧‧‧ Inspection unit 51‧‧‧CPU52‧‧‧ROM53‧‧‧RAM54‧‧‧Fixed disk 55‧‧‧‧ Display 56‧‧‧ Input unit 56a‧‧‧Keyboard 56b‧‧‧Mouse 57‧‧ ‧Reading device 58‧‧‧Communication department 80‧‧‧Program 81‧‧‧Virtual plane 82, 84‧‧‧ Arrow 85‧‧‧ Illumination cross section 86, 87‧‧‧ Polyline 91‧‧‧ Inspection plane 92 ‧‧‧Linear area 93‧‧‧Defect 211‧‧‧ Illumination optical axis 221‧‧‧Camera optical axis 311‧‧‧LED device 321‧‧‧Diffusion plate 322, 324‧‧‧Fresnel lens 323‧‧ ‧Honeycomb structure 861‧‧‧Intersecting area 862‧‧‧ Adjacent area 931‧‧‧ Illumination direction 932‧‧‧ Imaging direction 933, 934‧‧‧Dark areas S11～S18‧‧‧ Procedure

FIG. 1 is a diagram showing the configuration of an inspection device. 2 is a plan view showing the arrangement relationship of the illumination unit, the imaging unit, and the substrate. 3 is a diagram showing the configuration of a computer. 4 is a block diagram showing the functional configuration of the inspection device. 5 is a diagram showing the flow of the operation of the inspection device. 6 is a diagram showing the internal structure of the lighting unit. 7 is a diagram showing the internal structure of the lighting unit. FIG. 8 is a diagram showing the light quantity distribution in the auxiliary optical element and the linear region. 9 is a diagram showing the relationship between the illumination direction and the imaging direction in the adjacent area. FIG. 10 is a diagram showing the relationship between the illumination direction and the imaging direction in the intersection area when there is no auxiliary optical element. 11 is a diagram showing the relationship between the illumination direction and the imaging direction in the intersection area when the auxiliary optical element is present. 12 is a diagram showing another example of the auxiliary optical element.

21‧‧‧ Lighting Department

31‧‧‧Light Source Department

32‧‧‧Lighting optical system

33‧‧‧Auxiliary optics

81‧‧‧Virtual face

84‧‧‧arrow

92‧‧‧Linear area

311‧‧‧LED device

321‧‧‧Diffusion plate

322, 324‧‧‧ Fresnel lens

323‧‧‧Honeycomb structure

Claims (6)

An inspection device, comprising: a support portion that supports an object having an inspection surface as an inspection object; an illumination portion that illuminates a linear area on the inspection surface; an imaging portion that controls the linear shape Shooting an area; and a moving mechanism that causes the support portion to face the illumination portion and the imaging portion in a moving direction that is parallel to the inspection plane and perpendicular to the lateral direction in which the linear area extends Moving, the imaging optical axis of the imaging unit is perpendicular to the lateral direction, and the illumination unit includes: a light source unit; an illumination optical system that converts the light emitted from the light source unit into linear light while The linear region guide, the linear light having directivity in a direction parallel to a plane perpendicular to the lateral direction and including a virtual plane including the imaging optical axis; and an auxiliary optical element arranged at a distance from the The light source unit reaches the optical path of the linear region, and a part of the light from the light source unit is inclined with respect to the virtual plane while being directed toward the linear region including the linear region and the The intersection area guide at the position where the virtual plane intersects. The inspection device according to item 1 of the patent application scope, wherein: in the linear region, the illumination light is in a direction parallel to the virtual plane in the region away from the intersection region in the lateral direction Directivity. The inspection device according to item 2 of the patent application scope, wherein: between the intersection area and the area away from the intersection area in the lateral direction, the illumination light inclined with respect to the virtual plane The amount gradually changes. The inspection device according to item 3 of the patent application scope, wherein: the auxiliary optical element changes the propagation direction of light due to refraction, and at the arrangement position of the auxiliary optical element, the width of the auxiliary optical element relative to the beam cross section The existence ratio of is gradually changed depending on the position in the lateral direction, whereby the amount of illumination light inclined with respect to the virtual plane is gradually changed. The inspection device according to item 2 of the patent application scope, wherein: between the intersection area and the area away from the intersection area in the lateral direction, the illumination light inclined with respect to the virtual plane The tilt angle gradually changes. An inspection method, comprising: a) a step of relatively moving an object having an inspection surface as an inspection object in a moving direction parallel to the inspection surface relative to the illumination unit and the imaging unit; b) step , In parallel with the step a), using the lighting section to illuminate a linear region on the inspection plane perpendicular to the moving direction; and step c) in parallel with the step a) Using the imaging unit to repeatedly image the linear region to obtain an image of the inspection surface; the imaging optical axis of the imaging unit is perpendicular to the lateral direction in which the linear region extends, so In the step b), the illumination unit guides the light emitted from the light source unit to the linear region while converting it into linear light, the linear light includes a surface perpendicular to the lateral direction and includes The virtual plane of the imaging optical axis is directed in a direction parallel to the virtual plane, and a part of the light from the light source section is inclined to the virtual plane while including the linear area The intersection area where the virtual plane intersects is guided.

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