JP7095966B2 - Inspection equipment and inspection method - Google Patents

Description

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

Conventionally, the linear region on the inspection surface of the object is illuminated with linear illumination light, and the inspection surface is repeatedly imaged while moving the object with respect to the illumination unit and the imaging unit. An inspection device that acquires an image of a light beam is used in various fields. When an image is acquired using such an inspection device, shadows of convex portions and concave portions are less likely to appear in the lateral direction in which linear illumination light extends. Therefore, there is a possibility that the ridge-shaped convex portion or the groove-shaped concave portion extending in the moving direction of the object may not be detected as a defect.

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

Japanese Unexamined Patent Publication No. 2015-105904

By the way, when a plurality of pseudo-parallel lights are used, it is necessary to drastically change the structure of the illumination unit from the conventional one. In addition, the size and complexity of the lighting unit are increased. When imaging is performed while alternately irradiating a plurality of pseudo-parallel lights, the moving speed of the inspection target or the resolution of the image depends on the blinking speed of the pseudo-parallel lights. Therefore, it becomes difficult to increase the speed of imaging and the resolution of the image.

The present invention has been made in view of the above problems, and an object of the present invention is to enable detection of convex or concave defects extending in the moving direction of the inspection surface to be inspected without complicating the structure of the illumination unit. There is.

The invention according to claim 1 is an inspection device, which comprises a support portion that supports an object having an inspection surface to be inspected, an illumination portion that illuminates a linear region on the inspection surface, and the linear shape. The support portion is relatively moved with respect to the illumination unit and the image pickup unit in a movement direction parallel to the inspection surface and perpendicular to the lateral direction in which the linear region extends. The image pickup optical axis of the image pickup unit is perpendicular to the lateral direction, and the illumination unit causes the light source unit and the light emitted from the light source unit to be directed to the lateral direction. An illumination optical system that leads to the linear region while converting it into linear light that is a vertical surface and has directionality in a direction parallel to the virtual surface including the imaging optical axis, and the linear region from the light source unit. A part of the light from the light source unit is uniformly inclined with respect to the virtual surface, and the linear region and the virtual surface of the linear region intersect with each other. Light from the light source unit is parallel to the virtual surface in an adjacent region of the linear region adjacent to the intersection region in the lateral direction, including an auxiliary optical element leading to the intersection region including the position. When viewed from the moving direction, the imaging direction of the imaging unit with respect to the intersecting region is perpendicular to the inspection surface, and the imaging direction with respect to the adjacent region is the method of the inspection surface. Tilt with respect to the line direction.

The invention according to claim 2 is the inspection apparatus according to claim 1 , which is inclined with respect to the virtual surface between the intersection region and a region laterally separated from the intersection region . The amount of illumination light gradually changes.

The invention according to claim 3 is the inspection apparatus according to claim 2 , wherein the auxiliary optical element changes the propagation direction of light by refraction, and the width of the light flux cross section at the arrangement position of the auxiliary optical element. The abundance ratio of the auxiliary optical element with respect to the virtual surface gradually changes depending on the position in the lateral direction, so that the amount of illumination light inclined with respect to the virtual surface gradually changes.

The invention according to claim 4 is an inspection method, in which a) an object having an inspection surface to be inspected is moved in a moving direction parallel to the inspection surface, relative to an illumination unit and an imaging unit. A step of moving, b) a step of illuminating a linear region on the inspection surface perpendicular to the moving direction by the lighting unit in parallel with the step a), and a step of c) the step a). In parallel, the imaging unit includes a step of acquiring an image of the inspection surface by repeatedly imaging the linear region, and the imaging optical axis of the imaging unit is in the lateral direction in which the linear region extends. In step b), the illumination unit directs the light emitted from the light source unit to a surface perpendicular to the lateral direction and parallel to a virtual surface including the image pickup optical axis. Of the linear region, the linear region is guided to the linear region while being converted into linear light having directionality in the direction, and a part of the light from the light source unit is uniformly inclined with respect to the virtual surface. , Leading to an intersecting region including a position where the linear region and the virtual surface intersect, and light from the light source portion in an adjacent region of the linear region adjacent to the intersecting region in the lateral direction. However, it has a directivity in a direction parallel to the virtual surface, and when viewed from the moving direction, the imaging direction of the imaging unit with respect to the intersecting region is perpendicular to the inspection surface, and the imaging direction with respect to the adjacent region. Is inclined with respect to the normal direction of the inspection surface.

According to the present invention, convex or concave defects extending in the moving direction of the inspection target 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 relation of the illumination part, the image pickup part, and a substrate. It is a figure which shows the structure of a computer. It is a block diagram which shows the functional structure of an inspection apparatus. It is a figure which shows the flow of operation of an inspection apparatus. It is a figure which shows the internal structure of a lighting part. It is a figure which shows the internal structure of a lighting part. It is a figure which shows the auxiliary optical element, and the light amount distribution in a linear region. It is a figure which shows the relationship between the illumination direction and the image pickup direction in the adjacent area. It is a figure which shows the relationship between the illumination direction and the image pickup direction in the intersection region in the absence of an auxiliary optical element. It is a figure which shows the relationship between the illumination direction and the image pickup direction in the intersection region in the presence of an auxiliary optical element. It is a figure which shows the other example of the auxiliary optical element.

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

The upper surface of the substrate 9 is an inspection surface 91 to be inspected. The inspection device 1 includes a device main body 2 that captures an image of the inspection surface 91, and a computer 5 that controls the overall operation of the inspection device 1 and realizes various functions described later. The apparatus main body 2 has an illumination unit 21, an image pickup 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 arrangement relationship of the illumination unit 21, the image pickup unit 22, and the substrate 9. The left-right direction of FIG. 1 corresponds to the up-down direction of FIG.

The illumination unit 21 is long in the horizontal direction, which is the left-right direction in FIG. The lighting unit 21 illuminates a linear region 92 extending laterally on the inspection surface 91. The linear region 92 is a region to be imaged by the imaging unit 22 having a line sensor. The region to be irradiated with the illumination light may correspond to the linear region 92, but usually, the illumination light is irradiated to the linear region having a width 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, when a virtual surface 81 that is perpendicular to the lateral direction and includes the image pickup optical axis 221 of the image pickup unit 22 is assumed, the illumination light is emitted from the illumination unit 21 in parallel with the virtual surface 81. It is light having many components toward the linear region 92.

As described above, the image pickup unit 22 has a line sensor which is an image pickup device and an image pickup optical system. The image pickup unit 22 takes an image of the linear region 92 via the image pickup optical system. The imaging device is not limited to the line sensor. For example, the imaging unit 22 may have a two-dimensional sensor, and a part of the two-dimensional sensor may be used to image the linear region 92. The image pickup optical axis 221 of the image pickup unit 22 is perpendicular to the lateral direction in which the linear region 92 extends. The image pickup optical axis 221 is tilted 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 the support portion 23, various structures can be adopted as long as the substrate 9 can be supported. For example, the support portion 23 may have a structure that grips the outer edge of the substrate 9.

The moving mechanism 24 is composed of a ball screw, a guide rail, a motor, and the like. As the moving mechanism 24 moves the support portion 23, the substrate 9 having the inspection surface 91 moves with respect to the illumination unit 21 and the image pickup unit 22 in the movement direction parallel to the inspection surface 91. The direction of movement is perpendicular to the lateral direction, as indicated by the arrows with reference numerals 82 in FIGS. 1 and 2. Due to the movement of the substrate 9, the illumination region and the linear region 92 move with respect to the inspection surface 91. As a result, the linear region 92, which is the imaging region, scans on the inspection surface 91. The support unit 23 may move relative to the illumination unit 21 and the image pickup unit 22, and the illumination unit 21 and the image pickup unit 22 may move relative to the support unit 23.

The computer 5 controls the lighting unit 21, the imaging unit 22, and the moving mechanism 24. Illumination light is irradiated from the illumination unit 21 to the inspection surface 91 in parallel with the movement of the substrate 9, and further, the imaging unit 22 repeatedly images the linear region 92. As a result, the 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 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 has 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") for receiving 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, and a photomagnetic disk, and a communication unit 58 that transmits / receives a signal between another configuration of the inspection device 1. Including further.

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

FIG. 4 is a block diagram showing a 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, and the like of the computer 5 is surrounded by a broken line rectangle with reference numeral 5. The computer 5 has an image pickup control unit 41, a shading correction unit 42, an image processing unit 43, and an inspection unit 44. Although not shown, the computer 5 also realizes an overall control unit that controls the operation of each functional configuration. It should be noted that these functions may be constructed by a dedicated electric circuit, or a partially dedicated electric circuit may be used.

FIG. 5 is a diagram showing an operation flow of the inspection device 1. When the substrate 9 is supported by the support unit 23, the illumination control unit 41 starts emitting illumination light from the illumination unit 21 and starts the movement of the support unit 23 (steps S11 and S12). As described above, the imaging unit 22 repeats imaging of the linear region 92. The image of the inspection surface 91 is acquired by moving the linear region 92 from one end of the substrate 9 toward the other end (step S13). After that, the movement of the support unit 23 is stopped, and the emission of the illumination light from the illumination unit 21 is also stopped (steps S14 and S15). 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 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, the variation in the intensity of the illumination light and the variation in the sensitivity of the line sensor are corrected. The coefficient used for the correction is obtained in advance from the image obtained by imaging the inspection surface without defects. As will be described later, in the present embodiment, the change in the amount of illumination light in the lateral direction is large, but this change in the amount of light is also removed by the 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 mean, to be exact, the difference or variation in the "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). To be precise, 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 views showing the internal structure of the illumination unit 21. In FIGS. 6 and 7, the illumination unit 21 is shown so that the traveling direction of the light is downward. In reality, the traveling direction of the light is inclined with respect to the inspection surface 91 as shown in FIG. 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 left-right direction in FIG. 7 is the lateral 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 approximate state of light divergence and convergence is shown by a broken line.

The light source unit 31 has a plurality of LED elements 311. The plurality of LED elements 311 are arranged in the horizontal direction at equal intervals. In reality, a large number of LED elements 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 diffuser 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 laterally long linear Fresnel lenses. Various diffuser plates 321 can be used, but in this embodiment, LSD (Light Shaping Diffusers) is used. The two Fresnel lenses 322 and 324 have positive power in the left-right direction of FIG. 6, that is, in the direction from the light source unit 31 toward the linear region 92 and in the direction perpendicular to the lateral direction. In FIG. 6, the Fresnel lens is shown as a rectangle. The honeycomb structure 323 has a honeycomb-like structure having a large number of hexagonal cross sections perpendicular to the traveling direction of light. 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 at the top and bottom.

The light from the light source unit 31 is diffused by the diffuser plate 321. As a result, fluctuations in the amount of light in the lateral direction are reduced. The spread of the light from the diffuser plate 321 in the left-right direction in FIG. 6 is suppressed by the Fresnel lens 322. Light is further guided into the honeycomb structure 323. The honeycomb structure 323 blocks the scattered light, and light substantially parallel to the direction in which the through hole of the honeycomb structure 323 extends is derived from the honeycomb structure 323. As a result, substantially parallel light parallel to the virtual surface 81 (see FIG. 2) and perpendicular to the lateral direction can be obtained. In FIG. 7, the position of the virtual surface 81 is shown by a two-dot chain line. The Fresnel lens 324 converges the light in the left-right direction of FIG. As a result, linear light having a linear light flux cross section and illuminating the linear region 92 can be 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 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. The direction can be regarded as the traveling direction of the light incident on this 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 surface 81 and perpendicular to the lateral direction. Hereinafter, the direction parallel to the virtual surface 81 and toward the linear region 92 from the illumination optical system 32 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 from the light source unit 31 in the illumination optical axis direction is planar. In FIG. 6, a reference numeral 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 arranged 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 arranged 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 uniformly directed to the left side of FIG. 7, as shown by the arrow 84 in FIG. Is inclined to lead 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 seen along the illumination optical axis 211. The outer shape of the auxiliary optical element 33 is a parallelogram. In FIG. 8, the cross section 85 of the illumination light is shown by the broken line. At the position where the auxiliary optical element 33 is arranged, the illumination light has a certain width. The alternate long and short dash line in the center indicates the position of the virtual surface 81 in the lateral direction. The auxiliary optical element 33 is a parallelogram with two sides facing laterally. Therefore, 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 gradually decreases from the left to the right. Therefore, the amount of the gradient light indicated by reference numeral 84 in FIG. 7 also gradually increases from the left to the right and then gradually decreases. The polygonal line 86 in the middle of FIG. 8 shows an increase / decrease in the amount of gradient light. The horizontal axis in the middle row indicates the position in the horizontal direction corresponding to the upper row, and the vertical axis indicates the amount of light.

The auxiliary optical element 33 is arranged so as to be laterally displaced from the virtual surface 81 so that the maximum position of the amount of oblique light substantially coincides with the position of the virtual surface 81. As a result, in the linear region 92, a large amount of light inclined with respect to the virtual surface 81 is incident on the region in the range of the middle section of FIG. 8 with reference numeral 861. A large amount of light parallel to the illumination optical axis 211 and the virtual surface 81 is incident on the region of the linear region 92 in the range marked with the reference numeral 862. Since the illumination light is not completely parallel light, the light parallel to the virtual surface 81 is, to be exact, pseudo-parallel light substantially parallel to the virtual surface 81.

Since the region of the linear region 92 in the range marked with the reference numeral 861 includes the position where the linear region 92 and the virtual surface 81 intersect, it is hereinafter referred to as “intersection region 861”. The region of the linear region 92 to which the reference numeral 862 is attached is hereinafter referred to as “adjacent region 862”.

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

Since the illumination light converges in a direction parallel to the virtual surface 81 and perpendicular to the illumination optical axis direction from the auxiliary optical element 33 toward the linear region 92, the auxiliary optical element 33 is made into a parallel quadrilateral. As a result, 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.

The polygonal line 87 in the lower part of FIG. 8 shows the light intensity distribution of the illumination light in the linear region 92. Since the auxiliary optical element 33 blocks the light directly incident on the linear region 92 from the illumination optical system 32, the light amount distribution in the linear region 92 changes in a complicated manner as shown by the polygonal line 87. However, as described above, since the shading correction unit 42 in FIG. 4 corrects the influence of the light amount distribution, it does not pose a problem in acquiring an image. Further, since the auxiliary optical element 33 gradually changes the amount of gradient light between the intersecting region 861 and the adjacent region 862, it is possible to prevent the amount of illumination light from changing discontinuously in the linear region 92. Since the boundary between the intersection region 861 and the adjacent region 862 is not strictly defined, generally speaking, at least between the intersection region 861 and the region laterally separated from the intersection region 861, a virtual region is formed. By gradually changing the amount of illumination light inclined with respect to the surface 81, it is possible to prevent the amount of illumination light from changing discontinuously in the linear region 92.

FIG. 9 is a diagram showing the relationship between the illumination direction and the imaging direction in the adjacent region 862, and shows a state of viewing along the moving direction of the substrate 9. It is assumed that a groove-shaped defect 93 extending in the moving direction of the substrate 9 exists on the inspection surface 91. As shown by reference numeral 931, the illumination light is vertically incident on the inspection surface 91 when viewed from the moving direction. As shown by reference numeral 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 region indicated by reference numeral 933 appears as a dark region in the image, and defects can be detected. That is, since the illumination direction and the imaging direction are different when viewed from the moving direction, it is possible to detect a convex or concave defect extending in the moving direction. The defect is, for example, a wrinkle in a thin metal film.

On the other hand, assuming that the auxiliary optical element 33 does not exist, in the intersecting region 861 near the virtual surface 81, as shown in FIG. 10, the illumination direction 931 and the imaging direction 932 are parallel when viewed from the moving direction. 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, as shown in FIG. 11, since the illumination direction 931 is tilted with respect to the image pickup direction 932, the region indicated by reference numeral 934 appears as a dark region in the image. 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, it is possible to detect a convex or concave defect extending in the moving direction.

When viewed from the lateral direction, the illumination optical axis direction and the image pickup optical axis 221 are not parallel, so convex or concave defects extending in the lateral direction appear in the image regardless of the presence or absence of the auxiliary optical element 33. , Detectable.

As described above, in the inspection device 1, the auxiliary optical element 33 guides a part of the light from the light source unit 31 to the intersecting region 861 while inclining it with respect to the virtual surface 81. As a result, 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, defect detection of the entire imaging range is realized by one illumination optical system 32 having a simple structure. Further, as compared with the case where the direction of the illumination light is switched as in the prior art, the decrease in the imaging speed and the decrease in the resolution of the image are prevented.

The traveling direction of the illumination light in the adjacent region 862 is not limited to the illumination optical axis direction, but from the viewpoint of simplifying the structure of the illumination unit 21 and preventing deterioration of the accuracy of defect detection in the adjacent region 862, the adjacent region In 862, it is preferable that the illumination light has a directivity parallel to the virtual surface 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 outer shape of the auxiliary optical element 33 is a parallelogram, but the ratio of the auxiliary optical element 33 to the width of the light flux cross section at the arrangement position of the auxiliary optical element 33 gradually depends on the position in the lateral direction. If it changes, the outer shape of the auxiliary optical element 33 may have 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 line is perpendicular to the virtual surface 81. The outer shape 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 showing another example of the auxiliary optical element and corresponds to FIG. 7. The same components as those in FIG. 7 are designated by the same reference numerals. In the auxiliary optical element 33a shown in FIG. 12 , a large number of prisms are arranged in the lateral direction, and the inclination angle of the refractive plane of the prisms gradually changes in the lateral direction. Each refracting surface exists over the entire width of the illumination light (in the depth direction of FIG. 12). As a result, as shown by the arrow 84, the inclination angle of the illumination light with respect to the virtual surface 81 is gradually increased and then gradually decreased in the lateral direction. As described above, 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 is the light in the relationship between the incident direction and the amount of light from the incident direction. It shall point in the direction in which the amount of light becomes maximum.

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

The auxiliary optical element 33a shown in FIG. 12 can also detect convex or concave defects 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. can. The variation in the amount of linear light generated by the auxiliary optical element 33a in the lateral direction 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 for manufacturing the printed wiring board. The inspection device 1 can be used for inspection of various substrates that require inspection of convex or concave defects. Further, the object is not limited to a plate shape, but may be a sheet shape or a three-dimensional object having a flat inspection surface. The inspection surface is not limited to the one having a metal thin film. Various inspection surfaces are subject to inspection as long as the surface has convex or concave defects. However, when the inspection surface has a metallic luster, defects are less likely to appear in the image when the illumination direction and the imaging direction are parallel to each other when viewed from the moving direction. Therefore, the inspection device 1 inspects the surface having the metallic luster. Especially suitable for.

The structure of the lighting unit 21 can be changed in various ways. Preferably, the auxiliary optical element 33 is arranged at a position where the illumination light does not converge linearly.

Any auxiliary optical element 33 may be used as long as it can change the direction of light. For example, the auxiliary optical element 33 may be one prism having only one large refracting surface. Further, a lens-shaped optical element in which the inclination of the refracting surface changes continuously may be used. Thereby, as in the case of FIG. 12, the inclination of the illumination light can be gradually changed in the lateral direction.

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

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

The above-described embodiments and configurations in the respective modifications may be appropriately combined as long as they do not conflict with each other.

1 Inspection device 9 Board (object)
21 Illumination unit 22 Imaging unit 23 Support unit 24 Moving mechanism 31 Light source unit 32 Illumination optical system 33, 33a Auxiliary optical element 81 Virtual surface 91 Inspection surface 92 Linear area 221 Imaging optical axis 861 Crossing area 862 Adjacent area S11 to S15 Step

Claims (4)

It ’s an inspection device,
A support part that supports an object having an inspection surface to be inspected,
A lighting unit that illuminates the linear area on the inspection surface,
An imaging unit that captures the linear region and
A moving mechanism that moves the support portion relative to the illumination unit and the image pickup unit in a movement direction parallel to the inspection surface and perpendicular to the lateral direction in which the linear region extends.
Equipped with
The image pickup optical axis of the image pickup unit is perpendicular to the lateral direction, and is perpendicular to the lateral direction.
The lighting unit
Light source part and
The linear region while converting the light emitted from the light source unit into linear light that is a plane perpendicular to the lateral direction and has directionality in a direction parallel to the virtual plane including the imaging optical axis. Illumination optical system that leads to
The linear region of the linear region is arranged on the optical path from the light source portion to the linear region, and a part of the light from the light source portion is uniformly inclined with respect to the virtual surface. Auxiliary optical elements leading to the intersection region including the position where the virtual surface intersects with the virtual surface.
Including
In the region adjacent to the intersection region in the lateral direction of the linear region, the light from the light source unit has directivity in a direction parallel to the virtual surface.
When viewed from the moving direction, the imaging direction of the imaging unit with respect to the intersecting region is perpendicular to the inspection surface, and the imaging direction with respect to the adjacent region is inclined with respect to the normal direction of the inspection surface. A featured inspection device. The inspection device according to claim 1.
An inspection apparatus characterized in that the amount of illumination light inclined with respect to the virtual surface gradually changes between the intersection region and a region distant from the intersection region in the lateral direction. The inspection device according to claim 2.
The auxiliary optical element changes the direction of light propagation by refraction.
The amount of illumination light inclined with respect to the virtual surface by gradually changing the abundance ratio of the auxiliary optical element to the width of the light flux cross section depending on the position in the lateral direction at the arrangement position of the auxiliary optical element. An inspection device characterized by a gradual change in. It ’s an inspection method,
a) A step of moving an object having an inspection surface to be inspected relative to an illumination unit and an image pickup unit in a movement direction parallel to the inspection surface.
b) In parallel with the step a), the step of illuminating the linear region perpendicular to the moving direction on the inspection surface by the lighting unit.
c) In parallel with the step a), the step of acquiring an image of the inspection surface by repeatedly imaging the linear region by the imaging unit.
Equipped with
The image pickup optical axis of the image pickup unit is perpendicular to the lateral direction in which the linear region extends.
In the step b), the illumination unit directs the light emitted from the light source unit in a direction perpendicular to the lateral direction and parallel to the virtual surface including the image pickup optical axis. Of the linear regions, the linear region and the linear region are guided to the linear region while being converted into linear light, and a part of the light from the light source unit is uniformly inclined with respect to the virtual surface. The light from the light source unit is parallel to the virtual surface in the region adjacent to the intersection region in the lateral direction of the linear region, which leads to the intersection region including the position where the virtual surface intersects. Has directionality in any direction
When viewed from the moving direction, the imaging direction of the imaging unit with respect to the intersecting region is perpendicular to the inspection surface, and the imaging direction with respect to the adjacent region is inclined with respect to the normal direction of the inspection surface. Characteristic inspection method.

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