JP7175214B2 - inspection equipment - Google Patents

Description

The present invention relates to an inspection apparatus that inspects an object from image data obtained by irradiating the object with light.

2. Description of the Related Art In place of visual inspection, an inspection apparatus is being introduced that illuminates an object to be inspected, takes an image, and performs inspection based on image data.
In particular, when inspecting coins and banknotes, there are many things to check, such as surface scratches and color, and the scratches and characteristic parts that need to be detected are small. is required to be constant and to secure a sufficient amount of light.
However, in the so-called epi-illumination method, in which a half mirror or the like is used to illuminate an object to be inspected from the side of a conventional imaging device, the amount of light from the light source is attenuated by the half mirror, and the size of the device itself can be reduced. There were problems such as the difficulty of
On the other hand, a method of uniformly illuminating using a plurality of light sources with different incident angles is also known (see Patent Documents 1 to 6, for example). However, in such a configuration, there is a problem that light from a plurality of locations is reflected on the imaging plane as stray light.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a novel inspection apparatus capable of suppressing glare even when a plurality of light sources are used.

An inspection apparatus according to the present invention is an inspection apparatus for inspecting the appearance of an object, comprising: an imaging unit for imaging the object on an imaging plane with a predetermined viewing angle; a first illumination unit that illuminates a surface of the object with first illumination light whose angle is equal to or greater than the oblique incidence angle corresponding to the viewing angle; a second illumination unit that illuminates the surface of the object with second illumination light having a smaller incident angle, wherein the first illumination unit makes the illuminance of the first illumination light uniform on the surface of the object. and the second illumination unit includes a second diffusion unit for adjusting the illuminance of the second illumination light to be uniform on the surface of the object, The first illumination unit and the second illumination unit are provided on both sides of a virtual auxiliary line that passes through the outer edge of the imaging surface and has the same oblique incidence angle as the oblique incidence angle corresponding to the viewing angle. The external appearance is inspected using a bright field image of the object obtained from the first illumination light and a dark field image of the object obtained from the second illumination light, and the imaging is performed. The diameter of the field of view of the part: WL, the maximum oblique incident angle of the second illumination light: θ3, the angle formed by the surface of the object when the center of the optical axis of the second illumination light passes through the center of the surface of the object: θ5, θ3>θ5>1.5θα, where θα is an angle formed by a line connecting the outer edge of the field of view of the imaging unit and the outer edge of the first diffusion unit and the surface of the object. and

According to the inspection apparatus of the present invention, it is possible to reduce the influence of stray light by suppressing glare even when a plurality of light sources are used.

It is a figure showing an example of an inspection device as an embodiment of the present invention. It is a figure which shows an example of illumination by high angle illumination. It is a figure which shows an example of illumination by low-angle illumination. It is a sectional view showing an example of an inspection device of the present invention. 2 is a diagram showing an example of a path of first irradiation light of the inspection apparatus shown in FIG. 1; FIG. 2 is a diagram showing an example of a path of second irradiation light of the inspection apparatus shown in FIG. 1; FIG. FIG. 4 is a diagram showing an example of arrangement of the first diffusion part of the inspection device; It is a figure which shows each oblique-incidence angle of an inspection apparatus, and the positional relationship of a 1st diffusion plate. FIG. 4 is a diagram showing a specific example of the arrangement of the second diffusion section of the inspection device; It is a figure which shows the concrete numerical example of arrangement|positioning of an inspection apparatus. FIG. 11 is a diagram showing another example of the arrangement of inspection devices;

As a conceptual diagram of the first embodiment of the present invention, FIG. 1 shows an inspection apparatus 100 equipped with an imaging device 10 .
In the following description, the direction of the optical axis of the lens of the imaging device 10 is the Z direction, and among the directions perpendicular to the Z axis, the lateral direction of the paper surface shown in FIG. is the X direction.

The inspection apparatus 100 includes an imaging device 10 as an imaging unit that captures an image of a workpiece M, which is an inspection target, from the Z direction at _a predetermined viewing angle θ1, and a high-angle imaging unit that illuminates an irradiation surface P of the workpiece M with a first illumination light L1. It has the 1st illumination part 11 as illumination, and the 2nd illumination part 12 as low-angle illumination which illuminates the irradiation surface P with the 2nd illumination light L2.
The inspection apparatus 100 also has an image recognition section 20 that inspects the appearance of the work M based on the image data 50 obtained from the imaging device 10 .
The image recognition unit 20 uses the bright field image of the work M obtained from the first illumination light L1 and the dark field image of the work M obtained from the second illumination light L2 as the image data 50 to recognize the work M. It has a function as an inspection unit that inspects appearance.
Further, in this embodiment, as shown in FIG. 4, a cover glass 30 is provided on the imaging surface W to place the workpiece W thereon so that the imaging surface W can be photographed from below.

The imaging device 10 is a camera attached to the work M in the -Z direction, and is an imaging unit for capturing image data 50 by photographing the work M from the -Z direction side.
As schematically shown in FIG. 1, the image capturing apparatus 10 captures an image of an image capturing plane W with a field of view of _a viewing angle θ1 on the YZ plane. Also, the viewing angle θ ₁ is shown in FIG. 1 as an angle θ ₂ =90°−θ ₁ when viewed from the imaging surface W. As shown in FIG. Thus, the angle between the incident direction of the ray and the boundary surface is expressed as "grazing incidence angle".
Further, as will be described later, the intersection point O of the lines indicating the viewing angle θ1 is _a reference point, which is indicated as the position of the entrance pupil of the imaging device 10 .

First, high-angle illumination by the first illumination unit 11 will be described with reference to FIG. In FIG. 2, in order to simplify the explanation, the case where there is no cover glass 30 between the work M and the imaging device 10 and the effects of refraction, scattering, etc. can be ignored will be explained.
In FIG. 2, an auxiliary line O′ indicated by a dashed line is an auxiliary line that schematically shows a region in which specularly reflected light enters within the viewing angle θ ₁ , and is “similar to the oblique incidence angle θ ₂ of the viewing angle θ ₁ . auxiliary line having an oblique incidence angle and passing through the outer edge Q of the imaging plane W'. The first lighting unit 11 is arranged on the -Z side of the auxiliary line O'.

The first illumination unit 11 irradiates the irradiation surface P with the first illumination light L1, which is diffusive light.
Among the radiated first illumination light L1, light beams specularly reflected by striking the irradiation surface P enter the imaging device 10 as indicated by the two-dot chain line in FIG.
At this time, the first illumination unit 11 is arranged so that the specularly reflected light of the _first illumination light L1 falls within the viewing angle θ1. _In other words, when the minimum oblique incident angle of the _first illumination light L1 is θ4, the arrangement that satisfies θ2≦θ4 allows the _first illumination light L1 to fall within the viewing angle θ1 of the imaging device ₁₀ as directly reflected light. incident on

When the work M is placed on the imaging surface W, the first illumination light L1 is applied to the work M, and the regular reflection component is incident on the imaging device 10 . The color, shape, size, and the like of the workpiece M can be measured from such specular reflection components.
Illumination using the first illumination light L1 is referred to as "high-angle illumination", and an image captured using the imaging device 10 under high-angle illumination is referred to as a "bright field image".

Next, low-angle illumination by the second illumination section 12 will be described with reference to FIG. Note that the illustration of the cover glass 30 is omitted in order to simplify the explanation, as in FIG.
The auxiliary line indicated by the dashed-dotted line in FIG. ₃ is an auxiliary line that schematically shows the area where specularly reflected light enters within the viewing angle θ1, as in FIG. A part 12 is arranged. That is, the _first illumination unit 11 and the _second illumination unit 12 have an oblique incidence angle similar to the oblique incidence angle θ2 of the viewing angle θ1, and the auxiliary line O′ passing through the outer edge Q of the image pickup surface W. are placed on both sides of the
In FIG. 3, the maximum oblique incident angle of the second illumination light L2 is indicated as θ ₃ .

The second illumination unit 12 irradiates the irradiation surface P with the second illumination light L2, which is diffuse light.
The maximum oblique incident angle θ ₃ of the second illumination light L2 is set to satisfy θ ₂ >θ ₃ . Therefore, the specularly reflected light (directly reflected light) of the second illumination light L2 does not enter the viewing angle of the imaging device 10, but when the work M is placed on the imaging surface W, the surface of the work M is If there is a scratch or unevenness, irregular reflection occurs due to the inclination of the edge portion or the scratch, and part of the irregularly reflected light enters the imaging device 10 .
That is, only the edge portion of the workpiece M is detected by the imaging device 10, and an image of the edge portion is obtained.
Illumination using the scattered light of the second illumination light L2 is called "low-angle illumination", and an image captured using the imaging device 10 with low-angle illumination is called a "dark field image".

By arranging the second illumination unit 12 in this way, out of the second illumination light L2 emitted from the second illumination unit 12 to the imaging surface W, specularly reflected light does not enter the imaging device 10, and the workpiece M A part of the light scattered or reflected by the surface 10 is incident on the imaging device 10 .

As described with reference to FIGS. 2 and 3, the imaging device 10 has a bright field image 51 obtained by reflected light of the first illumination light L1 and a dark field image 52 obtained by reflected light of the second illumination light L2. and image data 50 including .
Therefore, the imaging device 10 captures the specularly reflected light of the first illumination light L1 as the bright field image 51 and the diffused light of the second illumination light L2 as the dark field image 52, respectively.
In this embodiment, the case where the bright-field image 51 and the dark-field image 52 are individually photographed will be described, but the configuration is not limited to this. Further, in the present embodiment, the imaging surface W of the imaging device 10 and the irradiation surface P, which is a high-angle imaging surface, are described as being in substantially the same range (W≈P). P may be different.

FIG. 4 shows a cross-sectional view of an inspection apparatus 100 as a specific embodiment of this embodiment.
As shown in FIG. 4, the first illumination section 11 has an LED light 13 functioning as a light source and a first diffusion plate 15 as a first diffusion section.
The LED lights 13 and the first diffusion plate 15 are formed in a circumferential shape so as to surround the imaging device 10, respectively. - It is arranged so as to tilt in the Z direction.
That is, the first diffusion plate 15 has a truncated cone shape with the bottom and top removed.
The light emitted from the LED light 13 along the Z direction is diffused in directivity by the first diffuser plate 15, and irradiated as the first illumination light L1 onto the irradiation surface P so that the illuminance becomes uniform. .

The second illumination section 12 has an LED light 14 functioning as a light source, a second diffusion plate 16 as a second diffusion section, and a light guide element 17 as a light guide path.
The light emitted from the LED light 14 along the Z direction is diffused in directivity by the second diffusion plate 16, and irradiated as the second illumination light L2 onto the irradiation surface P so that the illuminance becomes uniform. .
The second diffusion plate 16 is an anisotropic diffusion plate that has diffusion in the XY plane and little or no diffusion in the plane containing the Z axis. That is, the second irradiation light L2 emitted from the second diffusion plate 16 is difficult to be diffused with respect to the oblique incident angle, and the substantially circular imaging surface is irradiated with uniform illuminance.
In this embodiment, the LED lights 13 and 14 are used as the light sources, but the configuration is not limited to this, and various other light sources can be used.

5 and 6 show the maximum oblique incidence angle of the second illumination light L2: θ ₃ and the minimum oblique incidence angle of the first illumination light L1 for the light beams emitted from the first illumination unit 11 and the second illumination unit 12, respectively. θ ₄ , respectively. For simplification of explanation, FIG. 5 shows the first illumination section 11, and FIG. 6 shows the second illumination section 12, respectively.

As is clear from FIG. 5, when the minimum oblique incident angle of the first illumination light L1 is _θ4 , the _first illumination light L1 is directly reflected light and falls within the viewing angle θ of the imaging device ₁₀ due to θ2≦θ4. to be incident.
In the present embodiment, the first diffuser plate 15 is arranged to be inclined with respect to the irradiation surface P, so that the diffuser plate 11' is not arranged to be inclined as indicated by the dashed line in FIG. While the size of the first diffuser plate 15 is made smaller than in the case where the first diffusion plate 15 is arranged parallel to the irradiation surface P), the minimum oblique incident angle _θ4 is increased to maintain the conditional expression _θ2 ≦ _θ4 . are placed in By arranging the first diffuser plate 15 obliquely in this way, it is possible to ensure both the illumination range and the size reduction.

As shown in _FIG . 6, the maximum oblique incident angle θ3 of the _second illumination light L2 is set to satisfy θ2> _θ3 . Therefore, as already described, the specularly reflected light (directly reflected light) of the second illumination light L2, which is low-angle illumination, does not enter the viewing angle of the imaging device 10, but the work M is on the imaging surface W. When the work M is arranged, if there are scratches or unevenness on the surface of the work M, diffused reflection occurs due to the inclination of the edge portion or the scratches, and part of the diffusely reflected light enters the imaging device 10 .
In other words, only the edge portion of the workpiece M is detected by the imaging device 10, and the dark field image 52 for this edge portion is obtained.

By the way, in addition to high-angle illumination using the first illumination light L1, in the case of photographing with low-angle illumination using the second illumination light L2, as shown in FIG. It has been newly clarified that the direct reflected light of the second illumination light L2 impinges on the 1 diffusion plate 15 and is re-diffused and enters the imaging device 10 as stray light.
In particular, as shown in this embodiment, when the viewing angle θ ₁ of the imaging device 10 is within a predetermined range (for example, 30°≦θ ₁ ≦60°) and when the viewing angle is wider, the first diffusion Since the distance between the plate 15 and the imaging plane W is shortened, there is a concern that the second illumination light L2 from the second illumination section 12 will strike the first diffuser plate 15 and be diffused.
That is, if the first diffusion plate 15 is simply formed into a deep truncated cone as shown in FIG. 7A, the second illumination light L2 will be There is a possibility that the light hits the first diffuser plate 15 and is diffused, resulting in stray light.
On the other hand, when the first diffusion plate 15 is arranged parallel to the irradiation surface P as shown in FIG. However, when shooting with high-angle illumination using the first illumination unit 11, it is difficult to secure a sufficient illumination range.
In order to secure a sufficient amount of light while suppressing such a reflection phenomenon, in this embodiment, as shown in FIGS. When the distance to W is H and the diameter of the imaging surface W is W, conditional expression (1) is satisfied.
Furthermore, as shown in FIG. 7C, when the first diffusion plate 15 is arranged parallel to the imaging surface W, there is a concern that the size of the inspection apparatus 100 increases. By arranging the first diffusion plate 15 obliquely as shown in , it can be arranged compactly while maintaining the oblique incident angle, which contributes to miniaturization of the inspection apparatus 100 . Furthermore, since it is possible to prevent the optical path from being obstructed by the arrangement of supports, walls, and the like for supporting the first lighting unit 11 and the second lighting unit 12, the flexibility of the space is improved.

By satisfying the conditional expression (1) in this way, by adjusting the distance from the imaging surface W to the imaging device 10 and the interval from the lower limit position of the first diffusion plate 15 to the imaging surface W, the first 2. Since it is possible to prevent the illumination light L2 from hitting the first diffusion plate 15 and becoming stray light, it is possible to obtain the dark field image 52 with high accuracy by suppressing reflection while ensuring the amount of light.

Since the viewing angle θ1 of the imaging device ₁₀ is constant, the diameter WL of the imaging surface W is a function of the distance h from the imaging surface W to the reference point O, which is the entrance pupil of the imaging device 10 .
Similarly, the minimum oblique incident angle of high-angle illumination: θ4 depends _on the arrangement of the first diffuser plate 15, but in the aspect in which it is inclined in the Z direction as in the present embodiment, it is shown as a dashed line in FIG. As described above, the light rays emitted from the lowermost end toward the edge of the irradiation surface P should have the minimum oblique incident angle: _θ4 .
Since the irradiation surface P and the imaging surface W are substantially equal, if the distance from the irradiation surface P or the imaging surface W to the lower end of the first diffuser plate 15 is set to H, the specularly reflected light of the second illumination light L2 of the low-angle illumination does not hit the first diffusion plate 15, that is, when the angle formed by the imaging surface W and the line connecting the outer edge Q of the field of view of the imaging device 10 and the outer edge of the first diffusion section 11 is θα , may satisfy the formula (2).

Further, as shown in FIG. 9, the first diffusion plate ₁₅ has an angle of θ5 with respect to the irradiation surface P when the second illumination light L2 passes through the center of the irradiation surface P. When the angle formed by the imaging plane W and the line connecting the outer edge of the first diffusion plate 15 is θα, the formula (3) is satisfied.

More preferably, it satisfies Equation (4).

Further, in the present embodiment, the formulas (1) and/or (3) are satisfied while increasing the diameter of the first diffusion plate 15 so as to satisfy the formulas (1) and/or (3). In order to satisfy the requirements, the first diffusion plate 15 has a truncated cone side shape and is arranged so as to surround the imaging device 10 . In other words, the first diffusion plate 15 is arranged to be inclined with respect to the irradiation surface P. As shown in FIG.
That is, in the present embodiment, when the distance from the lower end of the _first diffusion plate 15 to the imaging surface W is H, and the width of the imaging surface _W at the viewing angle θ1 is WL, conditional expression (2) is satisfied. do.
With such a configuration, a sufficient size of the diffusion plate on the high angle side can be ensured, and as shown in FIG. It is also possible to suppress the phenomenon that the board is reflected.
With such a configuration, it is possible to reduce the influence of stray light by suppressing mutual reflection between the dark field and the bright field.

A method of acquiring the image data 50 of the work M and inspecting the appearance of the work M in such a configuration will be described.

First, the inspection apparatus 100 uses the first illumination unit 11 to perform high-angle illumination, and images the irradiation surface P, which is one surface of the workpiece M, using the imaging device 10 .
Photographing with such high-angle illumination is acquired by the imaging device 10 as a bright-field image 51, and is excellent in measuring the color, shape, size, and the like of the work M.
Next, the inspection apparatus 100 performs low-angle illumination using the second illumination unit 12 and photographs the illuminated surface P. As shown in FIG.
In photographing with such low-angle illumination, if the surface of the work M is flat, the reflection angle is the _second incident angle θ2, so no reflected light should enter the imaging device 10. However, if the surface of the workpiece M has scratches or unevenness, irregular reflection occurs due to the inclination of the edge portion or the scratches, and part of the irregularly reflected light enters the imaging device 10 .

That is, when photographing the work M with low-angle illumination, if the work M has a flat surface, only the edge portion of the outer appearance of the work M can be seen. Since irregular reflection may occur depending on the scratch, the image is captured by the imaging device 10 .
That is, in low-angle illumination, the imaging device 10 functions as unevenness detection means. Also, the low-angle illumination is acquired by the imaging device 10 as a dark field image 52 .

The imaging device 10 transmits the obtained bright-field image 51 and dark-field image 52 to the image recognition unit 20, and the image recognition unit 20 uses the bright-field image 51 and the dark-field image 52 to identify the workpiece M. Inspect appearance.

By using such a method, the inspection apparatus 100 uses both photographing using high-angle lighting for detecting such colors and shapes and photographing using low-angle lighting for detecting patterns and flaws, so that the appearance of the work M can be accurately determined. inspect. In other words, the appearance of the workpiece M is inspected using the image data 50 including the bright field image 51 and the dark field image 52 .

Now, in such low-angle illumination, most of the second illumination light L2 emitted from the second illumination unit 12 does not enter the imaging device 10, so there is a problem that the amount of light is small.
When trying to capture the reflected light of such a small amount of low-angle illumination, the light of the second illumination light L2 that happens to hit the first diffuser plate 15 is diffused by the first diffuser plate 15 and emitted into the imaging device 10. It was newly clarified that it enters as stray light in the

Therefore, in the present embodiment, even if the light emitted from the second illumination unit 12 irradiates the first diffusion plate 15, in order to ensure the amount of light at the time of photographing with high-angle illumination, as already described, The angle formed by the second illumination light L2 with the irradiation surface P when it passes through the center of the irradiation surface P is θ5, and the line connecting the outer edge Q of the field of view of the imaging device ₁₀ and the outer edge of the first diffusion plate 15 is When the angle formed with the irradiation surface P is θα, they are arranged so as to satisfy the formula (3).

By adjusting the positional relationship between the first lighting unit 11 and the second lighting unit 12 in this manner, reflection between the dark field and the bright field is suppressed, and the influence of stray light is reduced.

That is, the inspection apparatus ₁₀₀ according to the present embodiment is an inspection apparatus for inspecting the appearance of the workpiece M. The imaging apparatus 10 images the workpiece M at _a predetermined viewing angle θ1, A _first illumination unit 11 that illuminates the irradiation surface P with the _first illumination light L1 having the maximum oblique incidence angle θ4 that is _equal to or greater _than the oblique incidence angle θ2 formed on the irradiation surface; Appearance inspection is performed based on the second illumination unit 12 that illuminates the irradiation surface P with the _second illumination light L2 having the minimum oblique incident angle _θ3 smaller than the incident angle θ4 and the image data 50 obtained from the imaging device 10. and an image recognition unit 20 for performing.
Further, the image recognition unit 20 uses, as image data 50, a bright field image 51 of the workpiece M obtained from the first illumination light L1 and a dark field image 52 of the workpiece M obtained from the second illumination light L2. Inspect the appearance.
According to such a configuration, it is possible to reduce the influence of stray light by suppressing mutual reflection between the dark field and the bright field.

Further, in this embodiment, the first illumination unit 11 includes a first diffusion plate 15 for adjusting the illuminance of the first illumination light L1 so as to be uniform on the irradiation surface P, and the second illumination unit 12 includes A second diffusion plate 16 is included for adjusting the illuminance of the second illumination light L2 so as to be uniform on the irradiation surface P. As shown in FIG.
With such a configuration, the illuminance of the light on the irradiation surface P becomes uniform, so the appearance of the workpiece M can be inspected more accurately.

Further, in this embodiment, the first diffusion plate 15 is inclined with respect to the irradiation plane P. As shown in FIG.
With this configuration, the length of the first diffusion plate 15 can be increased, and the specularly reflected light enters the imaging optical system of the imaging device 10 within the viewing angle of the first illumination light L1 with respect to the irradiation surface P. As a result, a sufficient amount of light can be ensured, making it easy to ensure a sufficient amount of light, especially in high-angle illumination.

In this embodiment, the angle formed by the center of the optical axis of the second illumination light L2 and the irradiation surface P when passing through the center of the irradiation surface P is θ5, and the outer end Q of the field of view of the imaging device ₁₀ and the first diffusion plate When the angle formed by the line connecting the outer end of 15 and the irradiation surface P is θα, the formula (3) is satisfied.

Further, in the present embodiment, the second diffusion plate 16 is an anisotropic diffusion plate that has diffusion in the XY plane and little or no diffusion in the plane including the Z axis. That is, the second irradiation light L2 emitted from the second diffusion plate 16 is difficult to be diffused with respect to the oblique incident angle, and the substantially circular imaging surface is irradiated with uniform illuminance.
With such a configuration, the second illumination light L2 irradiated to the workpiece M is uniform in the circumferential direction, but the incident angle is unlikely to increase. The amount of irradiated light can be made uniform.

Numerical Example 1 below shows a specific numerical example having the above configuration.
It should be noted that the present invention is not limited to such numerical examples, and any numerical range may be adopted within the content described in the scope of claims.

(Numerical example 1)
As shown in FIG. 10, in Numerical Example 1, the distance between the imaging device 10 and the irradiation surface P: 21 mm, the camera diameter of the imaging device 10 is φ10 mm, the outer diameter of the first diffusion plate 15 is φ52 mm, the 1 The inclination angle between the diffusion plate 15 and the irradiation surface P is 24°.
At this time, the imaging range of the bright-field image 51 by high-angle illumination is φ32 mm, and the angle θα between the irradiation surface P and the line connecting the outer edge of the irradiation surface P and the outer edge of the first diffusion section 11 is 18° or more. is. In this numerical embodiment, in order to improve shading and light quantity as the second diffusion plate 16, an anisotropic diffusion plate having a half-value full angle of 60° in the circumferential direction and a half-value full angle of 1° in the center direction of the imaging surface W is used. are using.

In addition, the first lighting unit 11 and the second lighting unit 12 may be arranged near each other on the extension line of the auxiliary line O′ within the range that satisfies the formula (1).
Specifically, as shown in FIG. 11, the first illumination unit 11 and the second illumination unit 12 may be configured to contact each other on a virtual auxiliary line O'.
In such a configuration, ideally θ ₂ =θ ₃ =θ ₄ .

Although the preferred embodiment has been described in detail above, it is not limited to the above-described embodiment, and various modifications and substitutions can be made to the above-described embodiment without departing from the scope of the claims. can be added.
For example, in the present embodiment, the image recognition unit 20 is provided as an inspection unit and the appearance of the object to be measured is inspected by analyzing image data, but visual inspection may also be used.
Also, the first diffuser plate may have a flat shape as well as an inclined shape.

10... Imaging unit (imaging device)
REFERENCE SIGNS LIST 11: First illumination section 12: Second illumination section 15: First diffusion section (first diffusion plate)
16... Second diffusion part (second diffusion plate)
20... Inspection unit (image recognition unit)
50 Image data 51 Bright-field image 52 Dark-field image 100 Inspection device O Entrance pupil O' Auxiliary line θ ₁ Viewing angle θ ₂ Angle θ ₃ of viewing angle θ ₁ viewed from imaging surface W Second oblique incident angle (maximum oblique incident angle of second illumination light L2)
θ ₄ . . . First oblique incidence angle (minimum oblique incidence angle of first illumination light L1)
L1 First illumination light L2 Second illumination light _θ5 Angle formed with the irradiation surface P when the second illumination light L2 passes through the center of the irradiation surface P

JP 2018-066590 A JP 2018-048895 A JP 2017-040510 A Publication of WO16135910 JP 2015-094642 A Japanese Patent No. 6121253

Claims (6)

An inspection device for inspecting the appearance of an object,
an imaging unit that captures an image of the object on an imaging plane with a predetermined viewing angle;
a first illumination unit that illuminates the surface of the object with first illumination light having an incident angle equal to or less than the viewing angle, that is, having a minimum oblique incident angle equal to or greater than the oblique incident angle corresponding to the viewing angle;
a second illumination unit that illuminates the surface of the object with second illumination light having a maximum oblique incidence angle smaller than the oblique incidence angle and the minimum oblique incidence angle of the first illumination light;
has
The first illumination unit includes a first diffusion unit for adjusting the illuminance of the first illumination light so as to be uniform on the surface of the object,
The second illumination unit includes a second diffusion unit for adjusting the illuminance of the second illumination light so as to be uniform on the surface of the object,
The first illumination unit and the second illumination unit are provided on both sides of a virtual auxiliary line that passes through the outer edge of the imaging surface and has the same oblique incidence angle as the oblique incidence angle corresponding to the viewing angle. placed and
Inspecting the appearance using a bright field image of the object obtained from the first illumination light and a dark field image of the object obtained from the second illumination light ,
The diameter of the field of view of the imaging unit: WL, the maximum oblique incident angle of the second illumination light: θ3, the angle formed by the surface of the object when the center of the optical axis of the second illumination light passes through the center of the surface of the object: θ5 and the angle formed by the line connecting the outer edge of the field of view of the imaging unit and the outer edge of the first diffusion unit and the surface of the object: θα,
θ3>θ5>1.5θα
An inspection device characterized by satisfying The inspection device according to claim 1,
When the distance from the lower end of the first diffusion section to the imaging surface is H,

An inspection device characterized by satisfying The inspection device according to claim 2 ,
The inspection apparatus, wherein the first diffusion section is inclined with respect to the surface of the object. The inspection device according to claim 2 or 3 ,
The distance from the lower end of the first diffusion portion to the imaging surface is set to H,
When the distance from the entrance pupil of the imaging unit to the imaging surface is h:
H≧h/2
An inspection device characterized by satisfying The inspection device according to any one of claims 1 to 4 ,
The inspection apparatus , wherein the second diffusion unit is an anisotropic diffusion plate . The inspection device according to any one of claims 1 to 5 ,
The inspection apparatus , wherein the first illumination unit and the second illumination unit are arranged in the vicinity on an extension line of the auxiliary line .

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