HK1243169B - Inspection illumination device and inspection system - Google Patents

Description

Inspection lighting device and inspection system

Technical Field

The present invention relates to an inspection lighting device and an inspection system, which are used, for example, to irradiate an inspection object with inspection light to inspect the appearance, scratches, defects, etc. of a product.

Background Art

One example of an inspection lighting device used for product appearance inspection, for example, is coaxial lighting, which aligns the direction of imaging with the direction of illuminating the inspection object, as described in Patent Document 1. This coaxial lighting device includes a light source that emits inspection light in a direction parallel to the inspection object surface, and a half-mirror that is disposed obliquely between the inspection object and an imaging device positioned above the inspection object. The half-mirror is configured to reflect the inspection light toward the inspection object while transmitting reflected light from the inspection object toward the imaging device.

However, in recent years, there has been a growing demand for detecting features such as defects from captured images, which are difficult to detect even with inspection lighting devices such as those described above. More specifically, because the surface properties of the product being inspected are not perfectly mirror-like, it is difficult to precisely control the optical axis and the shape of the illumination angle to obtain the necessary shading information for the feature points on the inspection surface. Even when inspection light can be illuminated, the difference in brightness varies significantly depending on the location of the feature points on the inspection object, making it difficult to discern the feature points.

For example, it is conceivable to use an aperture or the like to limit the irradiation range of the inspection light to only the inspection object, thereby reducing reflected light and scattered light (stray light) from outside the inspection object, thereby improving inspection accuracy.

However, even if stray light entering the imaging device is reduced by this approach, in the case of very minute defects, the brightness change of the captured image has a large deviation, and therefore it is sometimes difficult to detect it as a defect.

More specifically, even if a tiny defect on the inspection object causes a slight change in the direction of reflection of the inspection light, if the change is small enough to fit within the camera's solid angle of observation, the brightness of the captured image will remain unchanged regardless of the presence or absence of the defect. Alternatively, if the inspection light's solid angle of illumination is large and the inclination of its optical axis varies at every point on the inspection object, not only will the tiny change in reflection direction not be captured as a change in light intensity within the camera's solid angle of observation, but the change in light intensity within the camera's solid angle of observation will also vary at every point on the inspection object. Consequently, machine vision cannot accurately capture such tiny defects within the inspection object.

Prior art literature

Patent Literature

Patent Document 1: Japanese Patent Application Laid-Open No. 2010-261839

Summary of the Invention

Problems to be solved by the invention

The present invention is made in view of the above-mentioned problems, and its purpose is to provide an inspection system and an inspection lighting device, so that even if the characteristic points such as defects are very small or tiny and the changes in reflection and scattering at the characteristic points are tiny, at each point within the shooting range of the inspection object, no matter where the characteristic points are located in the field of view, the amount of light within the observation solid angle of the shooting device can be changed at a constant amount, thereby enabling the details of such tiny characteristic points to be detected.

Solutions for solving problems

That is, the present invention is based on the following new concept: it is possible to make the size, shape, inclination and other conditions of the illumination solid angle of the inspection light emitted from the inspection lighting device uniform, and to arbitrarily distinguish and illuminate the changing elements other than the propagation direction of the light within the illumination solid angle, such as different wavelengths, polarization planes or light quantities, and it is possible to adjust the said changing elements. Thus, even if the defects in the inspection object are small and the change in reflection and scattering caused by the defects is extremely small, it is possible to capture the change in light quantity for each area of the different wavelength bandwidths, polarization planes or light quantities distinguished within the observation solid angle of the shooting device, thereby obtaining an image with the change as light and dark information.

More specifically, the inspection lighting device of the present invention is an inspection lighting device for irradiating inspection light onto an inspection object, and is characterized in that it is suitable for an inspection system composed of a photographing device for photographing light reflected, transmitted or scattered by the inspection object, and the inspection lighting device comprises: a surface light source for emitting inspection light; a lens, which is arranged between the surface light source and the inspection object and uses the light emitted from the surface light source as the inspection light for irradiating the inspection object, forming an irradiation solid angle for the inspection object; and at least either one of a first light shield and a first filter unit, which is arranged between the surface light source and the lens, before and after the focal position of the lens as the center, wherein the first light shield blocks light to form a solid angle toward The first filter unit locally divides the inspection light into arbitrary solid angle regions having different light properties using light of different wavelength bandwidths, different polarization planes, or different light quantities, with respect to the observation solid angle of each point of the inspection object formed when the light from the inspection object is captured by the imaging device. The shape or size, inclination, and the solid angle regions having different light properties, such as different wavelength bandwidths, different polarization planes, or different light quantities, of the entire illumination solid angle can be arbitrarily set within the illumination solid angle. Furthermore, the first light shield and the first filter unit can be integrated into a single third filter unit having the functions of both, the third filter unit being a unit for forming an illumination solid angle having arbitrary solid angle regions, in such a manner that desired changes in brightness at each point are achieved in each solid angle region having different light properties, such as different wavelength bandwidths, different polarization planes, or different light quantities.

In addition, it is characterized in that between the first light shield and the surface light source, and near the imaging of the inspection object by the lens, there is also at least one of a second light shield and a fourth filter unit that only transmits light with specific properties. The second light shield or the fourth filter unit can be used to arbitrarily generate an irradiation area and an irradiation pattern of the inspection light for the inspection object.

If it is this type of inspection system and inspection lighting device, the lens and the first light shield or the first filter unit can be used to roughly uniformly form the irradiation solid angle of the inspection light irradiated to each point of the inspection object, and arbitrarily form the solid angle area with different light properties such as different wavelength bandwidth, polarization plane or light quantity. On this basis, the lens and the second light shield or the fourth filter unit can be used to irradiate the inspection light only to the necessary part of the inspection object, and the irradiation range of the inspection light can be formed by using an area with arbitrary light properties.

In other words, for example, when using a conventional surface light source or other lighting device, the shape and inclination of the irradiation solid angle for each point of the inspection object are determined separately according to the relationship between each point of the inspection object and the shape of the light source surface of the lighting device. Therefore, it is difficult to obtain uniform inspection light. However, in the present invention, the shape and inclination of the irradiation solid angle for each point of the inspection object can be made roughly uniform, and the irradiation solid angle can be divided into solid angle areas with different light properties such as different wavelength bandwidths, polarization planes or light quantities, and the irradiation form of the irradiation solid angle can be adjusted. It is also possible to irradiate inspection light only to necessary areas, thereby preventing stray light from the inspection object.

In addition, even if tiny defects in the inspection object cause slight changes in the intensity or direction of reflected light, transmitted light or scattered light, the first light shield or the first filter unit can be used to appropriately set the irradiation solid angle shape and angle of the inspection light irradiated to each point of the inspection object according to the relative relationship between the size, shape and angle of the observation solid angle of the shooting device, and appropriately set it according to the surface properties of the feature points on the object surface, so that according to the changed part, the amount of light changes in each solid angle area with different light properties within the observation solid angle of the shooting device, thereby making it easy to detect tiny defects, etc., or making them impossible to detect.

In addition, different illumination solid angles can be formed in such a manner that only the central portion of the illumination solid angle of each point of the inspection object becomes a dark area, and only the peripheral portion becomes a bright area, and the said solid angle area with different light properties is further formed inside the illumination solid angle. Thus, the reflected light and the transmitted light on the inspection object are prevented from entering the observation solid angle of the shooting device, and only the scattered light is shot, or the changes in the propagation direction of the reflected light and the transmitted light on the inspection object are observed as the light and dark information of each point of the inspection object based on the inclusion relationship between the reflected light, the transmitted light and the observation solid angle. In addition, the shooting device also has a second filter unit, which can selectively shoot the said solid angle area with different light properties within the illumination solid angle reflected in the solid angle of the reflected light and the transmitted light. Thus, in each of the said arbitrary solid angle areas, the changes generated at the feature points of the inspection object can be captured, and the inspection light can be irradiated with a reliable form of illumination solid angle that is adapted to the tiny light changes generated by various inspection objects and various feature points to be detected.

Here, as a second filtering unit, the photographing device may also selectively split the reflected light and the transmitted light on the inspection object according to different light properties, and then use a light sensor to photograph the respective light quantities. It may also be provided with a filter that selectively transmits only light with different light properties for each pixel of the light sensor.

According to the present invention, when irradiating an inspection object with inspection light having a substantially uniform illumination solid angle, even when the reflected or transmitted light's solid angle changes due to defects, etc., are extremely small, the changes are captured. To this end, the relative relationship between the inspection light illumination solid angle and the observation solid angle of the imaging device is adjusted in terms of shape, angle, and size so that the change in light intensity within the observation solid angle is maximized and any other changes are minimized relative to the change in solid angle. This allows selective capture of only the change in the solid angle of the reflected or transmitted light. Furthermore, by setting arbitrary solid angle regions with different light properties within the illumination solid angle, light intensity changes in each solid angle region can be simultaneously observed, allowing continuous compensation of light changes corresponding to light changes at various feature points of the inspection object. While capturing such extremely small light changes caused by microscopic defects is difficult with conventional illumination devices whose illumination solid angles vary in shape, angle, and size at each point on the inspection object surface, the illumination device of the present invention can capture such changes.

In order to roughly uniformly control the size of the solid angle of illumination of the inspection light irradiated at each point on the inspection object and to adjust the tilt distribution of the solid angle of illumination relative to the center of the optical axis, the first light shield and the first filter unit, or the third filter unit that integrates the functions of both, can be positioned in front of and behind the focal position of the lens. The following description uses the first light shield as a representative example. That is, by changing the opening of the first light shield, the solid angle of illumination at each point on the inspection object can be set to a desired shape and size. Furthermore, if the first light shield is positioned at the focal position of the lens, the optical axis of the solid angle of illumination of the inspection light is parallel to the optical axis of the inspection light. If the first light shield is positioned closer to the lens than the focal position of the lens, the solid angle of illumination of the inspection light is tilted in the direction in which the inspection light expands. If the first light shield is positioned outward from the focal position of the lens, the solid angle of illumination of the inspection light is tilted in the direction in which the inspection light narrows. In this manner, by varying the configuration and opening of the first light shield, the illumination solid angle of the inspection light, which directly affects the solid angles of reflected or transmitted light from the inspection object, can be adjusted in various ways. This allows the relative relationship between the inspection object and the observation solid angle of the imaging device that observes reflected, transmitted, or scattered light from the inspection object to be set to a configuration suitable for obtaining desired brightness and darkness information. Specifically, even if the observation optical system employed is not a telecentric optical system, but rather an optical system in which the optical axis inclination of the observation solid angle varies between the outer edges of the field of view and the center of the optical axis, the illumination solid angle and observation solid angle at each point within the entire field of view can be set to conform to a regular reflection direction.

In addition, by setting any of the three-dimensional angle areas with different light properties within the illumination three-dimensional angle, the illumination three-dimensional angle that is uniformly set for the inspection object can be further set into any three-dimensional angle area. The brightness of each point of the inspection object is not determined solely by the relative relationship between the illumination three-dimensional angle and the observation three-dimensional angle, and there is no need to reset the relative relationship between the illumination three-dimensional angle and the observation three-dimensional angle related to the shape, optical axis, etc. At all points within the field of view of the inspection object, under approximately the same conditions, as changes in the relative relationship relative to the observation three-dimensional angle, smaller light changes in each of the three-dimensional angle areas are observed simultaneously.

Thus, in the inspection lighting device of the present invention, and the inspection system using the inspection lighting device and composed of a photographing device that photographs light reflected, transmitted, or scattered by the inspection object, the reason why the required light and dark information can be obtained for tiny feature points is that the light and dark on each point of the inspection object is determined according to the amount of light directed toward the photographing device by the reflected light, transmitted light, or scattered light from each point of the inspection object, and the amount of light is determined according to the inclusion relationship between the solid angle of the reflected light, transmitted light, or scattered light from each point of the inspection object and the observation solid angle of the photographing device. Therefore, it can have the function of roughly uniformly adjusting the illumination solid angle of the inspection light that directly affects the reflected light or transmitted light from each point of the inspection object, and can divide the illumination solid angle into arbitrary solid angle areas with different wavelength bandwidths, polarization planes, or light amounts, and the photographing device can selectively observe the light amount according to each divided area.

In order to ensure that the brightness and darkness information of the inspection object captured by the imaging device varies approximately uniformly across the entire imaging range, it is necessary to maintain a substantially constant relationship between the observation solid angle formed by the imaging device at each point on the inspection object and the solid angle of reflected light, transmitted light, or scattered light from each point on the inspection object. This can be achieved by moving the first light shield and the first filter unit, or the third filter unit, before and after the focal position of the lens, so that the illumination solid angle of the inspection light and the solid angle region formed within the illumination solid angle are set to a substantially uniform shape and size, and adjusting the inclination thereof to match the inclination of the observation solid angle at each point on the inspection object.

Furthermore, in order to maintain the relative relationship between the solid angle of illumination of the inspection light on the inspection object and any solid angle region formed within the solid angle of illumination and the observation solid angle approximately constant for each point in the illumination range, and to arbitrarily generate an illumination area, illumination shape, or illumination pattern, the apparatus may further include, in addition to at least one of the first light shield or the first filter unit, or the third filter unit, at least one of the second light shield or the fourth filter unit, and be positioned near the position where the lens forms an image on the inspection object. This allows the inspection light's solid angle of illumination and the shape, size, and inclination of any solid angle region formed within the solid angle of illumination to be maintained approximately uniform, while independently adjusting the inspection light's illumination area on the inspection object and the optical properties of the illumination area, the solid angle of illumination for each point on the inspection object, and the solid angle region having specific optical properties.

To facilitate inspection of the three-dimensional shape of the inspection object, the second light shielding mask and fourth light filter unit, each formed with a predetermined mask pattern, can be used in addition to the first light shielding mask and first filter unit, or the third light filter unit, to image the pattern on the inspection object. With this configuration, the imaging device can obtain uniform light and dark information based on the substantially uniform illumination solid angle and the solid angle region with specific light properties, as adjusted by the first light shielding mask and first light filter unit. If the inspection object has a shape problem, the pattern obtained as light and dark information by the imaging device will be distorted, making it easier to detect shape defects.

When the solid angle of reflected or transmitted light at each point on the inspection object is substantially aligned with the observation solid angle formed by the camera at each point on the inspection object in terms of shape, size, and inclination, the inclusion relationship between the solid angle of the reflected or transmitted light and the observation solid angle changes even when a tiny feature point exists on the inspection object, resulting in a change in the brightness and darkness information for that tiny feature point. While the rate of change in brightness and darkness information caused by this change in inclusion can be controlled by appropriately setting the solid angle of the reflected or transmitted light and the observation solid angle, in this case, only constant brightness and darkness information can be obtained that depends on the size of the solid angles of the two. Therefore, if arbitrary solid angle regions with different wavelength bandwidths, polarization planes or light amounts are formed within the irradiation solid angle of each point of the inspection object, they are respectively reflected as solid angle regions with different wavelength bandwidths, polarization planes or light amounts within the solid angles of the reflected light or the transmitted light at each point of the inspection object. Therefore, as long as the change in the light and dark information of the feature point changes according to the inclusion relationship between the solid angle region reflected within the solid angle of the reflected light or the transmitted light and the observation solid angle, it is possible to simultaneously detect tiny changes corresponding to the amounts of the respective solid angle regions.

To this end, it is achieved in the following two ways: first, a semi-transparent and semi-reflective mirror is provided for changing the irradiation direction of the inspection light, and allowing the light from the inspection object to be transmitted and photographed by the photographing device, and the irradiation solid angle of the inspection light on each point of the inspection object is appropriately adjusted, so that the observation solid angle of the photographing device on each point of the inspection object is roughly consistent with the optical axis of the solid angle of the reflected light or the transmitted light emitted by each point; second, with respect to the irradiation direction of the inspection light, the observation solid angle of the photographing device is set in a direction that is line-symmetrical with respect to the normal of the inspection object, and the solid angle of the reflected light or the transmitted light of each point of the inspection object is roughly consistent with the optical axis of the observation solid angle of the photographing device on each point of the inspection object.

In addition, by setting a second filter unit in the shooting device, the light and dark changes occurring according to the inclusion relationship between the respective stereo angle areas and the observation stereo angle can be detected at the same time. The second filter unit is capable of selectively shooting the light of the stereo angle areas having different wavelength bandwidths, polarization planes or light quantities reflected within the stereo angle of the reflected light or the transmitted light.

Effects of the Invention

According to the inspection lighting device and inspection system of the present invention as described above, the irradiation solid angle of the inspection light irradiated to each point of the inspection object and its dark area, as well as the size and form of the solid angle areas with different wavelength bandwidths, polarization planes or light amounts formed within its irradiation solid angle can be freely adjusted. Therefore, the solid angle of the reflected light or transmitted light or scattered light from each point of the inspection object and the solid angle areas with different wavelength bandwidths, polarization planes or light amounts reflected within the solid angle, as well as the inclusion relationship with the observation solid angle formed at each point of the inspection object by the photographing device, can be set approximately uniformly. Therefore, even tiny defects that are difficult to detect using existing technologies can be detected under approximately the same inspection conditions.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a schematic three-dimensional diagram showing the appearance of an inspection lighting device and an inspection system according to one embodiment of the present invention, wherein the approximate outline of the outer shell of the inspection lighting device is represented by a dotted line, the first light shielding cover M1 refers to the cover of the light shielding portion, F1 refers to a portion that only allows a specific wavelength bandwidth, polarized light to pass through, or has a specific transmittance in the opening portion, and F3 refers to the entire illumination solid angle forming unit that integrates the two (refer to Figure 4).

2 is a schematic diagram showing the internal structure of the main parts of the inspection lighting device and the inspection system that form the irradiation solid angle of the embodiment, and the irradiation solid angle at each point of the inspection object, wherein the dotted lines represent the semi-transparent and semi-reflective mirror 4, the shooting device C, the inspection object W, and the light path when a semi-transparent and semi-reflective mirror is provided, the first light-shielding cover M1 refers to the cover of the light-shielding portion, F1 refers to the portion that only allows a specific wavelength band, wide or polarized light to pass through in the opening, or has a specific transmittance, and F3 refers to the entire irradiation solid angle forming unit that integrates the two (refer to FIG4 ).

Figure 3 is a schematic diagram showing the internal structure of the main parts of the inspection lighting device and the inspection system in which the inspection object is tilted to form the illumination solid angle of the embodiment, and the illumination solid angle at each point of the inspection object, wherein the first light shielding cover M1 refers to the cover of the light shielding portion, F1 refers to the portion that only allows a specific wavelength bandwidth, polarized light to pass through, or has a specific transmittance in the opening portion, and F3 refers to the entire illumination solid angle forming unit that integrates the two (refer to Figure 4).

FIG4 is a diagram showing an example of the structure of a first light shield, a first filter unit, and a third filter unit, wherein M1 is a light shielding portion, and F13, F12, and F11 are portions that transmit only a specific wavelength bandwidth or polarized light, or have a specific transmittance. The first light shield M1 is a cover of the light shielding portion, the first filter unit F1 is a portion that transmits only a specific wavelength bandwidth or polarized light, or has a specific transmittance within the opening, and the third filter unit F3 is the entire illumination solid angle forming unit that integrates the two. In the case of a light shield other than the first light shield, the light shield M1 can function as a portion that transmits only a specific wavelength bandwidth or polarized light, or has a specific transmittance.

FIG5 is a schematic diagram showing the structure of an inspection lighting device and an inspection system used in conventional lighting, and the illumination solid angle at each point of the inspection object, wherein the semi-transparent and semi-reflective mirror 4, the photographing device C, the inspection object W, and the light path when a semi-transparent and semi-reflective mirror is provided are represented by dotted lines, and the observation solid angle is represented by a thick solid line in any case.

6 is a schematic diagram showing the structure of the main parts of the inspection lighting device and the inspection system that form the illumination solid angle, and the illumination solid angle at each point of the inspection object according to one embodiment of the present invention, wherein the semi-transparent and semi-reflective mirror 4, the photographing device C, the inspection object W, and the optical path when a semi-transparent and semi-reflective mirror is provided are represented by dotted lines, and the observation solid angle is represented by thick solid lines in any case.

Figure 7 is a schematic diagram showing the structure of the inspection lighting device and inspection system in an embodiment in which a second light-shielding cover and a fourth filter unit are added, and the illumination solid angle at each point of the inspection object, wherein the semi-transparent and semi-reflective mirror 4, the shooting device C, the inspection object W, and the optical path are represented by dotted lines, M1, F1, and F3 are respectively M1 when the opening in the figure is regarded as the opening of the light-shielding cover, F1 when the specific wavelength bandwidth, polarization or specific transmittance is regarded as the opening in the figure, and the overall illumination solid angle forming unit integrating the two is F3 (refer to Figure 4), M2 and F4 are respectively M2 when the opening in the figure is regarded as the opening of the light-shielding cover, and F4 when the specific wavelength bandwidth, polarization or specific transmittance is regarded as the opening in the figure.

8 is a schematic diagram showing the main parts of the inspection lighting device that forms the solid angle of illumination according to one embodiment of the present invention, and the solid angle of illumination at each point of the inspection object with the distance between the inspection system and the inspection object as a parameter, (a) is a case where the distance between the inspection object and the inspection lighting device is relatively far, and (b) is a case where the distance between the inspection object and the inspection lighting device is relatively close, wherein the semi-transparent and semi-reflective mirror 4, the photographing device C, the inspection object W, and the optical path when a semi-transparent and semi-reflective mirror is provided are represented by dotted lines.

Figure 9 is a schematic diagram showing the irradiation solid angle at each point of the inspection object using the size of the opening of the first light shield of the inspection system and the inspection lighting device according to one embodiment of the present invention as a parameter, (a) is a case where the first light shield is located near the focal position with an extremely small transmission part, (b) is a case where the first light shield is located closer to the lens side than the focal position with a certain degree of size, and (c) is a case where the first light shield is located closer to the light source surface side than the focal position with a certain degree of size, wherein P1, P2, and P3 are the focal positions on the object side of lens 2, P4 and P5 are arbitrary points farther away from P1 on the object side of lens 2, and the plane half angle of the irradiation solid angle

Figure 10 is a diagram showing the relative relationship between the change in the solid angle of the reflected light caused by the local tilt of the inspection object and the illumination solid angle and the observation solid angle, (a) the change in the solid angle of the reflected light caused by the tilt of a part of the inspection object, (b) the change in the inclusion relationship between the change in the solid angle of the reflected light and the observation solid angle.

Figure 11 is a diagram showing the relative relationship between the change in the solid angle of the reflected light caused by the local tilt of the inspection object when there are solid angle areas with different light properties in the illumination solid angle, the illumination solid angle, and the observation solid angle. (a) When the inspection surface is flat, the reflected light is consistent with the optical axis of the observation solid angle. (b) When the inspection surface is tilted, the reflected light is offset from the optical axis of the observation solid angle.

FIG12 is a comparison diagram of the illumination solid angle of conventional lighting and the illumination solid angle of the lighting of the present invention, wherein (a) is the conventional lighting and (b) is the lighting of the present invention.

Figure 13 is a diagram of an example of the setting of the irradiation solid angle shape of the present invention, wherein it is a shading part M1 (depending on F1 or F3, it can also be a specific light attribute), an area IS1 with different light attributes, an area IS2 with different light attributes, an area IS3 with different light attributes, and an opening for transmitting light (depending on F1 or F3, it can also be a specific light attribute).

DETAILED DESCRIPTION

A first embodiment of the present invention will be described.

The inspection system 200 of the first embodiment, consisting of an inspection lighting device 100 and an imaging device C, employs so-called coaxial illumination, using a half mirror 4 to align the direction of imaging the inspection object W with the direction of illumination of the inspection object W. This system is used to make features such as defects on the inspection object W appear as contrasting features in the image captured by the imaging device C. In addition, in Figures 2 and 5 through 8, dashed lines indicate the presence of a half mirror, while solid lines indicate the absence of a half mirror. Furthermore, the first optical filter F1 selectively transmits light having specific properties, forming a solid angle region composed of light having these properties. Its function in forming the solid angle is similar to that of the first light shield M1, which forms an illumination solid angle by either blocking or transmitting light. The first filter F1 and the first light shield M1 are shown together with a third filter unit F3, a single component that integrates the functions of the two, as a representative first light shield M1 in Figures 1 through 3 and 6 through 9. F1 and F3 are collectively labeled above the corresponding reference numeral M1. Here, the characteristic points such as defects of the inspection object W include, for example, surface scratches, dents, deformation, external shape, the presence or absence of holes, and other various types of defects.

As shown in the stereoscopic diagram of Figure 1 and the schematic diagram of Figure 2, the inspection lighting device 100 has a roughly cylindrical shell, inside which and in the part reaching the inspection object W and the photographing device C, there are formed an irradiation light path L1 for irradiating inspection light from the surface light source 1 to the inspection object W and a reflection-transmission light path L2 until the reflected light or transmitted light from the inspection object W reaches the photographing device C. When a semi-transparent and semi-reflective mirror 4 is provided, the photographing device C is installed on the upper opening side of the shell, and the inspection object W is placed on the lower opening side of the shell.

In addition, as shown in Figures 1 and 2, when a semi-transparent and semi-reflective mirror 4 is provided, the illumination light path L1 is composed of a portion reaching the semi-transparent and semi-reflective mirror 4 from the surface light source 1 and a portion reflected by the semi-transparent and semi-reflective mirror and reaching the inspection object. When the semi-transparent and semi-reflective mirror 4 is not provided, the inspection light is directly irradiated to the inspection object according to the illumination light path L1. In the case of Figure 2, the light path from the transmitted light from the inspection object W to the photographing device C becomes L2.

On the illumination light path L1, arranged in the order in which the inspection light advances, there are: a surface light source 1 that emits the inspection light; at least one of a first light shielding mask M1 and a first filter unit, or a third filter unit F3 that combines the functions of both, arranged in a front-back position centered on the focal position of a lens 2; and a lens 2 that forms the solid angle of illumination of the inspection light emitted from the surface light source 1 onto the inspection object W. In the case where a semi-transparent mirror is provided, in addition to this, a semi-transparent mirror 4 is provided that is inclined relative to the reflection-transmission light path L2 and the illumination light path L1 in order to reflect a portion of the inspection light downward. In addition, in the case where a second light shielding mask and a fourth filter unit are provided for forming an illumination area for the inspection light, at least one of a second light shielding mask M2 and a fourth filter unit that forms an illumination area having specific light properties is provided between the surface light source 1 and the first light shielding mask and the first filter unit, or between the surface light source 1 and the third filter unit, and near the position where the lens 2 forms an image on the inspection object W. The inspection light is irradiated onto the inspection object W. In addition, regarding the case where the second light shield is provided, its specific function will be described with reference to FIG. 7 .

In addition, when a semi-transparent mirror is provided on the reflection-transmission optical path L2, a semi-transparent mirror 4 is provided, and the reflected light partially transmitted by the semi-transparent mirror 4 is observed by the photographing device C. When no semi-transparent mirror is provided, the optical path from the transmitted light from the inspection object W to the photographing device C in FIG2 becomes L2. In the optical path L2 in FIG1 and FIG2, there are no other components except the semi-transparent mirror 4. However, depending on the situation, a cover or aperture for blocking a portion of the reflected light or transmitted light from the inspection object may be provided for the purpose of cutting off stray light from the inspection object.

The following describes in detail the arrangement, structure, and function of each component.

The surface light source 1 is, for example, a light source formed by a chip-type LED or a diffuser plate, forming a light emitting surface 11 with a substantially uniform diffusion surface. Furthermore, as shown in FIG1 , the surface light source 1 is mounted within a cylindrical housing so as to be able to advance and retreat along the irradiation optical axis, and the starting position of the inspection light irradiation can be adjusted. In this manner, the uniformity and brightness distribution of the inspection light within the inspection object W can be controlled independently of the control of the irradiation solid angle formed by the first light shield M1 and the first filter unit F1, or the third filter unit F3 that combines the functions of both, as described later, and the arbitrary solid angle regions with different light properties within the irradiation solid angle, and the control of the irradiation region formed by the second light shield. The optical path of the inspection light, which is determined by the positional relationship between the first light shield M1 and the first filter unit F1, or the third filter unit F3 that combines the functions of both, the second light shield M2, the lens 2, and the surface light source 1. Since the irradiation light paths are different in different irradiation areas, for example, if the surface light source 1 is preliminarily provided with a predetermined brightness distribution, emission wavelength distribution, polarization characteristic distribution, etc., the distribution can be varied or made uniform according to the irradiation area.

As shown in Figure 1, the second light shield M2 and the fourth filter element are mounted within the cylindrical housing so as to be movable along the illumination optical axis. The second light shield itself can be adjusted to a position close to the imaging position of the inspection object, depending on the distance between the lens 2 and the inspection object. This allows, as shown in Figure 7, for blocking a portion of the illumination light from the surface light source 1, or for blocking only light with specific properties. Because the shape of the opening of the second light shield or the portion of the fourth filter that transmits only light with specific properties is roughly imaged on the inspection object W, by varying the shape and size of the opening of the second light shield M2 or the pattern of the fourth filter element, the illumination range of the inspection light or the illumination area of the inspection object W can be arbitrarily set. Furthermore, this adjustment and setting can be performed independently of the control of the illumination solid angle by the first light shield M1 and the first filter element F1, or by the third filter element F3, which combines the functions of both, as described later.

The first light shield M1 and the first filter unit F1, or the third filter unit F3, which functions as both, are positioned between the lens 2 and the surface light source at a forward and backward position centered at the focal point of the lens 2. As shown in FIG1 , they are mounted within the cylindrical housing so as to be movable forward and backward along the illumination optical axis. Here, using the first light shield M1 as a representative example of the first filter unit F1 and the third filter unit F3, which functions as both, for example, when the first light shield M1 is positioned at the focal point of the lens 2, as shown in FIG2 , the illumination solid angle IS at each point on the inspection object W remains the same in size, shape, and inclination. This also holds true even when the distance between each point on the inspection object and the lens 2 varies, as shown in FIG3 . Furthermore, as shown in FIG8 , this holds true regardless of the presence or absence of the half mirror 4 and regardless of the distance between the inspection object W and the lens 2. The above description using the first light shield M1 as a representative example is also applicable to the solid angle region formed by the first filter unit F1 and the third filter unit F3 having both functions.

Next, taking the first filter unit F1 as a representative example, a case where the first light shielding mask M1 and the first filter unit F1 or the third filter unit F3 having functions of both are located before and after the focal position of the lens 2 will be described.

As shown in FIG9(a), when the first light shield M1 is located near the focal position with an extremely small transmission portion, the solid angle of illumination is nearly zero. When the first light shield M1 is closer to the lens 2 than the focal position of the lens 2, as shown by the solid line in FIG9(a), the inspection light is formed by an optical path that is inclined so as to expand outward from the center of the optical axis. When the first light shield M1 is closer to the surface light source 1 than the focal position of the lens 2, as shown by the dotted line in FIG9(a), the inspection light is formed by an optical path that is inclined so as to converge toward the center of the optical axis. On the other hand, as shown in FIG9(b) and (c), the shape and size of the solid angle of illumination of the inspection light at each point on the inspection object are uniformly determined by the shape and size of the opening of the first light shield M1. Independently of this, the inclination of the solid angle of illumination can be controlled according to the position of the first light shield M1.

In FIG9 , points P1, P2, and P3 are located at a distance from the object-side focal position of lens 2. At least the light passing through P1 is the light that is captured by lens 2 and is parallel to the optical axis of surface light source 1. When the diameter of the opening of this light path is, for example, r, according to first light shield M1, as shown in the lower portion of FIG9 , the illumination solid angle at P1 is uniquely determined by the focal length f of lens 2 and the diameter r of the opening. Ideally, the same applies to points P2 and P3, which are at the same distance from lens P1. Furthermore, even at points P4 and P5 farther from the focal length of lens 2, the shape and size of their illumination solid angles are ideally identical to those of P1.

For example, as shown in Figure 4, the first light shield M1, the first filter unit F1, and the third filter unit F3 have a light shielding portion M1 that generally blocks light, with an opening formed in an arbitrary shape. While the light shielding portion is shown as a peripheral portion and an opening in the center in Figure 4, a portion of the opening may also constitute a light shielding portion. Furthermore, the light shielding portion may be a portion that blocks only light with specific properties. In Figure 4, the first filter unit F1 is positioned within the opening of M1, with a pattern F11, F12, and F13 formed to create three solid angle regions with different light properties. While this pattern is concentrically circular, it can be optimized to any desired pattern based on the characteristic points of interest of the inspection object. The integrated structure of the first light shield M1 and the first filter unit F1 corresponds to the third filter unit F3.

By using the first light shielding mask M1 and the first filter unit F1 or the third filter unit F3 shown in FIG4 , an illumination solid angle IS can be formed for a single point P of the inspection object W, as shown in FIG11 . The outermost shape of the illumination solid angle IS is determined by the opening in the center of the first light shielding mask M1. Furthermore, within the illumination solid angle, the first filter unit F1 forms solid angle regions IS1, IS2, and IS3 having different optical properties, corresponding to the mask patterns F11, F12, and F13 of the first filter unit F1, respectively.

In contrast to the inspection lighting of the present invention, which is capable of forming a substantially uniform illumination solid angle, conventional lighting using only a conventional light source surface, as shown in Figure 5 , has the shape, size, and inclination of the illumination solid angle IS of the inspection light at each point on the inspection object W differ from point to point. This is because the illumination solid angle IS at each point on the inspection object W is uniquely determined by the shape, size, and angle of the projection of the surface light source 1 when viewed in reverse from that point. Meanwhile, the observation solid angle OS at each point on the inspection object is determined by the relative relationship between the pupil position, shape, and size of the camera C and each point on the inspection object. The brightness at each point generated by the camera C is determined by the inclusion relationship between the solid angle RS of the reflected light or the solid angle TS of the transmitted light, which directly reflects the illumination solid angle IS at each point, and the observation solid angle OS. As can be seen from Figure 5 , this inclusion relationship varies depending on the location. When the reflected light solid angle RS or the transmitted light solid angle TS vary slightly, it is difficult to achieve the same amount of light variation at each point in the inspection area.

Generally speaking, the degree of inclination of the observation solid angle outside the principal optical axis is determined by the characteristics of the imaging optical system. This inclination varies concentrically from the principal optical axis due to the properties of typical lenses. To achieve uniform light variation in such an imaging optical system, and in particular, to achieve a uniform variation in the inclination of the solid angle of reflected or transmitted light at each point on the inspection object, the inclination of the illumination solid angle of the inspection light on the inspection object is varied concentrically with respect to the principal optical axis. This maintains a constant relative relationship between the illumination solid angle and the observation solid angle at each point.

In Figure 6, in an inspection system 200 that uses a portion of the inspection lighting device 100 according to the first embodiment of the present invention and is composed of a camera C, the positions of the first light shield M1 and the first filter unit F1, or the third filter unit F3 are offset from the focal position of the lens 2 relative to the observation solid angle OS formed by the camera C at each point of the inspection object. As a result, the optical axis of the solid angle RS of the reflected light or the solid angle TS of the transmitted light that directly reflects the irradiation solid angle IS at each point on the inspection object W is made consistent with the optical axis of the observation solid angle OS. In this way, when the solid angle RS of the reflected light or the solid angle TS of the transmitted light changes at each point on the inspection object W, the change can be captured at the same rate of change at each point and is captured as a change in the inclusion relationship with the observation solid angle OS, that is, a change in brightness at each point. At this time, if the optical axes of the observation solid angle OS at each point of the inspection object formed by the shooting device C are all oriented in the same direction, then as long as the positions of the first light shield M1 and the first filter unit F1, or the third filter unit F3 are set at the focal position of the lens 2, and the optical axes of the formed illumination solid angle IS are all oriented in the same direction, it can be consistent with the optical axes of the observation solid angle OS at each point on the inspection object W.

Here, the inclusive relationship between the illumination solid angle and the observation solid angle, and the brightness and darkness information obtained by the imaging device will be described using FIG. 10 .

Figure 10 (a) focuses on point P on the inspection object W, considers the situation when inspection light with an irradiation solid angle IS is irradiated onto the point P, shows how the brightness of point P changes when a part of the surface including point P of the inspection object is tilted, and shows how the relative relationship of each solid angle changes when the solid angle RS of the reflected light from point P changes like the solid angle RS′ relative to the observation solid angle OS formed by the camera C at point P.

In FIG10( a ), the shape and size of the solid angles RS and RS′ of the reflected light from point P are equal to the irradiation solid angle IS of the inspection light at point P. Furthermore, the inclination of the solid angle RS of the reflected light is in a direction that is line-symmetrical with the normal to point P and the irradiation solid angle IS of the inspection light, and is tilted at the same angle θ as the inclination of the irradiation solid angle IS of the inspection light. At this time, the observation solid angle OS formed by the camera C at point P coincides with the optical axis of the solid angle RS of the reflected light, and when the size of the observation solid angle OS is extremely small compared to the solid angle RS of the reflected light, the brightness of point P captured by the camera C is limited by the size of the observation solid angle OS. Within the range where this inclusion relationship does not change, the brightness of the reflected light does not change even if the solid angle RS of the reflected light is tilted. Furthermore, it is assumed that the light energy within the irradiation solid angle IS and the solid angles RS and RS′ of the reflected light is uniformly distributed within the solid angle.

Next, in FIG10(a), consider the case where the surface containing point P of the inspection object W is partially tilted. The solid angle RS of the reflected light from point P is tilted as indicated by the dashed line RS′ in the figure. At this time, if the solid angle RS′ of the reflected light from point P does not contain any observation solid angle OS formed by the camera C with respect to point P, the brightness of point P as observed by the camera C becomes zero. However, if the solid angle RS′ partially contains the observation solid angle OS formed by the camera C with respect to point P, the light contained in the overlapping solid angle portion is reflected at the brightness of point P. In other words, if the plane half angle of the solid angle RS′ of the reflected light from point P is larger than the angle obtained by subtracting the plane half angle of the observation solid angle OS from the tilt angle of the reflected light, and smaller than the angle obtained by adding the plane half angle of the observation solid angle OS to the tilt angle of the reflected light, the brightness of point P changes according to the tilt angle of the reflected light. However, if the plane half-angle of the illumination solid angle IS is greater than the angle obtained by adding the plane half-angle of the observation solid angle OS to the inclination angle of the reflected light caused by the partial tilt of the inspection object W, the brightness at point P does not change. Furthermore, if the plane half-angle of the observation solid angle OS is greater than the sum of the inclination angle of the reflected light and the plane half-angle of the solid angle RS of the reflected light, the brightness at point P remains unchanged. This indicates that the brightness at point P is ultimately determined by the inclusive relationship between the solid angle RS of the reflected light from point P and the observation solid angle OS of point P. By setting the relative relationship between the illumination solid angle IS of the inspection light irradiating point P and the shape, size, and inclination of the observation solid angle OS of point P, the brightness change at point P can be controlled.

Figure 10(b) is a cross-sectional view of the plane shown in (a) that includes the illumination optical axis of the inspection light, the normal to point P, and the reflected optical axis from point P. This allows for a more quantitative understanding of the inclination of each element and their inclusion relationship. Furthermore, Figure 10(b) illustrates a case where the observation solid angle OS is greater than the illumination solid angle IS, i.e., the solid angle RS of the reflected light. When the inspection object W is tilted and the solid angle RS of the reflected light from point P becomes RS', indicated by the dashed line, the light energy within the observation solid angle OS becomes zero because there is no inclusion relationship with the observation solid angle OS in this figure. Therefore, even if the light contained in the observation solid angle OS is refocused onto a point to form an image, only the dark point P will be visible. However, even in this case, if the relative relationship between the illumination solid angle IS and the observation solid angle OS is adjusted to establish an inclusion relationship between the reflected light solid angle RS and the observation solid angle OS, the brightness of point P will change according to the size of the overlapping portion.

In FIG10(b), assuming that the shape and size of the observation solid angle OS are identical to the illumination solid angle IS and coincide with the inclination of the solid angle RS of the reflected light from point P, if the inspection object W is slightly tilted from this state, the overlap between the observation solid angle OS and the reflected light solid angle RS decreases at least in proportion to the tilt, and the brightness of point P as seen through the observation solid angle OS changes accordingly. Furthermore, the smaller the solid angles, the greater the change in brightness at point P when the inspection object W is tilted at the same angle. Conversely, the larger the solid angles, the smaller the change in brightness at point P when the inspection object W is tilted at the same angle. Furthermore, by appropriately setting the shape, size, and inclination of the illumination solid angle IS and the observation solid angle OS to correspond to the changes in light generated at the desired feature point of the inspection object, it is possible to accurately detect feature points that have previously been difficult to detect reliably. In the present invention, focusing on this principle, a lighting device for inspection has been developed that can precisely control the shape, size, and inclination of the illumination solid angle.

Next, Figure 11 is used to illustrate how the brightness of point P on the inspection object changes according to the inclusion relationship between the solid angle of reflected light reflected from the point P and the observation solid angle formed by the shooting device C on the point P when there are solid angle regions with different light properties within the irradiation solid angle irradiated onto the inspection object.

The illumination solid angle IS shown in FIG11 is formed by solid angle regions IS1, IS2, and IS3 within it, each having different optical properties. In this case, the solid angle RS of reflected light from a point P on the inspection object W is identical to the illumination solid angle IS, with its optical axis located line-symmetrically with respect to the normal to point P on the inspection object W. Within the reflected light solid angle RS, corresponding to the solid angle regions IS1, IS2, and IS3 with different optical properties formed within the illumination solid angle, solid angle regions RS1, RS2, and RS3 are formed, each having the same optical properties as solid angle regions IS1, IS2, and IS3, respectively.

For simplicity, FIG11 considers the case where the observation solid angle OS formed by the camera C at a point P on the inspection object W is sufficiently small relative to the solid angle RS of the reflected light and the solid angle regions RS1, RS2, and RS3 having different optical properties formed within the reflected light solid angle RS. FIG11(a) illustrates a case where the observation solid angle OS is completely contained within solid angle region RS1. In this case, as long as the camera C includes a second filter unit capable of selectively detecting light having different optical properties, the brightness at point P on the inspection object is solely that of light having the optical properties of solid angle region RS1, and is captured at a constant brightness.

Next, as shown in FIG11(b), if the surface of the inspection object W is tilted, the optical axis of the solid angle RS of the reflected light is tilted, and the observation solid angle OS is included in the solid angle region RS3 having different light properties. In other words, in this case, the brightness of point P on the inspection object is only the light with the light properties of the solid angle region RS3, and is captured at a constant brightness.

Below, for a better understanding, as shown in FIG11 , it is assumed that the solid angle regions RS1, RS2, and RS3 with different light properties are, for example, blue light, green light, and red light, respectively, and the shooting device C is a color camera. In the case of FIG11 (a), the point P on the inspection object W is blue and appears to have a certain brightness, and in the case of FIG11 (b), it is red and appears to have a certain brightness. In addition, considering the case where the inclination angle of the inspection object W gradually increases, the point P on the inspection object W gradually changes from blue to green as the inclination angle gradually increases, and continuously changes from green to red. If the illumination solid angle does not contain a solid angle region with different light properties, then there is only light and dark information determined by the inclusion relationship between its illumination solid angle and the observation solid angle. However, according to the present invention, the inclination angle of the inspection object W can be continuously captured in a wider range.

Next, the semitransparent mirror 4 of the present invention is a circular, extremely thin member supported by a substantially square frame. By using this semitransparent mirror 4, the portion of the semitransparent mirror 4 where the reflective or transmissive surface is separated from the back surface can be made extremely thin. This minimizes ghosting caused by minute refractions and internal reflections that occur when reflected light from the inspection object W passes through the semitransparent mirror 4.

The first light shield and the second light shield may be apertures using multiple blades made of common optical materials, or may be a combination of an extremely thin light shielding plate and an aperture having an arbitrary opening. Components such as liquid crystals that can electronically set the opening may also be used.

Alternatively, as another embodiment of the opening of the first light shield, for example, the opening may be designed to be elliptical or slit-shaped rather than circular. This allows for anisotropic detection sensitivity when detecting feature points of the inspection object. Specifically, the illumination solid angle at each point of the inspection object expands along the same longitudinal direction as the slit of the first light shield, resulting in a very thin illumination solid angle in the width direction. In this case, the detection sensitivity for the inclination of the inspection object in the longitudinal direction can be set to be low, while the detection sensitivity in the width direction can be set to be high. Furthermore, in this case, the shape, size, and inclination of the observation solid angle formed by the camera at each point of the inspection object need to be relatively uniform across the width of the illumination solid angle. Alternatively, if the observation solid angle formed by the camera at each point of the inspection object is sufficiently small, a threshold value for the detected inclination can be set corresponding to the amount of expansion of the illumination solid angle.

Alternatively, as an alternative embodiment of the opening portion of the first light shield, for example, by providing a concentric circular light shielding portion and an opening portion, and by appropriately adjusting the width of the opening portion, it is possible to detect only a certain tilt angle range when a portion of the inspection object is tilted. By setting the required width in the required direction, the detection angle can also be anisotropic. Alternatively, by providing multiple levels of inspection illumination, surface tilt can be categorized and detected based on the degree of surface tilt. Furthermore, if the first light shield utilizes a component such as liquid crystal whose opening portion can be electronically adjusted, the opening pattern can be dynamically switched to obtain a variety of brightness and darkness information, enabling more detailed categorized detection.

Furthermore, the first optical filter unit F1 can utilize various light properties such as wavelength bandwidth, polarization state, and brightness. For example, if the light source 1 is configured to emit white light, the first optical filter unit F1 can be used to create arbitrary solid angle regions composed of light with different wavelength bandwidths. Furthermore, light with different wavelength bandwidths and in different patterns can be directed from any direction and shape, under the same conditions, to all points within the field of view of the inspection object W. Furthermore, if the first optical filter unit F1 utilizes a component such as a color liquid crystal whose pattern and transmittance can be electronically set, dynamic switching of the filter pattern can provide a variety of brightness and darkness information, enabling more detailed classification detection.

In addition, as an example of the configuration of the second optical filter, solid angle areas with different light properties can be clearly distinguished, or gradations can be set to have gradually different light properties. In this way, for example, when the brightness of the reflected light or transmitted light from the inspection object varies depending on the illumination angle or the observation angle, the brightness can be made uniform or the brightness can be changed conversely. For example, the brightness difference between the light directly reflected from the surface of the inspection object W and the part that emits scattered light such as a scratch can be freely adjusted. This can be achieved by reducing the amount of light in the irradiated solid angle area corresponding to the angle range of the light directly reflected from the surface of the inspection object W as regular reflection light, and gradually increasing the amount of light in the other solid angle areas.

The significant effect of the present invention lies in that, while arbitrarily changing the optical properties of the arbitrary pattern and the arbitrary shape of the illumination solid angle formed by the first light shield and the first filter unit, the illumination light can be irradiated under the same conditions at all positions within the entire field of view of the inspection object W captured by the camera C. Furthermore, the illumination optical axis and the illumination solid angle can be set to a state that is suitable for the optical characteristics of the camera. Figure 12(a) shows the illumination solid angles IS and IS' at different positions P and P' of the inspection object W when irradiating the inspection object W using conventional conventional lighting. As can be seen, the shapes of the illumination solid angles and the optical axes of the two illumination solid angles differ. Furthermore, Figure 12(b) shows the illumination light method of the present invention, which allows the illumination light to be irradiated under the same conditions at all positions within the entire field of view of the inspection object W. This approach is particularly promising in bright-field illumination methods for observing reflected light and transmitted light reflected from the inspection object W. Here, reflected light refers to regular reflected light reflected from a mirror, etc., and transmitted light refers to regular transmitted light passing through a transparent object. Furthermore, even in the dark-field illumination method for observing scattered light, the phenomenon that the scattered light changes depending on the properties of the irradiated light and the irradiation solid angle is common, and minute changes that cannot be detected in conventional illumination can be detected.

FIG13 illustrates an example of an arbitrary pattern formed by the first light shield and the first filter element, or the third filter element, and the resulting shape of the illumination solid angle. FIG13 (d) and (h) illustrate schematic diagrams of solid angle regions containing different light properties within the first light shield and the first filter element. In other patterns, the first filter element can also be used to impart a certain range of light properties to all or part of the illumination solid angle. The light shielding portion M1 can also be a portion that transmits only light with a specific property. In this case, the illumination solid angle IS forms the boundary between solid angle regions having different light properties.

Furthermore, since the second light shield forms an image on the inspection object, a fourth filter element is provided in the opening of the light shield, which transmits only light having a specific attribute. This allows the light attribute to be set for each irradiation range of the inspection light. In this case, if there is no need to set a range where light is not irradiated, the irradiation range can be set for each specific light attribute transmitted using only the fourth filter element.

In addition, if the second light shield uses a component such as liquid crystal whose opening can be set electronically, the irradiation area of the inspection light can be changed by dynamically switching the opening pattern. Even if the inspection object requires a different irradiation area, the inspection light can be irradiated according to each area, thereby obtaining a variety of light and dark information.

Furthermore, by combining color liquid crystal and the like with a white light source to form the surface light source, it is possible to cope with a wider variety of inspection objects. The color liquid crystal can dynamically change the emission wavelength distribution, brightness distribution, and polarization state distribution of its irradiation surface.

In addition, various modifications or combinations of the embodiments can be made without departing from the spirit of the present invention.

Description of Reference Numerals

200: Check system

100: Inspection lighting device

1: Area light source

11: Light exit surface

2: Lens

4: Half-transparent half-reflective mirror

C: Camera

L1: Illumination light path

L2: Reflection-transmission light path

M1: First light shield (and its light shielding part)

F1: First filter unit

F11: The portion of the first filter unit that transmits light having a certain optical property 1

F12: The portion of the first filter unit that transmits light having a certain optical property 2

F13: The portion of the first filter unit that transmits light having a certain optical property 3

F2: Second filter unit

F3: The third filter unit

F4: The fourth filter unit

M2: Second lens hood

W: Check object

P: Check a point on the object W

P′: Check other points on the object W

P1: Object-side focal point of lens 2

P2: The point at the same distance from lens 2 as from P1

P3: The point at the same distance from lens 2 as from P1

P4: Any point farther from the object side of lens 2

P5: Any point farther from the object side focus of lens 2

IS: Illumination solid angle

IS′: Other illumination solid angle

IS1: Solid angle region 1 with different light properties within the illuminated solid angle

IS2: Solid angle region 2 with different light properties within the illuminated solid angle

IS3: Illuminating solid angle region 3 with different light properties within the solid angle

OS: Observation solid angle

RS: solid angle of reflected light

RS′: solid angle of reflected light

RS1: Solid angle region 1 with different light properties within the solid angle of reflected light

RS2: Solid angle region 2 with different light properties within the solid angle of reflected light

RS3: Solid angle region 3 with different light properties within the solid angle of reflected light

TS: solid angle of transmitted light

Claims (6)

1. An inspection lighting device that illuminates an object under inspection with inspection light, characterized in that it comprises: A surface light source emits inspection light; A lens, disposed between the surface light source and the object to be inspected, is used to take light emitted from the surface light source as inspection light illuminating the object to be inspected, forming an illumination solid angle for the object to be inspected; and A first light shield and a first filter unit, or a third filter unit, are disposed between the surface light source and the lens, centered on the focal point of the lens. The first light shield forms a solid angle of illumination for the inspection light directed to various points on the object being inspected. The first filter unit forms multiple solid angle regions with different light properties within the solid angle of illumination. The third filter unit integrates the functions of the first light shield and the first filter unit. The inspection lighting device can set the shape or size, tilt, wavelength bandwidth, polarization state, and light intensity of the illumination solid angle and the solid angle region. 2. The inspection lighting device according to claim 1, characterized in that, Between the first light shield and the first filter unit and the surface light source, and near the location where the lens images the object to be inspected, there is at least one of a second light shield and a fourth filter unit. By using the second light shield or the fourth filter unit, the irradiation area, irradiation shape, irradiation pattern, or light properties of the inspection light on the object to be inspected can be arbitrarily set. 3. The inspection lighting device according to claim 1 or 2, characterized in that, In the inspection illumination device, between the lens and the object being inspected, there is a semi-transparent, semi-reflective mirror capable of changing the direction of the inspection light and allowing light from the object being transmitted and captured by the imaging device. The solid angle of the inspection light illuminating each point of the inspection object is approximately aligned with the optical axis of the solid angle of the imaging device observing each point of the inspection object. 4. The inspection lighting device according to claim 1 or 2, characterized in that, An inspection system suitable for use with an imaging device that captures light reflected, transmitted, or scattered by the object being inspected. In order to obtain the desired changes in brightness at each point, the solid angle of observation of each point of the object being inspected is set relative to the solid angle of observation formed when the object is photographed by the imaging device. The shape or size, tilt of the solid angle and the solid angle region, or the light properties contained in the solid angle and the solid angle region can be set. 5. The inspection lighting device according to claim 3, characterized in that, An inspection system suitable for use with an imaging device that captures light reflected, transmitted, or scattered by the object being inspected. In order to obtain the desired changes in brightness at each point, the solid angle of observation of each point of the object being inspected is set relative to the solid angle of observation formed when the object is photographed by the imaging device. The shape or size, tilt of the solid angle and the solid angle region, or the light properties contained in the solid angle and the solid angle region can be set. 6. An inspection system, characterized in that, The inspection illumination device according to any one of claims 1 to 5 is configured as an imaging device that captures light reflected, transmitted, or scattered by the object being inspected. In the inspection light illuminating the object to be inspected using the inspection illumination device, the shape or size and tilt of the illumination solid angle at each point of the object to be inspected are set based on the shape or size and tilt of the observation solid angle at each point of the object to be inspected by the imaging device, or the shape or size and tilt of the illumination solid angle and the observation solid angle are set relatively.