Defect detection device

Abstract

The present application relates to the field of industrial vision technology, and more specifically, to a defect detection device, which can solve the problem that when industrial products are subjected to 3D appearance defect detection or multi-faceted defect detection, multiple workstations and corresponding optical lenses need to be set up for defect detection to a certain extent; and when scratches and dirt exist at the same time, bright field detection and dark field detection need to be performed successively to distinguish scratches and dirt. The defect detection device includes: a light source assembly; a light sensor assembly for carrying imaging; a main optical path for making the reflected light from the front face of the product pass through a compensation mirror assembly, a spectroscope assembly, and an objective lens assembly to be imaged in a first area; a bright field optical path for making the reflected light from the side of the product pass through a bright field reflector assembly and the objective lens assembly arranged in sequence in the bright field optical path to be imaged in a second area of ​​the optical sensor assembly, and the second area is used for bright field detection of the side of the product.

Description

Technical Field

[0001] The present application relates to the field of industrial vision technology, and in particular to a defect detection device. Background Art

[0002] Appearance defect inspection of industrial products refers to the use of machine vision technology to detect whether there are defects such as dirt, hair, scratches, etc. on the surface of industrial products, and to image and display the defects obtained during the inspection so that quality inspectors can quickly locate the defects and accurately identify their types.

[0003] In the implementation of defect detection of some industrial products, an optical lens is usually used to perform defect detection on a certain detection surface of the industrial product. In bright field lighting detection, the optical lens is coaxial with the light sensor and the lighting source, and most of the light is reflected by the product being inspected and enters the light sensor. This detection method has a better detection effect on dirt and scratches; in dark field lighting detection, the optical lens is not coaxial with the light sensor and the lighting source, and a small part of the light is diffusely scattered by the product being inspected and enters the light sensor. This detection method has a better detection effect on scratches.

[0004] However, when performing defect inspection on the 3D appearance of industrial products or multiple inspection surfaces at the same time, optical lenses need to be set up in the positions corresponding to the multiple inspection surfaces, and the optical lens in each position is only responsible for inspecting its corresponding inspection surface; and when scratches and dirt exist on the inspection surface at the same time, bright field inspection and dark field inspection need to be performed successively to accurately distinguish between scratches and dirt. Summary of the invention

[0005] In order to solve the problem that when industrial products are subjected to 3D appearance defect detection or multi-faceted defect detection, multiple workstations and corresponding optical lenses need to be set up for defect detection; and when scratches and dirt exist at the same time, bright field detection and dark field detection need to be performed successively to distinguish scratches and dirt, the present application provides a defect detection device.

[0006] The embodiment of the present application is implemented as follows:

[0007] A first aspect of an embodiment of the present application provides a defect detection device, including:

[0008] A light source assembly, used to illuminate the product;

[0009] An optical sensor assembly for carrying an image of the product;

[0010] A main optical path, used to make the reflected light from the front face of the product pass through the compensation mirror assembly, the beam splitter assembly, and the objective lens assembly arranged in sequence on the main optical path, and imaged on the first area of ​​the optical sensor assembly, wherein the first area is used for bright field detection of the front face of the product;

[0011] A bright field optical path, used to make the reflected light from the side of the product pass through the bright field reflector assembly and the objective lens assembly arranged in sequence on the bright field optical path, and imaged on the second area of ​​the optical sensor assembly, wherein the second area is used for bright field detection of the side of the product;

[0012] The compensating mirror assembly is used to eliminate the optical path difference between the main light path and the bright field light path, so that the light sensor assembly can simultaneously image the front end surface and the bright field illumination imaging of the side surface.

[0013] In some embodiments, the bright field reflector assembly is in the shape of a curved sector;

[0014] The curved sector-shaped bright field reflector assembly is used to allow the reflected light from the side of the product to pass through the objective lens assembly and be imaged on the second area of ​​the light sensor assembly, where the second area is ring-shaped.

[0015] In some embodiments, the bright field reflector assembly comprises:

[0016] Four reflectors are respectively arranged above, below, in the proximal direction, and in the distal direction of the product, and are used to allow the reflected light from each side of the product to pass through the objective lens assembly and be imaged on four different areas of the optical sensor assembly respectively. The four different areas constitute the second area.

[0017] In some embodiments, the defect detection device further comprises:

[0018] A dark field optical path, used to image the scattered light from the front end face through the dark field reflector assembly and the objective lens assembly sequentially arranged in the dark field optical path to a third area of ​​the optical sensor assembly, wherein the third area is used for dark field detection of the front end face;

[0019] The compensating mirror assembly is also used to eliminate the optical path difference between the main optical path and the dark field optical path, so that the optical sensor assembly can simultaneously image the bright field illumination imaging and the dark field illumination imaging of the front end surface.

[0020] In some embodiments, the bright field reflector assembly comprises:

[0021] Three reflectors, respectively disposed on the upper side, the proximal side, and the distal side of the product, are used to allow the reflected light from the upper side, the proximal side, and the distal side of the product to pass through the objective lens assembly and be imaged on three different areas of the optical sensor assembly, respectively, and the three different areas constitute the second area;

[0022] The dark field reflector assembly is arranged at the lower side of the product, and is used to image the scattered light from the front end surface to the third area of ​​the light sensor via the objective lens assembly arranged in the dark field light path.

[0023] In some embodiments, the contrast of the objective lens assembly is configured to be greater than a preset threshold, and the preset threshold is used to determine whether defects corresponding to a preset level are detected. The contrast is the difference between the minimum resolution that the objective lens object can recognize and the maximum resolution that cannot be recognized.

[0024] In some embodiments, the objective lens assembly comprises:

[0025] A lens combination for zooming, wherein the lens combination comprises one or more combinations of a convex lens, a concave lens, a plane mirror, and a cylindrical mirror, and the lens combination is used to detect products with depth.

[0026] In some embodiments, the light source assembly comprises:

[0027] A first light source is used to emit incident light that passes through the beam splitter assembly and the compensation mirror assembly in sequence and is projected onto the front end surface and enters the main light path;

[0028] The second light source is used to emit incident light projected onto the side surface of the product, and the incident light enters the bright field light path after being reflected by the side surface.

[0029] In some embodiments, the light source assembly comprises:

[0030] The third light source is used to emit incident light that is input into the surface of the product, and the incident light enters the dark field light path after being scattered by the surface.

[0031] The beneficial effects of the present application are as follows: by constructing a main optical path, bright field detection of the front face of the product can be achieved; further by constructing a bright field optical path, bright field detection of the side of the product can be achieved simultaneously; further by constructing a compensation mirror assembly, the optical path difference between the main optical path and the bright field optical path can be eliminated; further by constructing a reflector assembly, the optical path turning can be achieved, so that the bright field optical path and the dark field optical path are off-axis, so as to distinguish them from the main optical path; further by constructing the first area and the second area, simultaneous bright field detection results of multiple faces of the product can be observed; further by constructing the third area, bright field and dark field detection of the front face can be achieved simultaneously, and defect detection of the 3D appearance of the product can be completed by a single station without the need for multi-station coordination, bright field and dark field simultaneous detection can be achieved, details that should be inspected can be detected and features that should not be inspected can be ignored, defect detection efficiency can be improved, the integration of the detection device can be improved, and the manufacturing and maintenance costs of the detection device can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0033] Figure 1 A schematic diagram of the structure of a defect detection device according to an embodiment of the present application is shown;

[0034] Figure 2 A schematic structural diagram of a defect detection device according to another embodiment of the present application is shown;

[0035] Figure 3 A schematic structural diagram of a defect detection device according to another embodiment of the present application is shown;

[0036] Figure 4A A schematic diagram of multi-station coordination for industrial product defect detection according to an embodiment of the present application is shown;

[0037] Figure 4B A schematic diagram showing the comparison between bright field illumination and dark field illumination in an embodiment of the present application is shown;

[0038] Figure 4C A schematic diagram showing the comparison between bright field illumination detection and dark field detection effects in an embodiment of the present application is shown;

[0039] Figure 4D A schematic diagram of the meridian system optical path of an industrial lens in a defect detection device according to an embodiment of the present application is shown;

[0040] Figure 4E A schematic diagram showing the principle of optical path imaging in a defect detection device according to an embodiment of the present application is shown;

[0041] Figure 4F A schematic diagram of a modulation transfer function simulation of a lens in a defect detection device according to an embodiment of the present application is shown;

[0042] Figure 4G A schematic diagram of image simulation results of different resolution line pairs passing through a high-contrast objective lens in a defect detection device according to an embodiment of the present application is shown. DETAILED DESCRIPTION

[0043] In order to make the purpose, implementation mode and advantages of the present application clearer, the exemplary implementation mode of the present application will be clearly and completely described below in conjunction with the drawings in the exemplary embodiments of the present application. Obviously, the described exemplary embodiments are only part of the embodiments of the present application, rather than all the embodiments.

[0044] It should be noted that the brief description of terms in this application is only for the convenience of understanding the embodiments described below, and is not intended to limit the embodiments of this application. Unless otherwise specified, these terms should be understood according to their common and usual meanings.

[0045] The terms "first", "second", "third", etc. in the specification and claims of this application and the above drawings are used to distinguish similar or similar objects or entities, and do not necessarily mean to limit a specific order or sequence, unless otherwise noted. It should be understood that the terms used in this way can be interchangeable under appropriate circumstances.

[0046] The terms "front end", "rear end", "proximal end", "distal end", "upper side", "lower side" and any variations thereof are all used in the specification. Figure 1 Based on the perspective of Figure 1 The side of the paper surface close to the reader is the near end, the side away from the reader is the far end, the direction upward of the paper surface is the upper side, the direction downward of the paper surface is the lower side, the right side of the paper surface is the front side, and the left side of the paper surface is the rear side.

[0047] The terms "comprises," "comprising," and any variations thereof, are intended to cover but not exclude inclusion, for example, a product or device comprising a list of components is not necessarily limited to all the components expressly listed but may include other components not expressly listed or inherent to such product or device.

[0048] Figure 1 A schematic structural diagram of a defect detection device according to an embodiment of the present application is shown.

[0049] In some embodiments, the defect detection device provided by the present application may include a light source component, a light sensor component, a main light path, and a bright field light path.

[0050] The present application will take the bright field reflector assembly implemented as a bright field reflector, the compensation mirror assembly implemented as a compensation mirror, the beam splitter assembly implemented as a beam splitter, the objective lens assembly implemented as an objective lens, the dark field reflector assembly implemented as a dark field reflector, and the light sensor assembly implemented as a light sensor as an example to explain the defect detection device provided in the present application.

[0051] In some embodiments, the main light path is used to image the reflected light from the front surface of the product through the compensation mirror assembly, the beam splitter assembly, and the objective lens assembly arranged in sequence on the main light path to the first area of ​​the light sensor assembly. The first area is used for bright field detection of the front surface of the product, which can also be called bright field detection of the normal field of view. The first area can be located, for example, at the center of the light sensor assembly.

[0052] Among them, the main optical path can be used to detect the front end of the product. Figure 1 The side of the product on the right side of the paper.

[0053] Although this application will Figure 1 The right side of the product, that is, the side facing the lens, is called the front end face, but the present application does not specifically limit the position of the front end face of the product. The front end face of the product to be inspected can be determined according to the actual situation based on the invention content disclosed in this application.

[0054] On the right side of the front end of the product, a compensation mirror assembly, a beam splitter assembly, and an objective lens assembly are arranged in sequence. The reflected light from the front end of the product passes through the compensation mirror assembly, the beam splitter assembly, and the objective lens assembly and is projected onto the light sensor assembly, and an image is formed in the first area.

[0055] By observing the imaging of the first area, defects such as scratches or dirt on the front face of the product can be found, that is, the main light path is used for bright field detection.

[0056] The beam splitter assembly can reflect incident light from the light source to the front face of the product; the beam splitter assembly also allows the reflected light from the front face of the product to pass through the beam splitter assembly itself and then be transmitted to the light sensor assembly via the objective lens assembly.

[0057] It should be noted that the compensation mirror assembly, or the beam splitter assembly, or the objective lens assembly can each be implemented as a lens combination, and the lens combination can include one or more combinations of convex lenses, concave lenses, plane mirrors, cylindrical mirrors, or other forms of mirrors. The present application does not make any specific limitation on the lens combination method.

[0058] In some embodiments, the bright field light path is used to allow reflected light from the side of the product to be imaged in the second area of ​​the optical sensor assembly through the bright field reflector assembly and the above-mentioned objective lens assembly arranged in sequence in the bright field light path. The second area is used for bright field detection of the side of the product.

[0059] Among them, the bright field reflector assembly makes the reflected light from the side of the product reflect through the objective lens assembly configured in the main light path.

[0060] It should be noted that although Figure 1 The middle bright field optical path shares the same objective lens assembly with the main optical path, and the bright field optical path can also use a separately configured objective lens assembly.

[0061] It can be understood that the bright field light path and the main light path share the same objective lens assembly, which can improve the integration of the defect detection device, reduce the number of parts in the device, reduce manufacturing costs, and improve device reliability.

[0062] In some embodiments, the bright field reflector assembly may be implemented as a single plane mirror, or a combination of multiple plane mirrors, or a lens combination, and the lens combination may include one or more combinations of convex lenses, concave lenses, plane mirrors, cylindrical mirrors, or other forms of mirrors, which can enable the reflected light from the side of the product to pass through the objective lens assembly and be imaged on the second area of ​​the light sensor assembly.

[0063] For example, the bright field reflector assembly may be implemented as Figure 1 The bright field reflector shown can be specifically implemented as a plane mirror. When performing bright field detection on the lower side of the product, the plane mirror can be set on the lower side of the product to reflect the light from the lower side of the product, so that the reflected light is imaged in the second area through the objective lens assembly. The bright field light path can be off-axis and separated from the main light path.

[0064] The compensating mirror assembly can be used to eliminate the optical path difference between the main light path and the bright field light path, so that the light sensor assembly can simultaneously image the front face of the product and the bright field illumination imaging of the side of the product.

[0065] The light source assembly is used to illuminate the product and provide incident light for the detection surface of the product. The incident light can be used for reflection or diffuse scattering.

[0066] For example, when the light source assembly is implemented as a light source, the incident light emitted by the light source is reflected by a beam splitter and projected to the front face of the product through a compensation mirror; then, after being reflected by the front face of the product, the incident light enters the main light path for bright field detection, such as Figure 1 shown.

[0067] In some embodiments, a second light source ( Figure 1 Not shown) to achieve bright field detection of the lower side of the product; that is, the incident light emitted by the second light source is projected onto the lower side of the product, and then the incident light is reflected from the lower side and projected onto the bright field reflector, and after being reflected by the bright field reflector, it passes through the objective lens of the bright field light path again and is finally imaged in the second area of ​​the light sensor.

[0068] The optical sensor receives light from the main optical path and the bright field optical path, images the front end surface in a first area, and images the lower side surface in a second area.

[0069] It should be noted that although Figure 1 The middle bright field reflector assembly is implemented as a bright field reflector and is arranged on the lower side of the product for bright field detection of the lower side of the product. However, the present application does not limit the position of the bright field reflector assembly. For example, the bright field reflector assembly can also be arranged in the upper side direction, the proximal side direction, and the distal side direction of the product for bright field detection of the upper side surface, the proximal side surface, and the distal side surface of the product, respectively.

[0070] Among them, through optical path design and adding lens components, the bright field reflector assembly can also be used for bright field detection of the rear end face of the product.

[0071] It can be understood that the side of the product is imaged on the second area of ​​the light sensor through the bright field light path, and the second area is located at a different position from the first area.

[0072] After combining the first area and the second area, a single lens can be set at a single station to perform bright field inspection on multiple sides of the product at the same time.

[0073] For example, through image processing technology, the images of the first area and the second area can be synthesized in 3D, thereby realizing multi-faceted appearance inspection of the product.

[0074] In some embodiments, a bright field light path is set for each side of the product so that the second area set corresponding to the multiple second areas can image all surfaces except the front end surface. The defect detection device can realize 3D appearance defect detection of the product.

[0075] It is understandable that the appearance of industrial products is diverse, so most industrial products have 3D contours. The defect detection device provided in this application, combined with computer image processing technology, can realize 3D imaging detection and 3D data reconstruction functions.

[0076] In some embodiments, the bright field reflector assembly can be implemented as a curved sector, which is used to allow the reflected light from the side of the product to pass through the objective lens assembly and be imaged on the second area of ​​the optical sensor assembly, and the second area corresponds to a ring shape.

[0077] For example, the bright field reflector assembly is implemented as a curved fan-shaped reflector, wherein the curved fan-shaped reflector includes an expanded opening, a narrowed opening, and a curved surface between the expanded opening and the narrowed opening.

[0078] The curved sector-shaped reflector can be arranged around the product to be tested, and a corresponding ring light source (not shown in the drawings) can also be arranged. The ring light source emits incident light for bright field detection, and the curved sector-shaped reflector reflects the reflected light from the side of the product so that it passes through the objective lens and forms an image in the second area of ​​the light sensor.

[0079] The second area may correspond to a circular ring, which may include an inner ring and an outer ring. By observing the bright field illumination imaging between the inner ring and the outer ring, bright field detection of the side of the product may be achieved.

[0080] It can be understood that the bright field reflector assembly is implemented as a curved sector, which has a good bright field detection effect on products with circular structural elements such as batteries.

[0081] The first area may be located at a center of the light sensor, and the second area may be located at a periphery of the first area.

[0082] It should be noted that the curved sector-shaped bright field reflector assembly can be implemented as a closed curved sector-shaped or an open curved sector-shaped.

[0083] For example, when the curved fan-shaped bright field reflector assembly is closed, bright field illumination imaging can be performed on all sides of the product; when the curved fan-shaped bright field reflector assembly is not closed, bright field illumination imaging can be performed on part of the continuous side of the product.

[0084] In some embodiments, the bright field reflector assembly can also be implemented to include four reflectors, which are respectively arranged in the upper side, lower side, proximal side, and distal side directions of the product, so as to make the reflected light from each side of the product pass through the objective lens assembly and be imaged in four different areas of the light sensor assembly respectively, and the four different areas constitute the second area.

[0085] For example, a first reflector for bright field detection is set on the upper side of the product, a second reflector for bright field detection is set on the lower side of the product, a third reflector for bright field detection is set on the distal side of the product, and a fourth reflector for bright field detection is set on the proximal side of the product.

[0086] By configuring the size of the objective lens and the distance between the reflector and the side of the product, the four reflectors can reflect the reflected light from the side of the product so that it passes through the objective lens and is finally projected onto the light sensor.

[0087] Correspondingly, a second area will be formed on the optical sensor, and the second area may include four different imaging areas. The above four imaging areas may surround the first area of ​​the main light path imaging, so that one defect detection device can be set up at one workstation, and bright field detection can be performed on five surfaces of the product at the same time, thereby improving the detection efficiency and reducing the required detection stations, detection equipment, and detection personnel.

[0088] It should be noted that, for the bright field detection of the rear end face of the product, on the basis of the above-mentioned embodiment, a reflector for bright field detection can be further added through the configuration of the reflective light path, so that the second area includes a fifth different imaging area, thereby realizing bright field detection of the six faces of the product at the same time and realizing bright field illumination imaging of the six faces; it can be understood that it is only necessary to set a suitable auxiliary reflector near the far end face so that the reflected light from the rear end face can enter the bright field light path, and the position setting of the auxiliary reflector is a conventional technical means, and this application does not limit it.

[0089] The defect detection device provided in the present application deflects the optical path through a reflector assembly, eliminates the aberration of off-axis imaging using a compensating mirror assembly, and compensates for the imaging optical paths of different fields of view, thereby enabling panoramic photography and detection of 3D objects with a single lens.

[0090] In some embodiments, multiple sides of a product are inspected. Assuming that the defect detection device is only provided with one main optical path, multiple workstations are required to configure the defect detection device, and then bright field inspection is performed on different sides of the industrial product at the same time.

[0091] like Figure 4A As shown, for 3D appearance defect inspection of industrial products, three workstations can be used, with lighting and inspection cameras set up separately;

[0092] Then, the industrial products are photographed at different angles to obtain three-dimensional data; based on the projection principle, algorithms are used to reconstruct the 3D contour features of the appearance and defects of the industrial products.

[0093] Figure 4D A schematic diagram of the meridian system optical path of an industrial lens in a defect detection device according to an embodiment of the present application is shown.

[0094] In some embodiments, in the optical design of a 3D industrial lens, imaging object planes exist in three dimensional directions, which can be represented as XOZ plane, YOZ plane and XOY plane respectively.

[0095] The light emitted from the YOZ field of view passes through the subsequent imaging lens, also called the objective lens, along the optical axis and is finally imaged at the center of the light sensor.

[0096] The light emitted from the XOZ and XOY fields of view first passes through the reflector to bend the optical path, and then passes through the subsequent imaging objective lens, also called the objective lens, in the off-axis direction, and finally forms an image on the upper and left sides of the light sensor, which can avoid the imaging confusion problem of different dimensional fields of view.

[0097] The fields of view of the XOZ plane and the XOY plane are folded once in the optical path, and have an optical path difference with the YOZ plane field of view transmitted along the optical axis. Therefore, a small optical path compensation mirror is added in front of the imaging objective lens to only allow the light of the YOZ plane field of view to pass through, so that the fields of view in each dimension can be focused on the light sensor for imaging.

[0098] For example, by setting four reflectors around the central field of view (YOZ field of view), the five directions of the product can be imaged on the optical sensor at the same time, thereby completing partial or full 3D appearance and 3D defect detection. Figure 4E shown.

[0099] It can be understood that the defect detection device provided in the present application, when specifically implemented as a 3D industrial imaging lens, can complete the function of single-station detection of the 3D appearance and defects of industrial products.

[0100] Figure 2 A schematic structural diagram of a defect detection device according to another embodiment of the present application is shown.

[0101] In some embodiments, the defect detection device provided by the present application also includes a dark field optical path, which is used to make the scattered light from the front end surface of the product pass through the dark field reflector assembly and the objective lens assembly arranged in sequence in the dark field optical path to image the third area of ​​the optical sensor assembly, and the third area is used for dark field detection of the front end surface.

[0102] The compensating mirror assembly in the main optical path can also be used to eliminate the optical path difference between the main optical path and the dark field optical path, so that the optical sensor assembly can simultaneously image the bright field illumination imaging and the dark field illumination imaging of the front end surface.

[0103] like Figure 2 As shown, when the bright field reflector is arranged at the lower side of the product, the dark field reflector can be arranged at the upper side of the product. The dark field reflector can also be arranged at the proximal side or the distal side.

[0104] The city that needs to be explained, although Figure 2 The bright field light path is set at the lower side of the product, and the dark field light path is set at the upper side of the product, but the present application does not specifically limit the position configuration of the bright field and dark field light paths. For example, the bright field light path can also be set at the upper side of the product, and the dark field light path can also be set at the lower side of the product.

[0105] In some embodiments, the bright field light path is arranged at the lower side of the product, and the dark field reflector can also be arranged at the lower side of the bright field reflector. By configuring the relative positions of the bright field reflector and the dark field reflector, the bright field light path and the dark field light path can be arranged on the same side of the product.

[0106] The dark field optical path is used for dark field detection of the detection surface corresponding to the main optical path. If the main optical path performs bright field detection on the front end surface, the dark field optical path can also perform dark field detection on the front end surface at the same time.

[0107] Bright field detection can sensitively detect dirt and scratches, while dark field detection can sensitively detect scratches.

[0108] By comparing the first area corresponding to the bright field detection of the front face and the third area corresponding to the dark field detection at the same time, it is possible to distinguish and identify the dirt and scratches when there are dirt and scratches on the front face at the same time, without the need to perform bright field detection and dark field detection respectively. Figure 4C shown.

[0109] It should be noted that although Figure 2 The intermediate dark field optical path and the main optical path share the same objective lens assembly, but the present application does not specifically limit the objective lens. In some embodiments, the dark field optical path may also use a separately configured objective lens.

[0110] In some embodiments, the dark field light path and the main light path share the same objective lens, which can improve the integration of the defect detection device, reduce the number of parts, reduce manufacturing costs, and improve the reliability of the device.

[0111] It can be understood that when the defect detection device includes bright field and dark field light paths, the light sensor imaging will include the first area, the second area and the third area.

[0112] The first area can be used for bright field inspection of the front face to detect possible dirt and scratches on the front face;

[0113] The second area can be used for bright field inspection of the side to detect possible dirt and scratches on the side;

[0114] The third area can be used for dark field inspection of the front end surface to detect possible scratches on the front end surface.

[0115] In some embodiments, the defect detection device provided by the present application can realize high-contrast 3D zoom defect detection combining bright and dark field illumination, and its structure may include six modules including an illumination light source, a beam splitter, a plurality of reflectors, an optical path compensation mirror, an objective lens and a light sensor.

[0116] When the object to be detected requires both 3D detection and synchronous detection of bright and dark fields, the reflector in one direction is responsible for transforming the diffuse reflection dark field information of the YOZ forward field of view; the reflectors in the other three directions are responsible for transforming the 3D information of the edge field of view of the object.

[0117] Under this structure, the light and dark field information of the forward field of view and the bright field information of the side edge field of view of the product to be inspected can be obtained simultaneously. A single station can complete 3D inspection and light and dark field parallel inspection.

[0118] It can be understood that under dark field conditions, scratch detection has extremely high sensitivity, while dirt detection has almost no response. Therefore, the defect detection device that combines light and dark field lighting can easily distinguish and identify scratches and stolen goods.

[0119] In some embodiments, when the defect detection device has only the bright field detection function of the main light path, or only the dark field detection function, in order to achieve simultaneous bright field and dark field detection or 3D appearance detection, the bright field detection station and the dark field detection station can be used simultaneously, such as Figure 4A shown.

[0120] By setting up bright field and dark field optical paths, the defect detection device can perform bright field detection and dark field detection at the same time, and can perform bright field detection on multiple surfaces at the same time, reducing the number of workstation settings and defect detection devices required for multi-surface detection. There is no need to perform bright field and dark field detection in order to distinguish between dirt and scratches, which can improve product defect detection efficiency, reduce detection costs, and make defect detection easier.

[0121] It is understandable that if only bright field detection is performed, dirt, hair and other contaminants on industrial products will be imaged on the optical sensor together with defects such as scratches and breakages, making it difficult to distinguish them.

[0122] In some embodiments, in bright field lighting, the optical lens is coaxial with the light sensor and the lighting source, and most of the light energy is reflected and transmitted through the inspected product into the light sensor and received. The advantage of this solution is high detection accuracy, but it cannot distinguish dirt and scratches.

[0123] In the dark field lighting mode, the optical lens is not coaxial with the light sensor and the lighting source, and only part of the light energy diffusely scattered by the product being inspected can enter the light sensor and be received. Figure 4B shown.

[0124] In some embodiments, the industrial product to be inspected has a high scattering coefficient, such as packaging inspection and semiconductor inspection.

[0125] The optical path configuration structure of the combination of bright and dark field illumination is similar to that of 3D imaging. A conventional coaxial light source is used for illumination. After the illumination light source is split by a beam splitter, it is irradiated on the detection surface. The light beam reflected by the object surface passes through the compensation mirror, beam splitter and objective lens in sequence along the optical axis, and finally forms an image in the center of the target surface of the optical sensor, such as Figure 3 The solid line in .

[0126] The light beam scattered by the detection surface is deflected by the reflector and passes through the objective lens in an off-axis imaging manner, thereby forming an image on the edge of the target surface of the optical sensor. Figure 3 The dotted line in .

[0127] Therefore, the defect detection device includes Figure 3 When the optical path is set, the single-station light and dark field illumination combined measurement can be completed, and the bright field detection and dark field detection can be combined at the same time.

[0128] In some embodiments, the defect detection device including a dark field optical path can also be configured such that its bright field reflector assembly includes: 3 reflectors, respectively arranged on the upper side, proximal side, and distal side of the product, for making the reflected light from the upper side, proximal side, and distal side of the product pass through the objective lens assembly and be imaged on 3 different areas of the optical sensor assembly respectively, and the 3 different areas constitute the second area.

[0129] The dark field reflector assembly is arranged at the lower side of the product, and is used to image the scattered light from the front end surface to the third area of ​​the light sensor via the objective lens assembly arranged in the dark field light path.

[0130] The dark field reflector assembly can be implemented as one dark field reflector, which is arranged at the bottom of the product. The bright field optical path and the dark field optical path can share the objective lens assembly and the light sensor assembly.

[0131] For the bright field light path, three bright field illumination sources corresponding to three bright field reflectors can be configured; for the dark field light path, one dark field illumination source corresponding to one dark field reflector can also be configured. The bright field illumination sources, the number of dark field illumination sources, and the illumination method can be configured according to actual conditions.

[0132] For example, when the product is placed on the inspection table, three bright field reflectors are set on the upper side, proximal side, and distal side of the product, corresponding to the three different areas included in the second area on the optical sensor, to achieve bright field detection of the upper side, proximal side, and distal side.

[0133] A dark field reflector arranged on the lower side of the product corresponds to the third area of ​​the optical sensor, which can realize dark field detection of the front end surface; the first area of ​​the optical sensor can realize bright field detection of the front end surface.

[0134] It should be noted that, although in this embodiment the dark field light path is arranged in the lower direction of the product and the bright field light path is arranged in the upper direction, the proximal side direction, and the distal side direction of the product, the present application does not specifically limit the position configuration of the bright field light path and the dark field light path. For example, the dark field light path may also be arranged in the upper direction of the product, and the bright field light path may also be arranged in the lower direction, the proximal side direction, and the distal side direction of the product.

[0135] In some embodiments, the defect detection device including a dark field optical path can also be configured as a bright field reflector assembly that can be implemented as a curved fan-shaped bright field reflector assembly. The curved fan-shaped bright field reflector assembly is used to allow the reflected light from the side of the product to pass through the objective lens assembly and finally be imaged on the second area of ​​the optical sensor assembly, and the second area is annular.

[0136] The dark field optical path is used to image the scattered light from the front end of the product through the dark field reflector assembly and the objective lens assembly arranged in sequence in the dark field optical path to the third area of ​​the optical sensor assembly, and the third area is used for dark field detection of the front end.

[0137] For example, the bright field reflector assembly is implemented as a curved fan-shaped reflector, and the curved fan-shaped reflector can be arranged around the product to be tested, and a corresponding annular light source can be arranged for bright field illumination.

[0138] The dark field reflector is arranged on the upper side of the product, and a dark field light source can be arranged correspondingly, so that the scattered light from the front surface of the product is reflected into the dark field light path; an image can be formed in the second area and the third area on the light sensor.

[0139] By implementing this technical solution, for cylindrical products or products whose sides cannot be clearly distinguished into multiple sides, it is possible to simultaneously detect multiple sides of the product, and to simultaneously realize bright field detection and dark field detection.

[0140] In some embodiments, the defect detection device including a dark field optical path can also be configured as a bright field reflector assembly, which can be implemented to include four reflectors, which are respectively arranged above, below, in the proximal direction, and in the distal direction of the product, for allowing the reflected light from each side of the product to pass through the objective lens assembly and be imaged on four different areas of the optical sensor assembly, respectively. The four different areas constitute the second area.

[0141] The dark field optical path is used to image the scattered light from the front end of the product through the dark field reflector assembly and the objective lens assembly arranged in sequence in the dark field optical path to the third area of ​​the optical sensor assembly, and the third area is used for dark field detection of the front end.

[0142] For example, a first reflector for bright field detection is set on the upper side of the product, a second reflector for bright field detection is set on the lower side of the product, a third reflector for bright field detection is set on the distal side of the product, and a fourth reflector for bright field detection is set on the proximal side of the product.

[0143] Then, a dark field reflector is set near the bright field reflector in any direction of the product. By configuring the dark field reflector and the bright field reflector so as not to block or interfere with each other, the bright field light path and the dark field light path can be realized separately.

[0144] Correspondingly, four different imaging areas will be displayed on the optical sensor, and the four different imaging areas constitute the second area;

[0145] The dark field optical path corresponds to the third area. The above four imaging areas can surround the first area corresponding to the main optical path. It is possible to set one lens at one workstation and perform bright field detection on the five surfaces of the product at the same time, and perform dark field detection on the front end surface at the same time, which can improve the detection efficiency and reduce the number of detection stations, equipment, and personnel.

[0146] In some implementations, a light source assembly includes a first light source and a second light source.

[0147] The first light source can be used to emit incident light that passes through the beam splitter component and the compensation mirror component in sequence and is projected to the front face to enter the main light path;

[0148] The second light source can be used to emit incident light that is projected onto the side of the product, and the incident light enters the bright field light path after being reflected by the side.

[0149] In some implementations, the light source assembly includes a third light source, which can be used to emit incident light that is projected onto the surface of the product, and the incident light enters the dark field light path after being scattered by the surface.

[0150] This solution uses a unique lighting light path design to enable a single workstation to combine both bright field and dark field lighting methods, thereby achieving the purpose of accurate and precise detection.

[0151] Figure 3 A schematic structural diagram of a defect detection device according to another embodiment of the present application is shown.

[0152] In some embodiments, the defect detection device provided by the present application may include a light source component, a light sensor component, a main light path, and a dark field light path.

[0153] For example, the main optical path is used to image the reflected light from the front end surface of the product to be inspected onto the first area of ​​the optical sensor through the compensation mirror, the beam splitter, and the objective lens arranged in sequence along the main optical path. The first area is used for bright field inspection of the front end surface of the product.

[0154] The dark field optical path can be set on the upper side of the product, and is used to make the scattered light from the front end surface of the product pass through the dark field reflector and the objective lens arranged in sequence in the dark field optical path to form an image in the third area of ​​the light sensor. The third area is used for dark field detection of the front end surface, and the third area and the first area are located in different areas.

[0155] The compensating mirror assembly in the main optical path can also be used to eliminate the optical path difference between the main optical path and the dark field optical path, so that the optical sensor assembly can simultaneously image the bright field illumination imaging and the dark field illumination imaging of the front end surface.

[0156] The city that needs to be explained, although Figure 1 It is set on the upper side of the product, but the present application does not impose any specific restrictions on the azimuthal arrangement of the dark field light path. The dark field light path can also be set in the direction of the lower side of the product, or in the opposite direction of the proximal side, or in the direction of the distal side, and the corresponding third area imaged on the light sensor will also be located at a different position.

[0157] The dark field optical path is used for dark field detection of the main optical path detection surface. For example, when the main optical path performs bright field detection on the front end surface, the dark field optical path simultaneously performs dark field detection on the front end surface.

[0158] Bright field detection can sensitively detect dirt and scratches, and dark field detection can sensitively detect scratches. By comparing the first area of ​​the front face bright field detection and the third area of ​​the front face dark field detection, when dirt and scratches exist on the front face at the same time, the above dirt and scratches can be distinguished, such as Figure 4C shown.

[0159] By setting up the main optical path and the dark field optical path, the defect detection device can perform bright field detection and dark field detection on the detection surface at the same time, reducing the setting of detection stations and the number of defect detection devices invested. There is no need to perform bright field and dark field detection in order to distinguish dirt and scratches. This can improve product defect detection efficiency, reduce detection costs, and make defect detection easier.

[0160] In some embodiments, the contrast of the objective lens assembly is configured to be greater than a preset threshold, which is used to determine whether defects corresponding to a preset level are detected. The contrast is the difference between the minimum resolution that the objective lens object can recognize and the maximum resolution that it cannot recognize.

[0161] For an objective lens, the ratio of the minimum resolution that the lens can distinguish to the maximum resolution that it cannot distinguish is called contrast.

[0162] In order to meet the inspection requirements of industrial products and to detect the details that should be inspected and ignore the features that should not be inspected, it is necessary to specially design the objective lens.

[0163] like Figure 4F As shown, the contrast of a lens is related to the decreasing gradient of its modulation transfer function (MTF).

[0164] The faster the gradient of the modulation transfer function decreases, the smaller the difference between the minimum resolution that the industrial lens can distinguish and the maximum resolution that it cannot distinguish. Therefore, the contrast of the lens is higher, and the setting of detection and non-detection between millimeters can be completed.

[0165] The objective lens can be configured so that the difference between the minimum resolution that can be resolved and the maximum resolution that cannot be resolved can be reduced to less than 50%, such as Figure 4G shown.

[0166] In some implementations, the objective lens assembly may include a lens combination for zooming, wherein the lens combination includes one or more combinations of a convex lens, a concave lens, a plane mirror, and a cylindrical mirror, and the lens combination is used to detect products with depth.

[0167] The defect detection device provided in the present application has an objective lens with high contrast, which can achieve the purpose of detecting the details that should be inspected in industrial products and ignoring the features that should not be inspected, thereby improving the efficiency of industrial detection.

[0168] In addition, the lens combination included in the objective lens also has a zoom function, which can be used for appearance defect detection of industrial products with a certain depth.

[0169] The beneficial effects of the embodiments of this part are that by constructing a main optical path, bright field detection of the front face of the product can be achieved; further by constructing a bright field optical path, bright field detection of the side of the product can be achieved simultaneously; further by constructing a compensation mirror assembly, the optical path difference between the main optical path and the bright field optical path can be eliminated; further by constructing a reflector assembly, the optical path turning can be achieved, so that the bright field optical path and the dark field optical path are off-axis, so as to distinguish them from the main optical path; further by constructing the first area and the second area, simultaneous bright field detection results of multiple faces of the product can be observed; further by constructing the third area, bright field and dark field detection of the front face can be achieved simultaneously, and defect detection of the 3D appearance of the product can be completed by a single station without the need for multi-station coordination, bright field and dark field simultaneous detection can be achieved, details that should be inspected can be detected and features that should not be inspected can be ignored, defect detection efficiency can be improved, the integration of the detection device can be improved, and the manufacturing and maintenance costs of the detection device can be reduced.

[0170] For the convenience of explanation, the above description has been made in conjunction with specific embodiments. However, the above discussion in some embodiments is not intended to be exhaustive or limit the embodiments to the specific forms disclosed above. According to the above teachings, various modifications and variations can be obtained. The selection and description of the above embodiments are to better explain the principles and practical applications, so that those skilled in the art can better use the embodiments and various different variations of the embodiments suitable for specific use considerations.

Claims

1. A defect detection device, It is characterized in that include: A light source assembly, used to illuminate the product; An optical sensor assembly for carrying an image of the product; A main optical path, used to make the reflected light from the front face of the product pass through the compensation mirror assembly, the beam splitter assembly, and the objective lens assembly arranged in sequence on the main optical path, and imaged on the first area of ​​the optical sensor assembly, wherein the first area is used for bright field detection of the front face of the product; A bright field optical path, used to make the reflected light from the side of the product pass through the bright field reflector assembly and the objective lens assembly arranged in sequence on the bright field optical path, and be imaged on the second area of ​​the optical sensor assembly, the second area is used for bright field detection of the side of the product, and the second area and the first area are located at different positions of the optical sensor assembly; The compensating mirror assembly is used to eliminate the optical path difference between the main light path and the bright field light path, so that the optical sensor assembly can simultaneously image the front end surface and the bright field illumination imaging of the side surface.

2. The defect detection device according to claim 1, It is characterized in that The bright field reflector assembly is in the shape of a curved sector; The curved sector-shaped bright field reflector assembly is used to allow the reflected light from the side of the product to pass through the objective lens assembly and be imaged on the second area of ​​the light sensor assembly, where the second area is ring-shaped.

3. The defect detection device according to claim 1, It is characterized in that The bright field reflector assembly comprises: Four reflectors are respectively arranged above, below, in the proximal direction, and in the distal direction of the product, and are used to allow the reflected light from each side of the product to pass through the objective lens assembly and be imaged on four different areas of the optical sensor assembly respectively. The four different areas constitute the second area.

4. The defect detection device according to claim 1, It is characterized in that Also includes: A dark field optical path, used to image the scattered light from the front end face through the dark field reflector assembly and the objective lens assembly sequentially arranged in the dark field optical path to a third area of ​​the optical sensor assembly, wherein the third area is used for dark field detection of the front end face; The compensating mirror assembly is also used to eliminate the optical path difference between the main optical path and the dark field optical path, so that the optical sensor assembly can simultaneously image the bright field illumination imaging and the dark field illumination imaging of the front end surface.

5. The defect detection device according to claim 4, It is characterized in that The bright field reflector assembly comprises: Three reflectors, respectively disposed on the lower side, the proximal side, and the distal side of the product, are used to allow the reflected light from the lower side, the proximal side, and the distal side of the product to pass through the objective lens assembly and be imaged on three different areas of the optical sensor assembly, respectively, and the three different areas constitute the second area; The dark field reflector assembly is arranged on the upper side of the product, and is used to image the scattered light from the front end surface to the third area of ​​the light sensor via the objective lens assembly arranged in the dark field light path.

6. The defect detection device according to claim 2 or 3, It is characterized in that Also includes: A dark field optical path, used to image the scattered light from the front end face through the dark field reflector assembly and the objective lens assembly sequentially arranged in the dark field optical path to a third area of ​​the optical sensor assembly, wherein the third area is used for dark field detection of the front end face; The compensating mirror assembly is also used to eliminate the optical path difference between the main optical path and the dark field optical path, so that the optical sensor assembly can simultaneously image the bright field illumination imaging and the dark field illumination imaging of the front end surface.

7. The defect detection device according to claim 1, It is characterized in that The contrast of the objective lens assembly is configured to be greater than a preset threshold, and the preset threshold is used to determine whether defects corresponding to a preset level are detected. The contrast is the difference between the minimum resolution that the objective lens assembly can recognize and the maximum resolution that cannot be recognized.

8. The defect detection device according to claim 1, It is characterized in that The objective lens assembly comprises: A lens combination for zooming, wherein the lens combination comprises one or more combinations of a convex lens, a concave lens, a plane mirror, and a cylindrical mirror, and the lens combination is used to detect products with depth.

9. The defect detection device according to claim 1, It is characterized in that The light source assembly comprises: A first light source is used to emit incident light that passes through the beam splitter assembly and the compensation mirror assembly in sequence and is projected onto the front end surface and enters the main light path; The second light source is used to emit incident light projected onto the side surface of the product, and the incident light enters the bright field light path after being reflected by the side surface.

10. The defect detection device according to claim 4 or 5, It is characterized in that The light source assembly comprises: The third light source is used to emit incident light that is input into the surface of the product, and the incident light enters the dark field light path after being scattered by the surface.

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