Thin film defect detection device

Abstract

The utility model discloses a film defect detection device. The film defect detection device comprises a light source and an imaging unit, an illumination light beam emitted by the light source is incident to the first surface of the to-be-detected film; the imaging unit receives transmission light of the to-be-measured film and obtains an image of the to-be-measured film; wherein a normal passing through the center of the light-emitting surface of the light source intersects with the first surface at a first intersection point, a normal passing through the center of the imaging unit intersects with the first surface at a second intersection point, and the first intersection point and the second intersection point are staggered by a preset distance. The thin film defect detection device provided by the utility model provides an excellent optical imaging scheme in order to effectively detect a coating missing defect of a glued transparent thin film so as to enhance the contrast ratio of a glued area and enable the defect to be more obvious, and the defect of the glued transparent thin film can be effectively detected by arranging a scheme that the light source obliquely emits light and / or the imaging unit obliquely receives light and the light source and the imaging unit are staggered. Therefore, a machine vision system can identify and analyze the glue leakage defect more accurately, and the detection reliability and efficiency are further improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to thin film detection technical field especially relates to a thin film defect detection device. BACKGROUND

[0002] The original film can effectively enhance its adhesion, improve the adhesion performance with other materials (such as metal, plastic, glass, etc.). It not only provides protection function, forms protective layer, but also improves performance, enhances the mechanical strength, wear resistance and chemical resistance of film. In addition, gluing helps subsequent processing, such as lamination and printing, improves processing efficiency and quality. Through gluing, the original film can better meet the needs of specific applications. However, due to process problems, the gluing original film may have missed coating defects, which need to be strictly controlled. The film material with more missed coating will cause product performance and quality problems. Therefore, detecting the missed coating defect of gluing is an important link to ensure product quality.

[0003] At present, the detection scheme of glue missing defect mainly includes eye observation, laser scanning, ultrasonic detection and machine vision detection. Compared with eye observation, machine vision detection can effectively reduce human error and the result is more consistent. Compared with laser and ultrasonic wave, machine vision detection has lower cost and is suitable for various materials and complex shapes. Machine vision detection has many advantages: it realizes high-speed and large-scale detection, improves production efficiency, provides high-precision image analysis and accurately identifies tiny defects. It can also automatically record and analyze data, which is convenient for quality traceability. Overall, machine vision is a more flexible and efficient detection scheme.

[0004] At present, the machine vision imaging station mainly uses back light direct transmission station and reflection station, but the imaging effect of glue missing defect of the gluing transparent film is poor, the defect is almost not imaged, and the stable detection of the glue missing defect of the gluing transparent film cannot be supported. UTILITY MODEL CONTENTS

[0005] The utility model provides a kind of thin film defect detection device, to realize the effective detection of the missed coating defect of gluing transparent film, provide an excellent optical imaging scheme, to enhance the contrast of gluing area, make defect more obvious, by setting light source oblique light and / or imaging unit oblique light collection, and the scheme of light source and imaging unit dislocation, so that machine vision system can more accurately identify and analyze glue missing defect, further improve the reliability and efficiency of detection.

[0006] According to an aspect of the utility model, a kind of thin film defect detection device is provided, including light source and imaging unit;

[0007] The light exit surface of the light source faces the first surface of the to-be-tested film, the imaging surface of the imaging unit faces the second surface of the to-be-tested film, the optical axis of the light source has a first preset non-zero included angle with the normal line of the first surface, and / or the optical axis of the imaging unit has a second preset non-zero included angle with the normal line of the second surface.

[0008] The illumination light beam emitted by the light source is incident on the first surface of the to-be-tested film, and the imaging unit receives the transmitted light of the to-be-tested film to obtain an image of the to-be-tested film.

[0009] The normal line passing through the center of the light exit surface of the light source intersects the first surface at a first intersection point, and the normal line passing through the center of the imaging unit intersects the first surface at a second intersection point, and the first intersection point and the second intersection point are misaligned by a preset distance.

[0010] Optionally, the optical axis of the light source has a first preset non-zero included angle with the normal line of the first surface, and the optical axis of the imaging unit is parallel to the normal line of the second surface.

[0011] Optionally, the optical axis of the light source is parallel to the normal line of the first surface, and the optical axis of the imaging unit has a second preset non-zero included angle with the normal line of the second surface.

[0012] Optionally, the first preset included angle is greater than or equal to 10° and less than or equal to 20°, and the second preset included angle is greater than or equal to 10° and less than or equal to 20°.

[0013] Optionally, the sum of the first preset included angle and the second preset included angle is less than or equal to 30°.

[0014] Optionally, the illumination light beam is a blue light beam or a violet light beam.

[0015] Optionally, the preset distance is greater than or equal to 10 mm.

[0016] Optionally, the apparatus further comprises a moving unit, the light source and / or the imaging unit is connected with the moving unit, and the moving unit controls the light source and / or the imaging unit to translate or rotate.

[0017] Optionally, the defects of the to-be-tested film include at least one of glue leakage defects, plate roller printing defects, uneven glue coating defects, mosquito and dirt contamination defects, or hole defects.

[0018] Optionally, the imaging unit comprises a lens and a camera located on the side of the lens away from the to-be-tested film, and the illumination light beam transmitted by the to-be-tested film is incident on the camera after passing through the lens.

[0019] The film defect detection device provided in the embodiment of the utility model, including light source and imaging unit, through setting the first surface of the light exit surface of light source towards the film to be measured, the imaging surface of imaging unit towards the second surface of the film to be measured, the optical axis of light source and the normal line of first surface have the first preset angle which is not zero, realize the oblique incidence of the illumination beam of light source exit to the first surface of the film to be measured, and / or the imaging surface optical axis of imaging unit and the normal line of second surface have the second preset angle which is not zero, realize the oblique exit light line received by imaging unit, the glue leakage area will produce different influence to the refraction and reflection of illumination beam due to the change of thickness and material, make these areas appear darker in imaging, the glue leakage feature is more obvious, through setting the imaging unit receives the transmission light of the film to be measured, obtain the image of the film to be measured, carry out defect detection according to the image, through setting the normal line through the light exit surface center of light source and first surface intersect at first intersection, the normal line through the center of imaging unit and first surface intersect at second intersection, first intersection and second intersection stagger preset distance, realize the staggered setting of light source and imaging unit, due to the non-uniformity of material of glue leakage area and non-glue leakage area, staggered setting will cause the light line to deviate from the expected path in the glue leakage area, produce obvious scattering.This makes the optical performance difference of normal area and defect area increase, the contrast of imaging improves, so that the glue leakage defect of transparent film can be detected well.The film defect detection device provided in the embodiment of the utility model in order to realize the effective detection of glue coating transparent film leakage defect, provide an excellent optical imaging scheme to enhance the contrast of glue coating area, make the defect more obvious, through setting light source oblique light and / or imaging unit oblique light receiving, and the scheme that light source and imaging unit stagger, make the machine vision system can more accurately identify and analyze the glue leakage defect, further improve the reliability and efficiency of detection.

[0020] It should be understood that the content described in this part is not intended to identify the key or important features of the embodiments of the utility model, nor is it used to limit the scope of the utility model. Other features of the utility model will become easy to understand through the following description. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical scheme in the embodiment of the utility model, the drawings needed to be used in the embodiment description will be briefly introduced below, obviously, the drawings in the following description are only some embodiments of the utility model, and for those skilled in the art, other drawings can be obtained according to these drawings without creating labor.

[0022] Figure 1 The structure diagram of the film defect detection device provided in the embodiment of the utility model is shown in the figure;

[0023] Figure 2Another structure schematic view of the film defect detection device is provided in the embodiment of the present application.

[0024] Figure 3 Another structure schematic view of the film defect detection device is provided in the embodiment of the present application.

[0025] Figure 4 The detection imaging schematic view of the transparent adhesive film glue leakage defect detected by the film defect detection device is provided in the embodiment of the present application.

[0026] Figure 5 Another structure schematic view of the film defect detection device is provided in the embodiment of the present application. DETAILED DESCRIPTION

[0027] In order to make the personnel in the technical field better understand the present application scheme, the technical scheme in the embodiment of the present application will be described clearly and completely in the following with reference to the drawings in the embodiment of the present application. Obviously, the described embodiment is only a part of the embodiment of the present application, not all. Based on the embodiment in the present application, all other embodiments obtained by the person skilled in the art without creative labor should belong to the protection scope of the present application.

[0028] It should be noted that the terms "first", "second" and the like in the specification and claims of the present application and the above drawings are used to distinguish similar objects, and do not have to be used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0029] Figure 1 A structure schematic view of the film defect detection device is provided in the embodiment of the present application, Figure 2 A structure schematic view of the film defect detection device is provided in the embodiment of the present application, Figure 3 A structure schematic view of the film defect detection device is provided in the embodiment of the present application, referring to Figures 1-3 The film defect detection device comprises a light source 10 and an imaging unit 20; the light emitting surface of the light source 10 faces the first surface of the film to be detected 30, Figures 1-3the imaging surface of the imaging unit 20 faces the second surface of the film to be measured 30 Figures 1-3 the imaging surface of the imaging unit 20 faces the second surface of the film to be measured 30

[0030] With reference to the above Figure 1 Optionally, the optical axis a of the light source 10 and the normal b of the first surface have a first preset angle a which is not zero, and the optical axis e of the imaging unit 20 and the normal f of the second surface are parallel, that is Figure 1 The embodiment of the light source 10 is inclined; with reference to the above Figure 2 Optionally, the optical axis a of the light source 10 and the normal b of the first surface are parallel, and the optical axis e of the imaging unit 20 and the normal f of the second surface have a second preset angle β which is not zero, that is Figure 2 The embodiment of the imaging unit 20 is inclined; with reference to the above Figure 3 Optionally, the optical axis a of the light source 10 and the normal b of the first surface have a first preset angle a which is not zero, and the optical axis e of the imaging unit 20 and the normal f of the second surface have a second preset angle β which is not zero, that is Figure 3 The embodiment of the light source 10 and the imaging unit 20 are both inclined. It should be noted that Figure 3 The light source 10 and the imaging unit 20 shown in the above are located on the right side of the normal, which is only illustrative. In other embodiments, the light source 10 can be located on the right side of the normal, and the imaging unit 20 can be located on the left side of the normal, or the light source 10 can be located on the left side of the normal, and the imaging unit 20 can be located on the right side of the normal. The specific implementation can be designed according to the actual situation.

[0031] It can be understood that the optical axis of the light source 10 is the axis line through the center of the light emitting surface of the light source 10, and the optical axis of the imaging unit 20 is the axis line through the center of the imaging unit 20. In the specific implementation, the first preset angle a and the second preset angle β can be designed according to the actual situation. In order to ensure the detection effect, the values of the first preset angle a and the second preset angle β should not be too large. Optionally, the first preset angle a can be designed to be greater than or equal to 10° and less than or equal to 20°, and the second preset angle β can be designed to be greater than or equal to 10° and less than or equal to 20°. Further, the sum of the first preset angle a and the second preset angle β can be designed to be less than or equal to 30°, which can be designed according to the actual situation in the specific implementation.

[0032] The film defect detection device provided in the embodiments of the present application can be used to detect glue leakage defects of a raw film, and the following embodiments are described by taking the detection of glue leakage defects as an example, and in other embodiments, the defects of the film to be detected can also include at least one of plate roller printing defects, uneven glue coating defects, mosquito and dirt contamination defects, or hole defects. In addition, it should be noted that the film defect detection device provided in the embodiments of the present application is not limited to be used in a glue coating film, and can also be used in other films with good light transmission, such as PET film and even glass and other materials.

[0033] In combination with Figure 1 The imaging principle of the film defect detection device is that the illumination light beam emitted by the light source 10 is incident on the lower surface of the film to be detected 30 at an oblique angle, and the glue leakage area will have different effects on the refraction and reflection of light due to the change in thickness and material, so that these areas appear darker in imaging, and the glue leakage features are more obvious. The light source 10 is not aligned with the imaging unit 20, and detection is performed through a certain misalignment. Due to the unevenness of the material of the glue leakage area and the non-glue leakage area, misalignment will cause the light to deviate from the expected path in the glue leakage area, resulting in obvious scattering. This increases the difference in optical performance between the normal area and the defect area, improves the contrast of imaging, and thus the glue leakage defects of the transparent film can be well detected.

[0034] Further, optionally, the illumination light beam is a blue light beam or a violet light beam. In specific implementation, a blue light source or a violet light source with a shorter wavelength is used. When a blue light source or a violet light source is used, the absorption and reflection characteristics of the glue to blue light or violet light are more obvious, so that the edge or thickness change of the glue can be highlighted, thereby improving the contrast between the glue leakage part and the non-glue leakage part. In addition, the imaging scheme detects through a certain misalignment, which usually causes the background to be dark, which is not conducive to image processing by the algorithm, and although imaging can be performed, it is not practical. However, the short wavelength of blue light or violet light reduces scattering and absorption in the film, enhances the intensity of transmitted light, makes the background brighter, and effectively improves the practicability of the scheme.

[0035] Exemplarily, Figure 4 The film defect detection device provided in the embodiments of the present application detects the imaging schematic diagram of the glue leakage defect of the transparent glue coating film. The film to be detected is a glue coating transparent film, and the black part is a glue leakage defect. Through image processing, it can be known that the contrast between the glue leakage defect and the background gray scale is greater than 60DN. The contrast is very high, and through post-processing by the algorithm, the glue leakage defect can be stably detected, and the difficulty of implementation in industry is relatively small.

[0036] On the basis of the above embodiments, optionally, the preset distance d can be greater than or equal to 10mm.

[0037] By setting the preset distance d greater than or equal to 10 mm, the optical performance difference between the normal area and the defect area is increased, the imaging contrast is improved, and thus the glue leakage defect of the transparent film can be well detected.

[0038] In another embodiment, the film defect detection device further comprises a moving unit, the light source and / or the imaging unit are connected with the moving unit, and the moving unit controls the light source and / or the imaging unit to translate or rotate.

[0039] In some embodiments, if the area of the film to be detected is large, the illumination light beam emitted by the light source cannot illuminate all areas of the film to be detected, and / or the imaging unit cannot image all areas of the film to be detected at one time, the moving unit can be arranged to translate the position of the light source and / or the imaging unit to realize scanning of all areas of the film to be detected. In some embodiments, the setting of the inclination angle of the light source and / or the imaging unit may be good for the detection of some films to be detected, but not good for the detection of other films to be detected, and the contrast between the normal area and the defect area is low, and then the moving unit can be arranged to rotate the inclination angle of the light source and / or the imaging unit to improve the detection quality.

[0040] For example, the light source and the imaging unit are connected with the moving unit, Figure 5 Another film defect detection device provided by the embodiment of the utility model has the structure diagram, reference Figure 5 The film defect detection device further comprises a moving unit 40, the moving unit comprises a first moving unit 41 and a second moving unit 42, the light source 10 is connected with the first moving unit 41, the imaging unit 20 is connected with the second moving unit 42, the first moving unit 41 controls the light source 10 to translate or rotate, and the second moving unit 42 controls the imaging unit 20 to translate or rotate.

[0041] For example, Figure 5 The directions of translation and rotation of the light source 10 and the imaging unit 20 are also shown, the translation direction can be parallel to the plane where the film to be detected 30 is located, when rotating, the intersection of the corresponding optical axis and the surface of the film to be detected 30 can be taken as the center to change the included angle with the normal line, and the translation distance and the rotation angle can be designed according to actual conditions, and the embodiment of the utility model is not limited thereto.

[0042] Continuing to refer to Figures 1-3 Or Figure 5 Optionally, the imaging unit 20 comprises a lens 21 and a camera 22 located on the side of the lens 21 away from the film to be detected 30, and the illumination light beam transmitted by the film to be detected 30 is incident to the camera 22 after passing through the lens 21.

[0043] The structure of the lens 21 can be designed according to actual conditions, for example, a fixed-focus lens or a zoom lens including multiple lenses can be selected, and the camera 22 can be an industrial camera, specifically a CCD camera or a CMOS camera, which can be selected according to actual conditions in specific implementation.

[0044] The above specific embodiments do not constitute a limitation on the protection scope of the present application. Those skilled in the art should understand that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A thin film defect detection apparatus characterized by comprising: The light source and the imaging unit are included. The light exit surface of the light source faces the first surface of the to-be-tested film, the imaging surface of the imaging unit faces the second surface of the to-be-tested film, the optical axis of the light source has a first preset angle with the normal line of the first surface, and / or the optical axis of the imaging unit has a second preset angle with the normal line of the second surface. The illumination light beam emitted by the light source is incident to the first surface of the to-be-tested film, and the imaging unit receives the transmitted light of the to-be-tested film to obtain the image of the to-be-tested film. The normal line passing through the center of the light exit surface of the light source intersects the first surface at a first intersection point, and the normal line passing through the center of the imaging unit intersects the first surface at a second intersection point, and the first intersection point and the second intersection point are misaligned by a preset distance.

2. The film defect inspection apparatus according to claim 1, wherein The optical axis of the light source is parallel to the normal line of the first surface, and the optical axis of the imaging unit is parallel to the normal line of the second surface.

3. The film defect inspection apparatus according to claim 1, wherein The optical axis of the light source is parallel to the normal line of the first surface, and the optical axis of the imaging unit is parallel to the normal line of the second surface.

4. The film defect inspection apparatus according to claim 1, wherein The first preset angle is greater than or equal to 10° and less than or equal to 20°, and the second preset angle is greater than or equal to 10° and less than or equal to 20°.

5. The film defect inspection apparatus according to claim 1, wherein The sum of the first preset angle and the second preset angle is less than or equal to 30°.

6. The film defect inspection apparatus according to claim 1, wherein The illumination light beam is a blue light beam or a violet light beam.

7. The film defect inspection apparatus according to claim 1, wherein The preset distance is greater than or equal to 10 mm.

8. The film defect inspection apparatus according to claim 1, wherein A moving unit is further included, the light source and / or the imaging unit is connected with the moving unit, and the moving unit controls the translation or rotation of the light source and / or the imaging unit.

9. The film defect inspection apparatus according to claim 1, wherein The defects of the to-be-tested film include at least one of glue leakage defects, plate roller printing defects, uneven glue coating defects, mosquito and dirt contamination defects, or hole defects.

10. The film defect detection apparatus of claim 1, wherein The imaging unit includes a lens and a camera located on the side of the lens away from the to-be-tested film, and the illumination light beam transmitted by the to-be-tested film is incident to the camera after passing through the lens.

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