Detection system for optical film

Abstract

The invention relates to a detection system for an optical film. The system comprises a first detection device and a second detection device, the first detection device comprises a mark detection part, the mark detection part detects whether a mark exists on the optical film or not, and for the optical film where the mark is detected, a to-be-detected area of the optical film is determined based on the position and the size of the mark on the optical film; the second detection device comprises a bright spot detection component which detects the to-be-detected area of the optical film so as to obtain a characteristic value related to a bright spot. According to the system, automation of feeding, conveying, detection and storage of the optical film is achieved, the detection accuracy is improved, meanwhile, the detection efficiency is improved, and manpower is greatly saved.

Description

Technical Field

[0001] This invention relates to a detection system for optical films. Background Technology

[0002] In the pre-processing stage of optical film manufacturing, defects in the optical film may be marked. Then, in the post-processing stage of slitting the optical film, the marked defects need to be identified again and further defect inspection needs to be performed. The traditional method is to use manual inspection, but this process is complex, time-consuming, inefficient, and lacks accuracy. Summary of the Invention

[0003] The purpose of this invention is to provide a detection system for automated detection of optical films, which automates the loading, conveying, detection and storage of optical films, improves the accuracy of detection, increases the efficiency of detection, and greatly saves manpower.

[0004] This invention discloses a detection system for optical films, the system comprising a first detection device and a second detection device;

[0005] The first detection device includes a mark detection component, which detects whether a mark exists on the optical film, and for the optical film in which the mark is detected, determines the area to be inspected on the optical film based on the position and size of the mark on the optical film;

[0006] The second detection device includes a spot detection component, which detects the area to be inspected in the optical film to obtain feature values ​​related to the spot.

[0007] Optionally, the mark detection component divides the area to be inspected to determine multiple detection areas and a detection sequence;

[0008] The spot detection component detects the plurality of detection areas in the area to be inspected according to the detection sequence, wherein the spot detection component includes a camera, and the size of the detection area is associated with a single effective field of view of the camera.

[0009] Optionally, the second detection device further includes a mark re-inspection component, which determines whether the area to be inspected is in a designated position, and when the area to be inspected is not in the designated position, the optical film is repositioned.

[0010] Optionally, the second detection device further includes a 3D detection component, which determines the degree of warpage of the area to be inspected at the designated location, and the depth of field of the camera of the spot detection component is adjusted based on the degree of warpage.

[0011] Optionally, the system further includes a third detection device;

[0012] The third detection device includes a reverse film detection component, which uses a filter set to detect whether the optical film has the release film layer facing upwards, and for the optical film detected to have the release film layer facing upwards, determines the filter in the filter set that matches the optical film;

[0013] The spot detection component selects a matching filter to detect the area to be inspected on the optical film.

[0014] Optionally, the system further includes one or more vehicle devices;

[0015] The optical film is carried by one or more carrier devices to move to a corresponding detection device; each carrier device includes a platform having a suction hole and a through hole, the suction hole adsorbing the optical film, and the through hole serving as the designated position allowing light to pass through and enter the camera of the spot detection component.

[0016] Optionally, the platform can translate in the X and Y directions and rotate about the Z direction to adjust the adsorbed optical film and move the optical film according to the detection sequence.

[0017] Optionally, the system further includes a feeding device;

[0018] The feeding device includes an adsorption component and a multi-piece detection component. The adsorption component adsorbs the optical film from the feeding hopper. The multi-piece detection component detects whether the adsorbed optical film is a single piece. For optical films detected as single pieces, the adsorption component places the optical film onto the carrier device.

[0019] Optionally, the system further includes a transfer device;

[0020] The transfer device transfers the optical film carried on one carrier device to another carrier device.

[0021] Optionally, the tested optical film is collected into a corresponding receiving bin.

[0022] The main differences and effects of this invention compared to existing technologies are as follows:

[0023] This invention automates the feeding, conveying, testing, and storage of optical films, improving testing accuracy and efficiency while significantly saving manpower. Attached Figure Description

[0024] Figure 1 This is an overall schematic diagram of the detection system according to an embodiment of the present invention;

[0025] Figure 2 This is a schematic diagram of the detection area according to an embodiment of the present invention;

[0026] Figure 3 This is a schematic diagram illustrating the detection sequence for detecting a detection area according to an embodiment of the present invention;

[0027] Figure 4 This is a schematic diagram of a spot detection component according to an embodiment of the present invention. Detailed Implementation

[0028] To make the objectives and technical solutions of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0029] Embodiments of the present invention relate to a detection system for detecting optical films.

[0030] Figure 1 This is a schematic diagram of a detection system according to an embodiment of the present invention. Figure 1 As shown, the detection system includes a feeding device 101, a first detection device, a second detection device, and one or more carrier devices. The first detection device includes a mark detection component 102, the second detection device includes a dot detection component 103, and the one or more carrier devices may include a first carrier device 104, a second carrier device 105, and a third carrier device 106.

[0031] The feeding device 101 includes an adsorption component. In one embodiment, the adsorption component is provided with a suction cup, and the suction cup is provided with multiple suction nozzles. During feeding, the feeding device 101 uses the suction cup of the adsorption component to pick up optical films from the feeding bin (not shown) and places the picked-up optical films onto the carrier device 104. In one embodiment, the feeding bin is also provided with grid-shaped bar clamps for clamping the stacked optical films to be picked up. The position of the bar clamps can be adjusted synchronously to clamp the optical film stacks for different sizes of optical films.

[0032] In addition, the feeding device 101 also includes multiple detection components. When picking up optical films, these multiple detection components detect the number of optical films picked up by the adsorption component in a single operation, for example, through photoelectric sensing. When multiple optical films are detected adsorbed on the nozzle, the nozzle can knock off excess or all of the multiple optical films by moving up and down, for example, and place them into the corresponding first receiving bin 107, preventing multiple films from stacking and affecting detection during subsequent testing. In one embodiment, the number of times multiple films are picked up can be displayed in real time, and the cumulative number of occurrences can be saved within a set time. If a set number of multiple films are picked up consecutively, the system's alarm shutdown function will be triggered. Additionally, if the knocked-off optical film lands on the aforementioned feed bar, the system's alarm shutdown function will be triggered. Furthermore, if the nozzle does not pick up an optical film during adsorption, the system's alarm shutdown function will also be triggered.

[0033] The detection system includes one or more carrier devices, specifically, a first carrier device 104, a second carrier device 105, and a third carrier device 106. (Reference) Figure 1 The first carrier device 104 carries the optical film from the feeding device 101 to the second carrier device 105, the second carrier device 105 carries the optical film to the first detection device, and the third carrier device 106 carries the optical film to the second detection device.

[0034] In this embodiment, the optical film detection system further includes a transfer device 108, which transfers the optical film, which has been detected by the first detection device and is carried on the second carrier device 105, to the third carrier device 106.

[0035] As an example, the transfer device 108 is a robotic arm. Furthermore, the robotic arm can have two grippers; while one gripper is performing a gripping and placing action, the other gripper is in a standby state. The two grippers work alternately in a cyclical manner to increase work efficiency. In addition, each type of optical film has its own fixed axis angle. The detection system writes different axis angles and the corresponding rotation angle values ​​into the system. Therefore, before the robotic arm transports the optical film to the spot detection carrier device, it rotates the optical film by the corresponding rotation angle stored in the system.

[0036] One or more carrier devices include a platform for carrying optical films, the platform having suction holes, allowing for visualized operational management of the adsorption capacity by controlling the air pressure in the air chamber, thus achieving stable adsorption of various optical films. Additionally, the platform has through-holes through which the optical films can be imaged, with a light source and a camera respectively positioned on opposite sides of the through-holes.

[0037] One or more carrier devices can translate in the X and Y directions and rotate about the Z direction, where the X and Y directions refer to the axial and vertical axial directions of the optical film, respectively, and the Z direction refers to the height direction of the optical film. When transporting the optical film via the carrier device, the position of the optical film can be adjusted using the rotation function of the carrier device. The adjustment method is as follows: First, determine the deflection angle θ of the long side of the optical film relative to the forward direction. Then, determine if θ < α (α is a predetermined deflection angle threshold, which is associated with the upper limit of the rotation function of the third carrier device 106), then the deflection angle θ is corrected by rotating the carrier device about the Z direction. If θ > α, it indicates that the rotation of the carrier device cannot completely correct the deflection angle θ, thus triggering the system's alarm shutdown function.

[0038] After the loading process is completed, the first carrier device 104 transports the adsorbed optical film to the first detection device. The first detection device includes a mark detection component 102, which operates on the optical film to be detected, including detecting whether a mark exists on the optical film.

[0039] The mark originates from the defect detection stage in the upstream process of manufacturing the optical film, indicating defects detected on the uncut optical film (such as glow spots that are light leakage points in the liquid crystal layer present in the optical film). After the optical film is cut, the mark may be located on one or more cut optical films, and some cut optical films may not have a mark. The presence of a mark on the cut optical film can be detected by means of, for example, image recognition.

[0040] The operation performed by the mark detection component 102 also includes determining the area to be inspected on the optical film based on the position and size of the mark on the optical film for detecting the mark.

[0041] The optical film to be inspected and its markings are located by calculating the center coordinates of the optical film and the markings to determine the position of the markings on the optical film. The size of the markings is also calculated. Based on the position and size of the markings on the optical film, the area to be inspected is determined. It is understood that the area to be inspected refers to the rectangular or non-rectangular area surrounding the markings. In one embodiment, when two or more areas to be inspected are detected on the optical film, or when no markings are detected on the optical film, no further inspection is performed, and the optical film is transported to the corresponding second receiving bin 109 using the transfer device 108. The second receiving bin 109 is used to receive other optical films besides the multiple absorber optical films received by the first receiving bin 107 mentioned above, and to classify them.

[0042] The operation performed by the mark detection component 102 also includes dividing the area to be inspected, determining multiple detection areas and detection order, so that the spot detection component, which will be mentioned later, can detect multiple detection areas in accordance with the detection order to obtain feature values ​​related to the spot.

[0043] It is understandable that the detection area refers to a rectangular or non-rectangular area smaller than the area to be inspected. Multiple detection areas constitute the area to be inspected, and the size of each detection area is related to the single effective field of view of the camera included in the spot detection component. For example, if the overall field of view of the camera is 21mm*16mm and the single effective field of view is 7mm*6mm, then the size of the detection area can also be 7mm*6mm, or slightly larger or smaller than 7mm*6mm.

[0044] In one embodiment, the divided detection regions may overlap to avoid missed detections. For example, see reference. Figure 2 The example shown, Figure 2 The six detection zones 202 are depicted within the area to be inspected 201. 1-6 In this configuration, detection area 2021 overlaps with detection areas 2022 and 2024, detection area 2022 overlaps with detection areas 2021, 2023, and 2025, detection area 2023 overlaps with detection areas 2022 and 2026, detection area 2024 overlaps with detection areas 2021 and 2025, detection area 2025 overlaps with detection areas 2022, 2024, and 2026, and detection area 2026 overlaps with detection areas 2023 and 2025. For example, the overlap is 1mm to 1.5mm.

[0045] The detection sequence refers to the order in which each detection area is detected in the subsequent spot detection operation. Specifically, by keeping the camera included in the spot detection component stationary, the second carrier device 105 located at the second detection device is moved, thereby causing the detection areas on the optical film carried thereon to move sequentially to the camera's imaging position according to the detection sequence, thus performing spot detection on the optical film. For example, see reference... Figure 3 The example shown, Figure 3 The six detection zones 202 are depicted within the area to be inspected 201. 1-6 Detection areas 2021, 2022, 2023, 2026, 2025, and 2024 are moved sequentially to the camera's imaging position in the direction indicated by the arrows.

[0046] After the mark detection is completed, the optical film is transported to the second detection device via the second carrier device 105. The second detection device includes a spot detection component 103. For example, see reference... Figure 4 The example shown, Figure 4 The specific configuration of the spot detection component 103 is described. This component includes a camera 401, a filter group 402, a field-of-view compensation plate 403, a bandpass filter 405, and a light source 406. The optical film 404 to be detected is placed between the field-of-view compensation plate 403 and the bandpass filter 405 for detection. As an example, the optical film to be detected is a polarizing film, comprising at least three layers: a protective layer, a polarizing layer, and a release layer, arranged sequentially. The spot detection component 103 detects multiple detection areas within the detection area on the optical film according to the aforementioned detection sequence to obtain feature values ​​related to the spot. These feature values ​​include, for example, the in-plane average grayscale, the spot area, and the maximum grayscale value of the spot.

[0047] The filter group 402 includes multiple filters, each with different light-receiving amounts. When performing glow point detection, a filter that matches the optical film is selected so that the gray value of that filter is the lowest (for example, selecting a filter with a gray value of 3 from multiple filters with gray values ​​of 3, 5, 8, 11, 7, 6, 5, and 4 as the matching filter), thereby making the glow point more obvious, that is, making the detection structure more accurate.

[0048] The field-of-view compensation patch 403 is used to improve the uniformity of the camera's effective field of view, that is, to keep the brightness range in the effective field of view area of ​​the camera small, and to make the brightness of each position in the field of view relatively similar, which is beneficial to improving the accuracy of the detection results.

[0049] Since the marks on the optical film may affect the detection of the glow point, a bandpass filter 405 is introduced into the glow point detection component 103 to remove the interference of the marks on the detection of the glow point.

[0050] Since it is necessary to eliminate interference from uncontrollable factors as much as possible during the detection process, the spot detection process can be carried out in a dark box, and a light source 406 is used to provide the light required for the detection process.

[0051] The optical film 404 to be tested is placed on a third carrier device 106 at the spot detection component 103. This third carrier device 106, also referred to as a spot detection carrier device, can be structurally identical to or different from the first carrier device 104 at the first detection device. The spot detection carrier device includes a platform for supporting the optical film, which has suction holes. The adsorption capacity can be visualized and managed by controlling the air pressure in the air chamber, achieving stable adsorption of various optical films. Additionally, the platform has through-holes through which the optical film can be imaged. A bandpass filter 405 and a light source 406 are located on one side of the through-hole, while a camera 401, a filter group 402, a field-of-view compensation plate 403, and the optical film 404 are located on the other side. For example, the through-hole size is 50mm*50mm. In another embodiment, the platform has two through-holes, the configuration of which can accommodate optical films of different sizes and different detection angles. For example, the sizes of the two through holes are 25mm*20mm and 50mm*50mm, respectively, and the center distance between the two through holes is 100mm. It is understood that, according to actual testing requirements, those skilled in the art can adjust the size of each through hole and the center distance between the two through holes without restriction.

[0052] Similar to the second carrier device 105 at the first detection device, the platform included in the spot detection carrier device can also translate in the X and Y directions and rotate about the Z direction as an axis. This allows the optical film to move to the imaging position of the camera when the platform moves in space, thereby causing the optical film adsorbed on its surface to move in an inching motion. This enables the sequential detection of multiple detection areas according to the detection order, and the platform can be rotated in space to correct the deflection angle of the optical film.

[0053] There can be multiple second receiving bins 109, and the type of optical film collected in each second receiving bin 109 can be set by the user, so that optical films that have undergone different detection processes can be transported to the corresponding second receiving bin 109. Specifically, optical films that have two or more areas to be inspected or have no detected markings at the first detection device can be transported to the corresponding second receiving bin 109, and optical films that have completed spot detection at the second detection device can be transported to the corresponding second receiving bin 109.

[0054] In one embodiment, the detection system further includes a third detection device. After the first carrier device 104 transports the optical film to the second carrier device 105, the second carrier device 105 first conveys the optical film to the third detection device, and then to the mark detection component 102. The third detection device includes a reflection detection component 110. Considering that the dot detection should be performed on optical films with the same facing side, and that the dot characteristic values ​​of optical films with different facing sides are not comparable, the reflection detection component 110 is provided here to detect whether the release film layer of the optical film is facing upwards. In this embodiment, when the protective layer of the optical film is facing upwards (i.e., the release layer is facing downwards), it is a reflection.

[0055] Due to the structural characteristics of the optical film, the release film layer and the protective film layer of the optical film have different polarizations of light. Therefore, the light source can be placed on one side of the through-hole of the platform included in the first carrier device 104, and the camera, filter group, and optical film can be placed on the other side of the through-hole of the platform. The reverse film detection component 110 detects whether the optical film has the release film layer facing upward by determining the gray value of the filter. When the release film layer is facing upward, the gray value of the filter is within a first range (such as 3 to 220), and when the release film layer is facing downward, the gray value of the filter is within a second range (such as 50 to 80). Based on this, when the gray values ​​of a group of filters are all within the second range (for example, the gray values ​​of the group of filters are 58, 60, 66, 69, 74, 71, 68, and 62 respectively), it indicates that the current optical film has the release film layer facing downward, and no further detection is performed. The optical film is then transported to the corresponding second receiving bin 109. If reverse film is detected multiple times consecutively, the system's alarm shutdown function is triggered.

[0056] In one embodiment, the reverse film detection component 110 has multiple filter groups, and each filter group includes multiple filters with different light-receiving amounts. For different types of optical films, it can automatically switch to the corresponding filter group according to the settings. If it is determined that the optical film has the release film layer facing up, but the gray values ​​of the corresponding filter group are all greater than the set threshold (for example, the gray values ​​of the filter group are 15, 16, 17, 18, 19, 20, 17, and 16 respectively), it indicates that the optical film is mixed, that is, the actual type of the optical film is different from the type it is marked, and no further detection is performed. The optical film is then transported to the corresponding second receiving bin 109. If a predetermined number of mixing situations occur consecutively, the system's alarm shutdown function is triggered.

[0057] Furthermore, the reverse film detection component 110 can also be used to select a matching filter for subsequent spot detection for the second detection device 103. That is, when the reverse film detection component 110 determines that the optical film is release film layer facing up and is not mixed material, it can further determine a filter that matches the optical film, such that the filter has the lowest gray value (for example, selecting a filter with a gray value of 3 from multiple filters with gray values ​​of 3, 5, 8, 11, 7, 6, 5, and 4 respectively). The matching filter information is sent to the second detection device 103 to select the corresponding filter from the filter group 402.

[0058] Therefore, the reverse film detection component 110 can simultaneously perform reverse film detection and select the best filter, which can save workstations.

[0059] In one embodiment, the second detection device may further include a mark re-inspection component 111. Before performing dot detection, the dot detection carrier device first transports the optical film to the mark re-inspection component 111. The mark re-inspection component 111 can determine whether the area to be inspected of the optical film is placed at the center of the through-hole of the platform included in the dot detection carrier device based on the center coordinates of the area to be inspected. When the area to be inspected is detected to be out of position, the optical film can be repositioned. In addition, the mark re-inspection component 111 can also determine the deflection angle of the optical film to be corrected by the rotation function of the platform. Furthermore, when the rotation function of the platform cannot correct the deflection of the optical film, the optical film is transported to the corresponding second receiving bin 109 using the transfer device 108.

[0060] In one embodiment, the second detection device may further include a 3D detection component 112. After the mark re-inspection, the dot matrix detection carrier device then conveys the optical film to the 3D detection component 112. The 3D detection component 112 measures the optical film using a 3D line scan measuring instrument, thereby obtaining a contour point cloud map of the optical film. The extreme or average value of the 3D measurement values ​​of each detection area located at the center of the through-hole can be calculated from the contour point cloud map, which can indicate the warpage of the detection area. This warpage is sent to the dot matrix detection component 103, so that the dot matrix detection component 103 can adjust the depth of field of the camera (e.g., ±0.5 mm) according to the warpage to correct the warpage of the corresponding detection area, and then sequentially detect each detection area within the normal depth of field range. Additionally, if the warpage of the optical film exceeds a set value, i.e., cannot be corrected by adjusting the depth of field of the camera, then subsequent dot matrix detection is not performed, and the optical film is instead transported to the corresponding second receiving bin 109. In addition, if the warping of multiple optical films exceeds the set value, the system's alarm shutdown function will be triggered.

[0061] It should be noted that in the claims and description of this invention, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one" does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0062] Although the invention has been illustrated and described with reference to certain preferred embodiments thereof, those skilled in the art will understand that various changes in form and detail may be made therein without departing from the spirit and scope of the invention.

Claims

1. A detection system for optical films, characterized by, The system comprises a first detection device and a second detection device; The first detection device comprises a mark detection component, which detects whether a mark exists on the optical film, and for the optical film on which the mark is detected, determines a to-be-inspected region of the optical film based on a position and size of the mark on the optical film; The second detection device comprises a highlight detection component, which detects the to-be-inspected region of the optical film to obtain a feature value related to a highlight.

2. The system of claim 1, wherein, The mark detection component divides the to-be-inspected region, determines a plurality of detection regions and a detection order; The highlight detection component detects the plurality of detection regions in the to-be-inspected region in the detection order, wherein the highlight detection component comprises a camera, and a size of the detection region is associated with a single effective field of view of the camera.

3. The system of claim 2, wherein, The second detection device further comprises a mark re-inspection component, which determines whether the to-be-inspected region is at a specified position, and when the to-be-inspected region is not at the specified position, the optical film is re-placed.

4. The system of claim 3, wherein, The second detection device further comprises a 3D detection component, which determines a degree of warping of the to-be-inspected region at the specified position, and a depth of field of the camera of the highlight detection component is adjusted based on the degree of warping.

5. The system of claim 4, wherein, The system further comprises a third detection device; The third detection device comprises a reverse sheet detection component, which uses a filter set to detect whether the optical film is a release film layer facing up, and for the optical film detected as the release film layer facing up, determines a filter in the filter set that matches the optical film; The highlight detection component selects the matched filter to detect the to-be-inspected region of the optical film.

6. The system of claim 5, wherein, The system further comprises one or more carrier devices; The one or more carrier devices carry the optical film to move to the corresponding detection device; each carrier device comprises a platform having a suction hole and a through hole, the suction hole adsorbs the optical film, and the through hole serves as the specified position to enable light to pass therethrough and enter the camera of the highlight detection component.

7. The system of claim 6, wherein, The platform is capable of translation in X and Y directions and rotation about a Z direction to adjust the adsorbed optical film and move the optical film in the detection order.

8. The system of claim 7, wherein, The system further comprises a feeding device; The feeding device comprises a suction component and a multiple-piece detection component, the suction component adsorbs the optical film from a feeding bin, and the multiple-piece detection component detects whether the adsorbed optical film is a single piece, and for the optical film detected as the single piece, the suction component places the optical film on the carrier device.

9. The system of claim 8, wherein, The system further comprises a transfer device; The transfer device transfers the optical film carried on one carrier device to another carrier device.

10. The system of claim 9, wherein, The detected optical film is collected into a corresponding collection bin.

Images