Appearance detection method for anti-dazzle film of polaroid

Abstract

According to the appearance detection method based on multi-angle and standardized shooting measurement, the traceability of detection parameters can be realized by controlling the shooting angle change of a light source and camera equipment, and the detection efficiency and operability are remarkably improved; meanwhile, through comparison between an image processing algorithm and a database, the reliability of a standardized detection result is ensured.

Description

Technical Field

[0001] The present invention relates to the field of detection technology, and specifically to a method for detecting the appearance of an anti-glare film outside a polarizer, specifically a detection method for high-precision appearance quality evaluation of an anti-glare film (AG film) using standardized parameters and multi-angle detection technology, covering reflected light evaluation, light spot uniformity analysis, etc. Background Art

[0002] Polarizers are important optical components of display devices and are widely used in liquid crystal displays (LCDs), organic light-emitting diode (OLED) displays and other fields. Their performance directly affects the optical effects and user experience of display devices. In order to meet the requirements of display devices for reduced glare, high contrast and high definition, the surface of polarizers is usually covered with functional coatings or films, among which AG (anti-glare) film is an extremely critical component.

[0003] Anti-glare film (AG film) achieves diffuse reflection effect through special surface treatment, effectively reducing screen reflected light, improving visibility in strong light environment, and enhancing the clarity and comfort of the display. The preparation of anti-glare film (AG film) must not only meet the requirements of good mechanical properties such as wear resistance and adhesion, but also have uniform diffuse reflection effect and high flatness and consistency of the film surface.

[0004] The realization of the above performance requirements is highly dependent on precise manufacturing processes. However, in large-scale production, due to the unevenness of raw materials, process fluctuations and interference from the external environment, the surface of the anti-glare film (AG film) is prone to appearance differences.

[0005] Therefore, the detection of the surface quality of the external anti-glare film (AG film) is a key link in ensuring the overall performance of the polarizer, and the appearance performance is the key to the evaluation of the anti-glare film (AG film) by the polarizer factory.

[0006] At present, the appearance inspection of polarizer anti-glare film (AG film) mainly relies on human eyes to observe the diffuse reflection effect of the protective film on external light and compare it with the standard sample. The traditional manual naked eye inspection method is time-consuming and has large errors, which makes it difficult to meet the efficiency and accuracy requirements of large-scale production lines. Specifically, there are the following problems: strong subjectivity, different inspectors are prone to fluctuations in test results due to personal experience and perception differences; at the same time, due to the high sensitivity of naked eye inspection to ambient light, there is a problem that changes in ambient light sources have a great impact on the test results; in addition, in different display application scenarios, there is a lack of universal inspection standards applicable to various specifications of anti-glare films (AG films); and the time-consuming manual evaluation process causes low inspection efficiency.

[0007] CN201420806640.7 discloses a reverse osmosis membrane appearance detection device, including a detection platform, a detection light source, a driving roller, a membrane unwinding mechanism and a membrane winding mechanism; the membrane unwinding mechanism and the membrane winding mechanism are respectively arranged on both sides of the detection platform, and a transparent detection panel is horizontally arranged on the detection platform. The driving roller includes a left driving roller and a right driving roller, and the left and right driving rollers are respectively mounted on both ends of the detection panel; the detection light source is arranged under the detection panel, and the membrane winding mechanism is connected to the driving mechanism.

[0008] CN202220355672.4 discloses a TPU film appearance detection device, including a base, a light source table is fixedly connected to the top of the base, a first slide groove is opened on one side of the light source table, a second slide groove is opened on the inner wall of the light source table away from the first slide groove, a first slide rod is slidably connected in the second slide groove, an end of the first slide rod away from the second slide groove passes through the first slide groove to be slidably connected, a thread is opened on the end of the first slide rod close to the first slide groove, and a first limiting ring is connected to the first slide rod through a thread.

[0009] CN202322567605.6 discloses an ITO film appearance inspection device, comprising a frame, an outer wall of the frame is provided with a display panel, and an inner bottom wall of the frame is fixedly connected to a fixed plate, the top of the fixed plate is fixedly connected to a fixed frame, and the inner wall bearing of the support plate is connected to a fixed rod, and the top of the fixed rod is fixedly connected to an adjustment plate.

[0010] CN202311798855.9 discloses a PET transparent film visual appearance detection device, which relates to the technical field of film appearance detection, including a workbench, on which a conveying mechanism for conveying the PET transparent film is provided, and on which a plurality of detection stations for detecting different appearance characteristics of the PET transparent film are provided, and the detection station is equipped with a light source for irradiation at different angles, and a visual detection component for detecting the front and back appearances of the PET transparent film; the visual detection component is arranged on both sides of the conveying mechanism, and the conveying mechanism, the light source and the visual detection component are connected to a control system.

[0011] The above appearance inspection equipment lacks a universal design for films with different optical properties and specifications, and is difficult to adapt to the needs of anti-glare film surface quality assessment. At the same time, the anti-interference ability to changes in ambient light is insufficient, and part of the inspection process still relies on manual observation or subjective comparison, which cannot achieve an efficient and accurate inspection process and cannot fully meet the needs of industrial production lines.

[0012] In order to overcome these problems, the present invention provides a multi-angle, high-precision and easy-to-operate anti-glare film (AG film) appearance inspection method. Summary of the invention

[0013] In order to solve the technical problems of existing anti-glare film (AG film) detection, the present invention provides an appearance detection method through multi-angle, standardized shooting and measurement. By controlling the shooting angle changes of the light source and the camera equipment, the traceability of the detection parameters can be achieved, which significantly improves the detection efficiency and operability. At the same time, by comparing the image processing algorithm with the database, the reliability of the standardized detection results is ensured.

[0014] The detection method firstly makes the anti-glare film (AG film) sheet into a flat sample with a black back surface to be observed, in order to eliminate the influence of stray light such as transmitted light on the detection accuracy and ensure that the reflected light tested is completely determined by the surface characteristics of the anti-glare film (AG film). Then, a standardized light source and shooting equipment are used to detect the diffuse reflection characteristics of the anti-glare film (AG film) surface.

[0015] The present invention first provides a method for detecting a membrane, comprising:

[0016] Step (1), sampling: selecting a film sample to be tested, a bonding adhesive, and a light-absorbing substrate;

[0017] Step (2), sample preparation: place the light-absorbing substrate on the operating table, and place the bonding adhesive and the film to be tested in sequence from bottom to top to ensure that the surface of the film to be tested is flat;

[0018] Step (3), assembly: select a light source and a photographing device, and adjust the angle θ of the light source and the photographing device so that the center of the incident light and the photographing center are aligned with the film sample to be tested;

[0019] Step (4), data acquisition: save high-resolution images in sequence according to preset shooting angles and mark angle parameters;

[0020] Step (5), detection: analyze the collected image, measure the diameter and area of ​​the reflected light, compare the uniformity, and confirm whether it meets the acceptance standard.

[0021] Furthermore, the film to be tested is an anti-glare film or an anti-glare anti-reflection film.

[0022] Furthermore, the bonding adhesive is OCA bonding adhesive, UV curing adhesive or other optically transparent bonding adhesive.

[0023] Furthermore, the light-absorbing substrate is a black light-absorbing substrate with a reflectivity less than 10%, or 5%, 2%, or 0%.

[0024] Furthermore, the light-absorbing substrate is a polymethyl methacrylate substrate, a polycarbonate substrate, a polyvinyl chloride substrate or a polystyrene substrate, and has a smooth surface.

[0025] Furthermore, the size of the membrane to be tested is a (mm)×a (mm), where a is less than or equal to 1000, or 800, 500, 400, 300, 200, 100, or 50.

[0026] Furthermore, the size of the bonding adhesive is b (mm) × b (mm), where b is less than or equal to 1000, or 800, 500, 400, 300, 200, 100, or 50.

[0027] Furthermore, the size of the light-absorbing substrate is c (mm)×c (mm), where c is less than or equal to 2000, or 1500, 1000, 800, 500, 400, 300, 200, or 100.

[0028] Furthermore, the light source is a D65 standard light source, the color temperature of the light source is fixed at 6500K, and the brightness stability deviation is less than ±1%.

[0029] Furthermore, the photographing device is a camera, a mobile phone or an industrial camera.

[0030] Furthermore, the aperture of the camera is fixed at F / 1.78, the shutter speed is fixed at 1 / 100s, and the focus mode uses the auto focus mode.

[0031] Furthermore, the angle θ is 20° to 85°, or 25°, 30°, 45°, 50°, 55°, 60°, or 75°.

[0032] The angle θ is the incident angle for the light source, which refers to the angle between the light source and the vertical line; for the shooting device, it is the shooting angle, which refers to the angle between the line connecting the shooting device and the sample and the vertical line.

[0033] Furthermore, the resolution of the high-resolution image is 1080p (1920x1080 pixels), 2K (2560x1440 pixels), 4K (3840x2160 pixels) or higher.

[0034] Furthermore, the light source and the photographing device are located on a liftable bracket.

[0035] Furthermore, the uniformity contrast includes light and shadow area, central bright spot, and optical texture.

[0036] Exemplarily, the testing method of the present invention is specifically performed as follows:

[0037] (1) Take a piece of anti-glare film (AG film) sample with a size of 100 mm × 100 mm, a piece of flat and pollution-free OCA bonding adhesive with a size of 100 mm × 100 mm, and a piece of black smooth polymethyl methacrylate (PMMA) substrate with a size of 200 mm × 200 mm and a reflectivity of 0%.

[0038] (2) Sample preparation. Place the PMMA plate on a clean, flat workbench and attach the OCA and anti-glare film (AG film) from bottom to top. Make sure the surface of the anti-glare film (AG film) is flat and has no wrinkles or bubbles. Figure 1 shown.

[0039] (3) Assembly. Figure 2 As shown, a detection platform is built in a non-reflective darkroom environment to ensure that the light source, camera equipment and corresponding height and angle adjustable brackets are stably placed.

[0040] Preferably, a D65 standard light source is used, the color temperature of the light source is fixed at 6500K, and the brightness stability deviation is less than ±1%.

[0041] Preferably, the aperture of the shooting camera is fixed at F / 1.78, the shutter speed is fixed at 1 / 100s, and the focus mode uses the auto focus mode.

[0042] Fix the sample to be tested horizontally in the center of the sample stage. Adjust the incident and shooting angles θ of the light source and camera.

[0043] Preferably, the incident and shooting angle θ is 20° to 85°.

[0044] Adjust the light source and camera height according to the angle setting to ensure that the center of the incident light and the shooting center are aligned with the target area of ​​the sample.

[0045] (4) Data collection: According to the preset shooting angle (such as 20°), save the high-resolution images in sequence and mark the angle parameters.

[0046] Preferably, the image resolution is 4K (3840x2160 pixels).

[0047] (5) Inspection: By analyzing the collected images, measuring the diameter and area of ​​the reflected light, and performing uniformity comparison (evaluating the light spot distribution), it is confirmed whether the acceptance standard is met.

[0048] (6) Reset and Correction. After the test is completed, the angle adjustment module is reset to the initial position. Clean the sample stage, remove the tested sample, and prepare for the next sample test.

[0049] Compared with the prior art, the test method provided by the present invention aims at the diffuse reflection characteristics of the anti-glare film (AG film) by setting a light source at a specific angle to illuminate the anti-glare film (AG film), and using a camera to capture the reflection image under the corresponding light source, and by image processing and comparing with the standard image, the appearance quality is evaluated, and has the following advantages or functions:

[0050] (1) Compared with the traditional method that relies on manual visual evaluation and is easily affected by lighting conditions, viewing angles, and subjective factors of operators, this method ensures more objective detection results through standardized light source angle settings and image acquisition equipment. It can also capture extremely subtle differences in the surface.

[0051] (2) Compared with the time-consuming manual visual judgment, the shooting and image analysis methods used in this method can greatly improve the detection efficiency.

[0052] (3) Automated testing reduces reliance on experienced inspectors, thereby saving labor costs.

[0053] (4) Standardized operating procedures and preset parameters ensure the repeatability of test results and avoid fluctuations caused by manual operations; introduce a standard sample database for comparison to achieve unified evaluation standards. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 Schematic diagram of the sample to be observed.

[0055] Figure 2 This is a schematic diagram of the appearance evaluation components.

[0056] Figure 3 Schematic diagram of the evaluation component with an incident and shooting angle θ of 20°.

[0057] Figure 4 Schematic diagram of the evaluation component with an incident and shooting angle θ of 60°.

[0058] Figure 5 This is a graph showing the test results of the standard sample and the high-quality sample in Example 1.

[0059] Figure 6 This is a graph showing the test results of the standard sample and the bad sample in Example 2.

[0060] Figure 7 This is a graph showing the test results of the standard sample and high-quality sample in Example 3.

[0061] Figure 8 This is a graph showing the test results of the standard sample and the bad sample in Example 4.

[0062] Explanation of the reference numerals: 1-AG film; 2-OCA bonding adhesive; 3-polymethyl methacrylate substrate; 4-prepared sample to be tested; 5-operating table; 6-first lifting bracket; 7-second lifting bracket; 8-light source equipment; 9-shooting camera. DETAILED DESCRIPTION

[0063] In order to make it easier to understand the structure of the present invention and the functional features and advantages that can be achieved, the following will be combined with the preferred embodiments of the present invention and described in detail as follows:

[0064] Example 1

[0065] Take a PMMA plate with a size of 200mm×200mm, an OCA adhesive with a size of 100mm×100mm, and a high-quality anti-glare film (AG film) sample with a size of 100mm×100mm, and laminate the OCA and anti-glare film (AG film) on the PMMA plate in sequence, ensuring that the surface is flat, and prepare group A test samples. Figure 1 shown.

[0066] Fix the test samples of group A horizontally in the center area of ​​the platform. Adjust the incident and shooting angles of the light source and camera to 20°, and adjust the height of the light source and camera according to the set angle to ensure that the incident light center and the shooting center are aligned with the target area of ​​the test sample. Set the aperture to F / 1.78, the shutter speed to 1 / 100s and the autofocus mode to collect image data. Figure 5 ) to perform optical reflection analysis, calculate the diameter and area of ​​the reflected light imaging, calculate the area of ​​the central highlight area, and evaluate the uniformity of the reflection edge and the distribution of optical texture. Compare the collected images of high-quality anti-glare film (AG film) samples with the standard sample images, and comprehensively judge the appearance quality based on the similarity of optical features.

[0067] Example 2

[0068] Take a PMMA plate with a size of 200mm×200mm, a piece of OCA adhesive with a size of 100mm×100mm, and a sample of bad anti-glare film (AG film) with a size of 100mm×100mm, and laminate OCA and anti-glare film (AG film) on the PMMA plate in sequence, ensuring that the surface is flat, to obtain group B test samples. Figure 1 shown.

[0069] Fix the test samples of group B horizontally in the center area of ​​the platform. Adjust the incident and shooting angles of the light source and camera to 20°, and adjust the height of the light source and camera according to the set angle to ensure that the incident light center and the shooting center are aligned with the target area of ​​the test sample. Set the aperture to F / 1.78, the shutter speed to 1 / 100s and the autofocus mode to collect image data. Figure 6 ) to perform optical reflection analysis, calculate the diameter and area of ​​the reflected light imaging, calculate the area of ​​the central highlight area, and evaluate the uniformity of the reflection edge and the distribution of optical texture. Compare the collected images of the bad anti-glare film (AG film) sample with the standard sample image, and comprehensively judge the appearance quality based on the similarity of optical characteristics.

[0070] Example 3

[0071] Take a PMMA plate with a size of 200mm×200mm, a piece of OCA adhesive with a size of 100mm×100mm, and a high-quality anti-glare film (AG film) sample with a size of 100mm×100mm, and laminate the OCA and anti-glare film (AG film) on the PMMA plate in sequence, ensuring that the surface is flat, and prepare the C group of test samples. Figure 1 shown.

[0072] Fix the C group of test samples horizontally in the center area of ​​the platform. Adjust the incident and shooting angles of the light source and camera to 60°, and adjust the height of the light source and camera according to the set angle to ensure that the incident light center and the shooting center are aligned with the target area of ​​the test sample. Set the aperture to F / 1.78, the shutter speed to 1 / 100s and the autofocus mode to collect image data. Figure 7 ) to perform optical reflection analysis, calculate the diameter and area of ​​the reflected light imaging, calculate the area of ​​the central highlight area, and evaluate the uniformity of the reflection edge and the distribution of optical texture. Compare the collected images of high-quality anti-glare film (AG film) samples with the standard sample images, and comprehensively judge the appearance quality based on the similarity of optical features.

[0073] Example 4

[0074] Take a PMMA plate with a size of 200mm×200mm, a piece of OCA adhesive with a size of 100mm×100mm, and a sample of bad anti-glare film (AG film) with a size of 100mm×100mm, and laminate OCA and anti-glare film (AG film) on the PMMA plate in sequence, ensuring that the surface is flat, and obtain group D test samples. Figure 1 shown.

[0075] Fix the D group of test samples horizontally in the center area of ​​the platform. Adjust the incident and shooting angles of the light source and camera to 60°, and adjust the height of the light source and camera according to the set angle to ensure that the incident light center and the shooting center are aligned with the target area of ​​the test sample. Set the aperture to F / 1.78, the shutter speed to 1 / 100s and the autofocus mode to collect image data. Figure 8 ) to perform optical reflection analysis, calculate the diameter and area of ​​the reflected light imaging, calculate the area of ​​the central highlight area, and evaluate the uniformity of the reflection edge and the distribution of optical texture. Compare the collected images of the bad anti-glare film (AG film) sample with the standard sample image, and comprehensively judge the appearance quality based on the similarity of optical characteristics.

[0076] Comprehensive evaluation:

[0077] Table 1 Appearance test results of Examples 1-2

[0078]

[0079] The optical reflection characteristics of the high-quality products in Group A at 20° are highly consistent with the reflection characteristics of the standard products, and they are judged to be qualified. The optical reflection characteristics of the defective products in Group B at 20° have problems with the reflected light and shadow area deviation exceeding the specification value, the central bright spot is visible, and the optical texture is greatly different from the standard products, and they are judged to be unqualified.

[0080] Table 2 Appearance test results of Examples 3-4

[0081]

[0082] The optical reflection characteristics of the high-quality products in group C at 60° are consistent with the reflection characteristics of the standard products, and they are judged to be qualified. The optical reflection characteristics of the defective products in group D at 60° have problems with the deviation of the reflected light and shadow area exceeding the specification value, and the central bright spot size and optical texture are greatly different from those of the standard products, and they are judged to be unqualified.

[0083] The conclusions of Examples 1-4 are consistent with those of the traditional subjective evaluation method. Therefore, the test method provided by the present invention is feasible, and compared with the traditional method, it greatly shortens the detection time, reduces human errors, improves the detection efficiency and the stability of product quality control, and is suitable for large-scale production environments.

[0084] The above is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention. All equivalent changes and modifications made according to the content of the present invention are included in the patent scope of the present invention.

Claims

1. A method for detecting a membrane, comprising: Step (1), sampling: selecting a film sample to be tested, a bonding adhesive, and a light-absorbing substrate; Step (2), sample preparation: place the light-absorbing substrate on the operating table, and place the bonding adhesive and the film to be tested in sequence from bottom to top to ensure that the surface of the film to be tested is flat; Step (3), assembly: select a light source and a photographing device, and adjust the angle θ of the light source and the photographing device so that the center of the incident light and the photographing center are aligned with the film sample to be tested; Step (4), data acquisition: save high-resolution images in sequence according to preset shooting angles and mark angle parameters; Step (5), detection: analyze the collected image, measure the diameter and area of ​​the reflected light, compare the uniformity, and confirm whether it meets the acceptance standard.

2. The method for detecting a membrane according to claim 1, characterized in that: The film to be tested is an anti-glare film or an anti-glare anti-reflection film.

3. The method for detecting a membrane according to claim 1, characterized in that: The bonding adhesive is OCA bonding adhesive, UV curing adhesive or other optically transparent bonding adhesive.

4. The method for detecting a membrane according to claim 1, characterized in that: The light-absorbing substrate is a black light-absorbing substrate, and its reflectivity is less than 10%, or 5%, 2%, or 0%.

5. The method for detecting a membrane according to claim 1, characterized in that: The light-absorbing substrate is a polymethyl methacrylate substrate, a polycarbonate substrate, a polyvinyl chloride substrate or a polystyrene substrate.

6. The method for detecting a membrane according to claim 1, characterized in that: The size of the membrane to be tested is a (mm)×a (mm), where a is less than or equal to 1000, or 800, 500, 400, 300, 200, 100, or 50.

7. The method for detecting a membrane according to claim 1, characterized in that: The size of the bonding adhesive is b (mm) × b (mm), where b is less than or equal to 1000, or 800, 500, 400, 300, 200, 100, or 50.

8. The method for detecting a membrane according to claim 1, characterized in that: The size of the light-absorbing substrate is c (mm)×c (mm), where c is less than or equal to 2000, or 1500, 1000, 800, 500, 400, 300, 200, or 100.

9. The method for detecting a membrane according to claim 1, characterized in that: The light source is a D65 standard light source, the color temperature of the light source is fixed at 6500K, and the brightness stability deviation is less than ±1%.

10. The method for detecting a membrane according to claim 1, characterized in that: The shooting device is a camera, a mobile phone or an industrial camera.

11. The method for detecting a membrane according to claim 1, characterized in that: The aperture of the camera is fixed at F / 1.78, the shutter speed is fixed at 1 / 100s, and the focus mode uses the autofocus mode.

12. The method for detecting a membrane according to claim 1, characterized in that: The angle θ is 20° to 85°, or 25°, 30°, 45°, 50°, 55°, 60°, or 75°.

13. The method for detecting a membrane according to claim 1, characterized in that: The high-resolution image has a resolution of 1080p (1920x1080 pixels), 2K (2560x1440 pixels), 4K (3840x2160 pixels) or higher.

14. The method for detecting a membrane according to claim 1, characterized in that: The light source and the shooting equipment are located on a liftable bracket.

15. The method for detecting a membrane according to claim 1, characterized in that: The uniformity contrast includes light and shadow area, central bright spot, and optical texture.

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