Appearance inspection method and apparatus for long optical laminated body

Abstract

To provide a method of favorably inspecting an appearance of a long-sized optical laminate having a long-sized antireflection layer with a smaller haze, an antiglare layer with a larger haze formed in a prescribed pattern on the antireflection layer, and a non-antiglare part formed on a prescribed location on the antiglare layer.SOLUTION: An inspection method of an optical laminate includes: a step of imaging a long-sized optical laminate to acquire image data; a step of detecting an edge part of the antiglare layer from the image data; a step of setting a borderline in a prescribed distance from the edge part to an inside, to set the inside of the borderline as an inspection region and an outside of the borderline as a non-inspection region; a step of analyzing the image data to extract a defect candidate part in the inspection region; a step of determining whether the defect candidate part has a size smaller than a reference value or not; and a step of detecting a defect according to the size of the defect candidate part.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a method and an apparatus for inspecting the appearance of a long optical laminate. [Background technology]

[0002] Some image display devices, such as mobile phones and notebook personal computers (PCs), are equipped with internal electronic components such as cameras. These image display devices often use optical films partially formed with non-optically functional portions. Examples of such optical films include polarizers partially formed with non-polarizing portions and anti-glare films partially formed with non-anti-glare portions. Non-optically functional portions, such as non-polarizing portions and non-anti-glare portions, are typically transparent portions. Optical films are typically produced by subjecting raw film rolls to visual inspection and then cutting them into pieces of a predetermined size (a size corresponding to the image display device to which they are applied). However, in the case of optical films partially formed with non-optically functional portions, the non-optically functional portions (typically, transparent portions) may be erroneously detected as defects during visual inspection. This can result in problems such as insufficient quality control, reduced yields, and reduced manufacturing efficiency. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6784540 Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention has been made to solve the above-mentioned problems, and a main object of the present invention is to provide a method for suitably inspecting the appearance of a long optical laminate having a long antireflection layer with low haze, an antiglare layer with high haze formed in a predetermined pattern on the antireflection layer, and a non-antiglare portion formed at a predetermined position on the antiglare layer. [Means for solving the problem]

[0005] [1] According to an embodiment of the present invention, there is provided a method for inspecting an optical laminate. The method inspects the appearance of a long optical laminate while transporting it in the longitudinal direction. The long optical laminate includes a long antireflection layer with a haze of less than 1.0%, an antiglare layer formed in a predetermined pattern on the antireflection layer with a haze of 5.0% or more, and a non-antiglare portion formed in a predetermined position on the antiglare layer. The inspection method includes the steps of: capturing an image of the optical laminate to obtain image data; detecting an edge of the antiglare layer from the image data; setting a boundary a predetermined distance inward from the edge, and defining the area inside the boundary as an inspection area and the area outside the boundary as a non-inspection area; analyzing the image data to extract defect candidate portions in the inspection area; determining whether the defect candidate portions have a size equal to or smaller than a reference value; and detecting defects based on the size of the defect candidate portions. [2] In the above [1], the step of detecting defects based on the size of the defect candidate portion includes: determining whether or not the defect candidate portion having a size exceeding a reference value has periodicity in the longitudinal direction only for the defect candidate portion; and detecting as defects defect candidate portions having a size equal to or smaller than the reference value and defect candidate portions having a size exceeding the reference value and not having periodicity in the longitudinal direction. [3] In the above [2], the presence or absence of periodicity of the defect candidate portions is determined based on the position coordinates of the defect candidate portions in the longitudinal direction. [4] In any one of the above [1] to [3], the image data is acquired based on continuous imaging of the optical stack. [5] In any one of the above items [1] to [4], the defect candidate portion is extracted based on luminance information of the image data. [6] In any one of the above [1] to [5], the anti-glare layer is formed at predetermined intervals in the longitudinal direction and the width direction. [7] In any one of the above [1] to [6], the antiglare layer is formed in a shape corresponding to the shape of an image display device to which the optical laminate is applied. [8] In any of [1] to [7] above, the non-antiglare portion is formed at a position corresponding to a camera portion of the image display device when the optical laminate is cut to be attached to the image display device. [9] According to another embodiment of the present invention, there is provided an inspection device for an optical laminate. The inspection device is an appearance inspection device for a long optical laminate used in any of the inspection methods [1] to [8] above. The inspection device includes an imaging device that images the long optical laminate to acquire image data, and an image analysis device that analyzes the image data to detect defects in the optical laminate. The image analysis device includes an inspection area determination unit that detects the edge of the anti-glare layer from the image data, sets a boundary a predetermined distance inward from the edge, and sets the area inside the boundary as an inspection area and the area outside the boundary as a non-inspection area; a defect candidate extraction unit that extracts defect candidate areas in the inspection area based on the image data; a size determination unit that determines whether the defect candidate areas have a size equal to or smaller than a reference value; a periodicity determination unit that determines whether the defect candidate areas have periodicity in the longitudinal direction; and a defect detection unit that detects defects based on the size of the defect candidate areas or the size of the defect candidate areas and the presence or absence of periodicity. [Effects of the Invention]

[0006] According to an embodiment of the present invention, it is possible to realize a method for suitably inspecting the appearance of a long optical laminate having a long antireflection layer with a small haze, an antiglare layer with a large haze formed in a predetermined pattern on the antireflection layer, and a non-antiglare portion formed at a predetermined position on the antiglare layer. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a schematic plan view of a long optical laminate that can be subjected to a visual inspection method according to an embodiment of the present invention. [Figure 2] 2 is a schematic cross-sectional view of the optical laminate of FIG. 1 taken along line II-II. [Figure 3] 1 is a schematic diagram illustrating a visual inspection apparatus that can be used in a visual inspection method according to an embodiment of the present invention. [Figure 4] 1A to 1C are schematic plan views illustrating a procedure for setting an inspection area in a visual inspection method according to an embodiment of the present invention. [Figure 5] 1 is a flowchart illustrating a specific procedure of an example of defect detection in a visual inspection method according to an embodiment of the present invention. [Figure 6] 10 is a flowchart illustrating a specific procedure of another example of defect detection in the visual inspection method according to the embodiment of the present invention. [Figure 7] FIG. 7 is a schematic diagram illustrating a specific procedure for detecting the defect in FIG. 6. DETAILED DESCRIPTION OF THE INVENTION

[0008] Representative embodiments of the present invention will be described below with reference to the drawings, but the present invention is not limited to these embodiments. Furthermore, for ease of viewing and understanding, the drawings are drawn schematically or conceptually, and the length, width, shape, size, ratio, direction, number, etc. may differ from the actual ones, and there may be no correspondence between the drawings (e.g., Figures 1 and 4).

[0009] A. Overview of visual inspection method According to an embodiment of the present invention, there is provided a visual inspection method for an optical laminate. The inspection method inspects the visual appearance of a long optical laminate, which includes a long antireflection layer with a haze of less than 1.0%, an antiglare layer formed in a predetermined pattern on the antireflection layer with a haze of 5.0% or more, and a non-antiglare portion formed at a predetermined position on the antiglare layer, while transporting the optical laminate in the longitudinal direction. The inspection method includes the steps of: imaging the optical laminate to obtain image data; detecting the edge of the antiglare layer from the image data; setting a boundary a predetermined distance inward from the edge, and defining the area inside the boundary as an inspection area and the area outside the boundary as a non-inspection area; analyzing the image data to extract defect candidate portions in the inspection area; determining whether the defect candidate portions have a size equal to or smaller than a reference value; and detecting defects based on the size of the defect candidate portions. The optical laminate to be inspected, the visual inspection device, and each step of the visual inspection method are described in detail below.

[0010] B. Optical laminate FIG. 1 is a schematic plan view of a long optical laminate that can be subjected to a visual inspection method according to an embodiment of the present invention; FIG. 2 is a schematic cross-sectional view of the optical laminate taken along line II-II of FIG. 1. As described above, the optical laminate is long. The illustrated optical laminate 100 includes a long antireflection layer 10 and an antiglare layer 20 formed in a predetermined pattern on the antireflection layer 10. The antiglare layer 20 typically includes antiglare portions 21 that occupy the majority of the antiglare layer and have antiglare function, and non-antiglare portions 22 formed at predetermined positions. The antiglare layer 20 is typically formed at predetermined intervals in the longitudinal and width directions of the antireflection layer 10. In one embodiment, the antiglare layer is formed in a shape corresponding to the shape of an image display device to which the optical laminate will be cut and applied. In other words, the antiglare layer may have a shape corresponding to the shape of the optical laminate to be ultimately used. The anti-glare layer in the illustrated example has a rectangular shape defined by a pair of opposing sides in the longitudinal and width directions of the anti-reflection layer. The non-anti-glare portion 22 is typically formed at a position corresponding to the camera section of the image display device when the optical laminate is cut into film strips for attachment to the image display device. In this specification, "long" refers to a narrow shape whose length is sufficiently longer than its width, including, for example, a narrow shape whose length is 10 times or more, preferably 20 times or more, its width. Long optical laminates can typically be transported by rolls.

[0011] The haze of the antireflection layer is less than 1.0%, preferably 0.8% or less, more preferably 0.5% or less, and even more preferably 0.3% or less. The lower the haze, the better, and the lower limit of the haze may be, for example, 0.1%. If the haze of the antireflection layer is within this range, when the optical laminate (film piece) is finally applied to an image display device, it can provide an antireflection function without adversely affecting the display performance.

[0012] The antireflection layer may have any suitable configuration as long as it has the desired antireflection properties and satisfies the above-mentioned haze. Specifically, the antireflection layer may be a cured layer of a curable resin composition, or a layer formed by a dry process. The curable resin composition typically contains a binder resin and, if necessary, a photopolymerization initiator. The binder resin typically contains a curable compound. Examples of the curable compound include a polyfunctional monomer, an oligomer or prepolymer derived from the polyfunctional monomer. Examples of layers formed by a dry process include a wet coating layer, a sputtering layer, or a vapor deposition layer of a low refractive index material.

[0013] The haze of the antiglare portion of the antiglare layer is 5.0% or more, preferably 15% to 55%, more preferably 25% to 45%, and even more preferably 30% to 40%. If the haze of the antiglare layer is within this range, when the optical laminate (film piece) is ultimately applied to an image display device, it can be imparted with good antiglare functionality (anti-glare functionality). The haze of the non-antiglare portion can typically be equivalent to that of an antireflection layer. The haze of the non-antiglare portion is, for example, less than 1.0%, preferably 0.8% or less, more preferably 0.5% or less, and even more preferably 0.3% or less. The lower the haze, the better, and the lower limit of the haze can be, for example, 0.1%.

[0014] The anti-glare layer may have any suitable configuration as long as it has the desired anti-glare function (anti-glare function) and satisfies the above-mentioned haze. Specifically, the anti-glare layer may be formed from a curable resin composition containing a binder resin and particles. The curable resin composition is similar to the anti-reflection layer except that it contains particles. Details of the anti-glare layer are described, for example, in JP 2021-139981 A. The description of this publication is incorporated herein by reference.

[0015] In one embodiment, the antiglare layer is formed directly on the antireflection layer. For example, the antiglare layer can be formed by applying the curable resin composition through a mask having a predetermined pattern and curing the applied film.

[0016] As described above, the optical laminate is typically used by cutting it into film pieces to be attached to an image display device. Typically, the area inside the outer edge of the anti-glare layer is cut a predetermined distance. By cutting in this way, the entire optical laminate (film piece) to be finally used is provided with anti-glare functionality (excluding the non-anti-glare portion).

[0017] The optical laminate is typically bonded to a polarizing plate and can be used as a functional layer-attached polarizing plate. The polarizer of the polarizing plate typically has a non-polarizing portion. The non-polarizing portion is typically formed in a position corresponding to the non-antiglare portion. The optical laminate and the polarizing plate may be cut into film pieces and then bonded together, or a long optical laminate and a long polarizing plate may be bonded together by roll-to-roll processing. In the functional layer-attached polarizing plate, the non-antiglare portion and the non-polarizing portion are formed in a position corresponding to the camera portion of the image display device. With this configuration, it is possible to impart desired characteristics to the image display device while suppressing adverse effects on camera performance.

[0018] C. Inspection equipment FIG. 3 is a schematic diagram illustrating an appearance inspection device that can be used in an appearance inspection method according to an embodiment of the present invention. In the illustrated embodiment, a long optical stack 100 is transported to an inspection device 300 for appearance inspection. The inspection device 300 includes an imaging device 50 that captures an image of the optical stack 100 to acquire image data, and an image analyzer 80 that analyzes the acquired image data to detect defects in the optical stack 100. The image analyzer 80 includes an inspection area determination unit 81 that detects the edge of the anti-glare layer from the acquired image data, sets a boundary a predetermined distance inward from the edge, and sets the area inside the boundary as an inspection area and the area outside the boundary as a non-inspection area; a defect candidate extraction unit 82 that extracts defect candidate portions in the inspection area based on the image data; a size determination unit 84 that determines whether the defect candidate portions have a size equal to or smaller than a reference value; a periodicity determination unit 86 that determines whether the defect candidate portions have periodicity in the longitudinal direction; and a defect detection unit 88 that detects defects based on the size of the defect candidate portions or the size of the defect candidate portions and the presence or absence of periodicity.

[0019] D. Each step of the visual inspection method D-1. Step of acquiring image data (1) Step (1) can be performed by obtaining image data by capturing an image of the optical laminate 100 using an imaging device 50. The imaging device 50 typically includes an illumination unit 52 and an imaging unit .

[0020] The illumination unit 52 may be configured using any appropriate light source. The light source may be a white light source or a monochromatic light source. Specific examples of the light source include a fluorescent lamp, a halogen lamp, a metal halide lamp, and an LED.

[0021] The imaging unit 54 is typically a camera configured using a lens and an image sensor. One or more imaging units are preferably provided so that the entire width of the optical laminate 100 can be imaged. The imaging unit is preferably capable of capturing continuous images in the longitudinal direction. In one embodiment, the imaging unit is a line sensor camera.

[0022] 3, light is irradiated onto the optical stack 100 from an illumination unit 52 disposed on one side of the optical stack 100, and an image of the light transmitted through the optical stack 100 is captured by an imaging unit 54 disposed on the other side of the optical stack 100 so as to face the illumination unit 52. By capturing an image of the transmitted light, an image can be obtained in which the brightness of areas other than the anti-glare layer is higher than the brightness of the area corresponding to the anti-glare layer.

[0023] In another embodiment (not shown), an illumination unit and an imaging unit are arranged on one side of the optical stack 100, and light is irradiated from the illumination unit onto the optical stack 100 from an oblique direction, and the light reflected by the optical stack 100 is imaged by the imaging unit arranged on the same side as the illumination unit.

[0024] In yet another embodiment (not shown), an illumination unit and an imaging unit are arranged on one side of the optical stack 100, and light is irradiated perpendicularly onto the optical stack 100 so that the optical axis of the camera of the imaging unit coincides with the optical axis of the irradiated light, and the reflected light is imaged.

[0025] By selecting an appropriate imaging method depending on the configuration of the optical stack 100 and imaging the optical stack 100, an image can be obtained in which the difference in brightness between the area corresponding to the anti-glare layer and the area corresponding to the other parts is large (as a result, the contrast ratio is large). The imaging of the optical stack 100 may be performed according to any one of the above embodiments, or may be performed by combining two or more embodiments.

[0026] Preferably, the image is taken while transporting the optical laminate 100 in the longitudinal direction. By taking images while transporting, it is possible to avoid stopping the production line and maintain production efficiency.

[0027] D-2. Step (2) of setting inspection and non-inspection areas In step (2), inspection and non-inspection areas are defined in the optical laminate. This configuration is unique to embodiments of the present invention, and this configuration can achieve unique effects. Specifically, it is as follows: When visually inspecting a long optical film, it is usually necessary to perform the visual inspection over the entire optical film. In this case, inspecting portions that do not need to be inspected can result in problems such as insufficient inspection efficiency (inspection speed). On the other hand, the optical laminate used in embodiments of the present invention has a long, low-haze (substantially transparent) anti-reflection layer on which a high-haze (substantially opaque) anti-glare layer is formed in a predetermined pattern. This allows the boundary between the anti-glare layer and portions where the anti-glare layer is not formed to be detected by imaging. Furthermore, the optical laminate can be cut into film pieces, and the size and shape of the film pieces can substantially correspond to the size and shape of the anti-glare layer. Therefore, since portions where the anti-glare layer is not formed become cutting waste, designating these portions as non-inspection areas can avoid the detection of unnecessary noise and unnecessary inspection. As a result, visual inspection can be achieved with high inspection accuracy and high inspection efficiency.

[0028] Step (2) typically includes detecting the edge of the anti-glare layer from the image data, and setting a boundary at a predetermined distance inward from the edge, and setting the area inside the boundary as an inspection area and the area outside the boundary as a non-inspection area. This will be described in detail below with reference to Figures 3 and 4.

[0029] The image data obtained by the imaging device 50 is transmitted as an electrical signal to the image analysis device 80. The transmitted image data is analyzed by the inspection area determination unit 81, and an inspection area A and a non-inspection area B are thereby set.

[0030] Typically, the edge of the anti-glare layer is detected based on the luminance information of the image data. Because the haze differs significantly between the anti-glare layer and other portions, the portion where the luminance information of the image data changes discontinuously can be recognized as the edge of the anti-glare layer (the boundary between the anti-glare layer and other portions). In the illustrated example, the anti-glare layer 20 (anti-glare portion 21) has a rectangular shape defined by a pair of opposing sides 23, 23 and sides 24, 24 perpendicular to the sides 23, 23. Furthermore, in the illustrated example, the sides 23, 23 are parallel to the width direction of the anti-reflection layer, and the sides 24, 24 are parallel to the length direction of the anti-reflection layer. Therefore, the sides 23, 23 are the edge of the anti-glare layer 21 in the length direction, and the sides 24, 24 are the edge of the anti-glare layer 21 in the width direction. The edge of the anti-glare layer is typically detected, preferably for both the sides 23 and 24 (in both the length direction and the width direction). By detecting in this manner, it is possible to set the non-inspection areas in both the longitudinal direction and the width direction with high accuracy. Note that it is sufficient to detect either one of the sides 23, 23 and the sides 24, 24. In this case, the detection of the end of the anti-glare layer can be typically performed for the side 23 on the same side (the upper or lower side 23 in the drawing) and the side 24 on the same side (the left or right side 24 in the drawing).

[0031] Next, a boundary 30 is set at a position a distance d inward from the detected edge, and an area A inside the boundary 30 (opposite the edge) is set as the inspection area. By setting it in this way, the area including the entire anti-glare layer (the area that will become the final product) can be set as the inspection area. As a result, it is possible to prevent the anti-glare layer from being overlooked in inspection. An area B outside the boundary 30 (toward the edge) is set as a non-inspection area. This makes it possible to avoid unnecessary inspections, thereby achieving appearance inspection with high inspection efficiency. Note that the inspection area A includes non-anti-glare parts as shown in the example.

[0032] D-3. Step (3) of extracting defect candidate parts Next, the image data for only the inspection area A is analyzed by the defect candidate extraction unit 82, and defect candidates are extracted.

[0033] In one embodiment, defect candidate areas are extracted based on brightness information in the image data. Specifically, a brightness standard for determining normality is set in advance by imaging a normal anti-glare layer, and defect candidate areas are extracted based on this standard. For example, high-brightness areas exceeding the upper limit of brightness determined as normal and low-brightness areas exceeding the lower limit of brightness determined as normal may be determined as defect candidate areas. Defective areas that cause appearance defects, such as foreign matter, bubbles, and pinholes, usually have different transmittance, reflectance, etc. from normal areas of the anti-glare layer, and are therefore extracted as defect candidate areas based on the brightness standard described above. Meanwhile, in the obtained image data, areas corresponding to non-anti-glare areas may also be extracted as defect candidate areas because their transmittance, reflectance, etc. are different from those of areas corresponding to the anti-glare layer.

[0034] The defect candidate extraction unit 82 preferably stores position information of the defect candidate portions (for example, position coordinates (X, Y) in the longitudinal and width directions in images that are continuous in the longitudinal direction) and transmits it to the periodicity determination unit 86.

[0035] D-4. Step (4) of determining whether the defect candidate portion has a size equal to or smaller than a reference value When defect candidate portions are extracted by defect candidate portion extraction portion 82, size determination portion 84 determines the size of each extracted defect candidate portion and further determines whether or not the size is equal to or less than a reference value. Ultimately, in step (6) of detecting defects, which will be described later, defect candidate portions having a size exceeding the reference value can be recognized and distinguished from non-anti-glare portions, and defect candidate portions having a size equal to or less than the reference value can be detected as defects.

[0036] The size of the defect candidate portion can be determined by any appropriate method. For example, the size can be determined based on the number of pixels, diameter, area, etc. of the defect candidate portion in the image data. The diameter of the defect candidate portion can typically be determined as the length of the longest straight line connecting any two points on the periphery of the defect candidate portion in the image data. The area can be calculated based on the number of pixels or the diameter.

[0037] The reference value can be determined by any appropriate method. For example, the reference value can be determined based on the size of the non-anti-glare portion. For example, when determining the size based on the diameter, the reference value (diameter reference value) can be determined as follows. That is, the diameter (theoretical value) of the non-anti-glare portion is calculated based on the designed shape and dimensions of the non-anti-glare portion, or the diameter (measured value) of the actually formed non-anti-glare portion is measured, and the reference value can be, for example, 90%, preferably 95%, of the obtained diameter of the non-anti-glare portion. Furthermore, for example, when the average size of the defects is sufficiently small compared to the size of the non-anti-glare portion (for example, when the average diameter of the defects is 1 / 8 or less of the diameter of the non-anti-glare portion), the reference value can be set to 1 / 4 to 1 / 2 of the diameter of the non-anti-glare portion. As a specific example, when the diameter of the non-anti-glare portion is approximately 2800 μm and the average diameter of the defects is 150 μm to 300 μm, the reference value can be set to approximately 1000 μm.

[0038] D-5. Step (5) of determining whether the defect candidate portion has periodicity in the longitudinal direction Step (5) determines whether the defect candidate portions have periodicity in the longitudinal direction. Step (5) is preferably performed in conjunction with step (4). That is, step (4) detects defect candidate portions having a size equal to or smaller than a reference value as defects, and step (5) also detects defect candidate portions that do not have periodicity as defects. By combining steps (4) and (5), defect candidate portions can be evaluated from the perspectives of both size and periodicity, thereby further improving inspection accuracy. Step (5) is performed by the periodicity determination unit 86. The periodicity determination unit 86 may determine the periodicity of all extracted defect candidate portions, or may determine only defect candidate portions that are confirmed by the size determination unit 84 to have a size exceeding a reference value. Preferably, only defect candidate portions that are confirmed by the size determination unit 84 to have a size exceeding a reference value are determined to be defects. This further improves inspection speed.

[0039] In one embodiment, when three or more defect candidate portions exist at equal intervals on a line extending in any direction, these defect candidate portions can be determined to have periodicity.

[0040] In the optical laminate to be inspected, non-antiglare portions are arranged at predetermined intervals at least in the longitudinal direction, so that periodicity can be determined based on the intervals between the non-antiglare portions in the longitudinal direction. Therefore, by determining the positions of the defect candidate portions to be determined in the optical laminate and screening those present at the predetermined intervals, the presence or absence of periodicity can be efficiently determined.

[0041] In one embodiment, the periodicity of the defect candidate portions is determined based on their position coordinates (e.g., their longitudinal position coordinates). For example, the position coordinates of the defect candidate portions (e.g., two or more, preferably three or more adjacent defect candidate portions in the longitudinal direction) transmitted from the defect candidate portion extraction unit are compared with the position coordinates of the designed (theoretical) non-anti-glare portions. If the position coordinates match, the defect candidate portions are determined to have periodicity. Furthermore, for example, the longitudinal position coordinates of the defect candidate portions transmitted from the defect candidate portion extraction unit are used to determine the longitudinal distance between the defect candidate portion to be determined and a non-anti-glare portion (which may be a defect candidate portion that has already been determined not to be a defect) located upstream of the defect candidate portion in the conveying direction. The determination is then performed based on whether the distance is a predetermined distance. The distance may be, for example, the spacing between the non-anti-glare portions in the longitudinal direction (i.e., the predetermined spacing in the longitudinal direction) or an integer multiple of the predetermined spacing.

[0042] D-6. Defect detection process (6) The defect detection unit 88 detects defects based on the size of the defect candidate portion, or the size of the defect candidate portion and whether or not the defect candidate portion has periodicity. Specifically, the defect detection unit 88 detects, as a defect, a defect candidate portion that the size determination unit 84 determines to have a size equal to or smaller than a reference value. The defect detection unit 88 can further recognize a defect candidate portion that the periodicity determination unit 86 determines to have periodicity as a non-anti-glare portion and distinguish it from the defect candidate portion, and detect the remaining defect candidate portions as defects. In other words, the defect detection unit 88 can detect, as defects, defect candidate portions that are determined to have a size equal to or smaller than a reference value and defect candidate portions that are determined not to have periodicity.

[0043] Fig. 5 is a flowchart illustrating a specific procedure for defect detection in one embodiment of the present invention. In the embodiment shown in Fig. 5, first, image data of the optical laminate is acquired (step (1) above). Next, the edge of the anti-glare layer is detected based on the image data, and a boundary is set at a predetermined distance inside the edge. The area inside the boundary is set as an inspection area, and the area outside the boundary is set as a non-inspection area (step (2) above). Next, defect candidate portions are extracted from the inspection area (step (3) above). Next, it is determined whether the defect candidate portions have a size equal to or smaller than a reference value (step (4) above). Defect candidate portions with a size exceeding the reference value are determined to be non-anti-glare portions, while defect candidate portions with a size equal to or smaller than the reference value are detected as defects (step (6) above).

[0044] FIG. 6 is a flowchart illustrating a specific procedure for defect detection in another embodiment of the present invention. In the embodiment shown in FIG. 6, first, image data of the optical laminate is acquired (step (1) above). Next, the edge of the anti-glare layer is detected based on the image data, and a boundary is set at a predetermined distance inward from the edge. The area inside the boundary is set as an inspection area, and the area outside the boundary is set as a non-inspection area (step (2) above). Next, defect candidate portions are extracted in the inspection area (step (3) above). Next, it is determined whether the defect candidate portions have a size equal to or less than a reference value (step (4) above), and for defect candidate portions with a size exceeding the reference value, it is determined whether or not they are periodic (step (5) above). Based on the obtained results, defect candidate portions with a size equal to or less than the reference value and defect candidate portions with a size exceeding the reference value but not having periodicity are detected as defects (step (6) above). Note that the white circles in Figure 7(a) indicate all defect candidate portions extracted in step (3) according to this embodiment, the white circles in Figure 7(b) indicate defect candidate portions that have a size exceeding a reference value and are to be judged as to whether or not they have periodicity, the black circles in Figure 7(c) indicate defect candidate portions (non-polarized portions) that are judged to have periodicity, the white circles indicate defect candidate portions (defects) that are judged not to have periodicity, and the white circles in Figure 7(d) indicate defects that are finally detected.

[0045] D-7. Marking process (7) The visual inspection apparatus 300 may further include a marking device (not shown). The marking device is connected to an image processing device, and when the image processing device (effectively a defect detection unit) detects a defect, it transmits position information of the defect to the marking device. The marking device marks the defective portion based on the position information. The marked area can be easily rejected as a defective product after cutting. Examples of marking methods include marking using a marker pen, inkjet marking, and laser marking. [Industrial Applicability]

[0046] The appearance inspection method according to an embodiment of the present invention is suitably used, for example, when manufacturing an optical laminate (e.g., a polarizing plate with a functional layer) to be provided in a camera-equipped image display device (liquid crystal display device, organic EL device) such as a mobile phone such as a smartphone, a notebook PC, or a tablet PC. [Explanation of symbols]

[0047] 10 Anti-reflection layer 20 Anti-glare layer 21 Anti-glare section 22 Non-anti-glare part 50 Imaging device 80 Image analysis equipment 81 Inspection area determination unit 82 Defect candidate extraction unit 84 Size Judgment Section 86 Periodicity judgment part 88 Defect detection section 100 Optical laminate 300 Inspection Equipment

Claims

1. A method for inspecting the appearance of a long optical laminate while transporting it in a longitudinal direction, the long optical laminate having a long antireflection layer with a haze of less than 1.0%, an antiglare layer formed in a predetermined pattern on the antireflection layer with a haze of 5.0% or more, and a non-antiglare portion formed at a predetermined position on the antiglare layer, the method comprising: A step of capturing an image of the optical laminate to obtain image data; detecting an edge of the anti-glare layer from the image data; a step of setting a boundary at a predetermined distance inward from the end portion, and setting the area inside the boundary as an inspection area and the area outside the boundary as a non-inspection area; analyzing the image data to extract defect candidate portions in the inspection area; determining whether the defect candidate portion has a size equal to or smaller than a reference value; detecting defects based on the size of the defect candidate portion; Including, detecting a defect based on the size of the defect candidate portion, determining whether or not a defect candidate portion having a size exceeding a reference value has periodicity in the longitudinal direction only for the defect candidate portion; and detecting, as defects, defect candidate portions having a size equal to or smaller than a reference value and defect candidate portions having a size exceeding the reference value and not having periodicity in the longitudinal direction; Including, Testing method.

2. 2. The inspection method according to claim 1, wherein the presence or absence of periodicity of the defect candidate portions is determined based on position coordinates of the defect candidate portions in the longitudinal direction.

3. The inspection method according to claim 1 , wherein the image data is acquired based on continuous imaging of the optical stack.

4. 2. The inspection method according to claim 1, wherein the defect candidate portion is extracted based on luminance information of the image data.

5. The inspection method according to claim 1 , wherein the anti-glare layer is formed at predetermined intervals in the longitudinal direction and the width direction.

6. The inspection method according to claim 5 , wherein the antiglare layer is formed in a shape corresponding to a shape of an image display device to which the optical laminate is applied.

7. The inspection method according to claim 6, wherein the non-antiglare portion is formed at a position corresponding to a camera unit of the image display device when the optical laminate is cut to be attached to the image display device.

8. An appearance inspection device for a long optical laminate used in the inspection method according to any one of claims 1 to 7, an imaging device that captures an image of the long optical laminate and acquires image data; an image analysis device that analyzes the image data to detect defects in the optical laminate, The image analysis device an inspection area determination unit that detects an edge of the anti-glare layer from the image data, sets a boundary at a predetermined distance inside the edge, and sets the inside of the boundary as an inspection area and the outside of the boundary as a non-inspection area; a defect candidate portion extraction unit that extracts defect candidate portions in the inspection area based on the image data; a size determination unit that determines whether the defect candidate portion has a size equal to or smaller than a reference value; a periodicity determination unit that determines whether the defect candidate portion has periodicity in the longitudinal direction; a defect detection unit that detects defects based on the size of the defect candidate portion or the size of the defect candidate portion and whether or not there is periodicity; Visual inspection equipment for long optical laminates.

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