CN116635710A - Edge detection method of optical film - Google Patents
Edge detection method of optical film Download PDFInfo
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- CN116635710A CN116635710A CN202180082017.4A CN202180082017A CN116635710A CN 116635710 A CN116635710 A CN 116635710A CN 202180082017 A CN202180082017 A CN 202180082017A CN 116635710 A CN116635710 A CN 116635710A
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- 239000012788 optical film Substances 0.000 title claims abstract description 54
- 238000000034 method Methods 0.000 title claims abstract description 44
- 238000003708 edge detection Methods 0.000 title claims abstract description 13
- 238000011144 upstream manufacturing Methods 0.000 claims abstract description 34
- 238000003384 imaging method Methods 0.000 claims description 34
- 230000001678 irradiating effect Effects 0.000 claims description 3
- 238000001514 detection method Methods 0.000 abstract description 7
- 239000010408 film Substances 0.000 description 64
- 239000004973 liquid crystal related substance Substances 0.000 description 62
- 238000011156 evaluation Methods 0.000 description 27
- 238000005286 illumination Methods 0.000 description 26
- 210000002858 crystal cell Anatomy 0.000 description 18
- 230000003287 optical effect Effects 0.000 description 15
- CIWBSHSKHKDKBQ-JLAZNSOCSA-N Ascorbic acid Chemical compound OC[C@H](O)[C@H]1OC(=O)C(O)=C1O CIWBSHSKHKDKBQ-JLAZNSOCSA-N 0.000 description 9
- 238000012545 processing Methods 0.000 description 9
- 238000007689 inspection Methods 0.000 description 8
- 238000004519 manufacturing process Methods 0.000 description 7
- 239000012790 adhesive layer Substances 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 2
- 238000012546 transfer Methods 0.000 description 2
- 238000004891 communication Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/84—Systems specially adapted for particular applications
- G01N21/86—Investigating moving sheets
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/84—Systems specially adapted for particular applications
- G01N21/88—Investigating the presence of flaws or contamination
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/84—Systems specially adapted for particular applications
- G01N21/88—Investigating the presence of flaws or contamination
- G01N21/95—Investigating the presence of flaws or contamination characterised by the material or shape of the object to be examined
- G01N21/958—Inspecting transparent materials or objects, e.g. windscreens
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Length Measuring Devices By Optical Means (AREA)
- Investigating Materials By The Use Of Optical Means Adapted For Particular Applications (AREA)
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Abstract
Provided is a method for detecting an edge of an optical film, which can reliably detect the edge of the optical film attached to a rectangular panel. The detection method comprises the following steps: a conveying step of conveying a rectangular panel on which an optical film is laminated; a photographing step of photographing a target area including an edge portion of the optical film on the rectangular panel; an optimal image selecting step of selecting an optimal image for detecting the edge portion from among a plurality of images obtained by photographing the object region at a plurality of positions; and an edge detection step of detecting an edge in the optimal image. In the photographing step, light is sequentially irradiated from a plurality of light sources arranged along the conveying direction of the rectangular panel, and the object region is photographed at a plurality of positions from the upstream side to the downstream side in the conveying direction by one photographing mechanism.
Description
Technical Field
The present invention relates to a method for detecting an edge of an optical film used for inspection of an optical display panel, and more particularly, to a method for detecting an edge of an optical film, which is capable of selecting an optimal image capable of most reliably detecting an edge of an optical film from a plurality of captured images when inspecting a bonding misalignment between a rectangular panel and an optical film bonded thereto, and detecting an edge of an optical film using the optimal image.
Background
In the optical display panel, various optical films having an optical function are attached to a rectangular panel as necessary, thereby realizing a display function. In the manufacturing process of the optical display panel, after the optical film is bonded to the surface of the rectangular panel, the bonding state between the rectangular panel and the optical film is checked (so-called bonding misalignment check) in order to confirm the bonding accuracy of both. As conventional bonding misalignment checking methods, for example, methods described in patent document 1 and patent document 2 have been proposed.
Patent document 1 discloses imaging by using a region camera or a line camera arranged so that a corner can be imaged from vertically above a corner of an optical display panel to which a polarizing plate and a liquid crystal panel are attached. The offset of the fit is calculated using the image taken by the camera. Further, patent document 2 discloses the following method: the attachment deviation can be inspected by photographing the corner of the panel using the area sensor camera while conveying the optical display panel having the optical film attached to the optical unit. In this method, the distance between the end of the optical unit and the end of the optical film is calculated from the captured image, and the fitting displacement is determined based on the distance.
Prior art literature
Patent literature
Patent document 1 Japanese patent application laid-open No. 2011-197281
Patent document 2 Japanese patent application laid-open No. 2016-118580
Patent document 3 Japanese patent No. 4377964
Disclosure of Invention
Problems to be solved by the invention
In the conventional bonding misalignment inspection methods including patent document 1 and patent document 2, a certain area (hereinafter referred to as a target area) including both corners of a rectangular panel and an optical film in an optical display panel enters an imaging area of a camera, and imaging is performed when the imaging point is reached. The imaging point is typically a position at which an edge of the optical film on the optical display panel (typically, the forefront side in the moving direction of the optical film) reaches a position vertically below the camera. In the captured image, the edge of the optical film appears as a line (bright line) that emits light by reflecting light from the light source at the edge of the optical film, and the edge of the optical film in the image can be detected by recognizing the reflected light. However, depending on the state of the edge of the optical film attached to the rectangular panel, it may be difficult to detect the edge from only the image captured when the edge reaches the imaging point.
For example, when the end face of the optical film in the captured image is shaped so as to be difficult to reflect light from the light source, or when the reflected light from the end face is at an angle at which it is difficult to reach the camera, it may be difficult to detect the edge of the optical film.
The invention aims to provide a method for detecting the edge of an optical film, which can reliably detect the edge of the optical film attached to a rectangular panel, so as to be used for an inspection method for accurately implementing the attachment deviation inspection of the rectangular panel and the optical film.
Means for solving the problems
The present invention has been completed based on the following findings: when an image obtained by photographing the edge of the optical film by irradiating light from a light source disposed on the upstream side in the conveying direction of the rectangular panel is compared with an image obtained by photographing the edge by irradiating light from a light source disposed on the downstream side in the conveying direction, it is possible to obtain an image in which the irradiation direction of the image of the edge is easily detected that differs depending on the position in the conveying direction of the optical film.
In the present invention, for an optical display panel in which an optical film is laminated on a rectangular panel, a plurality of images of a target area including the corner of the rectangular panel and the corner of the optical film are obtained by using light sequentially irradiated from a plurality of light sources, and an optimal image capable of most reliably detecting the edge of the optical film is selected from the plurality of images, and the edge of the optical film is detected using the optimal image.
That is, the present invention provides an optical film edge detection method for detecting an edge of an optical film laminated on a rectangular panel, including: a conveying step of conveying a rectangular panel on which an optical film is laminated; a photographing step of photographing a target area including an edge portion of the optical film on the rectangular panel; an optimal image selecting step of selecting an optimal image for detecting the edge portion from among a plurality of images obtained by photographing the object region at a plurality of positions; and an edge detection step of detecting an edge in the optimal image. In the photographing step, light is sequentially irradiated from a plurality of light sources arranged along the conveying direction of the rectangular panel, and the object region is photographed at a plurality of positions from the upstream side to the downstream side in the conveying direction by one photographing mechanism. The best image is selected based on the brightness of the edges in each of the images.
In one embodiment, the plurality of light sources preferably includes at least an upstream side light source disposed upstream in the conveying direction with respect to the imaging means of the imaging target area and a downstream side light source disposed downstream. In the imaging step, it is preferable that the light is irradiated from the upstream side light source and imaged when the edge is located on the upstream side in the conveying direction than the imaging point which is the position where the edge is located below the imaging means in the vertical direction, and the light is irradiated from the downstream side light source and imaged when the edge is located on the downstream side in the conveying direction than the imaging point.
In one embodiment, in the optimum image selecting step, it is preferable to select the optimum image based on the brightness of the plurality of portions set along the edge portion. In addition, in another embodiment, in the photographing step, it is preferable to photograph a plurality of images while stopping the rectangular panel at each photographing, and it is preferable to photograph a plurality of images also using light from light sources arranged oppositely in the width direction of the rectangular panel.
Effects of the invention
According to the present invention, since the optimal image capable of reliably detecting the bright line at the edge of the optical film is selected from the plurality of images that capture the predetermined region including the end portion of the optical film attached to the rectangular panel, it is possible to more easily and accurately check the attachment deviation of the optical film using the image.
Drawings
Fig. 1 is a schematic diagram showing a configuration of an edge detection device for detecting an edge of a polarizing film attached to a liquid crystal cell, which is used for manufacturing a liquid crystal panel.
Fig. 2 is a flowchart showing a flow of processing for selecting an optimal image from a plurality of captured images in the optical film edge detection method according to the embodiment of the present invention.
Fig. 3 is a flowchart showing details of the process of scoring in the method according to the embodiment of the present invention.
Fig. 4 is an image showing a step of the score processing.
Detailed Description
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
In the following description, a case where a polarizing film is used as an optical film, a liquid crystal cell is used as a rectangular panel, and an optical display panel having an optical film attached to the rectangular panel is a liquid crystal panel will be described as an example, but the present invention is not limited to these, and the present invention can be used similarly in the inspection of various optical display panels manufactured by attaching a film having an optical function to a rectangular panel.
[ outline of liquid Crystal Panel manufacturing apparatus and polarizing film edge detection apparatus ]
The film edge detection method of the present invention can be used, for example, in an apparatus for manufacturing a liquid crystal panel (RTP apparatus) by continuously bonding a polarizing film fed from a roll to a liquid crystal cell, for the purpose of detecting an edge of the polarizing film in order to inspect a case where the manufactured liquid crystal panel is bonded to a surface of the liquid crystal cell in a state where the polarizing film is deviated from a predetermined bonding position (hereinafter, referred to as bonding misalignment). The RTP method is as follows: in the manufacturing process of the liquid crystal panel, from a band-shaped laminate in which a plurality of sheet-shaped polarizing films are supported on a band-shaped release film via an adhesive layer, only a normal sheet-shaped polarizing film having no defects is peeled off from the release film in sequence together with the adhesive layer, and is bonded to a liquid crystal cell via the adhesive layer, thereby continuously manufacturing the liquid crystal panel. The continuous manufacturing system that realizes such a method is called a "continuous bonding (RTP; roll-to-sheet)" device, which is different from a conventional single bonding method that realizes bonding of a sheet of a pre-cut polarizing film to a liquid crystal cell. As the RTP system apparatus, for example, the apparatus described in patent document 3 can be used.
Fig. 1 is a schematic view showing an example of a configuration of a polarizing film edge detection device for detecting an edge of a polarizing film attached to a liquid crystal cell. The device can be assembled as a part of a device used in an inspection step in a step after a polarizing film is bonded to a liquid crystal cell manufactured by the above-described RTP method.
The apparatus shown in fig. 1 includes: a conveyance path 1 for conveying a liquid crystal panel P manufactured by bonding a polarizing film F to a liquid crystal cell C; an illumination 2 disposed above the conveyance path 1; and a camera 3 disposed above the illumination 2. When the target area a of the liquid crystal panel P conveyed by the conveying path 1 Is within the imaging range of the camera 3, the illumination 2 Is lighted a plurality of times from the upstream side to the downstream side in the conveying direction D of the liquid crystal panel P, and a plurality of images Is of the target area a are imaged by the camera 3. The target region a is a region for performing inspection of the bonding misalignment between the liquid crystal cell C and the polarizing film F, and is generally a region including the edge CE and the corner CC of the liquid crystal cell C and a region including the edge FE (which is the edge to be detected) and the corner FC of the polarizing film F bonded to the liquid crystal cell C, but the present invention is not limited thereto and may be any region including at least the edge CE and the edge FE. The plurality of images Is taken of the target area a at the plurality of positions are transmitted to a general-purpose computer, and in the computer, an optimal image for detecting the edge portion FE of the polarizing film F Is selected, and the edge portion FE Is detected using the selected optimal image.
It is preferable to use a plurality of illuminations 2 arranged in the conveying direction D so as to irradiate light to the object region a from different directions. The plurality of illuminations 2 are sequentially lighted at a plurality of positions during the period from the upstream side to the downstream side in the conveying direction D of the target area a. The plurality of illuminators 2 are preferably disposed at least on the upstream side and downstream side in the conveying direction D of the liquid crystal panel P (illuminators 21 and 22 in fig. 1), but are preferably disposed in a direction (width direction of the liquid crystal panel P) crossing the conveying direction D (illuminators 23 and 24 in fig. 1). By disposing the illumination 2 also in the width direction of the liquid crystal panel P, the edge FS in the width direction of the polarizing film F can be detected more reliably, and therefore, the bonding misalignment inspection can be performed with higher accuracy. Further, as the illumination 2, for example, one annular illumination in which a plurality of light sources are arranged in an annular shape and the plurality of light sources can be individually and sequentially lighted may be used. In the case of using such annular illumination, the light source is individually turned on at a plurality of portions in the circumferential direction, so that the light can be irradiated to the target area a from a plurality of directions.
The camera 3 used in the present invention can use a linear camera, an area camera, or the like, depending on the purpose. For example, when the image of the target area a is captured while the liquid crystal panel P is moved, a line camera is preferably used. In the case of using the line camera, the target area a may be photographed while moving the line camera in a state where the liquid crystal panel P is stopped. As a method of photographing the object region a while moving the liquid crystal panel P, a region camera may be used to perform photographing at a shutter speed sufficiently faster than the moving speed of the liquid crystal panel P. The area camera may be used in a case where the liquid crystal panel P is stopped when the object area a is photographed.
In the present embodiment described below, a configuration Is employed in which one illumination 21, 22 Is disposed on each of the upstream side and the downstream side in the conveying direction D of the liquid crystal panel P with respect to the target area a, and one illumination 23, 24 Is disposed on each of the width direction of the liquid crystal panel P, and a plurality of images Is are captured by one camera 3, and an optimal image Ib for detecting the edge portion FE of the liquid crystal film F Is selected from the images Is. Hereinafter, the present invention will be described as an embodiment of a method of photographing by sequentially lighting the four illuminations 21 to 24 arranged along the conveyance direction D of the liquid crystal panel P so that the height from the conveyance surface of the liquid crystal panel P is constant and the irradiation directions are different, while the edge FE is moving from the upstream side to the downstream side in the conveyance direction D.
[ detection of polarizing film edge portion ]
(transport of liquid Crystal Panel and shooting)
In the device shown in fig. 1, a plurality of images Is are captured for a target area a including both the edge CE and the corner CC of the liquid crystal cell C and the edge FE and the corner FC of the polarizing film F. The camera 3 arranged to be able to capture the target area a acquires a plurality of images Is in a period from when the target area a enters the capturing range of the camera 3 and then leaves the capturing range in accordance with the timing of lighting of the plurality of illuminations 21 and 22. Specifically, a plurality of images Is are acquired by stopping and capturing the conveyance of the liquid crystal panel P at a plurality of predetermined positions until the target area a enters the imaging range of the camera 3 and then leaves. The predetermined position may be set to be on the upstream side of the transfer direction D with respect to the imaging point, on the imaging point or the vicinity thereof, or on the downstream side of the transfer direction D with respect to the imaging point, or the like. For example, the imaging is performed by sequentially lighting the upstream side illumination 21 when the edge FE is located on the upstream side in the conveying direction D with respect to the imaging point, lighting the upstream side illumination 21 and the downstream side illumination 22 when the edge FE is located on the downstream side in the conveying direction D with respect to the imaging point, and lighting the downstream side illumination 22. The number of images Is to be obtained Is not limited, and may be determined in consideration of the accuracy required for detecting the edge portion FE of the polarizing film F and the speed of the process for selecting the optimal image for detecting the edge portion FE.
The plurality of images Is are preferably captured by stopping the liquid crystal panel P moving from the upstream side to the downstream side at each capturing as described above, but the present invention Is not limited thereto, and the liquid crystal panel P may be sequentially moved from the upstream side to the downstream side of the capturing range. When the liquid crystal panel P Is moved and photographed, a plurality of images Is can be obtained as follows: the shutter of the camera 3 is opened to capture an image at timing corresponding to the lighting of each of the illumination 21 and the illumination 22 until the target area a enters the field of view of the camera 3 and then leaves. Alternatively, the plurality of images Is may be acquired as follows: before the subject area a enters the field of view of the camera 3 and then leaves, the shutter of the camera 3 is opened to continuously perform shooting, and during this period, each of the illumination 21 and the illumination 22 is sequentially lighted. The plurality of acquired images Is are transmitted from the camera 3 to a general-purpose computer, not shown, for example, via a wire or wirelessly, and stored in a storage unit such as a hard disk.
(selection of best image)
The acquired plurality of images Is are retrieved from the storage unit, and the optimal image Ib Is selected from the images Is. The optimal image Ib Is an image capable of most reliably detecting the edge portion FE of the polarizing film F attached to the liquid crystal cell C, out of the plurality of images Is. Regarding the selection of the optimal image, the brightness of the edge portion FE of the polarizing film F may be measured for each of the plurality of captured images Is, the evaluation score may be obtained based on the brightness, the obtained evaluation scores may be compared between the images, and the image with the highest evaluation score may be selected as the optimal image Ib in which the edge portion FE can be detected most reliably.
Fig. 2 Is a flowchart 200 showing the overall flow of processing for selecting the optimal image Ib from the plurality of images Is. Fig. 3 Is a flowchart showing an example of a specific process of the scoring step for obtaining the evaluation scores of the plurality of images Is, and fig. 4 Is an image showing an example of the process of the scoring step. Hereinafter, a method of selecting the optimal image Ib will be specifically described with reference to fig. 2 to 4. The content of the optimal image selection process shown in fig. 2 to 4 is merely an example, and other processes may be adopted according to the type of the optical display panel.
First, in s201 of the flowchart 200, a plurality of images Is are obtained during conveyance of the liquid crystal panel P from the upstream side to the downstream side in the conveyance direction D. Next, in s202, the brightness of the film edge Is measured for each of the plurality of images Is, and the evaluation score of each of the images Is obtained based on the brightness. Next, in s203, the evaluation score Is compared among the plurality of images Is, and the image with the highest evaluation score Is selected as the best image Ib in which the edge FE can be detected most reliably.
Next, each process in the flowchart 200 is specifically described.
The acquisition of the image described in s201 of the flowchart 200 is described in the previous item of the image capturing of the liquid crystal panel. Next, as shown in s202 of the flowchart 200, for each of the obtained plurality of images Is, an evaluation score for evaluating the possibility of reliable detection of the edge portion FE of the polarizing film F Is obtained. Specifically, for each of the plurality of images Is, the luminance Is measured at a plurality of portions including the edge portion FE, the luminance at the plurality of portions Is scored, and for example, a total value, an average value, a maximum value, and the like are obtained, and these values are used as evaluation scores. The image with the highest evaluation score among the plurality of images Is the best image Ib in which the edge FE can be detected most reliably.
Fig. 3 Is a flowchart 300 showing details of an example of processing for obtaining an evaluation score for each of the plurality of images Is, selecting an optimal image, and determining the position of the edge portion FE of the polarizing film F in each of the images Is. First, in s301, a plurality of small areas including the position where the polarizing film edge is supposed to exist and the periphery thereof are set along the longitudinal direction of the polarizing film edge (quadrangle SR1 shown in fig. 4 (a)). The alignment marks provided in the liquid crystal cell C are read for a plurality of small areas, and the position of the polarizing film F when attached to the liquid crystal panel C is calculated based on the position of the alignment marks without being deviated, and the position thus calculated is set. The size of the small region is not limited, but it is preferable that the length of the small region in the direction crossing the edge of the polarizing film is set to a length such that the edge of the polarizing film F falls within the small region even if the polarizing film F is bonded to the liquid crystal panel C with a deviation. In addition, it is preferable to appropriately set the length of the small region along the longitudinal direction of the polarizing film edge in consideration of the detection accuracy and the processing speed of the edge. The number of small areas is not limited, and is preferably set in consideration of the detection accuracy and the processing speed of the edge. In a plurality of small areas, brightness is measured and plotted. As shown in fig. 4 (b), the curve can be expressed as a relationship between the distance from the end of the small region toward the inside of the liquid crystal panel P and the luminance.
Next, in s302, for each curve generated for each of the plurality of small areas, the intersection point of the line indicated as the curve and the predetermined threshold TH for determining the presence or absence of the edge portion FE of the polarizing film F is searched for. The luminance used as the threshold TH may be a value which is assumed to be larger than the maximum luminance (OBmax) indicating a bright line other than the edge FE and which enables the edge FE to be reliably detected in the image if the luminance is equal to or higher than the threshold TH. The bright line of the edge FE present in the image has a width, so there are typically two intersections of the curve with the threshold TH. The position CP1 of the intersection point corresponding to the inside direction of the liquid crystal panel P among the two intersection points is a position of the inside edge of the bright line representing the edge portion FE. When the positions of the inner edges of the small areas thus identified are connected, the straight line connecting the inner edges represents the bright line of the edge portion FE (s 303), and the positions represent the bright line of the edge portion FE of the polarizing film F.
On the other hand, in s304, the maximum luminance Bmax of the bright line representing the edge portion FE in the small region is divided for each of the plurality of small regions. The score may be expressed as, for example, a relative luminance when the luminance corresponding to the maximum incident energy acceptable to the light receiving element of the camera 3 is set to 100. Alternatively, the measured maximum luminance Bmax itself may be regarded as a fraction of the small region. The score of the small region is expressed as 82 minutes, 85 minutes, 90 minutes, or the like, for example, by the score of the luminance. After the score is calculated for each of the plurality of small areas, the scores of all the small areas are summed up, and the sum is used as the evaluation score of the image in s305, for example. The evaluation score of the image is not limited to the total value of the scores of the small areas as long as the detection reliability of the edge FE between the images can be determined. For example, the evaluation score of the image may be an average score of scores of a plurality of small areas, a number of small areas having a score equal to or higher than a specific score, or the like. The evaluation score Is thus obtained for each of the plurality of images Is, and the image with the highest evaluation score Is regarded as the optimal image Ib.
For example, for 2 images a and B, 10 small areas are set along the edge FE, and the brightness of each small area is measured. When the value obtained by summing up the scores of the small areas of the image a is 800 points and the value obtained by summing up the scores of the small areas of the image B is 700 points, it is determined that the image a having a high evaluation score is the optimal image Ib in which the polarizing film edge can be detected more reliably. The inner edge of the edge portion FE of the polarizing film F in the image a is a straight line connecting the inner edges in 10 small areas.
The data generated in the process of obtaining the evaluation score and the position of the edge of the polarizing film (s 202 in the process flow chart 200, s301 to s305 in the process flow chart 300) is stored in a storage unit such as a hard disk (not shown), for example, via a communication line. The stored data can be read from the storage unit as needed and used in the subsequent process, for example, a process of determining the bonding offset amount.
As described above, the optimal image Ib that can more accurately detect the edge portion FE of the polarizing film F attached to the liquid crystal cell C Is selected from the plurality of captured images Is. The edge portion FE may be detected using the selected optimal image Ib, and the bonding offset amount of the polarizing film FE may be obtained by a method known to those skilled in the art, for example, based on the relationship between the position of the detected edge portion FE and the position of the edge portion CE of the liquid crystal cell C.
As the edge FE and the position thereof in the selected optimal image Ib, the edge and the position thereof detected during the process of selecting the optimal image Ib in the image selected as the optimal image Ib may be directly used. As another method, the same processing as the detection processing (s 301 to s303 of the flowchart 300) of the inner edge position for each of the plurality of images Is may be performed again for the selected optimal image Ib, and the edge FE and the position thereof that are finally detected may be used as the edge and the position thereof for determining the bonding offset amount.
Examples
Hereinafter, examples of the present invention will be described.
In this example, 2 images including the edge portion of the front end of the polarizing film included in the liquid crystal panel were acquired using 1 camera (manufactured by Keyence, CA-035C, inc.) and two illuminations (manufactured by Keyence, CA-DBR8, inc.) disposed above the conveyance path of the liquid crystal panel. As the liquid crystal panel, a liquid crystal panel in which a polarizing film having a thickness of 0.1mm was laminated on a 32-inch liquid crystal cell having a thickness of 1.6mm was used. The two illuminators are disposed on the upstream side and the downstream side of the position of the camera in the conveying direction of the liquid crystal panel, respectively, and are each adjusted to irradiate light toward a photographing point vertically below the camera. The distance in the vertical direction between the position of the camera and the position of the liquid crystal panel was 91mm, and the distance in the vertical direction between the illuminated position and the position of the liquid crystal panel was 8mm. The captured 2 images were evaluated using the brightness measured by an image processing apparatus (manufactured by Keyence, XG-5000).
TABLE 1
Table 1 shows the evaluation results. In table 1, the "polarizing film edge position" is a position at which the liquid crystal panel is stopped in order to capture 2 images (image 1 and image 2), and the "upstream side", "imaging point", and "downstream side" refer to a case where the polarizing film edge is located upstream of the imaging point, a case where the polarizing film edge is located at the imaging point, and a case where the polarizing film edge is located downstream of the imaging point, respectively. The "irradiation direction" is a position and an irradiation direction of illumination in which light is irradiated toward an edge of the polarizing film when the liquid crystal panel is stopped for photographing, and the "from the upstream side" and the "from the downstream side" refer to irradiation of light toward the edge from illumination disposed on the upstream side of the camera and irradiation of light toward the edge from illumination disposed on the downstream side of the camera, respectively. The "polarizing film edge positions" and "irradiation directions" of each of examples 1 to 5 are shown in table 1. In the present embodiment, as the evaluation score for making selection of the best image, brightness is used. Three small areas including the position where the polarizing film edge exists and the periphery thereof are selected (see fig. 4), bmax is measured in each of the three small areas, and the average brightness of the three Bmax thus obtained is taken as an evaluation score.
In example 1, an image 1 captured by light irradiated from the upstream side at the polarizing film edge portion on the upstream side and an image 2 captured by light irradiated from the downstream side at the polarizing film edge portion on the upstream side are compared, and an optimal image is selected. Since the evaluation score (165) of image 1 is higher than the evaluation score (120) of image 2, image 1 is selected as the best image capable of reliably detecting the bright line of the polarizing film edge.
In example 2, the image 1 captured in the same manner as in example 1 and the image 2 captured by the light irradiated from the downstream side at the time of capturing the image point at the edge of the polarizing film were compared, and the optimal image was selected. In example 3, the image 1 captured in the same manner as in example 1 and the image 2 captured by the light irradiated from the downstream side when the edge portion of the polarizing film is located on the downstream side were compared, and the optimum image was selected. Image 1 was selected for both example 2 and example 3.
In example 4, an image 1 captured by light irradiated from the upstream side when the polarizing film edge portion is located at the imaging point and an image 2 captured by light irradiated from the downstream side when the polarizing film edge portion is located at the downstream side are compared, and the optimum image is selected. In this embodiment, since the evaluation score (150) of the image 2 is higher than the evaluation score (135) of the image 1, the image 2 is selected as an optimal image capable of reliably detecting the bright line of the polarizing film edge portion. In example 5, an optimal image was selected by comparing image 1 captured with light irradiated from the upstream side when the polarizing film edge was located on the downstream side with image 2 captured with light irradiated from the downstream side when the polarizing film edge was located on the downstream side. Image 2 is also selected in this embodiment.
Comparative example 1 was a result of obtaining an image using annular illumination (Keyence, CA-DRR8, manufactured by co-existence) coaxially arranged with a camera (Keyence, CA-035C, manufactured by co-existence) at the time of capturing a point at the polarizing film edge portion. In any of the cases of examples 1 to 5, the evaluation score of the image selected as the best image is higher than the evaluation score (127) of comparative example 1. Thus, by using the optimal image selected according to the present invention, the bright line of the edge portion of the optical film can be detected more reliably than the image captured according to the related art.
Claims (5)
1. An optical film edge detection method for detecting an edge of an optical film laminated on a rectangular panel, the optical film edge detection method comprising:
a conveying step of conveying a rectangular panel on which an optical film is laminated;
an imaging step of sequentially irradiating light from a plurality of light sources arranged along a conveying direction of the rectangular panel, and imaging a target area including an edge portion of the optical film on the rectangular panel at a plurality of positions from an upstream side to a downstream side in the conveying direction by one imaging mechanism;
an optimal image selection step of selecting, from among a plurality of images obtained by capturing the target area at a plurality of positions, an optimal image for detecting the edge based on the brightness of the edge in each image;
and an edge detection step of detecting the edge in the optimal image.
2. The method for detecting an edge of an optical film according to claim 1, wherein,
the plurality of light sources include at least an upstream light source disposed upstream in the conveying direction with respect to the one imaging mechanism and a downstream light source disposed downstream,
the shooting step comprises the following steps: when the edge is located on the upstream side of the conveying direction with respect to an imaging point which is a position of the edge below the imaging means in a vertical direction, light is irradiated from the upstream side light source to perform imaging, and when the edge is located on the downstream side of the imaging point in the conveying direction, light is irradiated from the downstream side light source to perform imaging.
3. The method for detecting an edge of an optical film according to claim 1 or 2, wherein,
the optimal image selection step includes: the optimal image is selected based on the brightness of a plurality of locations set along the edge.
4. The method for detecting an edge of an optical film according to any one of claim 1 to 3, wherein,
the shooting step comprises the following steps: the plurality of images are photographed while stopping the rectangular panel at each photographing.
5. The method for detecting an edge of an optical film according to any one of claim 1 to 4, wherein,
the shooting step comprises the following steps: the plurality of images are also captured using light from light sources disposed opposite in the width direction of the rectangular panel.
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|---|---|---|---|
| JP2020-202511 | 2020-12-07 | ||
| JP2020202511A JP2022090247A (en) | 2020-12-07 | 2020-12-07 | Detection method for marginal portion of optical film |
| PCT/JP2021/034605 WO2022123858A1 (en) | 2020-12-07 | 2021-09-21 | Method for detecting edge part of optical film |
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| CN116635710A true CN116635710A (en) | 2023-08-22 |
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| CN202180082017.4A Pending CN116635710A (en) | 2020-12-07 | 2021-09-21 | Edge detection method of optical film |
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| JP (1) | JP2022090247A (en) |
| KR (1) | KR20230113764A (en) |
| CN (1) | CN116635710A (en) |
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| JP3977503B2 (en) * | 1998-02-05 | 2007-09-19 | 住友化学株式会社 | Film inspection method and film inspection apparatus using the same |
| JP2007256106A (en) * | 2006-03-23 | 2007-10-04 | Sharp Corp | Display panel inspection device and display panel inspection method using the same |
| WO2009128115A1 (en) | 2008-04-15 | 2009-10-22 | 日東電工株式会社 | Optical film layered roll and method and device for manufacturing the same |
| JP4774123B1 (en) | 2010-03-18 | 2011-09-14 | 住友化学株式会社 | Method for inspecting bonding accuracy of polarizing plate and apparatus for inspecting bonding accuracy |
| KR102120507B1 (en) * | 2012-10-12 | 2020-06-08 | 스미또모 가가꾸 가부시키가이샤 | Detection apparatus, method for manufacturing optical member-bonded body, and method for manufacturing optical member-bonded body |
| JP6287454B2 (en) * | 2014-03-27 | 2018-03-07 | 日本電気株式会社 | Inspection apparatus and inspection method |
| CN204128496U (en) * | 2014-08-07 | 2015-01-28 | 日东电工株式会社 | Blooming bonding position determinator and optical display production line |
| JP6529250B2 (en) * | 2014-12-18 | 2019-06-12 | 日東電工株式会社 | Optical display panel manufacturing method and optical display panel manufacturing system |
| KR101674357B1 (en) * | 2016-07-08 | 2016-11-08 | 주식회사 엘지화학 | The system and method for manufacturing display unit |
| KR102469408B1 (en) * | 2017-03-03 | 2022-11-22 | 스미또모 가가꾸 가부시키가이샤 | Defect inspection system, film manufacturing apparatus, film manufacturing method, printing apparatus, and printing method |
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- 2020-12-07 JP JP2020202511A patent/JP2022090247A/en active Pending
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- 2021-09-21 WO PCT/JP2021/034605 patent/WO2022123858A1/en active Application Filing
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| JP2022090247A (en) | 2022-06-17 |
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| KR20230113764A (en) | 2023-08-01 |
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