TWI785535B - Method, device and system for detecting optical film - Google Patents

Abstract

A method for detecting an optical film is provided. The method includes: capturing, by an optical sensor, images to be inspected of an optical film to be inspected, wherein the optical film to be inspected is placed on a platform at three angles; receiving the images to be inspected from the optical sensor; and using a recognition model to detect the images to be inspected to determine the attribute of the optical film to be inspected.

Description

A method, device and system for detecting optical film

The present disclosure relates to a method, device and system for inspecting an optical film, and particularly relates to a method, device and system for inspecting an optical film using neural network technology.

Since the cutting mechanism in the optical film manufacturing process does not have the function of distinguishing the protective film on the surface of the optical film from the release film, after the optical film is cut, a lot of time must be spent by the production line personnel to visually inspect and classify it.

However, manual visual inspection and classification of optical films is prone to error.

Therefore, there is a need for a method, device and system for inspecting an optical film to replace manual visual inspection to distinguish between a surface protection film and a release film, so as to increase productivity.

The following disclosure is exemplary only and is not meant to be limiting in any way. In addition to the illustrated aspects, embodiments and features, further aspects, embodiments and features will be apparent by reference to the drawings and the following detailed description. That is, the following disclosure is provided to introduce the concepts, highlights, benefits, and advantages of the novel and non-obvious technologies described herein. Selected, but not all, examples are described in further detail below. Accordingly, the following disclosure is not intended to be an essential feature of the claimed subject matter, nor is it intended to be used in determining the scope of the claimed subject matter.

Therefore, the main purpose of the present disclosure is to provide a method, device and system for inspecting an optical film, so as to improve the above disadvantages.

The present disclosure proposes a system for inspecting an optical film, including: a platform; an optical sensor that photographs a surface of an optical film to be inspected placed on the platform at three angles to generate three images to be inspected; and a computing device, Execution: receiving the image to be inspected sent by the optical sensor; and using a recognition model to detect the image to be inspected to determine the property of the optical film to be inspected.

This disclosure proposes a method for inspecting an optical film, including: using an optical sensor to take images of an optical film to be inspected placed on a platform at three angles; receiving the image to be inspected sent by the optical sensor an image; and using a recognition model to detect the image to be detected to determine the property of the optical film to be detected.

The disclosure proposes a device for inspecting an optical film, including: at least one graphics processor; and at least one computer storage medium storing computer-readable instructions, wherein the graphics processor uses the computer storage medium to execute: The tester shoots an image to be inspected of an optical film to be inspected placed on a platform at three angles; and uses a recognition model to detect the image to be inspected to determine the property of the optical film to be inspected.

Aspects of the disclosure are described more fully hereinafter with reference to the accompanying drawings. This disclosure may, however, be embodied in many different forms and should not be construed as limited to any specific structure or function presented throughout this disclosure. Rather, these aspects are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. Based on the teachings herein, one skilled in the art will appreciate that the scope of the present disclosure is intended to encompass any aspect disclosed herein, whether implemented alone or in combination with any other aspect of the disclosure. For example, it may be implemented using any number of means or implementations presented herein. In addition, in addition to the various aspects of the disclosure set forth herein, the scope of the disclosure is intended to cover devices or methods implemented using other structures, functions, or both. It should be appreciated that any aspect disclosed herein may be embodied by one or more elements of the claimed claims.

The word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any aspect of the disclosure or design described herein as "exemplary" is not necessarily to be construed as preferred or superior to other aspects of the disclosure or design. Furthermore, like numerals designate like elements throughout the several drawings, and unless otherwise specified in the description, the articles "a" and "above" include plural references.

It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements may be present. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements present. Other words used to describe the relationship between elements should be interpreted in a like fashion (eg, "between" versus "directly between," "adjacent" versus "directly adjacent," etc.).

The composition of the optical film 100 is shown in FIG. 1 , which is composed of a surface protection film 102 , a protection layer 104 , a polarizing substrate 106 , a protection layer 108 , an adhesive layer 110 and a release film 112 . In one embodiment, an adhesive layer (not shown) is included between the surface protection film 102 and the protection layer 104 .

In some embodiments, the material of the polarizing base 106 can be polyvinyl alcohol (polyvinyl alcohol, PVA) resin film, which can be prepared by saponifying polyvinyl acetate resin. Examples of polyvinyl acetate resins include monopolymers of vinyl acetate, ie, polyvinyl acetate, copolymers of vinyl acetate and other monomers that can be copolymerized with vinyl acetate.

In some embodiments, polyvinyl alcohol (PVA) can be used as the polarizing matrix 106 after being treated. The foregoing treatment includes preparing a dyeing solution; immersing polyethylene in the dyeing solution; stretching polyvinyl alcohol; and drying.

In some embodiments, the protective layer 104 and the protective layer 108 can include optical gain, alignment, compensation, steering, orthogonal, diffusion, protection, anti-adhesion, scratch resistance, anti-glare, reflection suppression, high refractive index, etc. Aided diaphragm. In some embodiments, the protective layer 104 and the protective layer 108 can be a single-layer or multi-layer structure. The material of the protective layer 104 and the protective layer 108 can be, for example, a thermoplastic resin with excellent transparency, mechanical strength, thermal stability, and moisture barrier properties. Thermoplastic resins can include cellulose resins (for example: triacetate cellulose (TAC), diacetate cellulose (DAC), acetyl cellulose), acrylic resins (for example: polymethylmethacrylate) Esters (poly methyl methacrylate, PMMA)), polyester resins (e.g., polyethylene terephthalate (PET), polyethylene naphthalate), olefin resins, polycarbonate resins, cycloolefins Resin, oriented-polypropylene (OPP), polyethylene (polyethylene, PE), polypropylene (polypropylene, PP), cyclic olefin polymer (cyclic olefin polymer, COP), cyclic olefin copolymer ( cyclic olefin copolymer, COC), or any combination of the above.

In some embodiments, the adhesive layer 110 includes pressure sensitive adhesive (PSA), heat sensitive adhesive, solvent volatile adhesive, and UV curable adhesive, but not limited thereto. In some embodiments, the pressure sensitive adhesive comprises natural rubber, synthetic rubber, styrene block copolymer, (meth)acrylic block copolymer, polyvinyl ether, polyolefin, and poly(meth) Acrylate. In some embodiments, (meth)acrylic (or acrylate) refers to both acrylic and methacrylic. In other embodiments, the pressure sensitive adhesive comprises (meth)acrylate, rubber, thermoplastic elastomer, silicone, urethane, and combinations thereof. In some embodiments, the pressure sensitive adhesive is based on a (meth)acrylic pressure sensitive adhesive or based on at least one poly(meth)acrylate.

In some embodiments, the material of the surface protection film 102 and the release film 112 can be polyethylene terephthalate (polyethylene terephthalate, PET), polybutylene terephthalate, polycarbonate, polyarylate Esters, polyester resins, olefin resins, cellulose acetate resins, acrylic resins, polyethylene (PE), polypropylene (PP), cycloolefin resins, polysiloxane, or combinations thereof.

Figure 2 shows the images taken at different horizontal rotation angles on the two surfaces of the surface protection film and the release film of the optical film. As shown in Figure 2, the optical film is placed on a platform, with the surface of the surface protection film or the surface of the release film facing up, and the optical sensor is vertical to the surface of the surface protection film or the surface of the release film to take pictures of the first After one image is set as a 0-degree image, the optical film is rotated horizontally by 45 degrees on the platform to shoot the second image and set as a 45-degree image, and finally the optical film is rotated horizontally by 45 degrees on the platform to shoot the second image Three images are set as 90-degree images (that is, when the third image is taken, it has been horizontally rotated 90 degrees from the initial placement angle). In one embodiment, the image captured in the present disclosure includes a complete image of the optical film 100 . In one embodiment, the image captured in the present disclosure includes images of at least three boundaries of the rectangular optical film 100 . As shown in Figure 2, based on the visual angle of the human eye, it is not easy to distinguish the surface protection film at 0 degrees, 45 degrees and 90 degrees, and the release film at 0 degrees, 45 degrees and 90 degrees respectively. difference.

In order to reduce mistakes and reduce the cost of rework due to wrong judgments, the embodiments of the present disclosure provide a method, device and system for inspecting optical films, using neural network technology to further solve the problem of errors in the production process of optical films.

FIG. 3 is an exemplary schematic diagram of a system 300 for inspecting an optical film according to an embodiment of the present disclosure. The system 300 may at least include a platform 310 , an identification device 320 and an optical sensor 330 .

Platform 310 may include a backlight for an optical film 350 to be placed on. In one embodiment, the platform 310 may also have a rotation mechanism for rotating the optical film 350, which can rotate the optical film horizontally. In one embodiment, if the platform 310 has no rotation mechanism, the optical film 350 can be manually rotated horizontally instead. In one embodiment, the platform 310 rotates the optical film 350 horizontally at 0 degrees, 45 degrees and 90 degrees.

In one embodiment, the structure and material of the optical film 350 are the same as those of the optical film 100 , and will not be repeated here.

The optical sensor 330 can receive light signals, convert the light signals into electrical signals such as pixels, and transmit the electrical signals to the identification device for calculation. For example, the optical sensor 330 may include an active pixel sensor (APS), a CMOS image sensor, a photosensitive coupling device (CCD), an infrared sensing element, a photosensitive transistor, or various optical lenses. Moreover, the optical sensor can be a two-dimensional photosensitive element, that is to say, the optical sensor 330 cooperates with other devices, mechanisms or equipment to sequentially acquire part of the sub-images on the surface of the optical film 350 to be detected in a two-dimensional manner, and finally All partial sub-images are combined to obtain a complete surface image of the optical film 350 to be inspected. In a certain embodiment, the optical sensor 330 has a larger imaging range, and can obtain a complete surface image of the optical film 350 to be inspected at one time.

In some embodiments, the optical sensor 330 includes at least one lens 332, wherein the lens 332 can optionally be equipped with a polarizer (not shown in the figure) to photograph the optical film 350 placed on the platform 310 at multiple angles. surface image. In some embodiments, the optical sensor 330 is used to take images of the surface of the optical film 350 placed on the platform 310 at three angles, such as 0 degrees, 45 degrees and 90 degrees. The methods for obtaining images of 0 degrees, 45 degrees and 90 degrees are the same as those described in the preceding paragraph, and will not be repeated here.

In some embodiments, the optical sensor 330 is a color optical sensor and includes a lens 332 , where a polarizer (not shown) is mounted on the lens.

The recognition device 320 may include an input device 322 configured to receive input data from various sources. For example, the identification device 320 can receive the image transmitted by the optical sensor 330 through a network 340 . The recognition device 320 may also receive training images including the optical film, and train a recognizer configured to recognize properties of the optical film based on the received training images.

The recognition device 320 also includes a graphics processor 324 , a neural network (Neural Network) 326 and a memory 328 capable of storing a program 3282 . In addition, images can be stored in the memory 328 or in the neural network 326 . In one embodiment, the neural network 326 can be implemented by the GPU 324 . In another embodiment, identification device 320 may be used with other components, systems, subsystems and/or devices than those described herein.

Types of identification devices 320 range from small handheld devices (eg, mobile phones/laptops) to large host systems (eg, mainframe computers). Examples of portable computers include personal digital assistants (PDAs), notebook computers, and other devices. The network 340 may include but not limited to one or more local area networks (Local Area Network, LAN) and/or wide area networks (Wide Area Network, WAN).

It should be understood that the recognition device 320 shown in FIG. 3 is an example of the structure of the system 300 for detecting optical films. The recognition device 320 shown in FIG. 3 may be implemented by any type of computing device, such as the computing device 700 described with reference to FIG. 7 , as shown in FIG. 7 .

FIG. 4 is a flowchart showing a method 400 for inspecting an optical film according to an embodiment of the present disclosure. This method can be implemented in the graphics processor 324 of the recognition device 320 shown in FIG. 3 .

It should be noted first that, as used herein, the term "training" is used to identify objects used to train a recognition model. Therefore, the training image refers to the image used to train the recognition model.

In step S405 , the recognition device receives a plurality of training images captured by the optical sensor and placed on a platform with a backlight function at three angles of the plurality of optical films, wherein the above three angles include 0 degree, 45 degree and 90 degree. In more detail, the optical sensor needs to take pictures of the two surfaces of the optical film (the surface of the surface protection film and the surface of the release film) at three angles to obtain the training of the surface of the surface protection film and the surface of the release film at three angles. image.

Next, in step S410 , the recognition device trains a recognition model to classify the attribute of the optical film in the training image, wherein the attribute is a surface protection film or a release film.

Next, in step S415 , the identification device receives images to be inspected from the above three angles captured by the optical sensor for an optical film to be inspected. In step S420, the recognition device detects the image to be detected by using the recognition model to determine the property of the optical film to be detected.

In one embodiment, the recognition model trained by the recognition device in step S410 is based on a Convolutional Neural Network (CNN) model. Common CNN model architectures include LeNet, AlexNet, VGG, GoogleLeNet, ResNet, etc.

In another embodiment, the platform may include a rotating mechanism for horizontally rotating the optical film for training and the optical film to be inspected, so as to obtain multiple surface images.

The following will describe in detail in step S420 how the recognition device uses the recognition model to detect the image to be detected to determine the property of the optical film to be detected.

FIG. 5 is a flowchart showing a method 500 for judging the properties of the optical film to be inspected by the recognition device according to an embodiment of the present disclosure using a recognition model. This method can be implemented in the graphics processor 324 of the recognition device 320 shown in FIG. 3 .

Before the process starts, the recognition device has trained a recognition model for recognizing the properties of the optical film. In step S505, the identification device receives images to be inspected from three angles captured by the optical sensor for an optical film to be inspected. Next, in step S510 , the recognition device uses the recognition model to obtain similarity ratios of the images to be detected corresponding to different attributes at the above three angles. To describe in more detail, after the recognition device has trained the recognition model, the recognition model can accept training input (eg, optical film image) and generate output through a series of application layers. The output is the similarity ratio of the optical film corresponding to a property.

Next, in step S515, the identification device determines whether there are more than two similarity ratios corresponding to an attribute greater than a threshold. When two or more similarity ratios corresponding to an attribute are greater than the threshold ("Yes" in step S515), in step S520, the recognition device judges the attribute of the optical film to be detected according to the similarity ratio.

When two or more similarity ratios that do not correspond to an attribute are greater than the threshold ("No" in step S515), in step S525, the recognition device sends an error message to notify a user that the above-mentioned optical film to be detected has occurred Abnormal, wherein the above identification device can use the relevant user interface (for example: display, light emitting diode (LED), liquid crystal display (LCD), microphone, buzzer (Buzzer) and other devices) to remind the user of the optical film to be detected An exception occurs. After receiving the error message, the above-mentioned user can judge the attribute of the above-mentioned optical film to be detected by a manual method.

FIG. 6 is a table showing data for identifying properties of an optical film according to an embodiment of the present disclosure, which is inspected based on collected images to be inspected. As shown in the table, the recognition device recognizes that the optical film to be detected is a surface protection film with a similarity ratio of 0 degrees, 45 degrees and 90 degrees, respectively, 8%, 93.2% and 84.5%, and recognizes that the optical film to be detected is a release type The similarity proportions of 0 degrees, 45 degrees and 90 degrees are 92%, 6.8% and 15.5% respectively. In this embodiment, the defined threshold is 0.4 (that is, the similarity ratio is 40%). Therefore, the identification device judges whether the number of similarity ratios of the surface protection film or release film of the optical film to be detected at 0 degrees, 45 degrees and 90 degrees greater than the threshold value of 0.4 exceeds 2. As shown in the table, the 45-degree and 90-degree similarity ratio of the surface protection film of the optical film to be detected is greater than the threshold value of 0.4, so the identification device will determine that the optical film to be detected is a surface protection film.

It should be noted that although the value of the threshold in FIG. 6 is 0.4 as an example, the present disclosure is not limited to the embodiment shown in FIG. 6 , that is, the present disclosure can define other threshold values based on the training results of captured images.

In addition, the graphics processor 324 in the identification device 320 can also execute the program 3282 in the memory 328 to present the actions and steps described in the above embodiments, or other descriptions in the manual.

Therefore, through the method, device and system for inspecting optical films disclosed in the present disclosure, errors caused by manual inspection of optical films can be effectively avoided. After the introduction of automatic identification, the production line can reduce the corresponding manpower, and provide the distribution of the optical film defects in the production line, thereby improving the yield rate. In addition, it can save production and inspection costs, further reduce the risk of misjudgment of optical films, and win more reputation and goodwill from the perspective of quality.

With respect to the described embodiments of the present disclosure, the following describes an exemplary operating environment in which embodiments of the present disclosure may be implemented. With particular reference to FIG. 7 , FIG. 7 shows an exemplary operating environment, generally considered a computing device 700 , for implementing embodiments of the present disclosure. Computing device 700 is only one example of a suitable computing environment and is not intended to suggest any limitation as to the scope of use or functionality of the disclosure. Neither should the computing device 700 be interpreted as having any dependency or requirement relating to any one or combination of illustrated elements.

The present disclosure can be executed in computer code or machine-usable instructions, the instructions can be computer-executable instructions of program modules, and the program modules are executed by computers or other machines, such as personal digital assistants or other portable devices . Generally speaking, a program module includes routines, programs, objects, components, data structures, etc., and a program module refers to a program code that executes a specific task or implements a specific abstract data type. The present disclosure can be implemented in a variety of system configurations, including portable devices, consumer electronics, general purpose computers, more professional computing devices, and the like. The present disclosure may also be practiced in distributed computing environments, processing devices that are linked by a communication network.

Refer to Figure 7. Computing device 700 includes a bus 710 for coupling, directly or indirectly, to memory 712, a graphics processor 714 included in one or more processors (not shown), one or more display elements 716, input I/O port 718 , input/output (I/O) element 720 and illustrative power supply 722 . Bus 710 represents an element that may be one or more buses (eg, an address bus, a data bus, or a combination thereof). Although each block in Fig. 7 is shown with a line for the sake of brevity, in fact, the boundary of each element is not specific, for example, the presentation element of the display device can be regarded as an I/O element; the graphics processor can have a memory body. Computing device 700 generally includes various computer-readable media. In addition, the graphics processor 714 in the computing device 700 can also execute the programs and instructions in the memory 712 to present the actions and steps described in the above embodiments, or other descriptions in the manual.

Any specific order or hierarchy of steps in the processes disclosed herein is by way of example only. Based upon design preferences, it must be understood that any specific order or hierarchy of steps in the procedures may be rearranged within the scope of the disclosure in this document. The accompanying method claims present elements of the various steps in a sample order, and therefore shouldn't be limited to the specific order or hierarchy presented.

The use of ordinal numerals such as "first", "second", and "third" used to modify elements in the claims does not imply any priority, order of priority, order of priority among elements, or implementation of the method The order of the steps in the sequence is used only as an identification to distinguish between different elements with the same name (with different ordinal numbers).

Although this disclosure has disclosed the above with the implementation example, it is not used to limit this case. Anyone who is familiar with this technology can make some changes and modifications without departing from the spirit and scope of this disclosure. Therefore, the protection scope of this case should be Depends on what is defined in the appended patent application scope.

100: Optical film 102: Surface protection film 104: protective layer 106: Polarizing substrate 108: protective layer 110: Adhesive layer 112: Release film 300: system 310: platform 320: identification device 322: input device 324: graphics processor 326: Neural Networks 328: memory 3282:program 330: Optical sensor 332: Lens 340: Network 350: optical film 400: method S405, S410, S415, S420: steps 500: method S505, S510, S515, S520, S525: steps 700: computing device 710: busbar 712:Memory 714: graphics processor 716: display components 718:I/O port 720: I/O components 722: Power supply

Figure 1 is a schematic diagram showing the composition of the optical film. Figure 2 shows images taken from different angles of the surface protection film or release film of the optical film. FIG. 3 is an exemplary schematic diagram of a system for inspecting an optical film according to an embodiment of the present disclosure. FIG. 4 is a flowchart showing a method for inspecting an optical film according to an embodiment of the present disclosure. FIG. 5 is a flowchart showing a method for judging the properties of the optical film to be detected by the recognition device according to an embodiment of the present disclosure using a recognition model. FIG. 6 is a table showing data identifying properties of an optical film according to an embodiment of the present disclosure. FIG. 7 shows an exemplary operating environment for implementing embodiments of the present disclosure.

400: method S405, S410, S415, S420: steps

Claims (18)

A system for inspecting an optical film, comprising: a platform; an optical sensor, photographing a surface of an optical film to be inspected placed on the above-mentioned platform at three angles to generate three images to be inspected; and a computing device, executing: receiving The image to be detected transmitted by the optical sensor; and a recognition model is used to detect the image to be detected to determine the properties of the optical film to be detected; wherein before the computing device receives the image to be detected, the calculation The device further receives a plurality of training images captured by the optical sensor and placed on the platform at the above three angles, and trains the identification model to classify the attributes of the optical films in the training images. The system for detecting optical films as described in Claim 1, wherein the step of using the identification model to detect the image to be inspected to determine the properties of the optical film to be inspected further includes: using the identification model to obtain the image to be inspected in The above three angles correspond to the similarity ratios of different attributes; judge whether there are more than two similarity ratios corresponding to an attribute greater than a threshold; and when there are more than two similarity ratios corresponding to an attribute greater than the above threshold, according to the above similarity The ratio judges the property of the optical film to be detected above. In the system for detecting an optical film as described in Claim 2, the method further includes: when two or more similarity ratios that do not have a corresponding attribute are greater than the threshold, sending an error message to notify that the optical film to be detected is abnormal . The system for inspecting an optical film according to claim 1, wherein the optical sensor is a color optical sensor and includes at least one lens, wherein the lens is equipped with a polarizer. The system for inspecting an optical film according to claim 1, wherein the platform further includes a backlight, and/or a rotating mechanism for rotating the optical film to be inspected. The system for inspecting an optical film according to claim 1, wherein the above three angles include 0 degree, 45 degree and 90 degree. The system for inspecting an optical film as claimed in claim 1, wherein the property is a surface protection film or a release film. A method for inspecting an optical film, comprising: photographing an image to be inspected of an optical film to be inspected placed on a platform at three angles by an optical sensor; placing multiple training images on the above-mentioned platform, and training the above-mentioned recognition model to classify the attributes of the above-mentioned optical film in the above-mentioned training images; receiving the above-mentioned to-be-detected image sent by the above-mentioned optical sensor; and using a recognition model to classify the above-mentioned to-be-detected image The image is detected to determine the property of the above-mentioned optical film to be detected. The method for inspecting an optical film as described in Claim 8, wherein the step of using the identification model to detect the image to be inspected to determine the properties of the optical film to be inspected further includes: using the identification model to obtain the image to be inspected in The above three angles correspond to the similarity ratios of different attributes; judge whether there are more than two similarity ratios corresponding to an attribute greater than a threshold; and when there are more than two similarity ratios corresponding to an attribute greater than the above threshold, according to the above similarity The ratio judges the property of the optical film to be detected above. The method for inspecting an optical film as described in claim 9, the above method further includes: when two or more similarity ratios that do not have a corresponding attribute are greater than the above threshold value, sending an error message to notify that the optical film to be inspected is abnormal . The method for inspecting an optical film according to claim 8, wherein the optical sensor is a color optical sensor and includes at least one lens, wherein the lens is equipped with a polarizer. The method for inspecting an optical film according to claim 8, wherein the platform further includes a backlight, and/or a rotating mechanism for rotating the optical film to be inspected. The method for inspecting an optical film as claimed in claim 8, wherein the above three angles include 0 degree, 45 degree and 90 degree. The method for inspecting an optical film as claimed in claim 8, wherein the property is a surface protection film or a release film. A device for detecting an optical film, comprising: At least one graphics processor; and at least one computer storage medium storing computer-readable instructions, wherein the above-mentioned graphics processor uses the above-mentioned computer storage medium to execute: receive images taken by an optical sensor and place an optical film to be inspected at three angles An image to be inspected on a platform; and a recognition model is used to detect the image to be inspected to determine the properties of the optical film to be inspected; wherein before receiving the image to be inspected, the graphics processor further receives the image from the optical sensor The tester shoots multiple training images of multiple optical films placed on the platform at the above three angles, and trains the recognition model to classify the properties of the optical films in the training images. The device for inspecting optical films according to claim 15, wherein the optical sensor is a color optical sensor and includes at least one lens, wherein the lens is equipped with a polarizer. The device for inspecting an optical film according to claim 15, wherein the platform further includes a backlight, and/or a rotating mechanism for rotating the optical film to be inspected. The device for inspecting an optical film as claimed in claim 15, wherein the property is a surface protection film or a release film.

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