TWI882341B - Method of evaluating optical film structure and method of manufacturing display device - Google Patents

Abstract

The present disclosure provides an optical film structure, a method of evaluating an optical film structure, and a method of manufacturing a display device. The optical film structure includes an optical film, a surface protective film, and a release film. The optical film has a first surface and a second surface opposite to the first surface. The surface protective film is on the first surface of the optical film. The release film is on the second surface of the optical film. A coefficient of static friction between the surface protective film and the release film is equal to or less than 0.4.

Description

Optical film structure evaluation method and display manufacturing method

The present disclosure relates to an optical film structure, an evaluation method of the optical film structure, and a manufacturing method of a display.

Polarizers are optical components widely used in displays. As displays are used more and more widely, such as mobile phones and wearable devices, the requirements for the quality of polarizers are becoming higher and higher.

In some embodiments, the present disclosure provides an optical film structure, which includes an optical film, a surface protection film, and a release film. The optical film has a first surface and a second surface opposite to the first surface. The surface protection film is located on the first surface of the optical film. The release film is located on the second surface of the optical film. The static friction coefficient of at least one of the surface protection film and the release film relative to the other is equal to or less than 0.4.

In some embodiments, the present disclosure provides an optical film structure evaluation method, which includes: laminating a first optical film structure to a supporting surface of a slope mechanism; disposing a second optical film structure on the first optical film structure, and making the first surface of the second optical film structure contact the surface of the first optical film structure; adjusting the inclination of the supporting surface until the second optical film structure starts to fall off from the first optical film structure and stops, and measuring the inclination angle of the supporting surface; and using the inclination angle as an indicator to evaluate the adhesion characteristics between the first optical film structure and the second optical film structure.

In some embodiments, the present disclosure provides a method for manufacturing a display, which includes: providing a plurality of optical film structures stacked on each other; evaluating these optical film structures using the aforementioned optical film structure evaluation method; and picking one of the optical film structures and attaching it to a display panel.

The following disclosure provides many different embodiments or examples to show the different components of the embodiments of the present disclosure. The following will disclose specific examples of the components of this specification and their arrangement to simplify the description of the present disclosure. Of course, these specific examples are not used to limit the present disclosure. For example, if the following disclosure of this specification describes forming a first component on or above a second component, it means that it includes an embodiment in which the formed first component and the second component are in direct contact, and also includes an embodiment in which an additional component can be formed between the above-mentioned first component and the second component, and the first component and the second component are not in direct contact. In addition, the various examples in the description of the present disclosure may use repeated reference symbols and/or words. The purpose of these repeated symbols or words is to make the present disclosure simpler and clearer, and is not used to limit the relationship between the various embodiments and/or the configurations.

Furthermore, to facilitate description of the relationship between one element or component and another element or component in the drawings, spatially relative terms may be used, such as "under," "below," "lower," "above," "upper," and the like. In addition to the orientation depicted in the drawings, spatially relative terms also cover different orientations of the structure or device in use or operation. When the structure or device is rotated to a different orientation (e.g., rotated 90 degrees or other orientations), the spatially relative adjectives used therein will also be interpreted based on the orientation after rotation.

Here, the terms "about", "approximately", and "generally" generally mean within 20% of a given value or range, preferably within 10%, and more preferably within 5%, or within 3%, or within 2%, or within 1%, or within 0.5%. It should be noted that the quantities provided in the specification are approximate quantities, that is, in the absence of specific description of "about", "approximately", and "generally", the meaning of "about", "approximately", and "generally" can still be implied.

The embodiments disclosed herein provide an optical film structure and an evaluation method thereof, wherein the optical film structure comprises a surface protection film and a release film, and the static friction coefficient between the surface protection film and the release film is equal to or less than 0.4, so that multiple optical film structures (or polarizing plate structures) can be stacked on each other without causing sticking problems. Furthermore, in the evaluation method of the optical film structure, two optical film structures can be stacked on the supporting surface of the ramp mechanism, and the tilt of the supporting surface is adjusted until one of the optical film structures starts to fall off from the other and stops, and the tilt angle of the supporting surface at this time is used as an indicator to evaluate the adhesion characteristics between the optical film structures. It is not necessary to use complex specifications or instruments, and the adhesion characteristics test results between the optical film structures can be obtained through a simple sliding test. The following will further explain the implementation of the optical film structure in detail.

Please refer to Fig. 1, which is a schematic diagram of an optical film structure 10 according to some embodiments of the present disclosure. The optical film structure 10 includes an optical film 100, a surface protection film 200 and a release film 300.

In some embodiments, the optical film 100 has a surface 101 and a surface 102, and the surface 101 is opposite to the surface 102. In some embodiments, the optical film 100 includes a polarizing plate, an optical property adjustment film, or a combination thereof. In some embodiments, the structure of the optical film 100 may include multiple film layers. In some embodiments, the optical film 100 includes an optical functional film 110, protective layers 120 and 130, and adhesive layers 140 and 150, but the structure disclosed in the present invention is not limited thereto, for example, the protective layer 120 and/or the protective layer 130 may be omitted, or other optical functional films may be added.

In some embodiments, the optical functional film 110 may include polarizers. In some embodiments, the material of the polarizer may be a polyvinyl alcohol (PVA) resin, which may be prepared by saponifying polyvinyl acetate resin. The degree of saponification of the polyvinyl alcohol resin is generally about 85 mol% or more. Examples of polyvinyl acetate resins include monomers of vinyl acetate (i.e., polyvinyl acetate), copolymers of vinyl acetate, and other monomers that can be copolymerized with vinyl acetate. Examples of other monomers that can be copolymerized with vinyl acetate include unsaturated carboxylic acids (e.g., acrylic acid, methacrylic acid, ethyl acrylate, n-propyl acrylate, methyl methacrylate), olefins (e.g., ethylene, propylene, 1-butene, 2-methylpropylene), vinyl ethers (e.g., ethyl vinyl ether, methyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether), unsaturated sulfonic acids (e.g., vinyl sulfonic acid, sodium vinyl sulfonate), etc. Specific examples of copolymers of the above-mentioned vinyl acetate and other monomers that can be copolymerized therewith include ethylene-vinyl acetate copolymers, etc. The degree of polymerization of polyvinyl alcohol-based resins is generally about 1000 to 10000, and preferably about 1500 to 5000. The polyvinyl alcohol-based resins may be modified, for example, polyvinyl formaldehyde, polyvinyl acetaldehyde, polyvinyl butyral, etc. modified with aldehydes may be used. In some embodiments, the optical functional film 110 has a thickness of about 5-35 μm, preferably about 20-30 μm.

In some embodiments, the material of the protective layers 120 and 130 may be, for example, a thermoplastic resin having excellent transparency, mechanical strength, thermal stability, moisture barrier properties, etc. The thermoplastic resin may include acetyl cellulose resin (e.g., triacetate cellulose (TAC), diacetate cellulose (DAC)), acrylic resin (e.g., polymethyl methacrylate (PMMA), polyester resin (e.g., polyethylene terephthalate (PET), polyethylene naphthalate), olefin resin, polycarbonate resin, cycloolefin resin, oriented-polypropylene (OPP), polyethylene (PE), polypropylene (PP), cyclic olefin polymer (COP), cyclic olefin copolymer (COP), and the like. copolymer (COC), polycarbonate (PC), or any combination thereof. In addition, the materials of the protective layers 120 and 130 may also be, for example, the following thermosetting resins or UV-curing resins: (meth) acrylic acid series, urethane series (e.g., polyurethane (PU)), acrylic urethane series (e.g., polyacrylic urethane), epoxy series (e.g., , epoxy resin), silicone system (e.g., silicone resin), etc. In addition, the protective layers 120 and 130 may be further subjected to surface treatment, such as anti-glare treatment, anti-reflection treatment, hard coating treatment, antistatic treatment, or anti-fouling treatment. In addition, in some embodiments, the protective layers 120 and 130 are a single layer or multiple layers of optical film. In some embodiments, the thickness of the protective layers 120 and 130 may be about 5 to 90 microns, preferably about 35 to 80 microns, respectively.

In some embodiments, the adhesive layer 140 is located between the protective layer 120 and the optical functional film 110, and the adhesive layer 150 is located between the protective layer 130 and the optical functional film 110. The adhesive layers 140 and 150 may include a water-based adhesive, which generally uses a polyvinyl alcohol resin or a urethane resin as a main component of the water-based adhesive, and in order to improve adhesion, may be a composition prepared by adding a crosslinking agent or a curing compound such as an isocyanate compound or an epoxy compound. In some embodiments, when the main component of the water-based adhesive is a polyvinyl alcohol resin, in addition to partially saponified polyvinyl alcohol and completely saponified polyvinyl alcohol, modified polyvinyl alcohol resins such as carboxyl-modified polyvinyl alcohol, acetyl-modified polyvinyl alcohol, hydroxymethyl-modified polyvinyl alcohol, and amino-modified polyvinyl alcohol can also be used. The aqueous solution of such polyvinyl alcohol resin can be used as a water-based adhesive, and the concentration of the polyvinyl alcohol resin in the water-based adhesive is generally 1 to 10 parts by mass, preferably 1 to 5 parts by mass, relative to 100 parts by mass of water. In some embodiments, a water-based adhesive composed of an aqueous solution of a polyvinyl alcohol-based resin may be combined with a curable compound such as a polyvalent aldehyde, a water-soluble epoxy resin, a melamine-based compound, a zirconium oxide-based compound, and a zinc compound to improve adhesion as described above.

In some embodiments, the adhesive layers 140 and 150 may be UV-curable adhesives, and the materials may include, for example: acrylic adhesives, epoxy adhesives, urethane adhesives, polyester adhesives, polyvinyl alcohol adhesives, polyolefin adhesives, modified polyolefin adhesives, polyvinyl alkyl ether adhesives, rubber adhesives, vinyl chloride-vinyl acetate adhesives, SEBS (styrene-ethylene-butylene-styrene copolymer) adhesives, ethylene-styrene copolymers and other ethylene-based adhesives, ethylene-(meth)acrylate methyl copolymers, ethylene-(meth)acrylate ethyl copolymers and other acrylate-based adhesives, etc.

In some embodiments, the surface protection film 200 is located on the surface 101 of the optical film 100. In some embodiments, the static friction coefficient of the surface protection film 200 relative to the release film 300 is equal to or less than about 0.4, equal to or less than about 0.3, equal to or less than about 0.2, or equal to or less than about 0.1.

Based on the current demand for thinner products, it is often necessary to reduce the thickness of the polarizer. Although this may lead to the problem of insufficient rigidity of the polarizer structure during the processing, the rigidity of the overall structure can be improved by thickening the surface protective film (since the surface protective film will eventually be removed and will not exist in the product, it will not have an adverse effect on the thinning of the product and is only used to improve the rigidity of the polarizer structure during the processing). However, the thickened surface protective film may be more difficult to tear off during the processing. Although this problem can be solved by reducing the adhesion between the surface protective film and the polarizer, it may cause the time warping of the finished polarizer structure to be too small, which may easily cause sticking and make subsequent processing difficult. According to some embodiments of the present disclosure, when the static friction coefficient of the surface protection film 200 relative to the release film 300 meets the above conditions, multiple optical film structures 10 (or polarizer structures) can be stacked together without the problem of sticking. In this way, even if the surface protection film 200 in the optical film structure 10 has a large thickness and the adhesion between the surface protection film 200 and the optical film 100 is low, so that the time warping of the optical film structure 10 is relatively low, the optical film structure 10 still has sufficient rigidity, the surface protection film 200 can be easily torn off in the subsequent process, and can be stacked together without sticking, so it has good processability.

In some embodiments, the surface protection film 200 may include a surface protection layer 210 and a surface structure 220, wherein the surface protection layer 210 is located between the surface 101 of the optical film 100 and the surface structure 220. In some embodiments, the static friction coefficient of the surface structure 220 relative to the release film 300 is equal to or less than about 0.4, equal to or less than about 0.3, equal to or less than about 0.2, or equal to or less than about 0.1.

In some embodiments, the material of the surface structure 220 is different from the material of the surface protection layer 210. In some embodiments, the surface structure 220 may be an additionally manufactured or formed surface structure film layer, which is formed by setting or manufacturing an additional film layer on the surface protection layer 210. In some embodiments, the surface structure 220 includes a resin material, such as a thermosetting resin or a UV-curing resin. In some embodiments, the thermosetting resin of the surface structure 220 may include a urethane system (e.g., polyurethane (PU)), an acrylic urethane system (e.g., polyacrylic urethane), an acrylic styrene system, a polysiloxane system (e.g., polysiloxane), a polysilane system, a fluororesin system, etc. In some embodiments, the UV resin of the surface structure 220 may include a mixture of monomers, oligomers, and polymers of various resins such as acrylic, urethane, and epoxy. In some embodiments, the surface structure 220 may further include a lubricant greater than about 2.5 wt %. In some embodiments, the surface structure 220 includes about 5 to 30 wt %. In some embodiments, the lubricant may include fatty acid amide, fatty acid ester, polysilicone lubricant, fluorine lubricant, wax lubricant, or any combination thereof.

According to some embodiments of the present disclosure, the resin material of the surface structure 220 includes a polysiloxane system, a polysilane system and/or a fluororesin system, or the surface structure 220 further includes a lubricant, which can increase the smoothness of the surface structure 220, thereby helping to reduce the surface static friction of the surface structure 220. Furthermore, according to some embodiments of the present disclosure, the content of the lubricant has a critical influence on the characteristics of the surface structure 220. When the content of the lubricant is higher than 30wt%, it may cause the light transmittance of the surface structure 220 to decrease, or make the surface printability of the surface structure 220 poor. When the content of the lubricant is lower than 5wt%, it may cause the surface static friction of the surface structure 220 to be too high, and it is not possible to effectively solve the problem of subsequent processing of the adhesive film.

In some embodiments, the surface structure 220 may be formed by surface treating the outer surface of the surface protection film 200. In some embodiments, the surface structure 220 may include a sandblasted microstructure, a 3D printed material layer, a screen printed layer, a vector printed layer, a UV-cured adhesive layer, or any combination thereof.

In some embodiments, the thickness of the surface structure 220 is equal to or less than about 1 micron, equal to or less than about 0.5 micron, or equal to or less than about 0.2 micron. In some embodiments, the thickness of the surface structure 220 is about 0.05-1 micron, about 0.1-1 micron, about 0.05-0.5 micron, about 0.05-0.2 micron, or about 0.2-0.5 micron. In some embodiments, the thickness of the surface protection layer 210 and the surface structure 220 as a whole can be greater than 35 microns, or equal to or greater than 50 microns, preferably 50-90 microns. According to some embodiments of the present disclosure, when the surface protection film 200 has a surface protection layer 210 and a surface structure 220 and the overall thickness is within the above range, the problem of sticking can be avoided and sufficient rigidity can be provided to the optical film structure 10, thereby greatly improving the processability of the optical film structure 10.

In some embodiments, the material of the surface protection film 200 (or the surface protection layer 210) may be a thermoplastic resin having good transparency, mechanical strength, thermal stability, moisture barrier properties, etc. In some embodiments, the thermoplastic resin may include a cellulose resin (e.g., cellulose triacetate (TAC), cellulose diacetate (DAC)), an acrylic resin (e.g., polymethyl methacrylate (PMMA), a polyester resin (e.g., polyethylene terephthalate (PET), polyethylene naphthalate), an olefin resin, a polycarbonate resin, a cycloolefin resin, an oriented oriented polypropylene (OPP), polyethylene (PE), polypropylene (PP), a cycloolefin polymer (COP), a cycloolefin copolymer ... Olefin copolymer (COC), polycarbonate (PC), or any combination thereof. In addition, the material of the surface protection film 200 (or surface protection layer 210) may also be a thermosetting resin or UV curing resin such as (meth) acrylic acid, urethane, acrylic urethane, epoxy, or silicone. In addition, the surface protection film 200 (or surface protection layer 210) may be further subjected to surface treatment, such as anti-glare treatment, anti-reflection treatment, hard coating treatment, antistatic treatment, or anti-fouling treatment.

In some embodiments, the release film 300 is located on the surface 102 of the optical film 100. In some embodiments, the static friction coefficient of the release film 300 relative to the surface protection film 200 is equal to or less than about 0.4, equal to or less than about 0.3, equal to or less than about 0.2, or equal to or less than about 0.1. In some embodiments, the release film 300 may include polyethylene terephthalate (PET), polybutylene terephthalate, polycarbonate, polyarylate, polyester resin, olefin resin, cellulose acetate resin, acrylic resin, polyethylene (PE), polypropylene (PP), cycloolefin resin, or a combination thereof.

In some embodiments, the optical film structure 10 may further include adhesive layers 400 and 500, the adhesive layer 400 is located between the surface protection film 200 and the optical film 100, and the adhesive layer 500 is located between the release film 300 and the optical film 100. In some embodiments, the adhesive layers 400 and 500 include pressure sensitive adhesives (PSA), heat sensitive adhesives, solvent volatile adhesives, and/or UV curable adhesives. In some embodiments, the pressure sensitive adhesive may include natural rubber, synthetic rubber, styrene block copolymers, (meth) acrylic block copolymers, polyvinyl ethers, polyolefins, and/or poly (meth) acrylates. In some embodiments, (meth)acrylic acid (or acrylate) refers to both acrylic acid and methacrylic acid. In some embodiments, the pressure-sensitive adhesive may include (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 optical film structure 100 has a 2-week warp value of about 23 millimeters (mm), about 18 millimeters, about 16 millimeters, or about 9 millimeters. In some embodiments, the optical film structure 100 has a 4-week warp value of about 20 millimeters, about 13 millimeters, about 10 millimeters, or about 2 millimeters. In some embodiments, the optical film structure 100 has a 2-week warp value of about 8-23 millimeters, about 12-20 millimeters, or about 15-18 millimeters. In some embodiments, the optical film structure 100 has a 4-week warp value of about 1-20 millimeters, about 5-15 millimeters, or about 10-12 millimeters.

Please refer to FIG. 2, which is a schematic diagram of an optical film structure 10A according to some embodiments of the present disclosure. In some embodiments, the structure of the optical film structure 10A is similar to the optical film structure 10, and the differences are as follows. In addition, from now on, the same or similar elements as the above elements will use the same or similar element numbers, and the relevant descriptions of the same or similar elements can be found in the above, which will not be repeated here.

In some embodiments, the thickness of the surface protection film 200 may be greater than 35 microns, or equal to or greater than 50 microns, preferably 50-90 microns.

In some embodiments, the release film 300 may include a release layer 310 and a surface structure 320, wherein the release layer 310 is located between the surface 102 of the optical film 100 and the surface structure 320. In some embodiments, the static friction coefficient of the surface structure 320 relative to the surface protection film 200 is equal to or less than about 0.4, equal to or less than about 0.3, equal to or less than about 0.2, or equal to or less than about 0.1.

In some embodiments, the material of the surface structure 320 is different from the material of the release layer 310. In some embodiments, the surface structure 320 may be an additionally manufactured or formed surface structure film layer, formed by providing or manufacturing an additional film layer on the release layer 310. In some embodiments, the surface structure 320 includes a resin material, such as a thermosetting resin or a UV-curable resin. In some embodiments, the thermosetting resin of the surface structure 320 may include a urethane system (e.g., polyurethane (PU)), an acrylic urethane system (e.g., polyacrylic urethane), an acrylic styrene system, a polysilicone system (e.g., polysilicone resin), a polysilane system, a fluororesin system, etc. In some embodiments, the UV resin of the surface structure 320 may include a mixture of monomers, oligomers, and polymers of various resins such as acrylic, urethane, and epoxy. In some embodiments, the surface structure 320 may further include a lubricant greater than about 2.5 wt %. In some embodiments, the surface structure 320 includes about 5 to 30 wt %. In some embodiments, the lubricant may include fatty acid amide, fatty acid ester, polysilicone lubricant, fluorine lubricant, wax lubricant, or any combination thereof.

According to some embodiments of the present disclosure, the resin material of the surface structure 320 includes a polysiloxane system, a polysilane system and/or a fluororesin system, or the surface structure 320 further includes a lubricant, which can increase the smoothness of the surface structure 320, thereby helping to reduce the surface static friction of the surface structure 320. Furthermore, according to some embodiments of the present disclosure, the content of the lubricant has a critical influence on the characteristics of the surface structure 320. When the content of the lubricant is higher than 30wt%, it may cause the light transmittance of the surface structure 320 to decrease, or make the surface printing property of the surface structure 320 poor. When the content of the lubricant is lower than 5wt%, it may cause the surface static friction of the surface structure 320 to be too high, and it is not possible to effectively solve the problem of subsequent processing of the film.

Furthermore, according to some embodiments of the present disclosure, since the release film 300 includes the release layer 310 and the surface structure 320, the surface protection film 200 can have a relatively large thickness to provide the optical film structure 10A with sufficient rigidity, and the design of the release film 300 can effectively avoid the problem of sticking, thereby greatly improving the processability of the optical film structure 10A.

In some embodiments, the surface structure 320 may be formed by surface treating the outer surface of the release film 300. In some embodiments, the surface structure 320 may include a sandblasted microstructure, a 3D printed material layer, a screen printed layer, a vector printed layer, a UV-cured adhesive layer, or any combination thereof.

In some embodiments, the thickness of the surface structure 320 is equal to or less than about 1 micron, equal to or less than about 0.5 micron, or equal to or less than about 0.2 micron. In some embodiments, the thickness of the surface structure 320 is about 0.05-1 micron, about 0.1-1 micron, about 0.05-0.5 micron, about 0.05-0.2 micron, or about 0.2-0.5 micron.

In some embodiments, the release layer 310 may include polyethylene terephthalate (PET), polybutylene terephthalate, polycarbonate, polyarylate, polyester resin, olefin resin, cellulose acetate resin, acrylic resin, polyethylene (PE), polypropylene (PP), cycloolefin resin, or a combination thereof.

Please refer to Figure 3, which is a schematic diagram of an optical film structure 10B according to some embodiments of the present disclosure. In some embodiments, the structure of the optical film structure 10B is similar to the optical film structure 10 and/or the optical film structure 10A, and the differences are as follows.

In some embodiments, the surface protection film 200 of the optical film structure 10B includes a surface protection layer 210 and a surface structure 220 , and the release film 300 includes a release layer 310 and a surface structure 320 .

Please refer to Figure 4, which is a schematic diagram of an optical film structure 10C according to some embodiments of the present disclosure. In some embodiments, the structure of the optical film structure 10C is similar to the optical film structure 10, the optical film structure 10A, and/or the optical film structure 10B, and the differences are as follows.

In some embodiments, the surface protection film 200A and the release film 300A of the optical film structure 10C do not include an additionally formed surface structure. In some embodiments, the surface protection film 200A and the release film 300A include a silicone-containing resin, a fluorine-containing resin, or a combination thereof. In some embodiments, by selecting appropriate materials to form the surface protection film 200A and the release film 300A, the static friction coefficient of the surface protection film 200A relative to the release film 300A is equal to or less than about 0.4, equal to or less than about 0.3, equal to or less than about 0.2, or equal to or less than about 0.1.

Please refer to Figures 5, 6A and 6B, Figure 5 is a flow chart of the evaluation method of the optical film structure according to some embodiments of the present disclosure, and Figures 6A and 6B are schematic diagrams of the evaluation method of the optical film structure according to some embodiments of the present disclosure. As shown in FIG5 , the evaluation method of the optical film structure may include the following steps: laminating a first optical film structure onto a supporting surface of a ramp mechanism (step S10); placing a second optical film structure on the first optical film structure, and making the first surface of the second optical film structure contact the surface of the first optical film structure (step S20); adjusting the inclination of the supporting surface until the second optical film structure starts to fall off from the first optical film structure and stops, and measuring the inclination angle of the supporting surface (step S30); and using the inclination angle as an indicator, evaluating the adhesion characteristics between the first optical film structure and the second optical film structure (step S40).

Referring to FIG. 5 and FIG. 6A , in step S10, the optical film structure 10 may be attached to the supporting surface 510 of the ramp mechanism 50. In some embodiments, the optical film structure 10 may be fixed on the supporting surface 510 of the ramp mechanism 50. In some embodiments, the optical film structure 10 includes an optical film 100, a surface protection film 200, and a release film 300, and the optical film structure 10 may be fixed on the supporting surface 510 of the ramp mechanism 50 with the release film 300 facing upward. In some other embodiments, the optical film structure 10 may also be fixed on the supporting surface 510 of the ramp mechanism 50 with the surface protection film 200 facing upward.

Next, referring to FIG. 5 and FIG. 6A , in step S20, the optical film structure 10′ may be disposed on the optical film structure 10, and the surface 201′ of the optical film structure 10′ may contact the surface 301 of the optical film structure 10. In some embodiments, similar to the optical film structure 10, the optical film structure 10′ includes the optical film 100, the surface protection film 200, and the release film 300, and the optical film structure 10′ may be disposed on the optical film structure 10 with the surface protection film 200 facing downward. In some other embodiments, the release film 300 may also be disposed on the optical film structure 10 with the surface protection film 200 facing downward.

In some embodiments, in step S20, the surface 201' of the surface protection film 200 of the optical film structure 10' is brought into contact with the surface 301 of the release film 300 of the optical film structure 10. In some other embodiments, in step S20, the surface of the release film 300 of the optical film structure 10' may also be brought into contact with the surface of the surface protection film 200 of the optical film structure 10. In some embodiments, in step S20, the supporting surface 510 has an angle θ1 (also referred to as a "starting angle") relative to the horizontal plane, and the angle θ1 allows the optical film structure 10' to be stationary on the optical film structure 10 without loosening or sliding.

In some embodiments, in step S20, the optical film structure 10' has a surface 301' relative to the surface 201', and the surface 301' of the optical film structure 10' can be bonded to the surface 601 of the rigid substrate 60 before adjusting the inclination of the support surface 510 (step S30). In some embodiments, the surface 301' of the optical film structure 10' is completely within the range of the surface 601 of the rigid substrate 60. In some embodiments, the rigid substrate 60 is, for example, a glass plate. According to some embodiments of the present disclosure, the hard substrate 60 can improve the overall structural flatness of the optical film structure 10', so that the surface 201' of the optical film structure 10' can completely contact the surface of the optical film structure 10 in the subsequent testing step (step S30), thereby obtaining more consistent and accurate measurement data, reducing errors and improving the reliability of the evaluation method.

Next, referring to FIG. 5 and FIG. 6B , in step S30, the tilt degree of the supporting surface 510 may be adjusted until the optical film structure 10' begins to fall off (or loosen) from the optical film structure 10 and stops, and the tilt angle θ2 of the supporting surface 510 at this time is measured. In some embodiments, the tilt angle θ2 of the supporting surface 510 is measured when the relative position of the surface 201' of the optical film structure 10' and the surface 301 of the optical film structure 10 begins to change. In some embodiments, the tilt angle θ2 of the supporting surface 510 is greater than the starting angle θ1. In some embodiments, before the optical film structure 10' falls off (or loosens) from the optical film structure 10, the surface 201' of the optical film structure 10' is completely within the range of the surface 301 of the optical film structure 10. According to some embodiments of the present disclosure, the surface 201' of the optical film structure 10' is completely within the range of the surface 301 of the optical film structure 10, so that the surface 201' of the optical film structure 10' can completely contact the surface of the optical film structure 10 in step S30, thereby obtaining more consistent and accurate measurement data, reducing errors, and improving the reliability of the evaluation method.

Next, referring to FIG. 5 , in step S40 , the tilt angle θ2 may be used as an indicator to evaluate the adhesion characteristics between the optical film structure 10 and the optical film structure 10 ′.

In some embodiments, the static friction force of the surface 301 of the optical film structure 10 relative to the surface 201' of the optical film structure 10' increases with the increase of the tilt angle θ2 of the supporting surface 510. In some embodiments, the static friction coefficient of the surface 301 of the optical film structure 10 relative to the surface 201' of the optical film structure 10' increases with the increase of the tilt angle θ2 of the supporting surface 510.

In some embodiments, the adhesion characteristics between the optical film structure 10 and the optical film structure 10' may include the static friction of the surface of the optical film structure 10 (e.g., surface 301) relative to the surface of the optical film structure 10' (e.g., surface 201'), the static friction coefficient of the surface of the optical film structure 10 (e.g., surface 301) relative to the surface of the optical film structure 10' (e.g., surface 201'), or a combination of the above.

In some embodiments, the adhesion characteristics between the optical film structure 10 and the optical film structure 10' may include the static friction force and/or static friction coefficient of the surface protection film 200 of the optical film structure 10 relative to the release film 300 of the optical film structure 10', the static friction force and/or static friction coefficient of the release film 300 of the optical film structure 10 relative to the surface protection film 200 of the optical film structure 10', the static friction force and/or static friction coefficient of the surface protection film 200 of the optical film structure 10 relative to the surface protection film 200 of the optical film structure 10', the static friction force and/or static friction coefficient of the release film 300 of the optical film structure 10 relative to the release film 300 of the optical film structure 10', or a combination of the above.

In some embodiments, the adhesion characteristics between the optical film structure 10 and the optical film structure 10' can be evaluated based on the tilt angle θ2 and a lookup table. In some embodiments, the lookup table includes the relationship between the tilt angle θ2 and the static friction force, the relationship between the tilt angle θ2 and the static friction coefficient, or a combination thereof.

In some embodiments, the tilt angle θ2 may be equal to or less than a specific numerical range as an indicator. In some embodiments, the tilt angle θ2 may be equal to or less than 25 degrees as an indicator. In some embodiments, when the tilt angle θ2 meets the above-mentioned indicator conditions, the optical film structures 10 and 10' can pass the adhesion property test, which means that the optical film structures 10 and 10' are not prone to sticking.

The following adhesion test is conducted on samples of various optical film structures (polarizers), wherein the tilt angle θ2 of the support surface, the static friction coefficient between the two optical film structures, and the results of the adhesion test evaluation are shown in the following Table 1. Thus, the tilt angle θ2 of the support surface can be used as an indicator to evaluate the adhesion characteristics of the optical film structure.

(1) Static friction coefficient test: The static friction between optical film structures is measured according to JIS K7152. The first optical film structure is placed on a glass substrate with the release film facing upward. The second optical film structure is placed with the surface protection film facing downward as a sliding surface to contact the release film of the first optical film structure below. A load of 200 grams is placed on the second optical film structure. The sliding surface is then moved horizontally at a speed of 100 mm/min to measure the static friction between the two optical film structures. The static friction coefficient is then calculated based on the static friction and load. In the following embodiments and comparative examples, the surface protective film of the optical film structure includes a surface structure, and the surface structure of each surface protective film of the optical film structure includes a lubricant (polyether modified silicone, Shin-Etsu Chemical KP-105 additive) in different amounts. The method for making the surface structure is as follows: acrylic resin is mixed with lubricants and crosslinking agents in different weight proportions, and stirred for about 30 minutes and then fully mixed. Then, a transparent polyethylene terephthalate (PET) film with a thickness of 38 microns, a width of 20 cm, and a length of 30 cm is provided, and the above mixture is applied to the PET film using a rod coating machine, and then heated at 100°C for 5 minutes for drying, and the surface structure is formed after drying.

(2) Measurement of the tilt angle θ2 of the supporting surface: The test was performed using an initial adhesion tester as a slope mechanism, wherein the first optical film structure was cut into a size of 20 cm * 30 cm, and the second optical film structure was cut into a size of 8 cm * 8 cm (weight of approximately 1.23 g). The first optical film structure sample was then adhered to the slope of the test instrument (the supporting surface of the slope mechanism) with the release film facing upward, and the second optical film structure sample was adhered to a glass plate with a thickness of 0.5 mm and a size of 10 cm * 1 cm (the weight of the glass plate was approximately 16.65 g). The second optical film structure sample (total weight of approximately 17.88 g) was then adhered to the first optical film structure sample on the slope with the surface protection film facing downward and the glass plate facing upward. Next, adjust the tilt angle of the slope of the test instrument (the bearing surface of the slope mechanism) and record the tilt angle θ2 of each set of optical film structures when they loosen and slide off.

(3) Adhesion test evaluation: Cut the optical film structure sample into a size of 13.3 inches (295.76 mm * 168.24 mm), stack 50 optical film structure samples, put the 50 stacked optical film structure samples into an aluminum foil bag and evacuate the air. Then place them in an environment with a temperature of 25°C and a humidity of 55% for two weeks to simulate the time from packaging completion to delivery to the customer. Then, open the aluminum foil bag and take out the 50 stacked optical film structures. Place them with the surface protection film side facing up, use a vacuum suction device to absorb the optical film structure at the top and move it upward to confirm the adhesion condition. If a single suction operation can successfully absorb the uppermost single optical film structure, it is judged as passed "○", and if a single suction operation can absorb more than two optical film structures, it is judged as failed "×".

Table 1 Lubricant content (wt%) Static friction coefficient Tilt angle θ2 (degrees) Adhesion test Embodiment 1 20 0.17 10 ○ Embodiment 2 10 0.21 20 ○ Embodiment 3 5 0.33 25 ○ Comparative example 1 2.5 0.42 35 × Comparative example 2 0 0.55 45 ×

From the results in Table 1, it can be seen that the content of the lubricant has a key influence on the static friction coefficient, thereby affecting the adhesion of the optical film structure. In addition, from the results in Table 1, it can be seen that different tilt angles θ2 can correspond to different static friction coefficients, thereby determining the adhesion results of the optical film structure. Therefore, according to some embodiments of the present disclosure, the tilt angle θ2 is used as an indicator to evaluate the adhesion characteristics between optical film structures, and complex specifications or instruments are not required. For example, there is no need to measure static friction or static friction coefficient, and the adhesion characteristics test results between optical film structures can be obtained through a simple sliding test.

7A, 7B, 7C, 7D and 7E are flow charts of a method for manufacturing the display 1 according to some embodiments of the present disclosure.

As shown in FIG7A , a plurality of stacked optical film structures 10 may be provided. In some embodiments, each optical film structure 10 includes an optical film 100, a surface protection film 200, and a release film 300, and the optical film structures 10 are stacked with the surface protection film 200 facing upward. In some embodiments, of two adjacent optical film structures 10, the surface of the surface protection film 200 of one contacts the surface of the release film 300 of the other.

In some embodiments, the adhesion properties of the optical film structure 10 can be evaluated by the evaluation method described in the embodiments of the present disclosure, and the optical film structures 10 that have passed the adhesion property test can be stacked on each other. In some embodiments, after the adhesion properties of the optical film structure 10 are evaluated, the optical film structures 10 that have passed the adhesion property test can be stacked on each other. In some embodiments, the warp value of the optical film structure 100 after 2 weeks is equal to or less than about 23 mm, equal to or less than about 18 mm, equal to or less than about 16 mm, or equal to or less than about 9 mm. In some embodiments, the warp value of the optical film structure 100 after 4 weeks is equal to or less than about 20 mm, equal to or less than about 13 mm, equal to or less than about 10 mm, or equal to or less than about 2 mm. In some embodiments, the optical film structure 100 has a 2-week warp value of about 8-23 mm, about 12-20 mm, or about 15-18 mm. In some embodiments, the optical film structure 100 has a 4-week warp value of about 1-20 mm, about 5-15 mm, or about 10-12 mm.

As shown in FIG. 7B , one of the optical film structures 10 can be picked up from the stacked optical film structures 10. In some embodiments, the top optical film structure 10 can be picked up by the suction device 70. In some embodiments, the top optical film structure 10 of the stacked optical film structures 10 can be sucked by the vacuum suction device of the suction device 70. In some embodiments, the vacuum suction device of the suction device 70 can pick up the optical film structure 10 by vacuum adsorbing the surface protection film 200 of the optical film structure 10. According to some embodiments of the present disclosure, since the optical film structures 10 have all passed the adhesion property test, they can be picked up one by one for subsequent processing.

As shown in FIG. 7C , the release film 300 of the optical film structure 10 on the suction device 70 can be torn off. In some embodiments, the optical film structure 10 is temporarily fixed on the suction device 70 by vacuum adsorption, and the release film 300 is torn off from the optical film structure 10 by the tearing device 80. According to some embodiments of the present disclosure, since the optical film structure 10 has sufficient rigidity, when the release film 300 is torn off, the optical film structure 10 will not be pulled to cause vacuum damage, so that the optical film structure 10 will not fall off from the suction device 70.

As shown in FIG. 7D , the optical film 100 can be attached to the display panel 20. In some embodiments, the optical film 100 is temporarily fixed on the suction device 70 through the surface protection film 200, and the optical film 100 can be attached to the display panel 20 by moving the suction device 70. In some embodiments, the display panel 20 can be a liquid crystal display panel, such as an IPS liquid crystal display panel or a VA liquid crystal display panel. In some embodiments, the display panel 20 can be an OLED panel.

7E, the suction device 70 may be removed from the surface protection film 200. In some embodiments, the surface protection film 200 may be removed to form the display 1 including the optical film 100 and the display panel 20.

Although the present disclosure is disclosed as above with the aforementioned embodiments, it is not intended to limit the present disclosure. Those with ordinary knowledge in the technical field to which the present disclosure belongs can make some changes and modifications without departing from the spirit and scope of the present disclosure. Therefore, the protection scope of the present disclosure shall be determined by the scope of the attached patent application. In addition, each patent application constitutes an independent embodiment, and the combination of various patent application scopes and embodiments is within the scope of the present disclosure.

1: Display 10, 10', 10A, 10B, 10C: Optical film structure 20: Display panel 50: Slope mechanism 60: Hard substrate 70: Suction device 80: Removal device 100: Optical film 101, 102, 201', 301, 301', 601: Surface 110: Optical functional film 120, 130: Protective layer 140, 150: Adhesive layer 200, 200A: Surface protective film 210: Surface protective layer 220, 320: Surface structure 300, 300A: Release film 310: Release layer 400, 500: Adhesive layer 510: Carrying surface S10, S20, S30, S40: Steps θ1, θ2: Angles

In order to make the features and advantages of the present disclosure more clearly understandable, different embodiments are specifically cited below and are described in detail with the accompanying drawings. It should be noted that the various features in the drawings are not drawn according to the actual scale and are only used for illustration. In fact, the sizes of various elements in the drawings can be arbitrarily enlarged or reduced according to actual applications to clearly show the features of the embodiments of the present disclosure.

FIG. 1 is a schematic diagram of an optical film structure according to some embodiments of the present disclosure.

FIG. 2 is a schematic diagram of an optical film structure according to some embodiments of the present disclosure.

FIG. 3 is a schematic diagram of an optical film structure according to some embodiments of the present disclosure.

FIG. 4 is a schematic diagram of an optical film structure according to some embodiments of the present disclosure.

FIG5 is a flow chart of an evaluation method for an optical film structure according to some embodiments of the present disclosure.

6A-6B are schematic diagrams of an evaluation method for an optical film structure according to some embodiments of the present disclosure.

7A, 7B, 7C, 7D and 7E are flow charts of methods for manufacturing a display according to some embodiments of the present disclosure.

10: Optical film structure

100: Optical film

101,102: Surface

110: Optical functional film

120,130: Protective layer

140,150: Next is the agent layer

200: Surface protection film

210: Surface protective layer

220: Surface structure

300: Release film

400,500: Adhesive layer

Claims (8)

An evaluation method for an optical film structure includes: laminating a first optical film structure to a bearing surface of a ramp structure; arranging a second optical film structure on the first optical film structure, wherein the first optical film structure and the second optical film structure each include an optical film and a surface protection film and a release film respectively located on opposite surfaces of the optical film, the second optical film structure has a first surface and a second surface opposite to each other, and the first surface of the second optical film structure is in contact with a surface of the first optical film structure, wherein the first surface of the second optical film structure is in contact with a surface of the first optical film structure, wherein the first surface of the second optical film structure is in contact with a surface of the first optical film structure, and ... Before measuring the tilt degree of the support surface, the second surface of the second optical film structure is bonded to a surface of a hard substrate, wherein the second surface of the second optical film structure is completely within the range of the surface of the hard substrate; the tilt degree of the support surface is adjusted until the second optical film structure starts to fall off from the first optical film structure and stops, and a tilt angle of the support surface is measured; and the adhesion characteristics between the first optical film structure and the second optical film structure are evaluated using the tilt angle as an indicator. The evaluation method of the optical film structure as claimed in claim 1, wherein the adhesion property includes a static friction force of the surface of the first optical film structure relative to the first surface of the second optical film structure, a static friction coefficient of the surface of the first optical film structure relative to the first surface of the second optical film structure, or a combination thereof. The evaluation method of the optical film structure as claimed in claim 2, wherein the adhesion property includes a static friction force and/or a static friction coefficient of the surface protection film of the first optical film structure relative to the release film of the second optical film structure, a static friction force and/or a static friction coefficient of the release film of the first optical film structure relative to the surface protection film of the second optical film structure, a static friction force and/or a static friction coefficient of the surface protection film of the first optical film structure relative to the surface protection film of the second optical film structure, a static friction force and/or a static friction coefficient of the release film of the first optical film structure relative to the release film of the second optical film structure, or a combination of the above. The evaluation method of the optical film structure of claim 2 further includes: evaluating the adhesion characteristics between the first optical film structure and the second optical film structure according to the tilt angle and a lookup table, wherein the lookup table includes the relationship between the tilt angle and the static friction force, the relationship between the tilt angle and the static friction coefficient, or a combination thereof. The evaluation method of the optical film structure as claimed in claim 2, wherein the static friction force and/or the static friction coefficient of the surface of the first optical film structure relative to the first surface of the second optical film structure increases as the tilt angle of the bearing surface increases. The evaluation method of the optical film structure as claimed in claim 1, wherein before the second optical film structure falls off from the first optical film structure, the first surface of the second optical film structure is completely within the range of the surface of the first optical film structure. The evaluation method of the optical film structure as claimed in claim 1, wherein the tilt angle is equal to or less than 25 degrees as an indicator. A method for manufacturing a display comprises: providing a plurality of optical film structures stacked on each other, each of the optical film structures comprising the optical film as claimed in claim 1 and the surface protection film and the release film respectively located on opposite surfaces of the optical film; evaluating the optical film structures using the evaluation method of the optical film structure described in any one of claims 1 to 7; and picking up one of the optical film structures, and tearing off the release film of the picked optical film structure, so that the exposed optical film is attached to a display panel.

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