Method for manufacturing optical film

Abstract

The invention provides a method for manufacturing an optical film. The method comprises the steps that a roll-shaped film material and a roll-shaped impressing film sheet are unwound in the preset direction, the roll-shaped film material comprises a forming face, and the roll-shaped impressing film sheet comprises an impressing structure; coating a coating layer on the forming surface of the roll-shaped membrane material or the imprinting structure of the roll-shaped imprinting membrane; pressing the roll-shaped impressing membrane and the roll-shaped membrane material, so that the coating layer is clamped between the forming surface and the impressing structure; carrying out light curing treatment on the coating layer so as to cure the coating layer into an optical functional layer; and respectively rolling the roll-shaped film material and the roll-shaped imprint film so as to separate the optical structure of the optical functional layer from the imprint structure of the roll-shaped imprint film and combine the optical functional layer and the roll-shaped film material into the optical film. Therefore, the optical film can be continuously produced, and the production cost is reduced.

Description

Technical Field

[0001] This invention relates to a method for manufacturing an optical film, and more particularly to a method for continuously producing an optical film. Background Technology

[0002] Optical films are crucial components in optoelectronic products. They can be applied to other components as single or multilayer coatings, and through their physical properties, they exhibit unique optical properties to alter the transmission characteristics of light waves, such as controlling light amplification, reflection, filtering, or polarization. Optical films are widely used in optoelectronic products such as optical instruments, liquid crystal displays (LCDs), touch panels, solar cells, and optical waveguides. LCDs, in particular, are extensively used in electronic products such as laptops, smartphones, tablets, and LCD TVs.

[0003] Optical films include hard coat film, anti-reflection film, antiglare film (AG film), retardation film, polarizer, diffuser, and brightness enhancement film. For example, anti-glare films are designed to prevent light from focusing on a flat surface and entering the eye at a specific angle, causing dizziness and difficulty seeing the screen – a phenomenon known as "glare." With the widespread use of smartphones, glare problems must be addressed, and one solution is to incorporate anti-glare films on polarizers. By creating a rough, uneven surface, the light is scattered at different angles, preventing it from concentrating at a specific point and thus achieving an anti-glare effect.

[0004] With the significant increase in the application of optical films, the conventional method of manufacturing optical films using coating is not only time-consuming but also relatively expensive. Therefore, there is an urgent need to provide a method for manufacturing optical films that can increase production volume and reduce manufacturing costs. Summary of the Invention

[0005] One aspect of the present invention is to provide a method for manufacturing an optical film, which uses a roll-shaped imprinted film as a forming mold to continuously produce optical films.

[0006] According to one aspect of the present invention, a method for manufacturing an optical film is provided. The method includes unwinding a roll of film material and a roll of embossed film sheet along a predetermined direction, wherein the roll of film material and the roll of embossed film sheet are spaced apart, the roll of film material includes a forming surface, and the roll of embossed film sheet includes an embossing structure, with the embossing structure facing the forming surface; applying a coating layer to the forming surface of the roll of film material or the embossing structure of the roll of embossed film sheet; pressing the roll of embossed film sheet and the roll of film material together with at least one embossing roller, so that the coating layer is sandwiched between the forming surface and the embossing structure; performing a photocuring treatment on the coating layer to cure the coating layer into an optical functional layer having an optical structure, wherein the optical structure has a shape corresponding to the embossing structure; and respectively winding up the roll of film material and the roll of embossed film sheet, so that the optical structure of the optical functional layer is separated from the embossing structure of the roll of embossed film sheet, and the optical functional layer and the roll of film material are bonded together to form an optical film.

[0007] According to one embodiment of the present invention, the material of the roll film includes triacetyl cellulose (TAC), polyethylene terephthalate (PET), polymethyl methacrylate (PMMA), cycloolefin polymer (COP), or polycarbonate (PC).

[0008] According to one embodiment of the present invention, the peeling force for separating the optical functional layer from the imprinted structure is 1 gf / 25 mm to 8 gf / 25 mm.

[0009] According to one embodiment of the present invention, the embossing structure of the roll-shaped embossing film is a concave-convex structure.

[0010] According to an embodiment of the present invention, the method for manufacturing the roll-shaped imprinted film includes providing a substrate having a base surface; providing an optical functional film having a concave-convex structure with the concave-convex structure facing the base surface; coating a mold material layer on the base surface of the substrate or on the concave-convex structure of the optical functional film; pressing the substrate and the optical functional film together such that the mold material layer is sandwiched between the base surface of the substrate and the concave-convex structure of the optical functional film; performing photocuring treatment on the mold material layer to cure the mold material layer into an imprinted structure of the roll-shaped imprinted film, wherein the imprinted structure of the roll-shaped imprinted film and the concave-convex structure of the optical functional film are complementary; and detaching the roll-shaped imprinted film from the optical functional film.

[0011] According to one embodiment of the present invention, the above-mentioned mold material layer comprises perfluoropolyethers (PFPE), acrylic resin and photoinitiator, wherein the content of perfluoropolyethers is substantially 80% W / W to 90% W / W and the content of acrylic resin is substantially 5% W / W to 10% W / W.

[0012] According to an embodiment of the present invention, the above-mentioned perfluoropolyether comprises the structure of formula (I):

[0013] CH2=CH-CO-OXRX-CO-CH=CH2(I)

[0014] In equation (I), R represents CH2CF2O-[-(CF2CF2O)] a -(CF2O) b -]-CF2CH2, where a+b is between 20 and 40; and X represents (CH2). n -NH-CO-O-, where n is an integer between 0 and 10.

[0015] According to one embodiment of the present invention, the fluorine content of the above-mentioned perfluoropolyether is greater than 0% to 60%.

[0016] According to one embodiment of the present invention, the molecular weight of the perfluoropolyether is from 100 Daltons to 4000 Daltons.

[0017] According to one embodiment of the present invention, the above-mentioned acrylic resin has two or more double bonds.

[0018] According to one embodiment of the present invention, the contact angle between the above-mentioned mold material layer and water is greater than 80 degrees.

[0019] According to one embodiment of the present invention, the material of the substrate comprises cellulose triacetate, polyethylene terephthalate, polymethyl methacrylate, cyclic olefin polymer or polycarbonate.

[0020] According to an embodiment of the present invention, the coating layer comprises a variety of acrylic monomers and a photoinitiator, at least one of the acrylic monomers comprises an amide structure, the content of the acrylic monomers in the coating layer is substantially from 15% W / W to 30% W / W, and the molecular weight of the acrylic monomers is from 50 Daltons to 1000 Daltons.

[0021] According to an embodiment of the present invention, at least one of the above-mentioned acrylic monomers has more than one functional group.

[0022] According to one embodiment of the present invention, the coating layer further comprises at least one organic or inorganic particle, the refractive index of the organic or inorganic particle being 1.43 to 1.6, and the particle size of the organic or inorganic particle being in the range of 20 nm to 4 μm.

[0023] According to one embodiment of the present invention, the coating layer further comprises one or any combination of a defoamer, a leveling agent, and an antistatic agent.

[0024] The optical film manufacturing method of the present invention uses a roll-shaped imprinted film as a forming mold to combine the roll-shaped film material with an optical functional layer to form an optical film, thereby enabling continuous production of optical films, reducing production costs and avoiding mold contamination of finished products. Attached Figure Description

[0025] A better understanding of the present invention will be obtained by reading the following detailed description in conjunction with the accompanying drawings. It should be noted that, as is standard practice in the industry, many features are not drawn to scale. In fact, for clarity of discussion, the dimensions of many features may be arbitrarily scaled.

[0026] [ Figure 1 This is a flowchart illustrating a method for manufacturing an optical film according to some embodiments of the present invention.

[0027] [ Figure 2 This is a schematic diagram illustrating the overall process equipment for optical films according to some embodiments of the present invention.

[0028] [ Figure 3A ]to[ Figure 3D This is a partial cross-sectional view illustrating an intermediate stage of the manufacturing process of an optical film according to some embodiments of the present invention.

[0029] [ Figure 4 This is a flowchart illustrating a method for manufacturing a roll-shaped embossed film according to some embodiments of the present invention.

[0030] [ Figure 5A ]to[ Figure 5C This is a partial cross-sectional view illustrating an intermediate stage of the process of a roll-shaped imprinting film according to some embodiments of the present invention.

[0031] In the attached figures, the following labels are used:

[0032] 100: Method

[0033] 110, 120, 130, 140, 150: Operation

[0034] 200: Optical film

[0035] 210: Direction

[0036] 215: Sprayer Head

[0037] 220: Rolled membrane material

[0038] 225: Molding surface

[0039] 230: Rolled Imprinted Film

[0040] 235: Embossing Structure

[0041] 240: Coating layer

[0042] 245: Imprinting roller

[0043] 250: Optical Functional Layer

[0044] 255: Light source

[0045] 400: Method

[0046] 410, 420, 430, 440, 450: Operations

[0047] 510:Substrate

[0048] 515: Fundamentals

[0049] 520: Optical Functional Film

[0050] 525: Concave-convex structure

[0051] 530: Mold Material Layer Detailed Implementation

[0052] The following disclosure provides numerous different embodiments or illustrations to implement various features of the invention. The specific examples of components and configurations described below are for the purpose of simplifying the invention. These are, of course, merely illustrative and are not intended to be limiting. For example, a description of a first feature formed on or above a second feature includes embodiments where the first and second features are in direct contact, as well as embodiments where other features are formed between the first and second features such that the first and second features are not in direct contact. Furthermore, the invention repeats element symbols and / or letters in various specific examples. This repetition is for the purpose of simplifying and clarifying the description and does not imply a relationship between the various discussed embodiments and / or configurations.

[0053] Furthermore, spatially relative terms, such as "below," "below," "lower," "above," and "upper," are used to facilitate the description of the relationship between the parts or features depicted in the accompanying drawings and other parts or features. In addition to the directions depicted in the drawings, spatially relative terms also include different orientations of the elements during use or operation. Devices may be oriented in other ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used in this invention can also be interpreted in this way.

[0054] The manufacture and use of embodiments of the present invention are discussed in detail below. However, it will be understood that the embodiments provide many applicable inventive concepts that can be implemented in a wide variety of specific contexts. The specific embodiments discussed are for illustrative purposes only and are not intended to limit the scope of the invention.

[0055] As used in this invention, "around," "about," "approximately," or "substantially" generally mean within 20 percent, 10 percent, or 5 percent of the stated value or range.

[0056] As described above, the present invention provides a method for manufacturing an optical film, which uses a roll-shaped imprinted film as a forming mold to combine the roll-shaped film material with an optical functional layer to form an optical film, thereby enabling continuous production of optical films, reducing production costs and avoiding mold contamination of the finished product.

[0057] First, please also refer to Figure 1 , Figure 2 and Figure 3A Operation 110 involves unwinding a roll of film 220 and a roll of embossing film 230 along a predetermined direction 210. The roll of film 220 and the roll of embossing film 230 are spaced apart. The roll of film 220 includes a forming surface 225, while the roll of embossing film 230 includes an embossing structure 235, wherein the embossing structure 235 of the roll of embossing film 230 faces the forming surface 225 of the roll of film 220. In some embodiments, the embossing structure 235 of the roll of embossing film 230 may, for example, be an embossed structure.

[0058] In some embodiments, the material of the roll film 220 includes triacetyl cellulose (TAC), polyethylene terephthalate (PET), polymethyl methacrylate (PMMA), cycloolefin polymer (COP), or polycarbonate (PC).

[0059] Next, please refer to the following: Figure 1 and Figure 3B Operation 120 is performed, in which a coating layer 240 is applied to the forming surface 225 of the roll film 220 or the imprinting structure 235 of the roll imprinting film 230 using a conventional element (e.g., nozzle 215). Figure 1 and Figure 3B Taking the example of coating layer 240 being applied to the forming surface 225 of roll film 220.

[0060] In some embodiments, coating layer 240 comprises a variety of acrylic monomers and photoinitiators. In the foregoing embodiments, at least one of the acrylic monomers comprises an amide structure as shown in formula (II), such as methacrylamide or acrylamide.

[0061]

[0062] In formula (II), R, R' and R” represent hydrogen atoms or organic groups.

[0063] In some embodiments, the acrylic monomer content in the coating layer 240 is substantially between 15% W / W and 30% W / W. When the acrylic monomer has the aforementioned specific content, the coating layer 240 exhibits better adhesion to the roll film 220 and a suitable hardness. In some embodiments, the molecular weight of the acrylic monomer is between about 50 Daltons (Da) and about 1000 Da. When the acrylic monomer has the aforementioned specific molecular weight, the coating layer 240 can have a suitable viscosity to facilitate processing.

[0064] In the above embodiments, at least one of the acrylic monomers included in the coating layer 240 has one or more functional groups, such as 2-hydroxypropyl(meth)acrylate, 2-ethylhexyl(meth)acrylate (2-EH(M)A), 2-hydroxyethyl(meth)acrylate (2-HE(M)A), 2-hydroxybutyl(meth)acrylate (2-HB(M)A), 2-butoxyethyl(meth)acrylate, 1,6-hexanediol di(meth)acrylate (1,6-hexanediol di(meth)acrylate, HDD(M)A, 2-phenoxyethyl(meth)acrylate, PHE(M)A, tetrahydrofuran(meth)acrylate, THF(M)A, cyclic trimethylolpropane formal(meth)acrylate, CTF(M)A, lauryl(meth)acrylate, L(M)A, diethyleneglycol di(meth)acrylate, DEGD(M)A, pentaerythritol tetra(meth)acrylate The coating layer 240 may contain tetra(meth)acrylate, dipentaerythritolpenta(meth)acrylate (DPP(M)A), dipentaerythritolhexa(meth)acrylate (DPH(M)A), trimethylolpropane tri(meth)acrylate (TMPT(M)A), di(trimethylolpropane)tetra(meth)acrylate, and pentaerythritoltetraacrylate (PET4A), with pentaerythritoltetraacrylate having four functional groups being preferred, which helps to improve the hardness or abrasion resistance of the coating layer 240. In some embodiments, the coating layer 240 may comprise a linear, branched, or cross-linked network structure, and the viscosity of the coating layer 240 is from about 20 CPS to about 150 CPS. In some embodiments, the coating layer 240 may further comprise at least one organic or inorganic particle. In the foregoing embodiments, the refractive index of the organic or inorganic particles is from about 1.43 to about 1.6, and the particle size is from about 20 nm to about 4 μm. The refractive index or particle size of the organic or inorganic particles can be selected based on the thickness or optical properties (e.g., haze) of the coating layer 240. For example, adding inorganic particles to the coating layer 240 can help improve its hardness or abrasion resistance.

[0065] In some embodiments, the coating layer 240 further comprises a defoamer, a leveling agent, an antistatic agent, or any combination thereof.

[0066] Next, please refer to the following: Figure 1 , Figure 2 and Figure 3C Operation 130 involves pressing a roll of embossing film 230 and a roll of film material 220 together using an embossing roller 245, so that a coating layer 240 is sandwiched between the forming surface 225 and the embossing structure 235. Then, operation 140 involves photocuring the coating layer 240 to cure it into an optical functional layer 250. In some embodiments, since the coating layer 240 contains various acrylic monomers and photoinitiators, it can be cured into an optical functional layer 250 by irradiating it with ultraviolet light using a light source 255. The optical functional layer 250 has an optical structure, and the optical structure and the embossing structure 235 have corresponding concave and convex structures. It should be noted that the aforementioned corresponding concave and convex structures indicate that the contact surfaces of the optical functional layer 250 and the embossing structure 235 are complementary, that is, the protrusions of the optical functional layer 250 face the recesses of the embossing structure 235.

[0067] Next, please refer to the following: Figure 1 , Figure 2 and Figure 3D Operation 150 involves winding up the roll-shaped film 220 and the roll-shaped imprinted film 230 respectively, so that the optical structure of the optical functional layer 250 is separated from the imprinted structure 235 of the roll-shaped imprinted film 230. In some embodiments, the peel force separating the optical functional layer 250 from the imprinted structure 235 of the roll-shaped imprinted film 230 is from about 1 gf / 25 mm to about 8 gf / 25 mm. When the peel force is within the aforementioned range, the optical functional layer 250 can be effectively and completely separated from the imprinted structure 235 during the winding operation. Thus, the optical functional layer 250 and the roll-shaped film 220 are bonded together to form an optical film 200.

[0068] The aforementioned roll-shaped embossed film 230 serves as a forming mold for the optical film 200 of the present invention. In some embodiments, the aforementioned roll-shaped embossed film 230 is prepared using the following method.

[0069] First, please also refer to Figure 4 and Figure 5A Operation 410 is performed, providing a substrate 510 and an optical functional film 520. In some embodiments, the optical functional film 520 has a textured structure 525, and the textured structure 525 faces the base surface 515 of the substrate 510. In some embodiments, the material of the substrate 510 includes cellulose triacetate, polyethylene terephthalate, polymethyl methacrylate, cyclic olefin polymers, or polycarbonate.

[0070] Next, please refer to the following: Figure 4 and Figure 5BOperation 420 involves applying a mold material layer 530 to the base surface 515 of the substrate 510 or the uneven structure 525 of the optical functional film 520. Figure 5B The diagram illustrates the coating of mold material layer 530 onto the base surface 515 of substrate 510. In some embodiments, if the contact angle is too low, it may make it difficult to remove the mold in subsequent processes. Therefore, the contact angle between mold material layer 530 and water is greater than 80 degrees to give mold material layer 530 better demolding properties.

[0071] In some embodiments, the mold material layer 530 comprises perfluoropolyethers (PFPE), acrylic resin, and a photoinitiator. In the foregoing embodiments, the perfluoropolyether content in the mold material layer 530 is substantially 80% w / w to 90% w / w, while the acrylic resin content in the mold material layer 530 is substantially 5% w / w to 10% w / w. The mold material layer 530 having the aforementioned specific amounts of perfluoropolyether and acrylic resin allows the subsequently formed roll-shaped imprinting film 230 to have better hydrophilicity and release ability. In some embodiments, the acrylic resin has two or more double bonds, preferably three double bonds, to give the subsequently formed roll-shaped imprinting film 230 a better shrinkage rate.

[0072] In some embodiments, the perfluoropolyether comprises the structure of formula (I):

[0073] CH2=CH-CO-OXRX-CO-CH=CH2(I)

[0074] In equation (I) above, R represents CH2CF2O-[-(CF2CF2O)] a -(CF2O) b -]-CF2CH2, where a+b is 20 to 40, and X represents (CH2). n -NH-CO-O-, where n is an integer between 0 and 10.

[0075] In some embodiments, the fluorine content of the perfluoropolyether is greater than 0% to about 60%, preferably about 40% to about 60%. When the fluorine content of the perfluoropolyether is within the aforementioned range, the subsequently formed roll-shaped imprinted film 230 can have better hydrophilicity and release capability. In some embodiments, the molecular weight of the perfluoropolyether is about 100 Daltons to about 4000 Daltons, preferably about 1500 Daltons to about 2000 Daltons. When the molecular weight of the perfluoropolyether is within the aforementioned range, the subsequently formed roll-shaped imprinted film 230 can have better shrinkage and release capability.

[0076] Next, please refer to the following: Figure 4 , Figure 5B and Figure 5CIn operation 430, the substrate 510 and the optical functional film 520 are pressed together, such that the mold material layer 530 is sandwiched between the base surface 515 of the substrate 510 and the uneven structure 525 of the optical functional film 520. Then, in operation 440, the mold material layer 530 is photocured to solidify the mold material layer 530 into the imprint structure 235 of the roll-shaped imprint film 230. The imprint structure 235 of the roll-shaped imprint film 230 and the uneven structure 525 of the optical functional film 520 are complementary.

[0077] Method 400 continues with operation 450, causing the roll-shaped imprint film 230 to detach from the optical functional film 520, in order to obtain the roll-shaped imprint film 230 used in method 100.

[0078] According to the above embodiments, the optical film manufacturing method provided by the present invention uses a roll-shaped imprinted film as a forming mold to combine the roll-shaped film material with an optical functional layer to form an optical film, thereby continuously producing optical films, reducing production costs and avoiding mold contamination of finished products.

[0079] Although the present invention has been disclosed above with reference to several embodiments, it is not intended to limit the present invention. Anyone with common knowledge in the technical field to which this invention pertains may make various modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the scope defined in the appended claims.

Claims

1. A method of manufacturing an optical film, characterized by, The method comprises: spooling a film material and a relief film along a predetermined direction, wherein the film material and the relief film are spaced apart, the film material comprises a forming surface, the relief film comprises a relief structure, and the relief structure faces the forming surface; applying a coating layer on the forming surface of the film material or the relief structure of the relief film; pressing the relief film and the film material with at least one relief roller, so that the coating layer is sandwiched between the forming surface and the relief structure; performing a photocuring process on the coating layer to cure the coating layer into an optical functional layer, wherein the optical functional layer has an optical structure corresponding to the relief structure; spooling the film material and the relief film, respectively, so that the optical structure of the optical functional layer is separated from the relief structure of the relief film, and the optical functional layer is combined with the film material into an optical film. The material of the film material comprises triacetate cellulose, polyethylene terephthalate, polymethyl methacrylate, cyclic olefin polymer, or polycarbonate.

2. The method of making an optical film according to claim 1, wherein, The peeling force between the optical functional layer and the relief structure is 1 gf / 25 mm to 8 gf / 25 mm.

3. The method of making an optical film according to claim 1, wherein, The relief structure of the relief film is a concave-convex structure.

4. The method of making an optical film according to claim 1, wherein, The method for manufacturing the relief film comprises:

5. The method of making an optical film according to claim 1, wherein, providing a substrate, wherein the substrate has a base surface; providing an optical functional film, wherein the optical functional film has a concave-convex structure, and the concave-convex structure faces the base surface; applying a mold material layer on the base surface of the substrate or the concave-convex structure of the optical functional film; pressing the substrate and the optical functional film, so that the mold material layer is sandwiched between the base surface of the substrate and the concave-convex structure of the optical functional film; performing a photocuring process on the mold material layer to cure the mold material layer into the relief structure of the relief film, wherein the relief structure of the relief film and the concave-convex structure of the optical functional film are complementary; and separating the relief film from the optical functional film. The mold material layer comprises perfluoropolyether, acrylic resin, and photoinitiator, wherein the content of the perfluoropolyether is substantially 80% W / W to 90% W / W, and the content of the acrylic resin is substantially 5% W / W to 10% W / W.

6. The method of making an optical film according to claim 5, wherein, The perfluoropolyether comprises the following formula (I):

7. The method of manufacturing an optical film according to claim 6, wherein CH2=CH-CO-O-X-R-X-CO-CH=CH2(I) The fluorine content of the perfluoropolyether is greater than 0% to 60%. In this formula (I), R represents CH2CF2O-[-(CF2CF2O) a -(CF2O) b -]-CF2CH2, wherein a+b is from 20 to 40; and X represents (CH2) n -NH-CO-O-, wherein n is an integer between 0 and 10.

8. The method of manufacturing an optical film according to claim 6, wherein The molecular weight of the perfluoropolyether is 100 daltons to 4000 daltons.

9. The method of making an optical film according to claim 6, wherein, The acrylic resin has two or more double bonds.

10. The method of making an optical film according to claim 6, wherein, The contact angle of the mold material layer with water is greater than 80 degrees.

11. The method of manufacturing an optical film according to claim 5, wherein The material of the substrate comprises triacetate cellulose, polyethylene terephthalate, polymethyl methacrylate, cyclic olefin polymer, or polycarbonate.

12. The method of making an optical film according to claim 5, wherein, ​ 13. The method of making an optical film according to claim 1, wherein, The coating layer comprises a plurality of acrylic monomers and a photoinitiator, at least one of the acrylic monomers comprises an amide structure, the content of the acrylic monomers in the coating layer is substantially 15% W / W to 30% W / W, and the molecular weight of the acrylic monomers is 50 daltons to 1000 daltons.

14. The method of manufacturing an optical film according to claim 13, wherein At least one of the acrylic monomers has more than one functional group.

15. The method of making an optical film according to claim 13, wherein, The coating layer further comprises at least one organic particle or inorganic particle, the refractive index of the at least one organic particle or inorganic particle is 1.43 to 1.6, and the particle size of the at least one organic particle or inorganic particle ranges from 20 nm to 4 μm.

16. The method of making an optical film according to claim 13, wherein, The coating layer further comprises one of a defoaming agent, a leveling agent, an antistatic agent, or any combination of the foregoing.

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