Optical material film and preparation method thereof

Abstract

The invention relates to the field of optical elements, in particular to an optical material film and a preparation method thereof. The optical material film comprises a photoinitiator, alkali-soluble resin and a photopolymer, the alkali-soluble resin comprises a polymer of methacrylate, methacrylic acid and styrene, and the mass parts of the methacrylate, the methacrylic acid and the styrene are respectively 15-45 parts of methacrylate, 10-20 parts of methacrylic acid and 10-45 parts of styrene; the photopolymer accounts for more than 30% of the total mass, and the photopolymer has a bisphenol structure. According to the method, the polar small molecule volatile material is sprayed on the surface of the film layer before drying, and the oscillation treatment is carried out on the film layer by cooperatively utilizing the oscillation electric field with gradient change, so that the influence on the film forming uniformity caused by non-uniform molecular tension and internal stress before film forming can be effectively eliminated, and the film forming uniformity is improved.

Description

Technical Field

[0001] The present invention relates to the field of optical elements, and particularly to an optical material film applied in environments such as semiconductor etching and digital products, and a preparation method thereof. Background Art

[0002] With the development of optoelectronic technology, the application fields of optical elements are becoming more and more extensive.

[0003] In the printing field, optical materials such as PS plates, CTP plates, and printing films are commonly used materials. The market shares of PS plates and printing films are relatively large. CTP plates are mainly used for digital printing, and with the development of digital technology, their market space is continuously expanding.

[0004] With the popularization of electronic devices and the development of fields such as 5G and the Internet of Things, the demand for high-quality optical materials is increasing continuously. At the same time, the performance and quality requirements for optical materials are also getting higher and higher.

[0005] Therefore, preparing optical materials with excellent performance has great economic prospects and market value. Summary of the Invention

[0006] The present invention provides an optical material film with more excellent performance and a preparation method thereof, especially a preparation method of a photosensitive material film.

[0007] The inventors of the present application noticed during the research and development process that although optical materials, such as photosensitive materials, can achieve basically uniform coating through a coater, due to the action of molecular tension, problems with film layer uniformity still occur during the drying process, thereby affecting the quality of the optical material film. In view of this problem, the present application proposes a preparation method that can effectively eliminate the influence of internal tension before drying of the film layer on the film layer uniformity.

[0008] Specifically, the present invention provides an optical material film, and the optical material film includes a photoinitiator, an alkali-soluble resin, and a photopolymer. The alkali-soluble resin includes: a polymer of methacrylate, methacrylic acid, and styrene, and the mass parts of the three are 15 - 45 parts of methacrylate, 10 - 20 parts of methacrylic acid, 10 - 45 parts of styrene, and 0.2 - 0.6 parts of azo compound; The photopolymer accounts for more than 30% of the total mass, and includes a first monomer, a second monomer, and a third monomer. The first monomer is tetraethoxy bisphenol A dimethacrylate or pentaerythritol tetraacrylate. The second monomer is polyethylene glycol mono(meth)acrylate. The third monomer is neopentyl glycol di(meth)acrylate. Among them, the optical material film is processed as follows before film formation: A polar small molecule solvent is sprayed on the surface of the liquid optical material film by an atomizer; a low-frequency alternating electric field is applied to the liquid optical material film for 1-5 minutes, and the processed optical material film is dried at 70-95 degrees Celsius.

[0009] Furthermore, it also includes additives. The additives include one or more combinations of defoamers, color developers, plasticizers, leveling agents, and polymerization inhibitors. The percentage of the additives in the total mass of the remaining components of the optical material film is 0.3-10% Furthermore, the percentage of the alkali-soluble resin in the total mass of the optical material film is 20-69%, the percentage of the photoinitiator in the total mass of the optical material film is 1-10%, and the percentage of the photopolymer in the total mass of the optical material film is 30-70%.

[0010] Furthermore, the percentage of the alkali-soluble resin in the total mass of the optical material film is 25-60%, more preferably 30-50%.

[0011] Furthermore, the percentage of the photoinitiator in the total mass of the optical material film is 2-8%, more preferably 3-5%.

[0012] The percentage of the photopolymer in the total mass of the optical material film is 35-65%, more preferably 50-60%.

[0013] The present invention also provides a method for preparing an optical material film. The method includes: Step 1: Accurately weigh 15-45 parts of methacrylate, 10-20 parts of methacrylic acid, and 10-45 parts of styrene, mix the three, and stir evenly for standby; Step 2: Gradually add acetone or butanone to the mixture, raise the temperature, add 0.2-0.6 parts of azo compound, continue to mix and stir, and then lower the temperature to obtain Solution 1; Step 3: Accurately weigh 8-20 parts by weight of the first monomer, dissolve it with a sufficient amount of diethylene glycol methyl ether acetate to obtain Solution 2, stir, gradually heat up, and measure the solution temperature, controlling the temperature at 65-85 degrees; Step 4: Accurately weigh 6-18 parts each of the second monomer and the third monomer, add them to Solution 2, continue to stir for 2-6 hours, and then lower the temperature; Step 5: Mix Solution 1, Solution 2, and the photoinitiator with each other at room temperature. Among them, the percentage of Solution 1 in the total mass is 20-69%, the percentage of the photoinitiator in the total mass of the optical material film is 1-10%, and the percentage of the photopolymer in Solution 2 in the total mass is 30-70%. Stir evenly to form an optical material glue solution; Step 6: Prepare a clean substrate, and coat a layer of optical material glue on the surface of the clean substrate to form a liquid optical material layer; Step 7: Spray a predetermined amount of polar small molecule solvent on the surface of the liquid optical material layer by using an atomizer; Step 8: Apply a low-frequency alternating electric field below the substrate for 1 - 5 min, and dry the treated liquid optical material layer at 70 - 95 °C to obtain an optical material film attached to the surface of the substrate of the substrate.

[0014] Further, in Step 2, the temperature is raised to 50 - 90 °C; Further, each preparation step is carried out in an atmosphere of a protective gas.

[0015] Further, it also includes adding an additive in Step 4, and the additive includes one or a combination of more than one of an antifoaming agent, a color former, a plasticizer, a leveling agent, and a polymerization inhibitor.

[0016] Further, the polar small molecule solvent is ether, ethanol or acetone.

[0017] Further, the spraying amount of the polar small molecule solvent is 3% - 20% of the mass of the liquid optical material layer, preferably 5% - 15%.

[0018] Further, the photopolymer has a bisphenol structure.

[0019] Further, the alternating electric field includes: an electric field strength of 10 - 50 V / cm, a change frequency of 5 - 30 Hz, and a duration of 1 - 5 min.

[0020] Further, the applied electric field is a gradient electric field, and the electric field strength gradually weakens with time; further, the electric field strength decreases from 50 V / cm to 10 V / cm within 1 - 5 min.

[0021] Further, in Solution 1, the weight ratio of the total weight of methacrylate, methacrylic acid and styrene to the weight of acetone or butanone is 1:0.5 to 1:4, preferably 1:1.

[0022] Further, in Solution 2, the weight ratio of the total weight of the first, second and third monomers to the weight of diethylene glycol methyl ether acetate is 1:0.5 to 1:3, preferably 1:1 to 1:2.

[0023] In the present invention, by spraying a polar small molecule volatile material on the surface of the film layer before drying, a highly active electrophoresis region of the material is formed on the surface by the polar small molecule, and by cooperating with the use of an oscillating electric field with a gradient change to perform oscillating treatment on the film layer, the influence of the molecular tension and the uneven internal stress before film formation on the film formation uniformity can be effectively eliminated, and the film formation uniformity is improved.

[0024] The optical material film prepared by the present invention has good uniformity and higher quality, reducing the problem of defective products caused by uneven thickness. Brief Description of the Drawings

[0025] Figure 1 It is a schematic flow chart of the preparation method of the present invention.

[0026] Figure 2 It is a physical microscopic view of the optical material film prepared by the method of the present invention.

[0027] Figure 3 It is a microscopic view of the developed optical material film prepared by the method of the present invention.

[0028] Figure 4 It is a microscopic view of the developed defective product in the optical material film prepared by the method in Comparative Example 1. Detailed Description of the Invention

[0029] The present invention will be further described in detail below in conjunction with the embodiments and the drawings, but the embodiments of the present invention are not limited thereto.

[0030] The optical material film of the present invention includes: a photoinitiator, an alkali-soluble resin, and a photopolymer. Preferably, it further includes an additive. The percentage of the photopolymer in the total mass is preferably more than 30%, more preferably 35 - 65%, and even more preferably 50 - 60%.

[0031] The alkali-soluble resin includes: a polymer of methacrylate, methacrylic acid, and styrene. The mass fractions of the three are 15 - 45 parts of methacrylate, 10 - 20 parts of methacrylic acid, and 10 - 45 parts of styrene respectively. Preferably, the average molecular weight of the alkali-soluble resin is between 70,000 and 110,000. Preferably, it further includes an azo compound, such as azobisisobutyronitrile, 0.2 - 0.6 parts.

[0032] In a preferred implementation, the photopolymer has a bisphenol structure. The bisphenol structure can improve the development performance, such as improving the resolution.

[0033] In one implementation, the photopolymer includes a first monomer, a second monomer, and a third monomer. The first monomer is tetraethoxy bisphenol A dimethacrylate, 2,2 - bis(4 - ((methyl)acryloyloxypolyalkoxy)phenyl)propane, or pentaerythritol tetraacrylate or other bisphenol A structures. Preferably, it further includes a fourth monomer.

[0034] The second monomer is polyethylene glycol mono(meth)acrylate; The third monomer is neopentyl glycol di(meth)acrylate, and a small amount of azo compound.

[0035] The photoinitiator includes: benzoylcyclohexylaminocarbonylmorpholine (BCIM), 2,2',4-tris(2-chlorophenyl)-5-(3,4-dimethoxyphenyl)-4',5'-diphenyl-1,1'-biimidazole, or a mixture of one or both of 2,2',4-Tris(2-chlorophenyl)-5-(3,4-dimethoxyphenyl)-4',5'-diphenyl-1,1'-biimidazole (TCDM).

[0036] The additives include one or more combinations of defoamers, dyes, initiators, color formers, plasticizers, leveling agents, and polymerization inhibitors. The addition amount of the additives is between 0.2 and 5 parts.

[0037] The following Figure 1 describes the preparation method of the present invention.

[0038] Preparation method: Step 1: Accurately weigh 15-45 parts of methacrylate, 10-20 parts of methacrylic acid, and 10-45 parts of styrene, mix the three, and stir evenly for standby; Step 2: Under the atmosphere of a protective gas, gradually add acetone or butanone to the mixture, raise the temperature, add an azo compound, continue to mix and stir for 4-10 h, and then cool down to obtain Solution 1; Step 3: Accurately weigh 8-20 parts by weight of the first monomer (tetraethoxybisphenol A dimethacrylate), dissolve it with a sufficient amount of diethylene glycol methyl ether acetate to obtain Solution 2, stir, gradually heat up, and measure the solution temperature, and control the temperature at 65-85 °C; Step 4: Accurately weigh 6-18 parts each of the second monomer and the third monomer, add them to Solution 2, continue to stir evenly for 2-6 h, and then cool down; Step 5: Mix Solution 1, Solution 2, the photoinitiator, and the additives (if any) with each other at room temperature, and stir evenly to form an optical material glue solution; Step 6: Prepare a clean coating substrate or clean the surface of the material to be coated (collectively referred to as the substrate surface hereinafter), and coat a layer of the optical material glue solution on the clean substrate surface to form a liquid optical material layer; Step 7: Spray a small amount of polar small molecule solvent on the surface of the liquid optical material layer by using an atomizer; Step 8: Apply an alternating electric field below the substrate, with an electric field strength of 10-50 V / cm, a change frequency of 5-30 Hz, and a duration of 1-5 min, and dry the treated liquid optical material layer at 70-95 °C to obtain an optical material film attached to the substrate surface of the substrate.

[0039] Example 1 Step 1: Accurately weigh 22 g of methacrylate, 15 g of methacrylic acid, and 22 g of styrene. Mix the three and stir evenly for standby; Step 2: Under the atmosphere of protective gas, gradually add 59 g of butanone to the mixture, heat up to 75 °C, add 0.4 g of azobisisobutyronitrile, and continue mixing and stirring for 6 h (the same below). Cool down to room temperature to obtain Solution 1; Step 3: Accurately weigh 13 g of the first monomer, dissolve it with 33 g of diethylene glycol methyl ether acetate to obtain Solution 2, stir, gradually heat up, and measure the solution temperature, controlling the temperature at 65 - 85 °C; The first monomer is tetraethoxy bisphenol A dimethacrylate; The second monomer is polyethylene glycol mono(meth)acrylate; The third monomer is neopentyl glycol di(meth)acrylate; Step 4: Accurately weigh 10 g each of the second monomer and the third monomer, and 0.3 g of azobisisobutyronitrile, add them to Solution 2, continue stirring for 4 h (the same below), and cool down to room temperature; Step 5: Take 46 g of Solution 1, 55 g of Solution 2, and 4 g of photoinitiator (TCDM), mix them with each other at room temperature, and stir evenly to form an optical material adhesive solution; Step 6: Prepare a clean coating substrate or clean the surface of the material to be coated (collectively referred to as the substrate surface below). Coat a layer of optical material adhesive solution on the clean substrate surface to form a liquid optical material layer; Step 7: Use an atomizer to spray a polar small molecule solvent (ethanol) accounting for 10% of the total mass of the liquid optical material layer on the surface of the liquid optical material layer; Step 8: Apply an alternating electric field below the substrate, with an electric field strength of 50 V / cm and a variation frequency of 5 - 30 Hz (10 Hz in this example), for 5 min. Dry the treated liquid optical material layer at 85 - 90 °C to obtain an optical material film attached to the substrate surface of the substrate.

[0040] Example 2 Step 1: Accurately weigh 20 g of methacrylate, 18 g of methacrylic acid, and 23 g of styrene. Mix the three and stir evenly for standby; Step 2: Under the atmosphere of protective gas, gradually add 61 g of butanone to the mixture, heat up to 75 °C, add 0.4 g of azobisisobutyronitrile, continue mixing and stirring, and cool down to room temperature to obtain Solution 1; Step 3: Accurately weigh 12 g of the first monomer, dissolve it with 32 g of diethylene glycol methyl ether acetate to obtain Solution 2, stir, gradually heat up, and measure the solution temperature, controlling the temperature at 65 - 85 °C; Step 4: Accurately weigh 10 g each of the second monomer and the third monomer, and 0.3 g of azobisisobutyronitrile, add them to Solution 2, continue stirring evenly, and cool down; The components of the three monomers are the same as those in Example 1; Step 5: Mix 40 g of Solution 1, 58 g of Solution 2, and 2 g of photoinitiator TCDM with each other at room temperature, and stir evenly to form an optical material adhesive solution; Step 6: Prepare a clean coating substrate or clean the surface of the material to be coated (collectively referred to as the substrate surface hereinafter), and coat a layer of the optical material adhesive solution on the clean substrate surface to form a liquid optical material layer; Step 7: Spray a polar small molecule solvent (ethanol) accounting for 15% of the total mass of the liquid optical material layer on the surface of the liquid optical material layer by using an atomizer; Step 8: Apply an alternating electric field below the substrate, with an electric field strength of 40 V / cm, a change frequency of 10 Hz, and a duration of 3 - 5 min, and dry the treated liquid optical material layer at 85 - 90 °C to obtain an optical material film attached to the substrate surface of the substrate. In each example, the direction of the electric field is perpendicular to the film layer surface.

[0041] Example 3 Step 1: Accurately weigh 23 g of methacrylate, 12 g of methacrylic acid, and 23 g of styrene, mix the three, and stir evenly for standby; Step 2: Gradually add 58 g of methyl ethyl ketone to the mixture under a protective gas atmosphere, heat up to 75 °C, add 0.4 g of azobisisobutyronitrile and continue to mix and stir, and cool down to room temperature to obtain Solution 1; Step 3: Accurately weigh 13 g of the first monomer, dissolve it with 33 g of diethylene glycol methyl ether acetate to obtain Solution 2, stir, gradually heat up and measure the solution temperature, and control the temperature at 65 - 85 °C; Step 4: Accurately weigh 10 g each of the second monomer and the third monomer, and 0.3 g of azobisisobutyronitrile, add them to Solution 2, continue to stir evenly, and cool down to room temperature; the components of the three monomers are the same as those in Example 1; Step 5: Mix 47 g of Solution 1, 50 g of Solution 2, and 3 g of photoinitiator BCIM with each other at room temperature, and stir evenly to form an optical material adhesive solution; Step 6: Prepare a clean coating substrate or clean the surface of the material to be coated (collectively referred to as the substrate surface hereinafter), and coat a layer of the optical material adhesive solution on the clean substrate surface to form a liquid optical material layer; Step 7: Spray a polar small molecule solvent (ethanol) with a mass fraction of 15% of the total mass of the liquid optical material layer on the surface of the liquid optical material layer by using an atomizer; Step 8: Apply an alternating electric field below the substrate, with an electric field strength of 45 V / cm, a change frequency of 20 Hz, and a duration of 5 min, and dry the treated liquid optical material layer at 85 - 90 °C to obtain an optical material film attached to the substrate surface of the substrate.

[0042] Example 4 Step 1: Accurately weigh 23 g of methacrylate, 12 g of methacrylic acid, and 23 g of styrene. Mix the three and stir evenly for standby; Step 2: Under the atmosphere of protective gas, gradually add 60 g of butanone to the mixture, heat up to 75 °C, add 0.4 g of azobisisobutyronitrile and continue to mix and stir. Then cool down to obtain Solution 1; Step 3: Accurately weigh 13 g of the first monomer, dissolve it with 40 g of diethylene glycol methyl ether acetate to obtain Solution 2. Stir, gradually heat up, and measure the solution temperature, controlling the temperature at 65 - 85 °C; Step 4: Accurately weigh 10 g each of the second monomer and the third monomer, and 0.3 g of azobisisobutyronitrile, add them to Solution 2, continue to stir evenly, and cool down; The components of the three monomers are the same as those in Example 1; Step 5: Mix 47 g of Solution 1, 50 g of Solution 2, and 3 g of photoinitiator BCIM with each other at room temperature, stir evenly to form an optical material glue solution; Step 6: Prepare a clean coating substrate or clean the surface of the material to be coated (collectively referred to as the substrate surface hereinafter). Coat a layer of optical material glue solution on the clean substrate surface to form a liquid optical material layer; Step 7: Use an atomizer to spray a polar small molecule solvent (acetone) accounting for 10% of the total mass of the liquid optical material layer on the surface of the liquid optical material layer; Step 8: Apply an alternating electric field (perpendicular to the film surface) below the substrate, with a frequency of 20 Hz and a duration of 5 min. The electric field strength gradually weakens with time according to a certain gradient (starting from 50 V / cm and linearly decreasing to 10 V / cm within 5 minutes), and dry the treated liquid optical material layer at 85 - 90 °C to obtain an optical material film attached to the substrate surface of the substrate.

[0043] Example 5 Step 1: Accurately weigh 22 g of methacrylate, 15 g of methacrylic acid, and 22 g of styrene. Mix the three and stir evenly for standby; Step 2: Under the atmosphere of protective gas, gradually add 60 g of butanone to the mixture, heat up to 75 °C, add 0.4 g of azobisisobutyronitrile and continue to mix and stir, and cool down to room temperature to obtain Solution 1; Step 3: Accurately weigh 13 g of the first monomer, dissolve it with 35 g of diethylene glycol methyl ether acetate to obtain Solution 2. Stir, gradually heat up, and measure the solution temperature, controlling the temperature at 65 - 85 °C; The first monomer is ethoxylated dimethacrylate; The second monomer is polyethylene glycol mono(meth)acrylate; The third monomer is neopentyl glycol di(meth)acrylate; Step 4: Accurately weigh 10 g each of the second monomer and the third monomer, and 0.3 g of azobisisobutyronitrile, add them to Solution 2, continue to stir evenly, and cool down; Step 5: Mix 47 g of Solution 1, 50 g of Solution 2, and 3 g of photoinitiator BCIM with each other at room temperature, and stir evenly to form an optical material glue solution; Step 6: Prepare a clean coating substrate or clean the surface of the material to be coated (collectively referred to as the substrate surface hereinafter), and coat a layer of optical material glue solution on the clean substrate surface to form a liquid optical material layer; Step 7: Use an atomizer to spray a polar small molecule solvent (acetone) accounting for 15% of the total mass of the liquid optical material layer on the surface of the liquid optical material layer; Step 8: Apply an alternating electric field below the substrate, with a frequency of 15 Hz and a duration of 5 min. The electric field strength gradually weakens with time according to a certain gradient (starting from 50 V / cm, decreasing by 10 V per minute in the first four minutes within 5 minutes, and finally decreasing to 10 V / cm), and dry the treated liquid optical material layer at 85 - 90 °C to obtain an optical material film attached to the substrate surface of the substrate.

[0044] Figure 2 It is a physical microscopic view of the optical material film prepared by the method in Example 1 of the present invention. It can be seen from the figure that the surface texture of the optical material film has a good regular distribution, the surface distribution is uniform, and there is no obvious uneven distribution area.

[0045] Comparative Example 1 Step 1: Accurately weigh 22 g of methacrylate, 15 g of methacrylic acid, and 22 g of styrene, mix the three, and stir evenly for standby; Step 2: Gradually add 59 g of butanone to the mixture under a protective gas atmosphere, heat up, add 0.4 g of azobisisobutyronitrile and continue to mix and stir, and cool down to room temperature to obtain Solution 1; Step 3: Accurately weigh 13 g of the first monomer, dissolve it with 33 g of diethylene glycol methyl ether acetate to obtain Solution 2, stir, gradually heat up, and measure the solution temperature, and control the temperature at 65 - 85 °C; The first monomer is tetraethoxy bisphenol A dimethacrylate; The second monomer is polyethylene glycol mono(meth)acrylate; The third monomer is neopentyl glycol di(meth)acrylate; Step 4: Accurately weigh 10 g each of the second monomer and the third monomer, and 0.3 g of azobisisobutyronitrile, add them to Solution 2, continue to stir evenly, and cool down; Step 5: Take 46 g of Solution 1, 50 g of Solution 2, and 4 g of photoinitiator, mix them with each other at room temperature, and stir evenly to form an optical material glue solution; Step 6: Prepare a clean substrate surface, and coat a layer of optical material glue solution on the substrate surface to form a liquid optical material layer; Step 7: Dry the liquid optical material layer at 85 - 90 °C to obtain an optical material film adhered to the surface of the substrate base.

[0046] Comparative Example 2 Step 1: Accurately weigh 20 g of methacrylate, 18 g of methacrylic acid, and 23 g of styrene. Mix the three and stir evenly for standby. Step 2: Gradually add 61 g of methyl ethyl ketone to the mixture under a protective gas atmosphere. Heat up, add 0.4 g of azobisisobutyronitrile and continue to mix and stir. Then cool down to obtain Solution 1. Step 3: Accurately weigh 12 g of the first monomer and dissolve it with 32 g of diethylene glycol methyl ether acetate to obtain Solution 2. Stir, gradually heat up, and measure the solution temperature, controlling the temperature at 65 - 85 °C. Step 4: Accurately weigh 10 g each of the second monomer and the third monomer, and 0.3 g of azobisisobutyronitrile, and add them to Solution 2. Continue to stir evenly and cool down. The components of the three monomers are the same as in Example 1. Step 5: Mix 48 g of Solution 1, 50 g of Solution 2, and 2 g of photoinitiator with each other at room temperature and stir evenly to form an optical material glue solution. Step 6: Prepare a clean coating substrate or clean the surface of the material to be coated (collectively referred to as the substrate surface hereinafter). Coat a layer of optical material glue solution on the clean substrate surface to form a liquid optical material layer. Step 7: Spray a 10% mass fraction of non-polar small molecule solvent (carbon tetrachloride) on the surface of the liquid optical material layer using an atomizer. Step 8: Dry the liquid optical material layer at 85 - 90 °C to obtain an optical material film adhered to the surface of the substrate base.

[0047] Comparative Example 3 Step 1: Accurately weigh 22 g of methacrylate, 15 g of methacrylic acid, and 22 g of styrene. Mix the three and stir evenly for standby. Step 2: Gradually add 59 g of methyl ethyl ketone to the mixture under a protective gas atmosphere. Heat up to 75 °C, add 0.4 g of azobisisobutyronitrile and continue to mix and stir. Then cool down to room temperature to obtain Solution 1. Step 3: Accurately weigh 13 g of the first monomer and dissolve it with 40 g of diethylene glycol methyl ether acetate to obtain Solution 2. Stir, gradually heat up, and measure the solution temperature, controlling the temperature at 65 - 85 °C. The first monomer is tetraethoxy bisphenol A dimethacrylate; the second monomer is polyethylene glycol mono(meth)acrylate; the third monomer is neopentyl glycol di(meth)acrylate. Step 4: Accurately weigh 10 g each of the second monomer and the third monomer, and 0.3 g of azobisisobutyronitrile, and add them to Solution 2. Continue to stir evenly and cool down. Step 5: Mix 47 g of Solution 1, 50 g of Solution 2, and 3 g of photoinitiator at room temperature, and stir evenly to form an optical material adhesive solution; Step 6: Prepare a clean substrate surface, and coat a layer of the optical material adhesive solution on the substrate surface to form a liquid optical material layer; Step 7: Apply an alternating electric field below the substrate for 5 min. The electric field strength (starting at 50 V / cm and linearly decreasing to 10 V / cm within 5 minutes) gradually weakens with time. Dry the treated liquid optical material layer at 85 - 90 °C to obtain an optical material film attached to the substrate surface of the substrate.

[0048] Comparative Example 4 Step 1: Accurately weigh 22 g of methacrylate, 15 g of methacrylic acid, and 22 g of styrene, mix the three, and stir evenly for standby; Step 2: Gradually add 59 g of methyl ethyl ketone to the mixture under a protective gas atmosphere, heat up to 75 °C, add 0.4 g of azobisisobutyronitrile and continue to mix and stir, and cool to room temperature to obtain Solution 1; Step 3: Accurately weigh 13 g of the first monomer, dissolve it with 40 g of diethylene glycol methyl ether acetate to obtain Solution 2, stir, gradually heat up, and measure the solution temperature, controlling the temperature at 65 - 85 °C; The first monomer is tetraethoxy bisphenol A dimethacrylate; The second monomer is polyethylene glycol mono(meth)acrylate; The third monomer is neopentyl glycol di(meth)acrylate; Step 4: Accurately weigh 10 g each of the second monomer and the third monomer, and 0.3 g of azobisisobutyronitrile, add them to Solution 2, continue to stir evenly, and cool down; Step 5: Mix 41 g of Solution 1, 56 g of Solution 2, and 3 g of photoinitiator at room temperature, and stir evenly to form an optical material adhesive solution; Step 6: Prepare a clean substrate surface, and coat a layer of the optical material adhesive solution on the substrate surface to form a liquid optical material layer; Step 7: Spray a polar small molecule solvent with a mass fraction of 15% of the total mass of the liquid optical material layer on the surface of the liquid optical material layer, and dry the liquid optical material layer at 85 - 90 °C to obtain an optical material film attached to the substrate surface of the substrate.

[0049] It should be noted that other similar materials in the art can also be used for the photoinitiator and alkali-soluble resin mentioned in the present invention.

[0050] Uniformity tests were respectively carried out on the optical material films prepared in the above examples and comparative examples.

[0051] Test process: The ellipsometer is used to measure the thickness information of each part by analyzing the change in the polarization state of the incident light after reflection from the sample surface, and the uniformity is determined based on the thickness variance measured at each position. Specifically, two key parameters are measured: Ψ (Psi) and Δ (Delta), which are respectively related to the refractive index and thickness of the sample surface. Ψ represents the amplitude ratio of the reflected light. Δ represents the phase difference of the reflected light.

[0052] Based on the changes in the above parameters, the thickness and refractive index distributions of the thin film can be calculated, thereby determining the uniformity index of the optical material film.

[0053] During the test, the measuring instrument is first calibrated.

[0054] Then, check whether the surface of the optical material film is clean enough to ensure that the surface of the optical material film is clean, free of dust or fingerprint contamination. Place the optical material film on the sample stage and adjust the position to ensure that the measurement area is accurate.

[0055] Set the incident angle to 60°, 70° or 85°. According to the measurement accuracy, determine the number and position of the scanning points to cover the entire area to be measured, ensuring sufficient data density to evaluate the uniformity. In this embodiment, 60° is selected as the incident angle.

[0056] Start the measurement program to let the ellipsometer automatically scan the set points.

[0057] Select 5 pieces of each type of optical material film, and select 400 points for each piece. Record the Ψ and Δ values for each measurement point, and calculate the corresponding thickness data using the software built into the instrument body.

[0058] Statistically calculate the average thickness and standard deviation of each measurement point.

[0059] The statistical results are as follows:

[0060] From the above comparison, it can be seen that by spraying organic small molecules in combination with the action of an alternating electric field, the thickness uniformity of the optical material film can be effectively improved, and the quality stability of the optical material film can be enhanced. Moreover, the alternating descending gradient electric field is particularly beneficial for improving the thickness uniformity of the optical material film, which can greatly reduce the standard deviation of the thickness of the optical material film and form an optical material film with more excellent quality. In addition, it is also crucial to spray polar small molecule materials on the surface. If non-polar small molecules are sprayed on the surface or no material is sprayed, the effects achieved by spraying polar small molecules cannot be obtained, proving that there can be a certain interaction force between the polarity of small molecules and the optical material in the film layer under the action of an electric field, promoting the homogenization of the internal force field in the film layer.

[0061] Figure 3It is the micrograph after developing of the optical material film prepared by the method of the present invention; Figure 4 It is the micrograph after developing of the defective product appearing in the optical material film prepared by the method in Comparative Example 1. In the products prepared by the method of the present invention, due to better overall uniformity, the probability of defective products is greatly reduced. The higher the requirement for process quality, the greater the reduction in the defective rate.

[0062] Although the principle of the present invention has been described in detail above in conjunction with the preferred embodiments of the present invention, those skilled in the art should understand that the above embodiments are only explanations of the illustrative implementation modes of the present invention, and do not limit the scope of the present invention. The details in the embodiments do not constitute a limitation on the scope of the present invention. Without departing from the spirit and scope of the present invention, any obvious changes such as equivalent transformations and simple substitutions based on the technical solution of the present invention fall within the protection scope of the present invention.

Claims

1. An optical material film, characterized in that, The optical material film includes a photoinitiator, an alkali-soluble resin, and a photopolymer. The alkali-soluble resin includes a polymer of methacrylate, methacrylic acid, and styrene, with the mass fractions of the three being 15-45 parts of methacrylate, 10-20 parts of methacrylic acid, 10-45 parts of styrene, and 0.2-0.6 parts of azo compound. The photopolymer accounts for more than 30% of the total mass and includes a first monomer, a second monomer, and a third monomer. The first monomer is tetraethoxy bisphenol A dimethacrylate or pentaerythritol tetraacrylate. The second monomer is polyethylene glycol mono(meth)acrylate. The third monomer is neopentyl glycol di(meth)acrylate. Among them, the optical material film is processed as follows before film formation: Using an atomizer to spray a polar small molecule solvent on the surface of the liquid optical material film; applying a low-frequency alternating electric field to the liquid optical material film for 1-5 minutes, and drying the processed optical material film at 70-95 degrees Celsius.

2. The optical material film according to claim 1, wherein It also includes additives, and the additives include one or a combination of defoamers, color developers, plasticizers, leveling agents, and polymerization inhibitors. The percentage of the additives in the total mass of the remaining components of the optical material film is 0.3-10%.

3. The optical material film according to claim 1, wherein The alkali-soluble resin accounts for 20-69% of the total mass of the optical material film, the photoinitiator accounts for 1-10% of the total mass of the optical material film, and the photopolymer accounts for 30-70% of the total mass of the optical material film.

4. A method for preparing an optical material film, characterized in that, The method includes: Step 1: Accurately weigh 15-45 parts of methacrylate, 10-20 parts of methacrylic acid, and 10-45 parts of styrene, mix the three, and stir evenly for standby. Step 2: Gradually add acetone or butanone to the mixture, heat up, add 0.2-0.6 parts of azo compound, continue to mix and stir, and cool down to obtain Solution 1. Step 3: Accurately weigh 8-20 parts by weight of the first monomer, dissolve it with a sufficient amount of diethylene glycol methyl ether acetate to obtain Solution 2, stir, gradually heat up, and measure the solution temperature, controlling the temperature at 65-85 degrees. Step 4: Accurately weigh 6-18 parts each of the second monomer and the third monomer, add them to Solution 2, continue to stir for 2-6 hours, and cool down. Step 5: Mix Solution 1, Solution 2, and the photoinitiator with each other at room temperature. Among them, Solution 1 accounts for 20-69% of the total mass, the photoinitiator accounts for 1-10% of the total mass of the optical material film, and Solution 2 (the photopolymer) accounts for 30-70% of the total mass. Stir evenly to form an optical material glue solution. Step 6: Prepare a clean substrate, and coat a layer of the optical material glue solution on the surface of the clean substrate to form a liquid optical material layer. Step 7: Use an atomizer to spray a predetermined amount of polar small molecule solvent on the surface of the liquid optical material layer. Step 8: Apply a low-frequency alternating electric field below the substrate for 1-5 minutes, and dry the processed liquid optical material layer at 70-95 degrees Celsius to obtain an optical material film attached to the surface of the substrate.

5. The method for preparing the optical material film according to claim 4, characterized in that, The method includes: characterized in that, each preparation step is carried out in an atmosphere of protective gas.

6. The method for preparing an optical material film according to claim 4, wherein, The method includes: adding an additive, and the additive includes a combination of one or more of an antifoaming agent, a color former, a plasticizer, a leveling agent and a polymerization inhibitor.

7. The method for preparing an optical material film according to claim 4, characterized in that, The polar small molecule solvent is ether, ethanol or acetone.

8. The method for preparing the optical material film according to claim 4, wherein The photopolymer has a bisphenol structure.

9. The method for preparing the optical material film according to claim 4, wherein The applied electric field is a gradient electric field, and the electric field strength gradually weakens with time.

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