An optical material film and a method for manufacturing the same

Abstract

The application 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, an alkali-soluble resin and a photopolymer, the alkali-soluble resin comprises polymers 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; the percentage of the photopolymer in the total mass is more than 30%, and the photopolymer has a bisphenol structure. By spraying a small-polarity volatile material on the surface of the film layer before drying and cooperating with the use of a gradient oscillating electric field to oscillate the film layer, the influence of the molecular tension and the internal stress unevenness before film formation on the film formation uniformity can be effectively eliminated, and the film formation uniformity is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optical elements, in particular to an optical material film applied in the environment of semiconductor etching, digital products and the like and a preparation method thereof. BACKGROUND

[0002] With the development of optoelectronic technology, the application field of optical elements is also more and more extensive.

[0003] In the printing field, optical materials such as PS plates, CTP plates and printing films are commonly used materials. PS plates and printing films have a larger market share, and CTP plates are mainly used for digital printing. With the development of digital technology, its market space is continuously expanding.

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

[0005] Therefore, it has great economic prospects and market value to prepare optical materials with excellent performance. SUMMARY

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

[0007] The present inventors have noticed in the research and development process that although optical materials, such as photosensitive materials, can be basically uniformly coated by a coating machine, due to the effect of molecular tension, film layer uniformity problems still occur during drying, thereby affecting the quality of the optical material film. In view of this problem, the present application proposes a preparation method which can effectively eliminate the influence of internal tension before film layer drying on film layer uniformity.

[0008] Specifically, the present application provides an optical material film, which comprises a photoinitiator, an alkali-soluble resin and a photopolymer,

[0009] The alkali-soluble resin comprises a polymer of methacrylate, methacrylic acid and styrene, and the mass fractions 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;

[0010] The photopolymer accounts for more than 30% of the total mass and comprises a first monomer, a second monomer and a third monomer,

[0011] The first monomer is tetraethoxy bisphenol A dimethacrylate or pentaerythritol tetraacrylate,

[0012] The second monomer is polyethylene glycol mono(meth)acrylate,

[0013] The third monomer is neopentyl glycol di(meth)acrylate.

[0014] The optical material film is treated before film formation by the following process:

[0015] Spray a small polar molecule solvent on the surface of the liquid optical material film by using an atomizer; apply a low-frequency alternating electric field to the liquid optical material film for 1-5 min; and dry the treated optical material film at 70-95 degrees Celsius.

[0016] Further, an additive is added, which includes one or a combination of more than one of a defoaming agent, a color developing agent, a plasticizer, a leveling agent, and a polymerization inhibitor, and the additive accounts for 0.3-10% of the total mass of the remaining components of the optical material film.

[0017] Further, 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.

[0018] Further, the alkali-soluble resin accounts for 25-60% of the total mass of the optical material film, and more preferably 30-50%.

[0019] Further, the photoinitiator accounts for 2-8% of the total mass of the optical material film, and more preferably 3-5%.

[0020] The photopolymer accounts for 35-65% of the total mass of the optical material film, and more preferably 50-60%.

[0021] The application also provides a preparation method of an optical material film, which comprises:

[0022] Step 1: accurately weigh 15-45 parts of methacrylate, 10-20 parts of methacrylic acid, and 10-45 parts of styrene, mix them, and stir them uniformly for standby use;

[0023] Step 2: gradually add acetone or butanone to the mixture, heat, add 0.2-0.6 parts of azo compound, continue to mix and stir, and cool to obtain solution one.

[0024] Step 3: accurately weigh 8-20 parts of the first monomer by weight, dissolve it with sufficient diethylene glycol methyl ether acetate to obtain solution two, stir, gradually heat, control the temperature at 65-85 degrees, and measure the solution temperature.

[0025] Step 4: accurately weigh 6-18 parts of the second monomer and the third monomer, add them to solution two, and continue stirring for 2-6 hours while reducing the temperature;

[0026] Step 5: mix solution one, solution two, and the photoinitiator at room temperature, wherein solution one 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 two photopolymer accounts for 30-70% of the total mass, and stir until uniform to form an optical material glue solution;

[0027] Step 6: prepare a clean substrate and apply a layer of optical material glue solution to the surface of the clean substrate to form a liquid optical material layer;

[0028] Step 7: use an atomizer to spray a predetermined amount of polar small molecule solvent onto the surface of the liquid optical material layer;

[0029] Step 8: apply a low-frequency alternating electric field below the substrate for 1-5 minutes, and dry the treated liquid optical material layer at 70-95 degrees Celsius to obtain an optical material film attached to the surface of the substrate.

[0030] Further, in step 2, the temperature is raised to 50-90°C;

[0031] Further, each preparation step is carried out in a protective gas atmosphere.

[0032] Further, an additive is added in step 4, and the additive includes one or a combination of defoamers, colorants, plasticizers, leveling agents, and polymerization inhibitors.

[0033] Further, the polar small molecule solvent is diethyl ether, ethanol, or acetone.

[0034] Further, the amount of polar small molecule solvent sprayed is 3-20% of the mass of the liquid optical material layer, preferably 5-15%.

[0035] Further, the photopolymer has a bisphenol structure.

[0036] 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 minutes.

[0037] Further, the applied electric field is a gradient electric field, and the electric field strength gradually weakens over time; further, the electric field strength decreases from 50 V / cm to 10 V / cm within 1-5 minutes.

[0038] Further, in solution one, the total weight of methyl methacrylate, methacrylic acid, and styrene to the weight of acetone or butanone is 1:0.5 to 1:4, preferably 1:1.

[0039] Further, in the solution two, the weight ratio of the total weight of the first, second and third monomers to the diethylene glycol methyl ether acetate is 1:0.5 to 1:3, preferably 1:1 to 1:2.

[0040] The present application can effectively eliminate the influence of the unevenness of the film uniformity caused by the unevenness of the molecular tension and internal stress before film formation by spraying a polar small molecule volatile material on the surface of the film layer before drying, forming a high active electrophoretic area of the material on the surface by the polar small molecule, and oscillating the film layer by using a gradient changing oscillating electric field.

[0041] The optical material film prepared by the present application has good uniformity and higher quality, and reduces the problem of substandard products caused by uneven thickness. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 is a schematic flow chart of the preparation method of the present application.

[0043] Figure 2 is a real microscopic view of the optical material film prepared according to the method of the present application.

[0044] Figure 3 is a microscopic view of the optical material film prepared according to the method of the present application after development.

[0045] Figure 4 is a microscopic view of the substandard product appearing in the optical material film prepared according to the method of Comparative Example 1 after development. DETAILED DESCRIPTION

[0046] The present application will be further described in detail below in combination with examples and drawings, but the embodiments of the present application are not limited thereto.

[0047] The optical material film of the present application comprises: a photoinitiator, an alkali-soluble resin, a photopolymer, and preferably, an additive. The percentage of the photopolymer in the total mass is preferably more than 30%, more preferably 35-65%, and more preferably 50-60%.

[0048] The alkali-soluble resin comprises a polymer of methacrylate, methacrylic acid and styrene. The mass fraction of each of the three is 15-45 parts of methacrylate, 10-20 parts of methacrylic acid and 10-45 parts of styrene. Preferably, the weight average molecular weight of the alkali-soluble resin is between 70000 and 110000. Preferably, it further comprises an azo compound, such as azobisisobutyronitrile, 0.2-0.6 parts.

[0049] In a preferred implementation, the photopolymer has a bisphenol structure. The bisphenol structure can improve the performance of development, such as improving the resolution.

[0050] In an implementation, the photopolymer includes a first monomer, a second monomer, and a third monomer,

[0051] The first monomer is tetraethoxy bisphenol A dimethacrylate, 2,2-bis(4-((meth)acryloyloxy polyalkoxy)phenyl)propane, or pentaerythritol tetraacrylate, or other bisphenol A structure. Preferably, a fourth monomer is also included.

[0052] The second monomer is polyethylene glycol mono(meth)acrylate;

[0053] The third monomer is neopentyl glycol di(meth)acrylate, and a small amount of azo compound.

[0054] The photoinitiator includes one or a mixture of two of benzoyl cyclohexyl aminocarbonyl morpholine (BCIM), 2,2',4-tris(2-chlorophenyl)-5-(3,4-dimethoxyphenyl)-4',5'-diphenyl-1,1'-biimidazole, 2,2',4-tris(2-chlorophenyl)-5-(3,4-dimethoxyphenyl)-4',5'-diphenyl-1,1'-biimidazole (TCDM).

[0055] The additive includes a combination of one or more of defoaming agent, dye, initiator, color former, plasticizer, leveling agent, and polymerization inhibitor. The additive is added in an amount of 0.2-5 parts.

[0056] The following will be described in conjunction with Figure 1 The preparation method of the present application is described.

[0057] Preparation method:

[0058] Step 1: accurately weigh 15-45 parts of methacrylate, 10-20 parts of methacrylic acid, and 10-45 parts of styrene, mix the three, stir uniformly, and reserve;

[0059] Step 2: gradually add acetone or butanone to the mixture under a protective gas atmosphere, heat, add azo compound, continue to mix and stir for 4-10 h, cool down, and obtain solution one;

[0060] Step 3: accurately weigh 8-20 parts by weight of the first monomer (tetraethoxy bisphenol A dimethacrylate), dissolve with sufficient diethylene glycol methyl ether acetate to obtain solution two, stir, gradually heat, measure the solution temperature, and control the temperature at 65-85 degrees;

[0061] Step 4: accurately weigh 6-18 parts of the second monomer and the third monomer, add to solution two, continue to stir uniformly, and cool down for 2-6 h;

[0062] Step 5: Mix solution one, solution two, photo initiator, and additives (if any) at room temperature, and stir to form an optical material glue solution;

[0063] Step 6: Prepare a clean coating substrate or clean the surface of the material to be coated (hereinafter referred to as the substrate surface), and coat the optical material glue solution on the clean substrate surface to form a liquid optical material layer;

[0064] Step 7: Use a nebulizer to spray a small amount of polar small molecule solvent on the surface of the liquid optical material layer;

[0065] Step 8: Apply an alternating electric field below the substrate, with an electric field strength of 10-50 V / cm and a frequency of 5-30 Hz, 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 substrate surface.

[0066] Example 1

[0067] Step 1: Accurately weigh 22 g of methacrylate, 15 g of methacrylic acid, and 22 g of styrene, mix them, and stir to prepare;

[0068] Step 2: Under a protective gas atmosphere, gradually add 59 g of butanone to the mixture, heat to 75°C, add 0.4 g of azobisisobutyronitrile, continue to mix and stir for 6 h (the same below), and cool to room temperature to obtain solution one;

[0069] Step 3: Accurately weigh 13 g of the first monomer, dissolve it with 33 g of diethylene glycol methyl ether acetate to obtain solution two, stir, gradually heat, measure the solution temperature, and control the temperature at 65-85 degrees; the first monomer is tetraethoxy bisphenol A dimethacrylate; the second monomer is polyethylene glycol mono(meth)acrylate; and the third monomer is neopentyl glycol di(meth)acrylate;

[0070] Step 4: Accurately weigh 10 g of the second monomer and the third monomer, and 0.3 g of azobisisobutyronitrile, and add them to solution two, and continue to stir for 4 h (the same below), and cool to room temperature;

[0071] Step 5: Mix 46 g of solution one, 55 g of solution two, and 4 g of photo initiator (TCDM) at room temperature, and stir to form an optical material glue solution;

[0072] Step 6: Prepare a clean coating substrate or clean the surface of the material to be coated (hereinafter referred to as the substrate surface), and coat the optical material glue solution on the clean substrate surface to form a liquid optical material layer;

[0073] Step 7: Spraying 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 using an atomizer;

[0074] Step 8: Applying an alternating electric field below the substrate, electric field strength 50 V / cm, varying frequency 5-30 Hz (10 Hz in this example), lasting 5 min, and drying the treated liquid optical material layer at 85-90 degrees Celsius to obtain an optical material film attached to the substrate surface.

[0075] Example 2

[0076] Step 1: Accurately weighing 20 g of methacrylate, 18 g of methacrylic acid, and 23 g of styrene, mixing them, and stirring them evenly for use;

[0077] Step 2: Gradually adding 61 g of butanone to the mixture under a protective gas atmosphere, heating to 75°C, adding 0.4 g of azobisisobutyronitrile, and continuing to mix and stir, and then cooling to room temperature to obtain solution one;

[0078] Step 3: Accurately weighing 12 g of the first monomer, dissolving it with 32 g of diethylene glycol methyl ether acetate to obtain solution two, stirring, gradually heating, measuring the solution temperature, and controlling the temperature at 65-85 degrees;

[0079] Step 4: Accurately weighing 10 g of the second monomer and 10 g of the third monomer, and 0.3 g of azobisisobutyronitrile, adding them to solution two, and continuing to stir evenly and cool down; the composition of the three monomers is the same as in Example 1;

[0080] Step 5: Mixing 40 g of solution one, 58 g of solution two, and 2 g of photoinitiator TCDM at room temperature, stirring them evenly to form an optical material glue solution;

[0081] Step 6: Preparing a clean coating substrate or cleaning the surface of the material to be coated (hereinafter referred to as the substrate surface), coating an optical material glue solution on the clean substrate surface to form a liquid optical material layer;

[0082] Step 7: Spraying 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 using an atomizer;

[0083] Step 8: Applying an alternating electric field below the substrate, electric field strength 40 V / cm, varying frequency 10 Hz, lasting 3-5 min, and drying the treated liquid optical material layer at 85-90 degrees Celsius to obtain an optical material film attached to the substrate surface. The electric field direction in each example is perpendicular to the film surface.

[0084] Example 3

[0085] Step 1: accurately weigh 23 g of methacrylate, 12 g of methacrylic acid and 23 g of styrene, mix the three, stir evenly and reserve;

[0086] Step 2: gradually add 58 g of butanone to the mixture under a protective gas atmosphere, heat to 75 degrees, add 0.4 g of azobisisobutyronitrile and continue to mix and stir, and then cool to room temperature to obtain solution one;

[0087] Step 3: accurately weigh 13 g of the first monomer, dissolve it with 33 g of diethylene glycol methyl ether acetate to obtain solution two, stir, gradually heat and measure the solution temperature, and control the temperature at 65-85 degrees;

[0088] Step 4: accurately weigh 10 g of the second monomer and the third monomer, and 0.3 g of azobisisobutyronitrile, add them to solution two, continue to stir evenly, and cool to room temperature; the composition of the three monomers is the same as that of Example 1;

[0089] Step 5: mix 47 g of solution one, 50 g of solution two and 3 g of photoinitiator BCIM at room temperature, stir evenly to form an optical material glue solution;

[0090] Step 6: prepare a clean coating substrate or clean the surface of the material to be coated (hereinafter referred to as the substrate surface), apply a layer of optical material glue solution on the clean substrate surface to form a liquid optical material layer;

[0091] Step 7: use an atomizer to spray a 15% mass fraction of a small polar molecule solvent (ethanol) on the surface of the liquid optical material layer, which accounts for 15% of the total mass of the liquid optical material layer;

[0092] Step 8: apply an alternating electric field below the substrate, with an electric field strength of 45 V / cm and a frequency of 20 Hz, for 5 min, and then dry the treated liquid optical material layer at 85-90 degrees Celsius to obtain an optical material film attached to the substrate surface.

[0093] Example 4

[0094] Step 1: accurately weigh 23 g of methacrylate, 12 g of methacrylic acid and 23 g of styrene, mix the three, stir evenly and reserve;

[0095] Step 2: gradually add 60 g of butanone to the mixture under a protective gas atmosphere, heat to 75 degrees, add 0.4 g of azobisisobutyronitrile and continue to mix and stir, and then cool to room temperature to obtain solution one;

[0096] Step 3: accurately weigh 13 g of the first monomer, dissolve it with 40 g of diethylene glycol methyl ether acetate to obtain solution two, stir, gradually heat and measure the solution temperature, and control the temperature at 65-85 degrees;

[0097] Step 4: Accurately weigh 10 g of the second monomer and the third monomer, and 0.3 g of azobisisobutyronitrile, and add them to solution two, continue to stir and cool down; the composition of the three monomers is the same as that in Example 1;

[0098] Step 5: Mix 47 g of solution one, 50 g of solution two, and 3 g of photoinitiator BCIM at room temperature, stir evenly to form an optical material glue solution;

[0099] Step 6: Prepare a clean coating substrate or clean the surface of the material to be coated (hereinafter referred to as the substrate surface), and coat the optical material glue solution on the clean substrate surface to form a liquid optical material layer;

[0100] 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;

[0101] 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, and the electric field strength gradually decreases over time according to a certain gradient (initially 50 V / cm, linearly reduced to 10 V / cm within 5 min), and the treated liquid optical material layer is dried at 85-90 degrees Celsius to obtain an optical material film attached to the substrate surface.

[0102] Example 5

[0103] Step 1: Accurately weigh 22 g of methacrylate, 15 g of methacrylic acid, and 22 g of styrene, mix them, and stir evenly for use;

[0104] Step 2: In a protective gas atmosphere, gradually add 60 g of butanone to the mixture, heat to 75 degrees Celsius, add 0.4 g of azobisisobutyronitrile, continue to mix and stir, and cool to room temperature to obtain solution one;

[0105] Step 3: Accurately weigh 13 g of the first monomer, dissolve it with 35 g of diethylene glycol methyl ether acetate to obtain solution two, stir, gradually heat, measure the solution temperature, and control the temperature at 65-85 degrees Celsius; the first monomer is ethoxylated dimethyl acrylate; the second monomer is polyethylene glycol mono(meth)acrylate; and the third monomer is neopentyl glycol di(meth)acrylate;

[0106] Step 4: Accurately weigh 10 g of the second monomer and the third monomer, and 0.3 g of azobisisobutyronitrile, and add them to solution two, continue to stir and cool down;

[0107] Step 5: Mix 47 g of solution one, 50 g of solution two, and 3 g of photoinitiator BCIM at room temperature, stir evenly to form an optical material glue solution;

[0108] Step 6: Prepare a clean coating substrate or clean the surface of the material to be coated (hereinafter referred to as the substrate surface), coat the substrate surface with a layer of optical material glue solution to form a liquid optical material layer;

[0109] Step 7: Use an atomizer to spray 15% of the total mass of the liquid optical material layer with a small polar molecule solvent (acetone);

[0110] Step 8: Apply an alternating electric field to the substrate, with a frequency of 15 Hz and a duration of 5 minutes, and gradually weaken the electric field strength according to a certain gradient (initially 50 V / cm, within 5 minutes, the first four minutes decrease by 10 V each minute, and finally decrease to 10 V / cm). Dry the treated liquid optical material layer at 85-90 degrees Celsius to obtain an optical material film attached to the substrate surface.

[0111] Figure 2 The actual microscopic view of the optical material film prepared according to the method in Example 1 of the present application shows that the surface texture of the optical material film has a good regular distribution, the surface is uniformly distributed, and there is no obvious uneven distribution area.

[0112] Comparative Example 1

[0113] Step 1: Accurately weigh 22 g of methacrylate, 15 g of methacrylic acid, and 22 g of styrene, mix them, and stir them evenly for use;

[0114] Step 2: Under a protective gas atmosphere, gradually add 59 g of butanone to the mixture, continue to mix and stir while adding 0.4 g of azobisisobutyronitrile, and then cool to room temperature to obtain solution one;

[0115] Step 3: Accurately weigh 13 g of the first monomer, dissolve it with 33 g of diethylene glycol methyl ether acetate to obtain solution two, stir, gradually heat, measure the solution temperature, and control the temperature at 65-85 degrees. The first monomer is tetraethoxy bisphenol A dimethacrylate; the second monomer is polyethylene glycol mono(meth)acrylate; and the third monomer is neopentyl glycol di(meth)acrylate;

[0116] Step 4: Accurately weigh 10 g of the second monomer and the third monomer, and 0.3 g of azobisisobutyronitrile, and add them to solution two, continue to stir evenly, and cool;

[0117] Step 5: Mix 46 g of solution one, 50 g of solution two, and 4 g of a photoinitiator at room temperature, stir them evenly, and form an optical material glue solution;

[0118] Step 6: Prepare a clean substrate surface, coat the substrate surface with a layer of optical material glue solution to form a liquid optical material layer;

[0119] Step 7: drying the liquid optical material layer at 85-90 degrees Celsius to obtain an optical material film attached to the substrate base surface.

[0120] Comparative Example 2

[0121] 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 use;

[0122] Step 2: gradually add 61 g of butanone to the mixture under a protective gas atmosphere, continue to mix and stir while increasing the temperature and adding 0.4 g of azobisisobutyronitrile, and then cool to obtain solution one;

[0123] Step 3: accurately weigh 12 g of the first monomer, dissolve it with 32 g of diethylene glycol methyl ether acetate to obtain solution two, stir, gradually heat, measure the solution temperature, and control the temperature at 65-85 degrees;

[0124] Step 4: accurately weigh 10 g of the second monomer and the third monomer, and 0.3 g of azobisisobutyronitrile, add them to solution two, continue to stir evenly, and cool; the composition of the three monomers is the same as in Example 1;

[0125] Step 5: mix 48 g of solution one, 50 g of solution two, and 2 g of a photoinitiator at room temperature, stir evenly to form an optical material glue solution;

[0126] Step 6: prepare a clean coating substrate or clean the surface of the material to be coated (hereinafter referred to as the substrate surface), apply a layer of optical material glue solution to the clean substrate surface to form a liquid optical material layer;

[0127] Step 7: use a sprayer to spray 10% mass fraction of nonpolar small molecule solvent (carbon tetrachloride) on the surface of the liquid optical material layer;

[0128] Step 8: dry the liquid optical material layer at 85-90 degrees Celsius to obtain an optical material film attached to the substrate base surface.

[0129] Comparative Example 3

[0130] 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 use;

[0131] Step 2: gradually add 59 g of butanone to the mixture under a protective gas atmosphere, increase the temperature to 75°C, add 0.4 g of azobisisobutyronitrile, continue to mix and stir, and then cool to room temperature to obtain solution one;

[0132] Step 3: accurately weigh 13 g of the first monomer, dissolve it in 40 g of diethylene glycol methyl ether acetate to obtain solution two, stir, gradually heat and measure the solution temperature, and control the temperature at 65-85 degrees; the first monomer is tetraethoxy bisphenol A dimethacrylate; the second monomer is polyethylene glycol mono(meth)acrylate; and the third monomer is neopentyl glycol di(meth)acrylate;

[0133] Step 4: accurately weigh 10 g of the second monomer and the third monomer, respectively, and 0.3 g of azobisisobutyronitrile, and add them to solution two, and continue to stir until uniform, and then cool;

[0134] Step 5: mix 47 g of solution one, 50 g of solution two, and 3 g of a photoinitiator at room temperature, stir until uniform, and form an optical material glue solution;

[0135] Step 6: prepare a clean substrate surface, apply a layer of optical material glue solution to the substrate surface, and form a liquid optical material layer;

[0136] Step 7: apply an alternating electric field below the substrate, for 5 min, the electric field strength (initially 50 V / cm, linearly reduced to 10 V / cm within 5 min) gradually weakens over time, and the treated liquid optical material layer is dried at 85-90 degrees Celsius to obtain an optical material film attached to the substrate surface.

[0137] Comparative Example 4

[0138] Step 1: accurately weigh 22 g of methacrylate, 15 g of methacrylic acid, and 22 g of styrene, mix them, and stir until uniform for standby use;

[0139] Step 2: gradually add 59 g of butanone to the mixture under a protective gas atmosphere, heat to 75 degrees Celsius, add 0.4 g of azobisisobutyronitrile, continue to mix and stir, and cool to room temperature to obtain solution one;

[0140] Step 3: accurately weigh 13 g of the first monomer, dissolve it in 40 g of diethylene glycol methyl ether acetate to obtain solution two, stir, gradually heat, and measure the solution temperature, and control the temperature at 65-85 degrees; the first monomer is tetraethoxy bisphenol A dimethacrylate; the second monomer is polyethylene glycol mono(meth)acrylate; and the third monomer is neopentyl glycol di(meth)acrylate;

[0141] Step 4: accurately weigh 10 g of the second monomer and the third monomer, respectively, and 0.3 g of azobisisobutyronitrile, and add them to solution two, and continue to stir until uniform, and then cool;

[0142] Step 5: mix 41 g of solution one, 56 g of solution two, and 3 g of a photoinitiator at room temperature, stir until uniform, and form an optical material glue solution;

[0143] Step 6: Prepare a clean substrate surface, apply a layer of optical material glue on the substrate surface to form a liquid optical material layer;

[0144] 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 degrees Celsius to obtain an optical material film attached to the substrate surface.

[0145] It should be noted that the photoinitiator and alkali-soluble resin mentioned in the present application can also be realized by other similar materials in the art.

[0146] The optical material films prepared in the above examples and comparative examples were tested for uniformity.

[0147] Test process:

[0148] The thickness information of each part was determined by analyzing the polarization state change of the reflected light after the incident light passed through the sample surface using an ellipsometer. The uniformity was determined based on the measured thickness variance at each position. Specifically, two key parameters were measured: Psi and Delta, which are related to the refractive index and thickness of the sample surface, respectively. Psi represents the amplitude ratio of the reflected light. Delta represents the phase difference of the reflected light.

[0149] By changing the above parameters, the thickness and refractive index distribution of the film can be calculated to determine the uniformity index of the optical material film.

[0150] During testing, the measuring instrument was first calibrated.

[0151] Then, check if the optical material film surface is clean enough to ensure that the optical material film surface is clean, dust-free or fingerprint-free. Place the optical material film on the sample stage and adjust the position to ensure accurate measurement area.

[0152] 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 measurement area, ensuring sufficient data density to evaluate uniformity. In this embodiment, 60° is selected as the incident angle.

[0153] Start the measurement program and let the ellipsometer automatically scan the set points.

[0154] Select 5 optical material films of each type, and select 400 points for each film. Record the Psi and Delta values for each measurement point, and calculate the corresponding thickness data using the software provided with the instrument.

[0155] Calculate the average thickness and standard deviation of each measurement point.

[0156] The statistical results are as follows:

[0157] Measurement object Average thickness (pm) Standard deviation Example 1 25.13 0.22 Example 2 24.82 0.27 Example 3 24.89 0.32 Example 4 25.14 0.14 Example 5 25.07 0.11 Comparative Example 1 25.34 0.65 Comparative Example 2 24.82 0.47 Comparative Example 3 25.18 0.37 Comparative Example 4 24.93 0.41

[0158] From the above comparison, it can be seen that the thickness uniformity of the optical material film can be effectively improved by spraying the organic small molecules in combination with the action of the alternating electric field, and the quality stability of the optical material film is improved. The gradient electric field with alternating decrease is particularly beneficial to the improvement of the thickness uniformity of the optical material film, and can greatly reduce the standard deviation of the thickness of the optical material film, thereby forming an optical material film with more excellent quality. Moreover, it is also crucial to spray the polar small molecule material on the surface. If non-polar small molecules or no material is sprayed on the surface, the effect of spraying the polar small molecules cannot be achieved, which proves that the polarity of the small molecules and the optical material in the film layer can form a certain force under the action of the electric field, thereby promoting the uniformization of the force field in the film layer.

[0159] Figure 3 A microscopic image of the optical material film prepared according to the method of the present application after development;

[0160] Figure 4 A microscopic image of the substandard product in the optical material film prepared according to the method in Comparative Example 1 after development. In the product prepared according to the method of the present application, the overall uniformity is better, and the probability of substandard product is greatly reduced. The higher the process quality requirement is, the greater the reduction of the substandard product rate is.

[0161] Although the principles of the present application have been described in detail above in combination with the preferred embodiments of the present application, those skilled in the art should understand that the above embodiments are only illustrative implementations of the present application, and are not a limitation on the scope of the present application. The details in the embodiments do not constitute a limitation on the scope of the present application. Any equivalent transformation, simple replacement, etc. based on the technical solutions of the present application, without departing from the spirit and scope of the present application, all fall within the protection scope of the present application.

Claims

1. A method for preparing an optical material film, characterized in that: The method comprises: 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 later use; Step 2: gradually add acetone or butanone to the mixture, increase the temperature, add 0.2-0.6 parts of azo compound, continue mixing and stirring, and cool to obtain solution 1; Step 3: Accurately weigh 8-20 parts by weight of the first monomer, dissolve it in a sufficient amount of diethylene glycol methyl ether acetate to obtain a second solution, stir, gradually heat, and measure the solution temperature to control the temperature at 65-85 degrees Celsius. The first monomer is tetraethoxybisphenol A dimethacrylate or pentaerythritol tetraacrylate. Step 4: Accurately weigh 6-18 parts of the second monomer and the third monomer, add them to the second solution, continue stirring for 2-6 hours, and cool down. The second monomer is polyethylene glycol mono(meth)acrylate, and the third monomer is neopentyl glycol di(meth)acrylate; Step 5: Mixing solution 1, solution 2, and a photoinitiator at room temperature, wherein 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 the photopolymer in solution 2 accounts for 30-70% of the total mass, and stirring uniformly to form an optical material glue; Step 6: Prepare a clean substrate and apply a layer of optical material glue on the surface of the clean substrate to form a liquid optical material layer; Step 7: using 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 under the substrate for 1-5 minutes, and dry the treated liquid optical material layer at 70-95 degrees Celsius to obtain an optical material film attached to the base surface of the substrate.

2. The method for preparing an optical material film according to claim 1, wherein: The method comprises: being characterized in that each preparation step is carried out under a protective gas atmosphere.

3. The method for preparing an optical material film according to claim 1, wherein: The method comprises: adding additives, wherein the additives comprise one or more types of combinations of defoaming agents, coloring agents, plasticizers, leveling agents and polymerization inhibitors.

4. The method for preparing an optical material film according to claim 1, wherein: The polar small molecule solvent is ether, ethanol or acetone.

5. The method for preparing an optical material film according to claim 1, wherein: The photopolymer has a bisphenol structure.

6. The method for preparing an optical material film according to claim 1, wherein: The applied electric field is a gradient electric field, and the electric field intensity gradually decreases over time.

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