Low temperature blue light protection film and preparation method thereof

Abstract

The present application relates to a kind of low temperature blue light protection film and its preparation method, the method includes the following steps: silicon source is added to solvent, obtain mixed solution;Catalyst is added to mixed solution, mix, obtain hydrolysis solution;Crosslinking agent is added to hydrolysis solution, mix, obtain silica precursor sol;Silver source is added to silica precursor sol, mix, aging, obtain silver doped silica precursor sol;Silver doped silica precursor sol is coated on the surface of substrate, after ultraviolet irradiation, drying and annealing, form low temperature blue light protection film on the surface of substrate, obtain blue light protection film piece.Compared with prior art, the present application has strong stability, can effectively absorb most harmful blue light, while retaining most of other waveband beneficial blue light, and ensure other visible light remaining waveband light high transmittance requirement, maintain the color balance of transmitted light, while avoiding the secondary damage of reflected blue light.

Description

Technical Field

[0001] This invention belongs to the field of blue light protection film technology, and relates to a low-temperature blue light protection film and its preparation method. Background Technology

[0002] With the development of display and lighting technologies, people are spending increasingly more time in front of artificial light sources such as electronic screens. Most white light lighting used in the industry uses blue light chips in combination with yellow phosphors to produce white light, and blue light (wavelength range of 400-500nm) is one of the three primary colors of light, which is indispensable in full-color displays and in regulating human biological rhythms.

[0003] However, prolonged exposure to high-energy blue light can cause visual fatigue, affect melatonin secretion and thus impact sleep quality, and may also induce diseases such as cataracts, retinal degeneration, and age-related macular degeneration. Therefore, in today's information age, preventing excessive exposure to harmful blue light and protecting our eyes is imperative.

[0004] Currently, blue light blocking films mainly employ three technologies: reflective, absorptive, and conversion. Reflective films, through a well-designed optical path model, utilize high- and low-refractive-index materials to create uniform multilayer films, achieving the function of an optical negative filter and exhibiting excellent optical performance. However, the high requirements for the thickness and precision of the multilayer films in the optical path design, coupled with demanding processes, equipment, and operator skills, make fabrication difficult. Furthermore, since its principle is to reflect harmful blue light, it may not only appear brighter on the surface but also potentially cause secondary blue light damage to those nearby. Conversion technology is still immature and cannot achieve satisfactory results. In contrast, absorptive blue light blocking films, using different materials to absorb blue light, are a more suitable solution. For example, some use transparent yellow pigments as functional additives to filter harmful blue light. However, these organic dyes typically have poor stability and are prone to aging. Others have used bismuth vanadate and other materials to prepare high-performance, stable, and non-toxic nano-thickness blue light blocking films (patent CN111333345A), but the 550℃ fabrication temperature limits the choice of substrate. Therefore, it is crucial to explore a high-performance, stable, non-toxic, simple, low-temperature, and low-cost method for preparing blue light blocking films. These films should possess good blue light blocking capabilities and high transmittance, and their preparation temperature should be able to meet the requirements of a wider range of display substrates.

[0005] Patent CN107892488A discloses a coated blue light blocking eye-protecting glass, comprising a glass substrate, a silicon oxide film, and a titanium oxide film. The silicon oxide film and the titanium oxide film are both coated on one side of the glass substrate, or the silicon oxide film and the titanium oxide film are respectively coated on both sides of the glass substrate. The silicon oxide film is doped with silver nanoparticles; the titanium oxide film is doped with rare earth oxides as light-absorbing materials. The glass coated with the silicon oxide film and the titanium oxide film has an absorption range of 400-450 nm. However, the preparation process of this patent is too complex and requires the addition of reducing agent Sn, which is not found in ordinary glass. 2+ . Summary of the Invention

[0006] The purpose of this invention is to overcome at least one of the defects in the existing technology, such as the damage of high-energy blue light to the human eye and the limitation of high preparation temperature of absorption-type blue light protection films, and to provide a low-temperature blue light protection film and its preparation method. This invention has strong stability, can effectively absorb most of the harmful blue light, while retaining most of the beneficial blue light in other wavelengths, and ensures the high transmittance requirements of the remaining wavelengths of other visible light, maintaining the color balance of transmitted light, and avoiding secondary damage from reflected blue light.

[0007] The objective of this invention can be achieved through the following technical solutions:

[0008] One of the technical solutions of the present invention is to provide a method for preparing a low-temperature blue light protection film, the method comprising the following steps:

[0009] S1. Add the silicon source to the solvent to obtain a mixed solution. Both alcohol and water are used as solvents for the silicon source, but water is also required for the hydrolysis of the silicon source.

[0010] S2. Add a catalyst to the mixed solution, mix, and obtain a hydrolysis solution. Adding a catalyst promotes hydrolysis and improves reaction efficiency.

[0011] S3. Add a crosslinking agent to the hydrolysis solution, mix, and obtain a silica precursor sol. Adding a crosslinking agent increases the viscosity of the sol, promotes the growth of particles in the sol, and improves the degree of crosslinking between particles.

[0012] S4. Add silver source to silica precursor sol, mix, and age to obtain silver-doped silica precursor sol.

[0013] S5. A silver-doped silica precursor sol is coated onto the surface of a substrate. After being subjected to UV irradiation, drying, and annealing, a low-temperature blue light protection film is formed on the surface of the substrate, resulting in a blue light protection film.

[0014] Further, in step S1, the silicon source includes tetraethyl orthosilicate, n-methylsilane, or methyl orthosilicate, and the solvent is a mixture of alcohol and water, including ethanol, methanol, or ethylene glycol methyl ether, with a volume ratio of alcohol to water of (5-30):(0.2-2), and a volume ratio of silicon source to alcohol of (0.2-1.5):(5-30).

[0015] Furthermore, the catalyst in step S2 includes nitric acid, ammonia, or triethanolamine, and the volume ratio of the catalyst to the silicon source in step S1 is (0.005-0.1):(0.2-1.5).

[0016] As a preferred technical solution, the concentration of the nitric acid is 1-65%, and the concentration of the ammonia water is 2-25%.

[0017] Furthermore, in step S3, the crosslinking agent is polyethylene glycol with an average molecular weight of 200-800, and the volume ratio of the crosslinking agent to the silicon source in step S1 is (0.05-0.8):(0.2-1.5).

[0018] Furthermore, in step S4, silver nitrate is used as the silver source, and the molar / volume ratio of the silver source to the silicon source in step S1 is (0.1-2 mol):(0.2-1.5 L).

[0019] As a preferred technical solution, the molar / volume ratio of the silver source in step S5 to the silicon source in step S1 is (0.1-0.4 mol):(0.2-1.5 L).

[0020] As a preferred technical solution, the substrate in step S5 is a glass cover plate or polycarbonate.

[0021] As a preferred technical solution, mechanical stirring is used for mixing in steps S2 to S4.

[0022] Furthermore, the mixing temperature in steps S2 and S3 is 30-40℃, the stirring speed is 200-1000 r / min, and the time is 10-20 min.

[0023] Furthermore, in step S4, the mixing temperature is 30-40℃, the stirring speed is 600-1000 r / min, and the time is 2-4 h;

[0024] The aging time is 2-7 days.

[0025] As a preferred technical solution, step S5 involves initial cleaning, drying, and re-cleaning of the substrate before coating.

[0026] As a preferred technical solution, the reagent for the first cleaning is selected from one or more of the following: scouring powder, water, acetone, and ethanol.

[0027] As a preferred technical solution, the drying gas is selected from one or more inert gases such as nitrogen and argon.

[0028] As a preferred technical solution, the re-cleaning method is selected from one or more of ozone and ultraviolet light, and the cleaning time is 5-20 minutes.

[0029] As a preferred technical solution, the coating in step S5 involves two coating processes.

[0030] As a preferred technical solution, the spin coating acceleration for the first coating is 70-150 r / s, the spin coating speed is 400-800 r / min, and the holding time is 4-10 s;

[0031] The second coating is applied with a spin-coating acceleration of 70-200 r / s, a spin-coating speed of 1500-4000 r / min, and a holding time of 30-90 s.

[0032] Furthermore, in step S5, the power of ultraviolet irradiation is 100-300W, the irradiation distance is 10-100mm, and the time is 8-13min;

[0033] The drying temperature is 80-150℃, and the time is 5-20 minutes.

[0034] Furthermore, in step S5, the annealing heating rate is 20-100℃ / min, the temperature is 200-500℃, and the time is 15-80min.

[0035] As a preferred technical solution, in step S5, the annealed material is allowed to cool naturally to room temperature in the air.

[0036] One of the technical solutions of the present invention is to provide a low-temperature blue light protection film prepared by the method described above. The low-temperature blue light protection film is coated on one or both sides of the substrate. In addition to single-layer coating, blue light protection films can also be coated on both sides of the substrate respectively. On the one hand, it improves the blue light cutoff rate, and on the other hand, it reduces the decrease in transmittance of other visible light bands due to the mutual influence between film layers.

[0037] The material of the low-temperature blue light protection film is silver-doped silicon dioxide.

[0038] One of the technical solutions of the present invention is to provide an application of the aforementioned low-temperature blue light protection film, wherein the low-temperature blue light protection film is used in the preparation of lighting or display devices.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] (1) The present invention uses silver-doped silicon dioxide as the material of the blue light protection film. Silver-doped silicon dioxide is non-toxic and has good chemical stability. Therefore, the blue light protection film has strong stability and can meet the requirements of long life and multi-environment application of lighting and display products using the present invention.

[0041] (2) The present invention uses silver-doped silicon dioxide as the material of the blue light protection film. While effectively absorbing most of the harmful blue light (such as 415-455nm), it can retain most of the beneficial blue light in other wavelengths (such as 460-500nm, which is beneficial to maintaining the color balance of transmitted light and is beneficial to the human body), ensuring the high transmittance requirements of the remaining wavelengths of other visible light, maintaining the color balance of transmitted light, and avoiding secondary damage from reflected blue light.

[0042] (3) The heat treatment temperature of existing absorptive blue light protection films is as high as 500-600℃, which greatly affects the diversity of substrate selection. The preparation temperature of the present invention can be as low as 200℃, which has wide applicability and convenience in display and lighting products.

[0043] (4) The present invention uses a solution method to prepare silver-doped silicon dioxide thin film as a blue light protection film. The process is simple, the preparation temperature is low, and it can be prepared on a large scale with low cost. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the structure of the blue light blocking film in an embodiment of the present invention;

[0045] Figure 2 This is a schematic diagram of the structure of an optional blue light blocking film in an embodiment of the present invention;

[0046] Figure 3 The ultraviolet-visible transmission spectra of the low-temperature blue light protection films in Examples 1 to 3 of this invention are shown.

[0047] Figure 4 The ultraviolet-visible light transmission spectra of the low-temperature blue light protection films in Examples 1, 4 to 6 of this invention are shown.

[0048] Figure 5 This is a CIE 1931 chromaticity chart comparing the low-temperature blue light protection film before and after coating in Example 1 of the present invention;

[0049] Figure 6 This is a CIE 1931 chromaticity chart comparing the blue light protection film before and after coating in Example 3 of the present invention.

[0050] Explanation of markings in the diagram:

[0051] 1—Substrate, 2—First film layer, 3—Second film layer. Detailed Implementation

[0052] The present invention will now be described in detail with reference to specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0053] Unless otherwise specified, the equipment used in the following embodiments is conventional equipment in the art; unless otherwise specified, the reagents used are commercially available products or prepared by conventional methods in the art. In the following embodiments, unless otherwise described in detail, conventional experimental methods in the art can be used.

[0054] A type of blue light blocking film, such as Figure 1 As shown, a low-temperature blue light protection film is coated on one side surface of the substrate 1 as the first film layer 2;

[0055] like Figure 2 As shown, a low-temperature blue light protection film can also be used as the first film layer 2 and the second film layer 3 to be coated on both sides of the substrate 1.

[0056] The material of the low-temperature blue light protection film is silver-doped silicon dioxide;

[0057] The substrate 1 uses a glass cover plate.

[0058] Example 1:

[0059] A low-temperature blue light protection film and its preparation method are described below:

[0060] S1. Take 10 mL of anhydrous ethanol and 427 μL of deionized water and mix them together in a brown bottle. Then add 368 μL of tetraethyl orthosilicate to obtain a mixed solution.

[0061] S2. Add 60 μL of concentrated nitric acid to the mixed solution, stir magnetically at 600 r / min for 10 min at 30℃, and heat in a constant temperature water bath to ensure the hydrolysis reaction proceeds smoothly, and obtain the hydrolysis solution.

[0062] S3. Inject 192 μL of polyethylene glycol 400 into the hydrolysis solution and magnetically stir at 600 r / min for 20 min at 30 °C to obtain silica precursor sol.

[0063] S4. Add 256 μL of 1.5 mol / L silver nitrate solution to the silica precursor sol, stir magnetically at 800 r / min for 2 h at 30 °C, and then age for 2 days to obtain silver-doped silica precursor sol.

[0064] S5. Before coating, first clean the glass cover plate with scouring powder, deionized water, acetone and anhydrous ethanol in sequence. When using, blow it dry with nitrogen and clean it with ozone for 10 minutes.

[0065] Next, a glass cover plate with a thickness of 0.7 mm was placed on the turntable of the spin coater. Then, the silver-doped silica precursor sol was dropped onto one side surface of the glass cover plate. The spin coater was accelerated from 100 r / s to 500 r / min and held for 5 seconds. Then, the spin coater was accelerated from 100 r / s to 2000 r / min and held for 60 seconds.

[0066] Next, place the coated glass cover plate with the wet film at a distance of 40mm under a 150W ultraviolet (UV) lamp for UV irradiation for 10 minutes.

[0067] Finally, dry on a drying table preheated to 100°C for 10 minutes, then heat to 200°C at a rate of 50°C / min for annealing for 20 minutes. After that, remove it and allow it to cool naturally to room temperature in the air to form a low-temperature blue light protection film on one side of the glass cover, thus obtaining the blue light protection film.

[0068] Example 2:

[0069] A low-temperature blue light protection film and its preparation method are basically the same as those in Example 1, except that the annealing temperature is increased from 200°C to 300°C in step S5 to form a low-temperature blue light protection film.

[0070] Example 3:

[0071] A blue light protection film and its preparation method are basically the same as those in Example 1, except that the annealing temperature is increased from 200°C to 500°C in step S5 to form a blue light protection film.

[0072] Example 4:

[0073] A low-temperature blue light protection film and its preparation method are basically the same as those in Example 1, except that in step S4, the volume of the silver nitrate solution is reduced from 256 μL to 128 μL to form a low-temperature blue light protection film.

[0074] Example 5:

[0075] A low-temperature blue light protection film and its preparation method are basically the same as those in Example 1, except that in step S4, the volume of the silver nitrate solution is increased from 256 μL to 384 μL to form a low-temperature blue light protection film.

[0076] Example 6:

[0077] A low-temperature blue light protection film and its preparation method are basically the same as those in Example 1, except that in step S4, the volume of the silver nitrate solution is increased from 256 μL to 512 μL to form a low-temperature blue light protection film.

[0078] The transmittance of the above-mentioned blue light blocking film in the ultraviolet-visible spectrum (300-800nm) was measured at room temperature using a spectrophotometer (U-3900 / 3900H, Hitachi, Japan), and the chromaticity of the above-mentioned blue light blocking film was measured using a spectrophotometer (SRC-600, Yuanfang, China).

[0079] like Figure 3 As shown, the transmittance of Examples 1 to 3 all decreased in the blue light range, indicating that the film has a high absorption rate for blue light. The position of the absorption peak for blue light also changes with different annealing temperatures; it first red-shifts and then blue-shifts with increasing temperature, and the full width at half maximum (FWHM) of the absorption peak first increases and then decreases with increasing temperature, while the maximum absorption rate first decreases and then increases.

[0080] like Figure 4 As shown, it can be seen that the absorption rate of Examples 1, 4 to 6 decreases in the blue light range. The absorption of blue light is related to the concentration of silver doping, and the higher the concentration, the more blue light is absorbed, but the position of the absorption peak remains basically unchanged.

[0081] The transmittance of different embodiments in different bands is shown in Table 1.

[0082] Table 1. Transmittance of Examples 1 to 6 in different wavelength bands

[0083]

[0084] As shown in Table 1, Examples 5 and 6 exhibit extremely low transmittance in the high-energy blue light band of 415-455 nm, but also relatively low transmittance in the 455-500 nm and 500-800 nm bands. Example 1, on the other hand, not only has a low preparation temperature but also retains most of the beneficial blue light while blocking most of the harmful blue light. Furthermore, it achieves a relatively balanced transmittance of 95.12% in other visible light bands.

[0085] like Figure 5 As shown, it can be seen that in Example 1, before coating the film (blue square in the figure) and after coating the film (red triangle in the figure), the color coordinates changed from (0.3275, 0.3428) to (0.3562, 0.3639), a change of only 7%. The color coordinates of the light source did not change much, proving that it had little impact on the display device.

[0086] like Figure 6 As shown, in Example 3, before coating the film (blue square in the figure) and after coating the film (red triangle in the figure), the color coordinates changed from (0.3275, 0.3428) to (0.3469, 0.3643), a change of only 5%. The color coordinates of the light source did not change much, proving that it had little impact on the display device.

[0087] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A method for preparing a low temperature blue light protection film, characterized in that, The method includes the following steps: S1. Add the silicon source to the solvent to obtain a mixed solution; S2. Add the catalyst to the mixed solution, mix, and obtain the hydrolysis solution; S3. Add a crosslinking agent to the hydrolysis solution, mix, and obtain a silica precursor sol. S4. Add silver source to silica precursor sol, mix, and age to obtain silver-doped silica precursor sol. S5. The silver-doped silica precursor sol is coated on the surface of the substrate (1). After ultraviolet irradiation, drying and annealing, a low-temperature blue light protection film is formed on the surface of the substrate (1) to obtain the blue light protection film. In step S3, polyethylene glycol is used as the crosslinking agent, and the volume ratio of the crosslinking agent to the silicon source in step S1 is (0.05-0.8):(0.2-1.5). In step S4, silver nitrate is used as the silver source, and the molar / volume ratio of the silver source to the silicon source in step S1 is (0.1-2 mol):(0.2-1.5 L). In step S5, the annealing heating rate is 20-100 ℃ / min, the temperature is 200-300 ℃, and the time is 15-80 min.

2. The method for preparing a low-temperature blue light protection film according to claim 1, characterized in that, In step S1, the silicon source includes tetraethyl orthosilicate, n-methylsilane, or methyl orthosilicate, and the solvent is a mixture of alcohol and water. The alcohol includes ethanol, methanol, or ethylene glycol methyl ether. The volume ratio of alcohol to water is (5-30):(0.2-2), and the volume ratio of silicon source to alcohol is (0.2-1.5):(5-30).

3. The method of claim 1, wherein the low temperature blue light protective film is prepared by the steps of: (a) preparing a solution of a polymer and a blue light absorbing agent; (b) coating the solution on a substrate; (c) drying the solution; and (d) removing the substrate. The catalyst in step S2 includes nitric acid, ammonia, or triethanolamine, and the volume ratio of the catalyst to the silicon source in step S1 is (0.005-0.1):(0.2-1.5).

4. The method of claim 1, wherein the low temperature blue light protective film is prepared by the steps of: (a) preparing a solution of a polymer and a blue light absorbing agent; (b) coating the solution on a substrate; (c) drying the solution; and (d) removing the substrate. The average molecular weight of the polyethylene glycol is 200-800.

5. The method of claim 1, wherein the low temperature blue light protective film is prepared by the steps of: (a) preparing a solution of a polymer and a blue light absorbing agent; (b) coating the solution on a substrate; (c) drying the solution; and (d) removing the substrate. The mixing temperature in steps S2 and S3 is 30-40 ℃, the stirring speed is 200-1000 r / min, and the time is 10-20 min.

6. The method of claim 1, wherein the low temperature blue light protective film is prepared by the steps of: (a) preparing a solution of a polymer and a blue light absorbing agent; (b) coating the solution on a substrate; (c) drying the solution; and (d) removing the substrate. In step S4, the mixing temperature is 30-40 ℃, the stirring speed is 600-1000 r / min, and the time is 2-4 h; The aging time is 2-7 days.

7. The method of claim 1, wherein the low temperature blue light protective film is prepared by the steps of: (a) preparing a solution of a polymer and a blue light absorber; (b) coating the solution on a substrate; (c) drying the solution; and (d) curing the solution. In step S5, the power of ultraviolet irradiation is 100-300 W, the irradiation distance is 10-100 mm, and the time is 8-13 min. The drying temperature is 80-150 ℃, and the time is 5-20 min.

8. A low temperature blue light protection film prepared by the method of any one of claims 1 to 7, characterized in that, The low-temperature blue light protection film is coated on one or both sides of the substrate (1), and the material of the low-temperature blue light protection film is silver-doped silicon dioxide.

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