A modified light diffusing particle, a preparation method thereof, and a diffusion film

Abstract

The present application discloses a modified light-diffusing particle, a preparation method thereof, and a diffusion film. The preparation method of the modified light-diffusing particle includes: subjecting PMMA spherical diffusion powder with a particle size of 3 to 15 μm and a refractive index of 1.49 to ultrasonic oscillation in anhydrous ethanol and deionized water with a ratio of 2:1 to obtain a PMMA powder mixed solution; heating the PMMA mixed solution to 90°C, and then slowly adding the PMMA mixed solution at 90°C to an aqueous aluminum paste and refluxing and stirring at a constant temperature of 90°C for 6 h to obtain a modified solution; subjecting the modified solution to vacuum filtration to obtain a filter cake, and washing the filter cake three times with anhydrous ethanol during vacuum filtration; heating the filter cake to 120°C and drying it at 120°C for 12 h to obtain a block; pulverizing the block to obtain modified light-diffusing particles. Coating the modified light-diffusing particles in the light-diffusing layer of the diffusion film helps to improve the brightness of the diffusion film.

Description

Technical Field

[0001] This application relates to the field of optical thin film technology, and particularly to a modified light diffusing particle, a preparation method thereof, and a diffusion film. Background Art

[0002] In the field of LCD liquid crystal displays, the backlight module is an indispensable part for supplying light sources for liquid crystal displays. The backlight module is mainly composed of a reflector, a light guide plate, and optical films such as a diffusion film, a brightness enhancement film, etc. Among them, the diffusion film plays a key role in homogenizing the optical effect and enhancing the brightness in the backlight module.

[0003] In recent years, with the booming development of the game e-sports industry, consumers have higher and higher requirements for the brightness and viewing angle of e-sports screens. For the diffusion film in the backlight module, it not only needs to have high brightness characteristics, but also has to ensure a certain viewing angle range. Conventional optical diffusion films are mainly composed of a substrate, a front light diffusion layer, and a back anti-adhesion layer. In the diffusion layer and the anti-adhesion layer, there are usually resin film-forming substances, spherical light diffusing particles, and various additives.

[0004] In order to effectively improve the brightness of the diffusion film, usually a large amount of diffusion powders with different particle sizes are added to the diffusion film, and by adjusting the mixing ratio of diffusion powders with different particle sizes, the purpose of brightness improvement is achieved. However, this method of adding a large amount of diffusion powders not only greatly increases the production cost of the diffusion film, but also inevitably reduces the viewing angle while increasing the brightness, making it difficult to meet the comprehensive requirements of the current market for high-quality and high-performance diffusion films. Summary of the Invention

[0005] The first aspect of this application provides a preparation method of a modified light diffusing particle, including:

[0006] Performing ultrasonic oscillation on PMMA spherical diffusion powder with a particle size of 3 - 15 μm and a refractive index of 1.49 in anhydrous ethanol and deionized water with a ratio of 2:1 to obtain a PMMA mixed solution;

[0007] Heating the PMMA mixed solution to 90°C, and then slowly adding the 90°C PMMA mixed solution to aqueous aluminum paste and carrying out constant temperature reflux for 6 h to obtain a modified solution;

[0008] Performing vacuum filtration on the modified solution to obtain a filter cake, and washing the filter cake three times with anhydrous ethanol during vacuum filtration;

[0009] Heating the filter cake to 120°C and drying it at 120°C for 12 h to obtain a block;

[0010] Crushing the block to obtain modified light diffusing particles.

[0011] Optionally, when the PMMA spherical diffusion powder is ultrasonically oscillated in absolute ethanol and deionized water, the frequency of the ultrasonic wave is 20 KHz, and the oscillation duration is 4 h.

[0012] Optionally, when the PMMA mixed solution heated to 90 °C is slowly added to the aqueous aluminum paste, the mass ratio of the aqueous aluminum paste to the PMMA mixed solution is 1:9.

[0013] Optionally, the particle size of the modified light diffusion particles is 3-17 μm, and the refractive index is 1.27.

[0014] The second aspect of the present application provides a modified light diffusion particle, which is prepared by the preparation method of the modified light diffusion particle described in the first aspect.

[0015] The third aspect of the present invention provides a diffusion film, and the light diffusion layer of the diffusion film is coated with the modified light diffusion particles.

[0016] Optionally, the diffusion film includes: a substrate, a light diffusion layer, and an anti-blocking layer;

[0017] The upper layer of the substrate is the light diffusion layer, and the lower layer is the anti-blocking layer;

[0018] The light diffusion layer includes a resin film-forming substance, modified light diffusion particles, and an auxiliary agent;

[0019] The anti-blocking layer includes a resin film-forming substance, spherical light diffusion particles, and an auxiliary agent;

[0020] The substrate is selected from one of polyethylene terephthalate, polymethyl methacrylate, polycarbonate, polyamide, polyimide, or polystyrene with a thickness of 25-250 μm.

[0021] Optionally, the spherical light diffusion particles in the anti-blocking layer are selected from one or a mixture of n-butyl polymethacrylate, polypropylene, polyethylene, polyamide, or polystyrene;

[0022] The auxiliary agent in the light diffusion layer and the auxiliary agent in the anti-blocking layer include a dispersant, a leveling agent, an antifoaming agent, a curing agent, a lubricant, or an antistatic agent.

[0023] Optionally, the refractive index of the resin film-forming substance of the light diffusion layer and the anti-blocking layer is 1.49-1.52.

[0024] Optionally, the thickness of the light diffusion layer is 10-17 μm; the thickness of the anti-blocking layer is 5-8 μm.

[0025] It can be seen from the above technical solutions that the present application has the following advantages:

[0026] The PMMA mixed solution at 90 °C was slowly added to the aqueous aluminum paste. The PMMA spherical diffusion powder originally had a certain light diffusion ability. After ultrasonic oscillation treatment in a mixed solvent of absolute ethanol and deionized water, it could be more uniformly dispersed in the solution, enabling the nano-aluminum to uniformly coat the surface of the PMMA main body, thereby obtaining modified light diffusion particles. The modified light diffusion particles obtained through improvement had a lower refractive index. On the premise of maintaining the same haze, they could not only reduce the addition amount of PMMA powder, but also improve the brightness of the diffusion film, ensuring that the viewing angle remained unchanged, thus effectively reducing the production cost of the diffusion film and effectively enhancing the market competitiveness of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the present application, the following will briefly introduce the drawings required for use in the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0028] Figure 1 It is a schematic flow chart of the preparation method of the modified light diffusion particles in Embodiment 1 provided by the present application;

[0029] Figure 2 It is a schematic cross-sectional view of the structure of the modified light diffusion particles in Embodiment 1 provided by the present application;

[0030] Figure 3 It is a schematic cross-sectional view of the diffusion film in Embodiment 2 provided by the present application.

[0031] In the figure: 1. PMMA main body layer; 2. Nano-aluminum coating layer; 3. Substrate layer; 4. Light diffusion layer; 5. Anti-adhesion layer; 6. Resin film former; 7. Modified light diffusion particles; 8. Spherical light diffusion particles; 9. Auxiliary agent. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] The following will clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described examples are only one of the embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0033] The present application provides a modified light diffusion particle, a preparation method, and a diffusion film. Applying the modified light diffusion particle to the diffusion film can improve the brightness of the diffusion film.

[0034] Embodiment 1, please refer to Figure 1 and Figure 2, this application provides a preparation method of modified light-diffusing particles, including:

[0035] S101. Ultrasonically oscillate PMMA spherical diffusion powder with a particle size of 3 - 15 μm and a refractive index of 1.49 in anhydrous ethanol and deionized water with a weight ratio of 2:1 to obtain a PMMA mixed solution;

[0036] After adding PMMA spherical diffusion powder with a particle size of 3 - 15 μm and a refractive index of 1.49 into a mixed solvent of anhydrous ethanol and deionized water with a weight ratio of 2:1, then use ultrasonic waves with a frequency of 20 KHz to oscillate for 4 h. Ethanol has good compatibility. Using ultrasonic oscillation can promote the full dispersion of PMMA spherical diffusion powder to obtain a PMMA mixed solution.

[0037] S102. Heat the PMMA mixed solution to 90 °C, then slowly add the 90 °C PMMA mixed solution into the aqueous aluminum paste and keep it under constant temperature reflux for 6 h to obtain a modified solution;

[0038] The composition of the aqueous aluminum paste is aqueous polyurethane resin and aluminum particles with a size of 100 - 200 nm, and the solid content is 78%. Heat the PMMA mixed solution. When the temperature of the PMMA mixed solution is 90 °C, then mix the 90 °C PMMA mixed solution with the aqueous aluminum paste and keep it under constant temperature reflux for 6 h to obtain a modified solution, where the mass ratio of the aluminum paste to the PMMA mixed solution is 1:9.

[0039] S103. Vacuum filter the modified solution to obtain a filter cake, and wash the filter cake three times with anhydrous ethanol during vacuum filtration;

[0040] Vacuum filter the modified solution to obtain a filter cake; continue to maintain the vacuum state and wash the filter cake with anhydrous ethanol during vacuum filtration. Use a dropper to suck up anhydrous ethanol and slowly drip it onto the filter cake to make the anhydrous ethanol evenly cover the surface of the filter cake, removing impurities and unreacted aqueous aluminum paste in the filter cake.

[0041] S104. Heat the filter cake to 120 °C and dry it at 120 °C for 12 h to obtain a block;

[0042] Dry the filter cake at 120 °C for 12 h. While drying, the residual solvent in the filter cake can be removed, and the filter cake can be further cured to obtain a block.

[0043] S105. Crush the block to obtain modified light-diffusing particles.

[0044] Through crushing, the obtained modified light-diffusing particles have a particle size of 3 - 17 μm and a refractive index of 1.27. The modified light-diffusing particles include a PMMA main body layer and a nano-aluminum coating layer, and the nano-aluminum coating layer wraps the PMMA main body layer.

[0045] In this embodiment, the PMMA mixed solution at 90 °C is slowly added to the aqueous aluminum paste. The PMMA spherical diffusion powder originally has a certain light diffusion ability. After ultrasonic oscillation treatment in a mixed solvent of absolute ethanol and deionized water, it can be more uniformly dispersed in the solution, enabling the nano-aluminum to uniformly coat the surface of the PMMA main body, thereby obtaining modified light diffusion particles. The modified light diffusion particles obtained through improvement have a lower refractive index. On the premise of maintaining the same haze, they can not only reduce the addition amount of PMMA powder, but also improve the brightness of the diffusion film, ensuring that the viewing angle remains unchanged, thus effectively reducing the production cost of the diffusion film and effectively enhancing the market competitiveness of the product.

[0046] The modified light diffusion particles provided in this application are prepared by the preparation method of the modified light diffusion particles in Example 1. The modified light diffusion particles have the effect of improving the light diffusibility of the diffusion film and can also improve the brightness of the diffusion film.

[0047] Example 2, please refer to Figure 3 , the present invention provides a diffusion film, which includes: a substrate, a light diffusion layer, and an anti-adhesion layer;

[0048] The upper layer of the substrate is the light diffusion layer, and the lower layer is the anti-adhesion layer;

[0049] The substrate is selected from one of polyethylene terephthalate, polymethyl methacrylate, polycarbonate, polyamide, polyimide, or polystyrene with a thickness of 25 - 250 μm.

[0050] The light diffusion layer includes a resin film-forming substance, modified light diffusion particles, and additives; the anti-adhesion layer includes a resin film-forming substance, spherical light diffusion particles, and additives;

[0051] The resin film-forming substance in the light diffusion layer and the anti-adhesion layer is selected from resins with a refractive index of 1.49 - 1.52. The resin film-forming substance can be selected from one or a mixture of fluorinated acrylic resins, polycarbonates, modified polyester resins, silicone-modified acrylic resins, silicone-modified polyester resins, or alicyclic epoxy resins. The resin film-forming substance is the basis of the light diffusion layer and the anti-adhesion layer. It can level and dry and cure during the coating and processing process, providing a structural support for the light diffusion layer and the anti-adhesion layer, ensuring that the coating can completely cover the surface of the substrate.

[0052] The modified light diffusion particles in the light diffusion layer are the modified light diffusion particles prepared in Example 1 of this application. The particle size of the modified light diffusion particles is 3 - 17 μm, the refractive index is 1.27, and the addition amount of the modified light diffusion particles is 8% - 15% of the weight of the resin film-forming substance.

[0053] The spherical light-diffusing particles in the anti-adhesion layer are selected from one or more of poly(n-butyl methacrylate), polypropylene, polyethylene, polyamide, or polystyrene.

[0054] The additives in the light-diffusing layer and the additives in the anti-adhesion layer include dispersants, leveling agents, defoamers, curing agents, slip agents, or antistatic agents.

[0055] The dispersant can be one or more of sodium polyacrylate, polyacrylate ester, oleic acid, stearic acid, sodium oleate, or sodium stearate. The dispersant can adsorb on the surface of solid particles such as modified light-diffusing particles, reduce the surface tension between the particles, make the particles uniformly dispersed in the resin film-forming substance, prevent particle agglomeration, and ensure the uniform and stable optical properties of the light-diffusing layer.

[0056] The leveling agent can be one or more of acrylate leveling agents, silicone leveling agents, or fluorocarbon leveling agents. The leveling agent can reduce the surface tension of the coating, enable the coating to level quickly during the coating process, form a flat and smooth surface, and improve the flatness and gloss of the light-diffusing layer and the anti-adhesion layer.

[0057] The defoamer can be one or more of silicone defoamers, polyether defoamers, or mineral oil defoamers. During the preparation and coating process of the coating, the defoamer can eliminate the bubbles generated in the system, reduce the surface tension of the bubbles, cause the bubbles to burst, and prevent the bubbles from remaining in the coating to form defects.

[0058] The curing agent can be one or more of ethylenediamine or diethylenetriamine. The curing agent reacts chemically with the resin film-forming substance, causing the resin molecular chains to undergo a cross-linking reaction to form a three-dimensional network structure, thereby curing and shaping the coating, improving the hardness, strength, and other properties of the coating, and ensuring that the light-diffusing layer and the anti-adhesion layer have good stability and service life.

[0059] The slip agent can be one or more of oleic acid amide, erucic acid amide, or polydimethylsiloxane. The slip agent can reduce the friction coefficient on the surface of the coating, make the light-diffusing layer and the anti-adhesion layer have good slipperiness, and prevent adhesion between the two layers or between the coating and the surface of other objects.

[0060] The antistatic agent can be one or more of quaternary ammonium salts, alkyl sulfonates, or polyethylene glycol fatty acid esters. The antistatic agent can form a conductive layer on the surface of the coating to conduct away the accumulated static electricity. In the light-diffusing layer and the anti-adhesion layer, it can avoid the influence of particle adsorption caused by electrostatic attraction on the light-diffusion effect.

[0061] In this embodiment, the modified light diffusion particles in the light diffusion layer are combined with a resin film-forming material having a refractive index of 1.49 to 1.52 to achieve uniform diffusion of light, improve light utilization efficiency, the dispersant ensures uniform dispersion of the particles, and the leveling agent ensures a smooth surface. In the anti-adhesion layer, the resin film-forming material and the spherical light diffusion particles cooperate to prevent adhesion between layers and with the surfaces of other objects.

[0062] In an alternative embodiment, the light diffusion layer coating is prepared by the following steps:

[0063] Taking the acrylic resin as an example of the resin film-forming material, the acrylic resin is added to a stirring kettle for stirring, and the stirring speed is 300 to 500 r / min.

[0064] The dispersant and the defoaming agent are added in sequence, and stirring is continued for 15 to 20 minutes to fully disperse the additives in the resin.

[0065] The modified light diffusion particles are slowly added, and while adding, the stirring speed of the stirring kettle is increased to 800 to 1000 r / min, and stirring is carried out for 30 to 40 minutes to ensure uniform dispersion of the particles.

[0066] Finally, the curing agent, the slip agent, the leveling agent, and the antistatic agent are added, and stirring is carried out for 10 to 15 minutes to obtain the light diffusion layer coating.

[0067] In an alternative embodiment, the anti-adhesion layer coating is prepared by the following steps:

[0068] In a method similar to that of the light diffusion layer coating, the acrylic resin is added to a stirring kettle, and the stirring speed is 300 to 500 r / min.

[0069] The dispersant and the defoaming agent are added, and stirring is carried out for 15 to 20 minutes.

[0070] The spherical light diffusion particles are added, the stirring speed is increased to 800 to 1000 r / min, and stirring is carried out for 30 to 40 minutes.

[0071] The curing agent, the slip agent, the leveling agent, and the antistatic agent are added, and stirring is carried out for 10 to 15 minutes to obtain the anti-adhesion layer coating.

[0072] In an alternative embodiment, the diffusion film is prepared by the following steps:

[0073] The PET substrate is subjected to surface cleaning treatment to remove dust and oil on the surface.

[0074] The light diffusion layer coating is uniformly coated on the upper layer of the substrate using a coater, and coating methods such as bar coating, microgravure coating, knife coating, or spraying are used for coating.

[0075] The substrate coated with the light diffusion layer is placed in an oven and dried at 80-100° C. for 10-15 minutes to obtain a light diffusion layer with a dry thickness of 10-17 μm.

[0076] Then use a coating machine to evenly coat the anti-adhesion layer coating on the lower layer of the substrate, put the composite film coated with the anti-adhesion layer into the oven again, and dry it at 100-120°C for 20-30 minutes to obtain an anti-adhesion layer with a dry thickness of 5-8 μm.

[0077] In the above optional embodiments, PMMA spherical diffusion powder originally has a certain light diffusion ability, and the aluminum paste itself has strong strength and toughness and other properties. PMMA spherical diffusion powder and aluminum paste are made into modified light diffusion particles. By adding modified light diffusion particles to the light diffusion layer of the diffusion film, the diffusion effect and brightness of the diffusion film are improved, and the mechanical properties of the diffusion film are improved.

[0078] Example 3:

[0079]

[0080]

[0081] A light diffusion layer coating liquid was obtained by stirring according to the materials list in Table 1. The light diffusion layer coating liquid was applied to the upper surface of 100 μm thick PET and heated and cured to obtain a light diffusion layer with a coating thickness of 10 μm. An anti-adhesion layer coating liquid was obtained by stirring according to the materials list in Table 2. The anti-adhesion layer coating liquid was applied to the lower surface of 38 μm thick PET and heated and cured to obtain an anti-adhesion layer with a thickness of 5 μm. The test results of light transmittance, haze, brightness, and TCO are shown in Table 25. The closer the TCO value is to 1, the greater the viewing angle of the backlight.

[0082] Example 4:

[0083]

[0084]

[0085] A light diffusion layer coating liquid was prepared by stirring according to the materials listed in Table 3. This was applied to the upper surface of a 100 μm thick PET film and cured by heating to obtain a light diffusion layer with a coating thickness of 11 μm. An anti-blocking layer coating liquid was prepared by stirring according to the materials listed in Table 4. This anti-blocking layer coating liquid was applied to the lower surface of a 100 μm thick PET film and cured by heating to obtain an anti-blocking layer with a thickness of 6 μm. The test results for transmittance, haze, brightness, and TCO are shown in Table 17.

[0086] Example 5:

[0087]

[0088]

[0089] The light-diffusing layer coating liquid is obtained by stirring according to the bill of materials in Table 5. The light-diffusing layer coating liquid is coated on the upper surface of 100-μm PET. After heating and curing, a light-diffusing layer with a coating thickness of 12 μm is obtained. According to the bill of materials in Table 6, the anti-blocking layer coating liquid is obtained by stirring. The anti-blocking layer coating liquid is coated on the lower surface of 100-μm PET. After heating and curing, an anti-blocking layer with a thickness of 6 μm is obtained. The test results of light transmittance, haze, brightness, and TCO are shown in Table 25.

[0090] Example 6:

[0091]

[0092]

[0093] The light-diffusing layer coating liquid is obtained by stirring according to the bill of materials in Table 7. The light-diffusing layer coating liquid is coated on the upper surface of 100-μm PET. After heating and curing, a light-diffusing layer with a coating thickness of 13 μm is obtained. According to the bill of materials in Table 8, the anti-blocking layer coating liquid is obtained by stirring. The anti-blocking layer coating liquid is coated on the lower surface of 100-μm PET. After heating and curing, an anti-blocking layer with a thickness of 7 μm is obtained. The test results of light transmittance, haze, brightness, and TCO are shown in Table 25.

[0094] Example 7:

[0095]

[0096]

[0097] The light-diffusing layer coating liquid is obtained by stirring according to the bill of materials in Table 8. The light-diffusing layer coating liquid is coated on the upper surface of 100-μm PET. After heating and curing, a light-diffusing layer with a coating thickness of 14 μm is obtained. According to the bill of materials in Table 10, the anti-blocking layer coating liquid is obtained by stirring. The anti-blocking layer coating liquid is coated on the lower surface of 100-μm PET. After heating and curing, an anti-blocking layer with a thickness of 8 μm is obtained. The test results of light transmittance, haze, brightness, and TCO are shown in Table 25.

[0098] Example 8:

[0099]

[0100]

[0101] The light-diffusing layer coating liquid is obtained by stirring according to the bill of materials in Table 11. The light-diffusing layer coating liquid is coated on the upper surface of 100-μm PET. After heating and curing, a light-diffusing layer with a coating thickness of 15 μm is obtained. According to the bill of materials in Table 12, the anti-blocking layer coating liquid is obtained by stirring. The anti-blocking layer coating liquid is coated on the lower surface of 100-μm PET. After heating and curing, an anti-blocking layer with a thickness of 8 μm is obtained. The test results of light transmittance, haze, luminance, and TCO are shown in Table 25.

[0102] Example 9:

[0103]

[0104]

[0105] The light-diffusing layer coating liquid is obtained by stirring according to the bill of materials in Table 13. The light-diffusing layer coating liquid is coated on the upper surface of 100-μm PET. After heating and curing, a light-diffusing layer with a coating thickness of 16 μm is obtained. According to the bill of materials in Table 14, the anti-blocking layer coating liquid is obtained by stirring. The anti-blocking layer coating liquid is coated on the lower surface of 100-μm PET. After heating and curing, an anti-blocking layer with a thickness of 6 μm is obtained. The test results of light transmittance, haze, luminance, and TCO are shown in Table 25.

[0106] Example 10:

[0107]

[0108]

[0109] The light-diffusing layer coating liquid is obtained by stirring according to the bill of materials in Table 15. The light-diffusing layer coating liquid is coated on the upper surface of 100-μm PET. After heating and curing, a light-diffusing layer with a coating thickness of 17 μm is obtained. According to the bill of materials in Table 16, the anti-blocking layer coating liquid is obtained by stirring. The anti-blocking layer coating liquid is coated on the lower surface of 100-μm PET. After heating and curing, an anti-blocking layer with a thickness of 5 μm is obtained. The test results of light transmittance, haze, luminance, and TCO are shown in Table 25.

[0110] Tables 17 to 24 are the composition tables of the light-diffusing layer coating liquid and the anti-blocking layer coating liquid for Comparative Examples 1 to 4. Among them, Tables 17, 19, 21, and 23 are the composition tables of the light-diffusing layer coating liquid without adding modified diffusion particles.

[0111] Comparative Example 1:

[0112]

[0113]

[0114] The light-diffusing layer coating liquid was obtained by stirring according to the bill of materials in Table 17. The light-diffusing layer coating liquid was coated on the upper surface of 100-μm PET, and after heating and curing, a light-diffusing layer with a coating thickness of 10 μm was obtained. According to the bill of materials in Table 18, the anti-blocking layer coating liquid was obtained by stirring. The anti-blocking layer coating liquid was coated on the lower surface of 100-μm PET, and after heating and curing, an anti-blocking layer with a thickness of 8 μm was obtained. The test results of light transmittance, haze, luminance, and TCO are shown in Table 25.

[0115] Comparative Example 2:

[0116]

[0117]

[0118] The light-diffusing layer coating liquid was obtained by stirring according to the bill of materials in Table 19. The light-diffusing layer coating liquid was coated on the upper surface of 100-μm PET, and after heating and curing, a light-diffusing layer with a coating thickness of 14 μm was obtained. According to the bill of materials in Table 20, the anti-blocking layer coating liquid was obtained by stirring. The anti-blocking layer coating liquid was coated on the lower surface of 100-μm PET, and after heating and curing, an anti-blocking layer with a thickness of 5 μm was obtained. The test results of light transmittance, haze, luminance, and TCO are shown in Table 25.

[0119] Comparative Example 3:

[0120]

[0121]

[0122] The light-diffusing layer coating liquid was obtained by stirring according to the bill of materials in Table 21. The light-diffusing layer coating liquid was coated on the upper surface of 100-μm PET, and after heating and curing, a light-diffusing layer with a coating thickness of 16 μm was obtained. According to the bill of materials in Table 22, the anti-blocking layer coating liquid was obtained by stirring. The anti-blocking layer coating liquid was coated on the lower surface of 100-μm PET, and after heating and curing, an anti-blocking layer with a thickness of 5 μm was obtained. The test results of light transmittance, haze, luminance, and TCO are shown in Table 25.

[0123] Comparative Example 4:

[0124]

[0125]

[0126] The light diffusion layer coating liquid is obtained by stirring according to the bill of materials in Table 23. The light diffusion layer coating liquid is coated on the upper surface of 100-μm PET. After heating and curing, a light diffusion layer with a coating thickness of 17 μm is obtained. According to the bill of materials in Table 24, the anti-adhesion layer coating liquid is obtained by stirring. The anti-adhesion layer coating liquid is coated on the lower surface of 100-μm PET. After heating and curing, an anti-adhesion layer with a thickness of 7 μm is obtained. The test results of light transmittance, haze, luminance, and TCO are shown in Table 25.

[0127] The light transmittance, haze, and luminance of the diffusion film are tested. Five samples of Examples 3 to 10 and Comparative Examples 1 to 4 are prepared. A light transmittance and haze instrument is used to test the light transmittance. The haze is tested with a BM-7A brightness tester for the brightness and TCO value in the backlight module, and the average value of the above performance values is calculated. The structure of the tested diffusion film from bottom to top is white reflection, light guide plate, diffusion film, diffusion film, and brightness enhancement film. Among them, the tested backlight size is 27 inches. The specific values are shown in Table 25:

[0128]

[0129] As shown in Table 25, the substrate thicknesses of the examples and comparative examples are both 100 μm; the light transmittance of the examples is between 91.03% and 93.23%, while that of the comparative examples is between 83.47% and 92.13%; the haze range of the examples is from 30.12% to 96.16%, while that of the comparative examples is between 30.14% and 96.04%; the proportion of modified light diffusion particles in the examples increases from 8% to 15%, and no modified light diffusion particles are used in the comparative examples; the thicknesses of the light diffusion layer and the anti-adhesion layer increase with the increase of the modified light diffusion particles; the module luminance of the examples is between 2172 cd / m² and 2384 cd / m², while that of the comparative examples is between 2005 cd / m² and 2265 cd / m²; the TCO value is relatively stable in the examples, and the addition of modified light diffusion particles has little effect on the backlight viewing angle.

[0130] In the above examples and comparative examples, with the increase of the proportion of modified light diffusion particles, the haze of the diffusion film gradually increases. And under the same haze condition, the diffusion film using modified light diffusion particles has higher light transmittance and module luminance, but the TCO value is relatively stable, and the addition of modified light diffusion particles has little effect on the backlight viewing angle.

[0131] In practical applications, the PMMA mixed solution at 90 °C is slowly added to the aqueous aluminum paste. The PMMA spherical diffusion powder originally has a certain light diffusion ability. After ultrasonic oscillation treatment in a mixed solvent of absolute ethanol and deionized water, it can be more evenly dispersed in the solution, enabling the nano-aluminum to uniformly coat the surface of the PMMA main body, thereby obtaining modified light diffusion particles. The nano-aluminum particles have a relatively low refractive index. The modified light diffusion particles obtained through improvement can not only reduce the addition amount of PMMA powder while maintaining the same haze, but also enhance the brightness of the diffusion film, ensuring that the viewing angle remains unchanged, thus effectively reducing the production cost of the diffusion film.

[0132] The above embodiments only represent several implementation manners of the present invention, and the description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. A method for preparing a modified light-diffusing particle, characterized in that, Comprising: Performing ultrasonic oscillation on PMMA spherical diffusion powder with a particle size of 3 - 15 μm and a refractive index of 1.49 in anhydrous ethanol and deionized water with a volume ratio of 2:1 to obtain a PMMA mixed solution; Heating the PMMA mixed solution to 90°C, then slowly adding the PMMA mixed solution at 90°C to the aqueous aluminum paste and carrying out constant temperature reflux stirring for 6 h to obtain a modified solution, where the aqueous aluminum paste is an aqueous polyurethane resin and aluminum particles with a size of 100 - 200 nm; Performing vacuum filtration on the modified solution to obtain a filter cake, and washing the filter cake three times with anhydrous ethanol during vacuum filtration; Heating the filter cake to 120°C and drying it at 120°C for 12 h to obtain a block material.

2. The preparation method of the modified light diffusion particles according to claim 1, characterized in that, When performing ultrasonic oscillation on the PMMA spherical diffusion powder in anhydrous ethanol and deionized water, the frequency of the ultrasonic wave is 20 KHz and the oscillation duration is 4 h.

3. The preparation method of the modified light diffusion particles according to claim 1, characterized in that, When slowly adding the PMMA mixed solution heated to 90°C to the aqueous aluminum paste, the mass ratio of the aqueous aluminum paste to the PMMA mixed solution is 1:

9.

4. The preparation method of the modified light diffusing particles according to claim 1, wherein, The particle size of the modified light diffusion particles is 3 - 17 μm and the refractive index is 1.

27.

5. A kind of modified light diffusion particle, prepared by the preparation method of the modified light diffusion particle according to any one of claims 1 to 4.

6. A diffusion film, wherein the light diffusion layer of the diffusion film is coated with the modified light diffusion particles according to claim 5.

7. The diffusion film according to claim 6, wherein, The diffusion film comprises: a substrate, a light diffusion layer and an anti - adhesion layer; The upper layer of the substrate is the light diffusion layer and the lower layer is the anti - adhesion layer; The light diffusion layer comprises a resin film - forming substance, modified light diffusion particles and additives; The anti - adhesion layer comprises a resin film - forming substance, spherical light diffusion particles and additives; The substrate is selected from one of polyethylene terephthalate, polymethyl methacrylate, polycarbonate, polyamide, polyimide or polystyrene with a thickness of 25 - 250 μm.

8. According to the diffusion film of claim 7, characterized in that The spherical light diffusion particles in the anti - adhesion layer are selected from one or a mixture of butyl methacrylate, polypropylene, polyethylene, polyamide or polystyrene; The additives in the light diffusion layer and the additives in the anti - adhesion layer include dispersants, leveling agents, defoaming agents, curing agents, slip agents or antistatic agents.

9. The diffusion film according to claim 7, wherein The refractive index of the resin film - forming substances of the light diffusion layer and the anti - adhesion layer is 1.49 - 1.

52.

10. According to the diffusion film of claim 7, characterized in that The thickness of the light diffusion layer is 10 - 17 μm; the thickness of the anti - adhesion layer is 5 - 8 μm.

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