Denatured light diffusion particle, preparation method and diffusion film

Abstract

The invention discloses a denatured light diffusion particle, a preparation method and a diffusion film, and the preparation method of the denatured light diffusion particle comprises the following steps: carrying out ultrasonic oscillation on PMMA spherical diffusion powder with the particle size of 3-15 [mu] m and the refractive index of 1.49 in absolute ethyl alcohol and deionized water with the ratio of 2: 1 to obtain a PMMA powder mixed solution; heating the PMMA mixed solution to 90 DEG C, slowly adding the PMMA mixed solution with the temperature of 90 DEG C into water-based aluminum paste, and performing reflux stirring at the constant temperature of 90 DEG C for 6 hours to obtain a modified solution; performing vacuum filtration on the modified solution to obtain a filter cake, and cleaning the filter cake with absolute ethyl alcohol for three times during vacuum filtration; heating the filter cake to 120 DEG C, and drying at 120 DEG C for 12 hours to obtain a block material; and crushing the block material to obtain the denatured light diffusion particles. The denatured light diffusion particles are coated in a light diffusion layer of a diffusion film, so that the brightness of the diffusion film can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of optical thin films, and particularly relates 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 reflective sheet, 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 diffusing layer, and a back anti-adhesion layer. In the diffusing 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 the present application provides a preparation method of a modified light diffusing particle, including: 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; Heating the PMMA mixed solution to 90°C, and then slowly adding the PMMA mixed solution at 90°C to aqueous aluminum paste, and carrying out constant temperature reflux for 6 h to obtain a modified solution; 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; Crushing the block to obtain modified light diffusing particles.

[0006] Optionally, 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.

[0007] 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.

[0008] Optionally, the particle size of the modified light diffusing particles is 3 - 17 μm, and the refractive index is 1.27.

[0009] The second aspect of the present application provides a modified light diffusing particle, which is prepared by the preparation method of the modified light diffusing particle described in the first aspect.

[0010] The third aspect of the present invention provides a diffusion film, and the modified light diffusing particles are coated on the light diffusion layer of the diffusion film.

[0011] Optionally, the diffusion film includes: a substrate, a light diffusion layer, and an anti - sticking layer; The upper layer of the substrate is the light diffusion layer, and the lower layer is the anti - sticking layer; The light diffusion layer includes a resin film - forming substance, modified light diffusing particles, and additives; The anti - sticking layer includes a resin film - forming substance, spherical light diffusing 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.

[0012] Optionally, the spherical light diffusing particles in the anti - sticking layer are selected from one or a mixture of n - butyl polymethacrylate, polypropylene, polyethylene, polyamide, or polystyrene; The additives in the light diffusion layer and the additives in the anti - sticking layer include a dispersant, a leveling agent, an antifoaming agent, a curing agent, a lubricant, or an antistatic agent.

[0013] Optionally, the refractive index of the resin film - forming substance of the light diffusion layer and the anti - sticking layer is 1.49 - 1.52.

[0014] Optionally, the thickness of the light diffusion layer is 10 - 17 μm; the thickness of the anti - sticking layer is 5 - 8 μm.

[0015] It can be seen from the above technical solutions that the present application has the following advantages: 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 anhydrous 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 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, ensure that the viewing angle remains unchanged, thereby effectively reducing the production cost of the diffusion film and effectively enhancing the market competitiveness of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] 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 be obtained based on these drawings.

[0017] 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; 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; Figure 3 It is a schematic cross-sectional view of the diffusion film in Embodiment 2 provided by the present application.

[0018] 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

[0019] 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 of the 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.

[0020] 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.

[0021] Embodiment 1, please refer to Figure 1 and Figure 2 , the present application provides a preparation method of a modified light diffusion particle, including: 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 ratio of 2:1 to obtain a PMMA mixed solution; 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, ultrasonically oscillate it at a frequency of 20 KHz 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.

[0022] S102. Heat the PMMA mixed solution to 90 °C, and 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; 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.

[0023] S103. Vacuum filter the modified solution to obtain a filter cake, and wash the filter cake three times with anhydrous ethanol during vacuum filtration; 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 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.

[0024] S104. Heat the filter cake to 120 °C and dry it at 120 °C for 12 h to obtain a block; Dry the filter cake at 120 °C for 12 h. During drying, the residual solvent in the filter cake can be removed, and the filter cake can be further cured to obtain a block.

[0025] S105. Crush the block to obtain modified light diffusion particles.

[0026] Through crushing, the obtained modified light diffusion particles have a particle size of 3 - 17 μm and a refractive index of 1.27. The modified light diffusion particles include a PMMA main layer and a nano - aluminum coating layer, and the nano - aluminum coating layer wraps the PMMA main layer.

[0027] In this embodiment, a 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.

[0028] The modified light diffusion particles provided by 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 diffusion of the diffusion film and can also improve the brightness of the diffusion film.

[0029] 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; The upper layer of the substrate is the light diffusion layer, and the lower layer is the anti-adhesion layer; The substrate is selected from one of polyethylene terephthalate, polymethyl methacrylate, polycarbonate, polyamide, polyimide, or polystyrene with a thickness of 25 - 250 μm.

[0030] 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; In the resin film-forming substances in the light diffusion layer and the anti-adhesion layer, resins with a refractive index of 1.49 - 1.52 are selected. 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 to ensure that the coating can completely cover the surface of the substrate.

[0031] 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.

[0032] The spherical light diffusion particles in the anti-adhesion layer are selected from one or a mixture of n-butyl polymethacrylate, polypropylene, polyethylene, polyamide, or polystyrene.

[0033] The additives in the light diffusion layer and the additives in the anti-blocking layer include dispersants, leveling agents, defoamers, curing agents, slip agents or antistatic agents.

[0034] The dispersant can be one or more mixtures of sodium polyacrylate, polyacrylate, oleic acid, stearic acid, sodium oleate or sodium stearate. The dispersant can adsorb on the surface of solid particles such as modified light diffusion 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 diffusion layer.

[0035] 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 diffusion layer and the anti-blocking layer.

[0036] 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.

[0037] 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 diffusion layer and the anti-blocking layer have good stability and service life.

[0038] 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 diffusion layer and the anti-blocking layer have good slipperiness, and prevent adhesion between the two layers or between the coating and the surface of other objects.

[0039] 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 diffusion layer and the anti-blocking layer, it can avoid the influence of particle adsorption caused by static electricity attraction on the light diffusion effect.

[0040] In this embodiment, the modified light diffusion particles in the light diffusion layer are combined with a resin film-forming substance with a refractive index of 1.49 - 1.52 to achieve uniform diffusion of light, improve light utilization rate, the dispersant ensures uniform dispersion of the particles, and the leveling agent ensures a flat surface. The resin film-forming substance in the anti-blocking layer synergizes with the spherical light diffusion particles to prevent adhesion between each layer and the surface of other objects.

[0041] In an alternative embodiment, the light diffusion layer coating is prepared by the following steps: Taking the acrylic resin as an example of the resin film-forming substance, the acrylic resin is added to a stirring kettle and stirred at a stirring speed of 300-500 r / min.

[0042] The dispersant and defoamer are added in sequence, and stirring is continued for 15-20 minutes to fully disperse the additives in the resin.

[0043] The modified light diffusion particles are slowly added while increasing the stirring speed of the stirring kettle to 800-1000 r / min, and stirring is carried out for 30-40 minutes to ensure uniform dispersion of the particles.

[0044] Finally, the curing agent, slip agent, leveling agent, and antistatic agent are added, and stirring is carried out for 10-15 minutes to obtain the light diffusion layer coating.

[0045] In an alternative embodiment, the anti-adhesion layer coating is prepared by the following steps: 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 300-500 r / min.

[0046] The dispersant and defoamer are added, and stirring is carried out for 15-20 minutes.

[0047] Spherical light diffusion particles are added, and the stirring speed is increased to 800-1000 r / min, and stirring is carried out for 30-40 minutes.

[0048] The curing agent, slip agent, leveling agent, and antistatic agent are added, and stirring is carried out for 10-15 minutes to obtain the anti-adhesion layer coating.

[0049] In an alternative embodiment, the diffusion film is prepared by the following steps: The PET substrate is subjected to surface cleaning treatment to remove dust and oil on the surface.

[0050] A coating machine is used to uniformly coat the light diffusion layer coating on the upper layer of the substrate, and coating methods such as bar coating, microgravure coating, knife coating, or spraying are used for coating.

[0051] 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.

[0052] Then, a coating machine is used to uniformly coat the anti-adhesion layer coating on the lower layer of the substrate, and the composite film coated with the anti-adhesion layer is placed in the oven again and dried at 100-120 °C for 20-30 min to obtain an anti-adhesion layer with a dry thickness of 5-8 μm.

[0053] In the above several alternative embodiments, the PMMA spherical diffusion powder originally has a certain light diffusion ability, and the aluminum paste itself has characteristics such as strong strength and toughness. The PMMA spherical diffusion powder and the aluminum paste are made into modified light diffusion particles. By adding the modified light diffusion particles to the light diffusion layer of the diffusion film, the diffusion effect of the diffusion film and the brightness of the diffusion film are improved, and the mechanical properties of the diffusion film are improved.

[0054] Example 3:

[0055]

[0056] The coating liquid for the light diffusion layer is obtained by stirring according to the material list in Table 1, and the coating liquid for the light diffusion layer is coated on the upper surface of 100 μm PET. After heating and curing, a light diffusion layer with a coating thickness of 10 μm is obtained. According to the material list in Table 2, the coating liquid for the anti-sticking layer is obtained by stirring, and the coating liquid for the anti-sticking layer is coated on the lower surface of 38 μm PET. After heating and curing, an anti-sticking layer with a thickness of 5 μm is obtained. The test results of light transmittance, haze, brightness, and TCO are shown in Table 25. Among them, the closer the TCO value is to 1, the larger the viewing angle of the backlight.

[0057] Example 4:

[0058]

[0059] The coating liquid for the light diffusion layer is obtained by stirring according to the material list in Table 3, and the coating liquid for the light diffusion layer is coated on the upper surface of 100 μm PET. After heating and curing, a light diffusion layer with a coating thickness of 11 μm is obtained. According to the material list in Table 4, the coating liquid for the anti-sticking layer is obtained by stirring, and the coating liquid for the anti-sticking layer is coated on the lower surface of 100 μm PET. After heating and curing, an anti-sticking layer with a thickness of 6 μm is obtained. The test results of light transmittance, haze, brightness, and TCO are shown in Table 17.

[0060] Example 5:

[0061]

[0062] The light-diffusing layer coating liquid was obtained by stirring according to the bill of materials in Table 5. 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 12 μm was obtained. According to the bill of materials in Table 6, the anti-sticking layer coating liquid was obtained by stirring. The anti-sticking layer coating liquid was coated on the lower surface of 100-μm PET, and after heating and curing, an anti-sticking layer with a thickness of 6 μm was obtained. The test results of light transmittance, haze, luminance, and TCO are shown in Table 25.

[0063] Example 6:

[0064]

[0065] The light-diffusing layer coating liquid was obtained by stirring according to the bill of materials in Table 7. 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 13 μm was obtained. According to the bill of materials in Table 8, the anti-sticking layer coating liquid was obtained by stirring. The anti-sticking layer coating liquid was coated on the lower surface of 100-μm PET, and after heating and curing, an anti-sticking layer with a thickness of 7 μm was obtained. The test results of light transmittance, haze, luminance, and TCO are shown in Table 25.

[0066] Example 7:

[0067]

[0068] The light-diffusing layer coating liquid was obtained by stirring according to the bill of materials in Table 8. 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 10, the anti-sticking layer coating liquid was obtained by stirring. The anti-sticking layer coating liquid was coated on the lower surface of 100-μm PET, and after heating and curing, an anti-sticking layer with a thickness of 8 μm was obtained. The test results of light transmittance, haze, luminance, and TCO are shown in Table 25.

[0069] Example 8:

[0070]

[0071] The light-diffusing layer coating liquid was obtained by stirring according to the bill of materials in Table 11. 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 15 μm was obtained. According to the bill of materials in Table 12, 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.

[0072] Example 9:

[0073]

[0074] The light-diffusing layer coating liquid was obtained by stirring according to the bill of materials in Table 13. 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 14, 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 6 μm was obtained. The test results of light transmittance, haze, luminance, and TCO are shown in Table 25.

[0075] Example 10:

[0076]

[0077] The light-diffusing layer coating liquid was obtained by stirring according to the bill of materials in Table 15. 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 17 μm was obtained. According to the bill of materials in Table 16, 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.

[0078] 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, where Tables 17, 19, 21, and 23 are the composition tables of the light-diffusing layer coating liquid without adding modified diffusion particles.

[0079] Comparative Example 1:

[0080]

[0081] 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-sticking layer coating liquid was obtained by stirring. The anti-sticking layer coating liquid was coated on the lower surface of 100-μm PET, and after heating and curing, an anti-sticking layer with a thickness of 8 μm was obtained. The test results of light transmittance, haze, luminance, and TCO are shown in Table 25.

[0082] Comparative Example 2:

[0083]

[0084] 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-sticking layer coating liquid was obtained by stirring. The anti-sticking layer coating liquid was coated on the lower surface of 100-μm PET, and after heating and curing, an anti-sticking layer with a thickness of 5 μm was obtained. The test results of light transmittance, haze, luminance, and TCO are shown in Table 25.

[0085] Comparative Example 3:

[0086]

[0087] 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-sticking layer coating liquid was obtained by stirring. The anti-sticking layer coating liquid was coated on the lower surface of 100-μm PET, and after heating and curing, an anti-sticking layer with a thickness of 5 μm was obtained. The test results of light transmittance, haze, luminance, and TCO are shown in Table 25.

[0088] Comparative Example 4:

[0089]

[0090] The light-diffusing layer coating liquid is obtained by stirring according to the bill of materials in Table 23. The light-diffusing layer coating liquid is coated on the upper surface of 100-μm PET, and 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 24, 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, and after heating and curing, an anti-blocking layer with a thickness of 7 μm is obtained. The test results of light transmittance, haze, luminance, and TCO are shown in Table 25.

[0091] 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. The light transmittance is tested with a light transmittance and haze instrument, and the haze is tested with a BM-7A brightness tester for the brightness and TCO value in the backlight module. The average values of the above performance values are 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:

[0092] 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-diffusing particles in the examples increases from 8% to 15%, and no modified light-diffusing particles are used in the comparative examples; the thicknesses of the light-diffusing layer and the anti-blocking layer increase with the increase of the modified light-diffusing 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-diffusing particles has little effect on the backlight viewing angle.

[0093] In the above examples and comparative examples, with the increase of the proportion of modified light-diffusing particles, the haze of the diffusion film gradually increases. And under the same haze condition, the diffusion film using modified light-diffusing particles has higher light transmittance and module luminance, but the TCO value is relatively stable, and the addition of modified light-diffusing particles has little effect on the backlight viewing angle.

[0094] In practical applications, a 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 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 improve the brightness of the diffusion film, ensuring that the viewing angle remains unchanged, thus effectively reducing the production cost of the diffusion film.

[0095] 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 modified light-diffusing particles, characterized in that: include: PMMA spherical diffusion powder with a particle size of 3-15 μm and a refractive index of 1.49 is subjected to ultrasonic oscillation in anhydrous ethanol and deionized water in a ratio of 2:1 to obtain a PMMA mixed solution; The PMMA mixed solution is heated to 90° C., and then the PMMA mixed solution at 90° C. is slowly added into the aqueous aluminum paste, and refluxed and stirred at a constant temperature for 6 hours to obtain a modified solution; The modified solution is vacuum filtered to obtain a filter cake, and the filter cake is washed three times with anhydrous ethanol during the vacuum filtration; The filter cake was heated to 120°C and dried at 120°C for 12 h to obtain a block.

2. The method for preparing modified light-diffusing particles according to claim 1, characterized in that: When PMMA spherical diffusion powder is subjected to ultrasonic oscillation in anhydrous ethanol and deionized water, the frequency of the ultrasonic wave is 20 KHz and the oscillation time is 4 hours.

3. The method for preparing modified light-diffusing particles according to claim 1, characterized in that: 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.

4. The method for preparing modified light-diffusing particles according to claim 1, characterized in that: The particle size of the modified light diffusion particles is 3-17 μm, and the refractive index is 1.

27. 5 . A modified light-diffusing particle obtained by the method for preparing the modified light-diffusing particle according to claim 1 . 6 . A diffusion film, wherein a light diffusion layer of the diffusion film is coated with the modified light diffusion particles according to claim 5 .

7. The diffusion membrane according to claim 6, characterized in that 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 includes a resin film-forming material, modified light diffusion particles and an auxiliary agent; The anti-adhesion layer includes a resin film-forming material, spherical light diffusion particles and an additive; The substrate is selected from one of polyethylene terephthalate, polymethyl methacrylate, polycarbonate, polyamide, polyimide or polystyrene with a thickness of 25 to 250 μm.

8. The diffusion membrane according to claim 7, characterized in that The spherical light diffusion particles in the anti-adhesion layer are selected from a mixture of one or more of polybutyl methacrylate, polypropylene, polyethylene, polyamide or polystyrene; The auxiliary agent in the light diffusion layer and the auxiliary agent in the anti-blocking layer include a dispersant, a leveling agent, a defoaming agent, a curing agent, a lubricant or an antistatic agent.

9. The diffusion membrane according to claim 7, characterized in that: The refractive index of the resin film-formed materials of the light diffusion layer and the anti-adhesion layer is 1.49-1.

52.

10. The diffusion membrane according to 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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