A prism composite thin film and its preparation method

Abstract

This invention discloses a prism composite film and its preparation method, belonging to the field of optical thin film technology. The method includes the following steps: Step 1: Prepare a lower prism layer on the upper surface of a lower substrate layer for later use; Step 2: Coat a modified solvent-free adhesive on the lower surface of the upper substrate layer and bond it to the lower prism layer obtained in Step 1, then UV-cur it to form an adhesive layer; Step 3: After preparing an upper prism layer on the upper surface of the upper substrate layer of the composite film obtained in Step 2, perform quality inspection. If qualified, roll it up and store it in the warehouse to obtain a prism composite film. This invention uses a modified solvent-free adhesive to bond the upper and lower prism layers to obtain a prism composite film. The process is simple, and the adhesive layer formed by the modified solvent-free adhesive creates a haze layer, improving the shielding properties of the prism composite film while simultaneously increasing its brightness, meeting brightness requirements.

Description

Technical Field

[0001] This invention belongs to the field of optical thin film technology, specifically relating to a prism composite thin film and its preparation method. Background Technology

[0002] Optical composite films, also known as brightness enhancement films, are an indispensable component in the digital electronics industry. When assembled in front of a backlight, the prism structure of the prism layer has a light-gathering effect. Light passing through the prism structure of the prism layer will converge towards the center, thereby improving the brightness of the front display.

[0003] With the continuous development of LCD screen technology, screen resolutions are getting higher and higher (2K-4K-8K), and screen sizes are getting larger and larger. Correspondingly, higher requirements are placed on the viewing angle and adaptability of optical composite films to high-definition LCD screens: the screen viewing angle needs to be increased, the shielding effect needs to be improved, the anti-interference performance needs to be improved, and the brightness needs to be met. This makes it difficult to manufacture brightness enhancement films using traditional processes. Existing technologies mainly increase the viewing angle and improve shielding by increasing the back coating haze, but this process results in a significant decrease in brightness and fails to meet the brightness requirements. Alternatively, microlens structures can be added to the two-layer prism lamination film, but this process is complex.

[0004] Therefore, it is necessary to develop a prism composite film with high haze and high shielding performance that has a simple manufacturing process. Summary of the Invention

[0005] The purpose of this invention is to provide a prism composite film and its preparation method to solve the following technical problem: how to simplify the preparation method of the prism composite film and improve the haze and shading performance of the prism composite film without reducing the luminance and meeting the brightness requirements.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] A method for preparing a prism composite thin film includes the following steps:

[0008] Step 1: Prepare the lower prism layer on the upper surface (light-emitting surface) of the lower substrate layer for later use;

[0009] Step 2: Apply modified solvent-free adhesive to the lower surface (light-incident surface) of the upper substrate layer, bond it to the lower prism layer obtained in Step 1, and UV cure to form an adhesive layer.

[0010] Step 3: After preparing the upper prism layer on the upper surface (light-emitting surface) of the upper substrate layer of the composite film obtained in Step 2, a quality inspection is carried out. After passing the inspection, the film is wound up and stored to obtain a prism composite film.

[0011] As a further embodiment of the present invention, the thickness of the upper prism layer is 10.5 μm, the thickness of the upper substrate layer is 38-50 μm, the thickness of the adhesive layer is 6.5-7.5 μm, the thickness of the lower prism layer is 27 μm, and the thickness of the lower substrate layer is 38-50 μm.

[0012] As a further embodiment of the present invention, the materials of the upper substrate layer and the lower substrate layer are polyethylene terephthalate; the lower substrate layer is prepared by the following steps: slicing the material of the lower substrate layer, crystallizing and drying it at 150-180°C, melt-extruding it at 260-285°C, cooling it with a cooling roller, heating it to 80-120°C, and stretching it longitudinally by 3.0-3.8 times to obtain the lower substrate layer; the preparation steps of the upper substrate layer are the same as those of the lower substrate layer.

[0013] As a further aspect of the present invention, the conditions for UV curing in step two are: the wavelength of the ultraviolet light is 200-500nm, and the power is 2500-3000mw / cm². 2 The irradiation time is 10-20 seconds.

[0014] As a further aspect of the present invention, the prism direction of the upper prism layer forms a 90° angle with the prism direction of the lower prism layer; the upper prism layer is composed of a plurality of upper prism pillars, the cross-sections at both ends of the upper prism pillars are isosceles right triangles with right angles at the apex; the cross-sections at both ends of the lower prism layer are isosceles right triangles with right angles at the apex; the lower prism layer includes a plurality of parallel microprism structures of different heights.

[0015] As a further aspect of the present invention, the materials of the upper prism layer and the lower prism layer are any one of polyurethane acrylic resin, polyether acrylate, epoxy acrylic resin, and polyester acrylic resin; the lower prism layer is prepared by the following steps: pouring the material of the lower prism layer into a mold and UV curing it to obtain the lower prism layer; the preparation steps of the upper prism layer are the same as those of the lower prism layer.

[0016] As a further aspect of the present invention, the modified solvent-free adhesive is prepared by the following steps:

[0017] Add modified POSS to the acrylate monomer, ultrasonically disperse for 5-10 minutes, then add leveling agent, defoamer, and photoinitiator, and ultrasonically disperse for 5-10 minutes to obtain modified solvent-free adhesive.

[0018] As a further embodiment of the present invention, the mass ratio of the acrylate monomer, modified POSS, leveling agent, defoamer, and photoinitiator is 10-25:30-60:0.1-1:0.5-2:0.5-2.

[0019] As a further embodiment of the present invention, the acrylate monomer is any one of acrylate or methacrylate.

[0020] As a further aspect of the present invention, the modified POSS is prepared by the following steps:

[0021] Under nitrogen protection, deionized water and anhydrous methanol were mixed and heated to 30-40℃. The pH was adjusted to 2-3 with hydrochloric acid. A mixed solution of OTES (octyltriethoxysilane) and KH-570 (γ-methacryloyloxypropyltrimethoxysilane) was added dropwise. After reacting for 24-48 hours, the mixture was allowed to stand and separate into layers. The organic layer was separated and dissolved with hexane. The mixture was washed with water until the pH was neutral. The mixture was allowed to stand and separate into layers. The organic layer was separated and removed by vacuuming. Anhydrous CaCl2 was added to remove residual water to obtain modified POSS.

[0022] The reaction equation is as follows, where -R is -CH2(CH2)6CH3; -X is -(CH2)3OOC(CH3)=CH3:

[0023]

[0024] As a further embodiment of the present invention, the volume ratio of the mixed solution of deionized water, anhydrous methanol, OTES and KH-570 is 15-30:85-150:5-10; the mixed solution of OTES and KH-570 is prepared by mixing OTES and KH-570 in a molar ratio of 7:1.

[0025] As a further embodiment of the present invention, the defoamer is any one of BYK-067A, BYK-088, and BYK-057; the photoinitiator is any one of α-hydroxyketone photoinitiators and acylphosphine oxide photoinitiators; and the leveling agent is any one of BYK-371, BYK-UV3500, BYK-UV3530, and BYK-UV3570.

[0026] A prism composite film is prepared by the above-described preparation method.

[0027] The beneficial effects of this invention are:

[0028] The present invention features a simple process: an upper prism layer and a lower prism layer are bonded together using a modified solvent-free adhesive to obtain a prism composite film. The adhesive layer formed by the modified solvent-free adhesive creates a haze layer, improving the shielding properties of the prism composite film while simultaneously increasing its luminance to meet brightness requirements. The principle is as follows:

[0029] This invention first employs a co-hydrolysis method to co-hydrolyze and condense OTES and KH-570 under acidic conditions, preparing a modified POSS consisting of a core with a fully condensed cage-like structure composed of Si-O-Si and a shell with an active functional group—methacryloyloxypropyl—attached to the Si atom. Then, the modified POSS is further polymerized with a methyl methacrylate prepolymer at 50-90°C using free radical polymerization to form an adhesive layer. The modified POSS is aggregated and connected within the polymer chain segments, while simultaneously being uniformly dispersed within the methyl methacrylate prepolymer structure. The relatively large size of the POSS aggregates creates a uniform haze layer, improving the shielding properties of the prism composite film and effectively increasing the light divergence effect after passing through the upper and lower prism layers, thus enhancing the brightness within the viewing angle and ultimately improving the luminance of the composite film. Detailed Implementation

[0030] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0031] Example 1

[0032] Modified POSS is prepared by the following steps:

[0033] Under nitrogen protection, 15 mL of deionized water and 85 mL of anhydrous methanol were mixed and heated to 30 °C. The pH was adjusted to 2 with hydrochloric acid. 5 mL of a mixed solution of OTES and KH-570 (prepared by mixing OTES and KH-570 in a molar ratio of 7:1) was added dropwise. After reacting for 24 h, the mixture was allowed to stand and separate into layers. The organic layer was separated and dissolved with hexane. The mixture was washed with water until the pH was neutral. The mixture was allowed to stand and separate into layers. The organic layer was separated and removed by vacuuming. Anhydrous CaCl2 was added to remove residual water, yielding modified POSS.

[0034] Example 2

[0035] Modified POSS is prepared by the following steps:

[0036] Under nitrogen protection, 30 mL of deionized water and 150 mL of anhydrous methanol were mixed and heated to 30-40 °C. The pH was adjusted to 3 with hydrochloric acid. 10 mL of a mixed solution of OTES and KH-570 (OTES and KH-570 were prepared by mixing them in a molar ratio of 7:1) was added dropwise. After reacting for 48 h, the mixture was allowed to stand and separate into layers. The organic layer was separated and dissolved with hexane. The mixture was washed with water until the pH was neutral. The mixture was allowed to stand and separate into layers. The organic layer was separated and removed by vacuuming. Anhydrous CaCl2 was added to remove residual water, and modified POSS was obtained.

[0037] Example 3

[0038] The modified solvent-free adhesive is prepared by the following steps:

[0039] Add 30g of the modified POSS prepared in Example 1 to 10g of ethyl acrylate, ultrasonically disperse for 5min, then add 0.1g of leveling agent BYK-371, 0.5g of defoamer BYK-067A, and 0.5g of α-hydroxy ketone photoinitiator Darocure1173 (HMPP), ultrasonically disperse for 5min to obtain the modified solvent-free adhesive.

[0040] Comparative Example 1

[0041] Solvent-free bonding adhesives are prepared using the following steps:

[0042] Add 0.1g of leveling agent BYK-371, 0.5g of defoamer BYK-067A, and 0.5g of α-hydroxy ketone photoinitiator Darocure1173 (HMPP) to 10g of ethyl acrylate, and ultrasonically disperse for 5min to obtain modified solvent-free adhesive.

[0043] Compared with Example 3, this comparative example only omits the addition of "30g of the modified POSS prepared in Example 1", while all other steps and parameters are the same.

[0044] Comparative Example 2

[0045] The modified solvent-free adhesive is prepared by the following steps:

[0046] Add 30g of POSS (methacryloyloxypropyl cage-type polysilsesquioxane) to 10g of ethyl acrylate, and ultrasonically disperse for 5min. Then add 0.1g of leveling agent BYK-371, 0.5g of defoamer BYK-067A, and 0.5g of α-hydroxy ketone photoinitiator Darocure1173 (HMPP), and ultrasonically disperse for 5min to obtain the modified solvent-free adhesive.

[0047] Compared with Example 3, this comparative example only replaces "30g of modified POSS prepared in Example 1" with "30g of POSS", and all other steps and parameters are the same.

[0048] Example 4

[0049] The modified solvent-free adhesive is prepared by the following steps:

[0050] Add 60g of the modified POSS prepared in Example 1 to 25g of methyl methacrylate, ultrasonically disperse for 10min, then add 1g of leveling agent BYK-371, 2g of defoamer BYK-067A, and 2g of acylphosphine oxide photoinitiator phenylbis(2,4,6-trimethylbenzoyl), ultrasonically disperse for 10min to obtain the modified solvent-free adhesive.

[0051] Example 5

[0052] A method for preparing a prism composite thin film includes the following steps:

[0053] Step 1: Cut polyethylene terephthalate into slices, crystallize and dry at 150°C, melt extrude at 260°C, cool with cooling rollers, heat to 80°C, and stretch longitudinally by 3.0 times to obtain a lower substrate layer with a thickness of 50μm, for later use;

[0054] Polyethylene terephthalate was sliced, crystallized and dried at 150°C, then melt-extruded at 260°C, cooled by a cooling roller, heated to 80°C, and stretched longitudinally by 3.0 times to obtain a top substrate layer with a thickness of 50μm, which was then set aside.

[0055] Step 2: Pour the polyurethane acrylic resin into the mold and bond it to the upper surface (glossy surface) of the lower substrate layer, then perform UV curing (UV curing conditions are: UV wavelength of 200nm, power of 2500mw / cm²). 2 (Irradiation time is 10s) to obtain a lower prism layer with a thickness of 27μm. The cross-sections at both ends of the lower prism layer are isosceles right triangles with right angles at the apex. The lower prism layer includes multiple parallel microprism structures of different heights, for later use.

[0056] Step 3: Apply the modified solventless adhesive prepared in Example 3 to the lower surface (light-incident surface) of the upper substrate layer, bond it with the lower prism layer obtained in Step 1, and UV cure to obtain an adhesive layer with a thickness of 6.5 μm.

[0057] Step 3: Pour polyurethane acrylic resin into a mold and bond it to the upper surface (light-emitting surface) of the upper substrate layer of the composite film obtained in Step 2. Then, perform UV curing to obtain an upper prism layer with a thickness of 10.5μm. The upper prism layer is composed of several upper prism pillars. The cross-sections at both ends of the upper prism pillars are isosceles right triangles with right angles at the apex. The prism direction of the upper prism layer forms a 90° angle with the prism direction of the lower prism layer. After quality inspection, if qualified, it is wound up and stored to obtain a prism composite film.

[0058] Comparative Example 3

[0059] A method for preparing a prism composite thin film includes the following steps:

[0060] Step 1: Cut polyethylene terephthalate into slices, crystallize and dry at 150°C, melt extrude at 260°C, cool with cooling rollers, heat to 80°C, and stretch longitudinally by 3.0 times to obtain a lower substrate layer with a thickness of 50μm, for later use;

[0061] Polyethylene terephthalate was sliced, crystallized and dried at 150°C, then melt-extruded at 260°C, cooled by a cooling roller, heated to 80°C, and stretched longitudinally by 3.0 times to obtain a top substrate layer with a thickness of 50μm, which was then set aside.

[0062] Step 2: Pour the polyurethane acrylic resin into the mold and bond it to the upper surface (glossy surface) of the lower substrate layer, then perform UV curing (UV curing conditions are: UV wavelength of 200nm, power of 2500mw / cm²). 2 (Irradiation time is 10s) to obtain a lower prism layer with a thickness of 27μm. The cross-sections at both ends of the lower prism layer are isosceles right triangles with right angles at the apex. The lower prism layer includes multiple parallel microprism structures of different heights, for later use.

[0063] Step 3: Coat the modified solventless adhesive prepared in Comparative Example 1 on the lower surface (light-incident surface) of the upper substrate layer, bond it with the lower prism layer obtained in Step 1, and UV cure to obtain an adhesive layer with a thickness of 6.5 μm.

[0064] Step 3: Pour polyurethane acrylic resin into a mold and bond it to the upper surface (light-emitting surface) of the upper substrate layer of the composite film obtained in Step 2. Then, perform UV curing to obtain an upper prism layer with a thickness of 10.5μm. The upper prism layer is composed of several upper prism pillars. The cross-sections at both ends of the upper prism pillars are isosceles right triangles with right angles at the apex. The prism direction of the upper prism layer forms a 90° angle with the prism direction of the lower prism layer. After quality inspection, if qualified, it is wound up and stored to obtain a prism composite film.

[0065] Compared with Example 3, this comparative example only replaces "the modified solventless adhesive prepared in Example 3" with "the solventless adhesive prepared in Comparative Example 1", and all other steps and parameters are the same.

[0066] Comparative Example 4

[0067] A method for preparing a prism composite thin film includes the following steps:

[0068] Step 1: Cut polyethylene terephthalate into slices, crystallize and dry at 150°C, melt extrude at 260°C, cool with cooling rollers, heat to 80°C, and stretch longitudinally by 3.0 times to obtain a lower substrate layer with a thickness of 50μm, for later use;

[0069] Polyethylene terephthalate was sliced, crystallized and dried at 150°C, then melt-extruded at 260°C, cooled by a cooling roller, heated to 80°C, and stretched longitudinally by 3.0 times to obtain a top substrate layer with a thickness of 50μm, which was then set aside.

[0070] Step 2: Pour the polyurethane acrylic resin into the mold and bond it to the upper surface (glossy surface) of the lower substrate layer, then perform UV curing (UV curing conditions are: UV wavelength of 200nm, power of 2500mw / cm²). 2 (Irradiation time is 10s) to obtain a lower prism layer with a thickness of 27μm. The cross-sections at both ends of the lower prism layer are isosceles right triangles with right angles at the apex. The lower prism layer includes multiple parallel microprism structures of different heights, for later use.

[0071] Step 3: Coat the modified solventless adhesive prepared in Comparative Example 2 on the lower surface (light-incident surface) of the upper substrate layer, bond it with the lower prism layer obtained in Step 1, and UV cure to obtain an adhesive layer with a thickness of 6.5 μm.

[0072] Step 3: Pour polyurethane acrylic resin into a mold and bond it to the upper surface (light-emitting surface) of the upper substrate layer of the composite film obtained in Step 2. Then, perform UV curing to obtain an upper prism layer with a thickness of 10.5μm. The upper prism layer is composed of several upper prism pillars. The cross-sections at both ends of the upper prism pillars are isosceles right triangles with right angles at the apex. The prism direction of the upper prism layer forms a 90° angle with the prism direction of the lower prism layer. After quality inspection, if qualified, it is wound up and stored to obtain a prism composite film.

[0073] Compared with Example 3, this comparative example only replaces "the modified solventless adhesive prepared in Example 3" with "the modified solventless adhesive prepared in Comparative Example 2", and all other steps and parameters are the same.

[0074] Example 6

[0075] A method for preparing a prism composite thin film includes the following steps:

[0076] Step 1: Cut polyethylene terephthalate into slices, crystallize and dry at 150℃, melt extrude at 260-285℃, cool with cooling rollers, heat to 80℃, and stretch longitudinally by 3.0 times to obtain a lower substrate layer with a thickness of 50μm, for later use;

[0077] Polyethylene terephthalate was sliced, crystallized and dried at 180°C, then melt-extruded at 285°C, cooled by a cooling roller, heated to 120°C, and stretched longitudinally by 3.8 times to obtain a top substrate layer with a thickness of 38μm, which was then set aside.

[0078] Step 2: Pour the polyurethane acrylic resin into the mold and bond it to the upper surface (glossy surface) of the lower substrate layer, then perform UV curing (UV curing conditions are: UV wavelength of 500nm, power of 3000mw / cm²). 2 (Irradiation time is 20s) to obtain a lower prism layer with a thickness of 27μm. The cross-sections at both ends of the lower prism layer are isosceles right triangles with right angles at the apex. The lower prism layer includes multiple parallel microprism structures of different heights, for later use.

[0079] Step 3: Apply the modified solventless adhesive prepared in Example 4 to the lower surface (light-incident surface) of the upper substrate layer, bond it with the lower prism layer obtained in Step 1, and UV cure to obtain an adhesive layer with a thickness of 7.5 μm.

[0080] Step 3: Pour polyurethane acrylic resin into a mold and bond it to the upper surface (light-emitting surface) of the upper substrate layer of the composite film obtained in Step 2. Then, perform UV curing to obtain an upper prism layer with a thickness of 10.5μm. The upper prism layer is composed of several upper prism pillars. The cross-sections at both ends of the upper prism pillars are isosceles right triangles with right angles at the apex. The prism direction of the upper prism layer forms a 90° angle with the prism direction of the lower prism layer. After quality inspection, if qualified, it is wound up and stored to obtain a prism composite film.

[0081] Performance tests were conducted on Examples 5-6 and Comparative Examples 3-4:

[0082] (1) Brightness test: Place the film to be tested into a 24-inch backlight module, light up the module with a voltage of 24V, and test the brightness with a luminance meter (model BM-7);

[0083] (2) Haze was tested according to GB / T2410-2008;

[0084] The results are shown in Table 1:

[0085] Table 1

[0086] <![CDATA[Luminance (cd / m 2 )]]> 2462 2267 2478 1779 Haze 42％ 48％ 2％ 33％

[0087] As can be seen from Table 1, the brightness and haze of the prism composite films prepared in Examples 5-6 of the present invention are greater than those of the prism composite films prepared in Comparative Examples 3-4.

[0088] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0089] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a prism composite thin film, characterized in that, Includes the following steps: Step 1: Prepare a lower prism layer on the upper surface of the lower substrate layer for later use; Step 2: Apply modified solvent-free adhesive to the lower surface of the upper substrate layer, bond it to the lower prism layer obtained in Step 1, and UV cure to form an adhesive layer. Step 3: After preparing the upper prism layer on the upper substrate layer of the composite film obtained in Step 2, a quality inspection is carried out. After passing the inspection, the film is wound up and stored to obtain a prism composite film. The modified solvent-free adhesive is prepared by the following steps: Add modified POSS to the acrylate monomer, ultrasonically disperse for 5-10 minutes, then add leveling agent, defoamer, and photoinitiator, and ultrasonically disperse for 5-10 minutes to obtain modified solvent-free adhesive. The modified POSS is prepared by the following steps: Under nitrogen protection, deionized water and anhydrous methanol were mixed and heated to 30-40℃. Hydrochloric acid was added to adjust the pH to 2-3. A mixed solution of OTES and KH-570 was added dropwise. After reacting for 24-48 hours, the mixture was allowed to stand and separate into layers. The organic layer was separated. Hexane was added to dissolve the organic layer. The mixture was washed with water until the pH was neutral. The mixture was allowed to stand and separate into layers. The organic layer was separated. Hexane was removed by vacuuming. Anhydrous CaCl2 was added to remove residual water to obtain modified POSS. The reaction equation is as follows, where -R is -CH2(CH2)6CH3; -X is -(CH2)3OOC(CH3)=CH3: ； The volume ratio of the mixed solution of deionized water, anhydrous methanol, OTES and KH-570 is 15-30:85-150:5-10; the mixed solution of OTES and KH-570 is prepared by mixing OTES and KH-570 at a molar ratio of 7:

1.

2. The method for preparing a prism composite thin film according to claim 1, characterized in that, The upper prism layer has a thickness of 10.5 μm, the upper substrate layer has a thickness of 38-50 μm, the adhesive layer has a thickness of 6.5-7.5 μm, the lower prism layer has a thickness of 27 μm, and the lower substrate layer has a thickness of 38-50 μm.

3. The method for preparing a prism composite thin film according to claim 1, characterized in that, The upper substrate layer and the lower substrate layer are made of polyethylene terephthalate. The lower substrate layer is prepared by the following steps: slicing the material of the lower substrate layer, crystallizing and drying it at 150-180°C, melt-extruding it at 260-285°C, cooling it with a cooling roller, heating it to 80-120°C, and stretching it longitudinally by 3.0-3.8 times to obtain the lower substrate layer. The preparation steps of the upper substrate layer are the same as those of the lower substrate layer.

4. The method for preparing a prism composite thin film according to claim 1, characterized in that, The conditions for UV curing in step two are: the wavelength of the ultraviolet light is 200-500nm, and the power is 2500-3000mw / cm². 2 The irradiation time is 10-20 seconds.

5. The method for preparing a prism composite thin film according to claim 1, characterized in that, The materials of the upper prism layer and the lower prism layer are any one of polyurethane acrylic resin, polyether acrylate, epoxy acrylic resin, and polyester acrylic resin; the lower prism layer is prepared by the following steps: pouring the material of the lower prism layer into a mold and UV curing it to obtain the lower prism layer; the preparation steps of the upper prism layer are the same as those of the lower prism layer.

6. The method for preparing a prism composite thin film according to claim 1, characterized in that, The mass ratio of the acrylate monomer, modified POSS, leveling agent, defoamer, and photoinitiator is 10-25:30-60:0.1-1:0.5-2:0.5-2.

7. A prism composite film, characterized in that, It is prepared by the preparation method according to any one of claims 1-6.

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