A PDLC light control film, a preparation method thereof, and a display device

Abstract

The present application relates to the field of optical materials, and particularly relates to a PDLC light modulation film, a preparation method thereof and a display device. Through the structure and material design of the PDLC film, the present application realizes extremely low on-state light transmittance and extremely strong light scattering ability, thereby completely eliminating the mirror reflection bright spot on the screen surface, and converting the ambient light reflection into uniform and low-brightness diffuse reflection, and significantly improving the visual contrast of the display screen in a bright environment. The high-efficiency heat management function is effectively integrated in the PDLC film, so that the PDLC film can not only perform optical regulation and control, but also actively assist the LED display screen in heat dissipation, and effectively dissipate the internal heat through the enhancement of infrared radiation and the like, thereby reducing the working temperature of the screen and improving the long-term reliability.

Description

Technical Field

[0001] This invention relates to the field of optical materials, and in particular to a PDLC dimming film, its preparation method, and a display device thereof. Background Technology

[0002] As display technology continues to evolve towards higher density and higher dynamic range, small-pitch LED displays have become the core carrier for high-end visual presentation. However, their superior brightness and color performance are facing fundamental challenges in complex lighting environments: the high-gloss encapsulation material on the screen surface creates strong specular reflections, especially when displaying dark content. Bright spots and reflections caused by ambient light on the interface severely damage the optical purity of the image, resulting in an actual visual contrast that is far lower than the screen's theoretical performance specifications. At the same time, the increased driving power in pursuit of higher brightness makes the heat dissipation problem of LED chips increasingly severe. Increased junction temperature not only causes luminous efficacy decay and color drift but is also a key bottleneck restricting the long-term reliability and lifespan of the device. Traditional solutions attempt to address these issues by stacking optical films or strengthening heat dissipation structures, but they often fall into the contradiction of limited functionality, bulky size, or impact on display clarity, making it difficult to meet the needs of next-generation ultra-thin, flexible, and integrated display modules.

[0003] Against this backdrop, electrically controlled dimming materials such as polymer-dispersed liquid crystal (PDLC) films are seen as a potential comprehensive solution. However, conventional PDLC technology is mainly designed around architectural lighting and privacy control, and its light modulation mechanism has significant limitations in meeting display-level optical requirements: on the one hand, its light scattering efficiency in the off state is insufficient, with a transmittance typically higher than 2%, making it unable to effectively block ambient light to achieve a true "black state" display; on the other hand, its function is limited to light intensity regulation, lacking an inherent response to the thermal management needs of LED modules. More importantly, the rigid structure of traditional PDLC based on brittle indium tin oxide (ITO) electrodes cannot adapt to curved and flexible display forms, and the high driving voltage contradicts the energy efficiency goals of display systems. In recent years, although some studies have attempted to incorporate nanomaterials with near-infrared shielding functions (such as cesium tungsten bronze) into PDLC systems to endow them with thermal insulation properties, they often fail to achieve stable and uniform dispersion due to poor compatibility between nanoparticles and organic matrices. Instead, they introduce optical defects and electrical inhomogeneities into the film layer, leading to a decline in overall performance. Therefore, developing a high-performance PDLC composite film that can simultaneously achieve ultimate light control, efficient thermal management, and flexible and reliable characteristics has become an urgent issue to promote the development of LED display technology towards higher environmental adaptability and system integration. Summary of the Invention

[0004] In view of this, the present invention provides a PDLC dimming film, a method for preparing the same, and a display device. The PDLC dimming film provided by the present invention can simultaneously improve contrast and heat dissipation.

[0005] This invention provides a PDLC dimming film, comprising a first flexible transparent conductive substrate, a PDLC functional layer, and a second flexible transparent conductive substrate stacked sequentially.

[0006] The first flexible transparent conductive substrate includes a thin film and a conductive layer laminated on one side surface of the thin film; wherein the conductive layer is in contact with the PDLC functional layer;

[0007] The second flexible transparent conductive substrate includes a thin film and a conductive layer laminated to one side surface of the thin film; wherein the conductive layer is in contact with the PDLC functional layer;

[0008] The PDLC functional layer contains functional materials; the functional materials are formed from raw materials through ultraviolet light polymerization-induced phase separation; the raw materials include the following components (1)-(4):

[0009] (1) Liquid crystal: It accounts for 65.0%~75.0% of the total mass of components (1)-(3);

[0010] (2) Polymerizable monomer mixture: which accounts for 22.0%~30.0% of the total mass of components (1)-(3);

[0011] (3) Surface-functionalized thermal radiation nanomaterials: accounting for 1.0%~5.0% of the total mass of components (1)-(3);

[0012] (4) Photoinitiator: Its addition amount is 0.5%~2.0% of the mass of the polymerizable monomer mixture;

[0013] The polymerizable monomer mixture comprises the following monomers (a)-(b):

[0014] (a) A basic network forming monomer; the basic network forming monomer is a combination of a multifunctional monomer and a monofunctional monomer; the multifunctional monomer is at least one of a multifunctional acrylate and a multifunctional methacrylate; the monofunctional monomer is at least one of a monofunctional acrylate and a monofunctional methacrylate.

[0015] (b) Fluorinated modified monomer; wherein the fluorinated modified monomer is at least one of fluorinated acrylate and fluorinated methacrylate;

[0016] The surface-functionalized thermal radiation nanomaterial is a surface-functionalized hexagonal boron nitride nanosheet; the surface-functionalized hexagonal boron nitride nanosheet is obtained by surface modification of hexagonal boron nitride nanosheet with a silane coupling agent.

[0017] Preferably, the surface-functionalized hexagonal boron nitride nanosheets are prepared by the following method: mixing hexagonal boron nitride nanosheet powder, solvent and silane coupling agent, heating to react, then separating the solid and liquid to collect the solid, washing and drying to obtain surface-functionalized hexagonal boron nitride nanosheets.

[0018] Preferably, the silane coupling agent is a silane coupling agent containing at least one of vinyl, acryloyloxy, or methacryloxy.

[0019] The amount of the silane coupling agent is 3% to 5% of the mass of the hexagonal boron nitride nanosheet powder;

[0020] The heating reaction is performed under the condition of heating to reflux; the heating reaction time is 6-8 hours.

[0021] The heating reaction is carried out in a protective atmosphere.

[0022] Preferably, the multifunctional monomer is 1,4-butanediol diacrylate; the monofunctional monomer is lauryl methacrylate; and the mass ratio of the multifunctional monomer to the monofunctional monomer is 1:(1.2~2.0).

[0023] The fluorinated modified monomer is 1H,1H-pentafluoropropyl methacrylate;

[0024] The mass percentage of fluorinated modified monomers in the polymerizable monomer mixture is 1.0% to 5.0%, with the remainder being the basic network forming monomers.

[0025] Preferably, the liquid crystal is a nematic liquid crystal with a birefringence Δn ≥ 0.22 at 589 nm and 20 °C, and a clearing point ≥ 75 °C;

[0026] The photoinitiator is at least one of benzophenones, α-hydroxy ketones, or acylphosphine oxides as ultraviolet photoinitiators;

[0027] The film is a flexible polymer film;

[0028] The conductive material in the conductive layer is at least one of metal nanowires, metal mesh, conductive polymer, or graphene.

[0029] Preferably, the liquid crystal is a nematic liquid crystal E8;

[0030] The silane coupling agent is γ-(methacryloyloxy)propyltrimethoxysilane;

[0031] The photoinitiator is at least one of Irgacure 651, Irgacure 184, or Darocur 1173;

[0032] The film is a polyethylene terephthalate film, a polycarbonate film, or a cyclic olefin polymer film.

[0033] The conductive material in the conductive layer is silver nanowires;

[0034] The other side surface of the thin film in the first flexible transparent conductive substrate is provided with OCA adhesive, or the other side surface of the thin film in the second flexible transparent conductive substrate is provided with OCA adhesive.

[0035] The present invention also provides a method for preparing the PDLC dimming film described in the above technical solution, comprising the following steps:

[0036] S1. Mix surface-functionalized thermal radiation nanomaterials with a portion of liquid crystal to obtain a nanocomposite liquid crystal paste;

[0037] S2. Mix the nanocomposite liquid crystal paste obtained in step S1 with the remaining liquid crystal, polymerizable monomer mixture and photoinitiator to obtain a prepolymer composition.

[0038] S3. The first flexible transparent conductive substrate and the second flexible transparent conductive substrate are arranged opposite each other to form a cavity and assembled into a liquid crystal cell; the prepolymer composition obtained in step S2 is poured into the cavity of the liquid crystal cell, and then ultraviolet light is used for curing to form a PDLC functional layer to obtain a PDLC dimming film.

[0039] Preferably, the liquid crystal portion accounts for 10% to 20% of the total mass of the liquid crystal;

[0040] In step S1, the mixing method is grinding using a three-roll mill;

[0041] Step S2 specifically includes: mixing the nanocomposite liquid crystal paste obtained in step S1 with the remaining liquid crystal, polymerizable monomer mixture and photoinitiator, and placing the resulting mixture in a shaker for oscillation and mixing to obtain a prepolymer composition;

[0042] Step S3 specifically includes: forming a cavity by placing the first flexible transparent conductive substrate and the second flexible transparent conductive substrate opposite to each other, with the conductive layers in the two flexible transparent conductive substrates facing each other, and using microspheres as spacers between the two flexible transparent conductive substrates to assemble a liquid crystal cell; injecting the prepolymer composition obtained in step S2 into the cavity of the liquid crystal cell by vacuum-assisted capillary filling, and then performing ultraviolet light curing to form a PDLC functional layer to obtain a PDLC dimming film.

[0043] Preferably, the temperature of the shaker is 45±2℃; the rotation speed of the shaker is 200±10rpm; and the oscillation time is 1~1.5h.

[0044] The microspheres are PMMA microspheres; the diameter of the microspheres is 20±1μm;

[0045] The conditions for UV curing are as follows: prepolymerization is performed under a first light intensity, and then curing is performed under a second light intensity; wherein, the first light intensity is 3~8 mW / cm², and the prepolymerization time is 2~5 min; the second light intensity is 10~15 mW / cm², and the curing time is 8~12 min.

[0046] The present invention also provides a display device, including the PDLC dimming film described in the above technical solution or the PDLC dimming film prepared by the preparation method described in the above technical solution.

[0047] This invention provides a flexible PDLC dimming film integrating high-contrast optical control and active heat dissipation, which solves the problems of decreased contrast due to surface reflection in bright environments and reliability issues caused by chip heat in existing LED displays. Specifically, through the structural and material design of the PDLC film, extremely low off-state transmittance and extremely strong light scattering capability are achieved, thereby completely eliminating specular reflection bright spots on the screen surface and converting ambient light reflection into uniform, low-brightness diffuse reflection, significantly improving the visual contrast of the display in bright environments. The PDLC film effectively integrates efficient thermal management functions, enabling it not only to perform optical control but also to actively assist in heat dissipation of the LED display. By enhancing infrared radiation and other methods, internal heat is effectively dissipated, thereby reducing the screen's operating temperature and improving long-term reliability. It ensures that the aforementioned functional nanomaterials (such as high-infrared-radiation materials) are stably and uniformly dispersed in the organic matrix of the PDLC over a long period, avoiding optical defects, electrical performance degradation, or functional failure caused by agglomeration, and guaranteeing the uniformity and stability of the film layer performance.

[0048] The test results show that the off-state transmittance of the PDLC dimming film of the present invention is below 0.51%, the contrast ratio is above 153 times, and the surface temperature of the display screen is below 41.5℃, thus combining high contrast and high heat dissipation effect. Attached Figure Description

[0049] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0050] Figure 1 This is a schematic diagram of the structure of the PDLC dimming film provided by the present invention;

[0051] Figure 2This is a schematic diagram of the surface modification process of hexagonal boron nitride nanosheets;

[0052] Figure 3 This is a schematic diagram of the structure of an LED display. Detailed Implementation

[0053] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0054] In this article, the technical features described in an open-ended manner include both closed technical solutions composed of the listed features and open technical solutions that include the listed features.

[0055] The term “and / or” as used herein includes any and all combinations of one or more of the related listed items.

[0056] In this document, numerical ranges are referred to as continuous unless otherwise specified, and include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when a range refers to an integer, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0057] In this article, when referring to units for data ranges, if the unit is only followed by the right endpoint, it means that the units for the left and right endpoints are the same. For example, 100~125μm means that the units for the left endpoint "100" and the right endpoint "125" are both μm.

[0058] [First aspect]: The present invention provides a PDLC dimming film, comprising a first flexible transparent conductive substrate, a PDLC functional layer and a second flexible transparent conductive substrate stacked sequentially;

[0059] The first flexible transparent conductive substrate includes a thin film and a conductive layer laminated on one side surface of the thin film; wherein the conductive layer is in contact with the PDLC functional layer;

[0060] The second flexible transparent conductive substrate includes a thin film and a conductive layer laminated to one side surface of the thin film; wherein the conductive layer is in contact with the PDLC functional layer;

[0061] The PDLC functional layer contains functional materials; the functional materials are formed from raw materials through ultraviolet light polymerization-induced phase separation; the raw materials include the following components (1)-(4):

[0062] (1) Liquid crystal: It accounts for 65.0%~75.0% of the total mass of components (1)-(3);

[0063] (2) Polymerizable monomer mixture: which accounts for 22.0%~30.0% of the total mass of components (1)-(3);

[0064] (3) Surface-functionalized thermal radiation nanomaterials: accounting for 1.0%~5.0% of the total mass of components (1)-(3);

[0065] (4) Photoinitiator: Its addition amount is 0.5%~2.0% of the mass of the polymerizable monomer mixture;

[0066] The polymerizable monomer mixture comprises the following monomers (a)-(b):

[0067] (a) A basic network forming monomer; the basic network forming monomer is a combination of a multifunctional monomer and a monofunctional monomer; the multifunctional monomer is at least one of a multifunctional acrylate and a multifunctional methacrylate; the monofunctional monomer is at least one of a monofunctional acrylate and a monofunctional methacrylate.

[0068] (b) Fluorinated modified monomer; wherein the fluorinated modified monomer is at least one of fluorinated acrylate and fluorinated methacrylate;

[0069] The surface-functionalized thermal radiation nanomaterial is a surface-functionalized hexagonal boron nitride nanosheet; the surface-functionalized hexagonal boron nitride nanosheet is obtained by surface modification of hexagonal boron nitride nanosheet with a silane coupling agent.

[0070] See Figure 1 , Figure 1 This is a schematic diagram of the PDLC dimming film provided by the present invention. In the diagram, 1 is a thin film, 2 is a conductive layer, 3 is a PDLC functional layer, 4 is a conductive layer, and 5 is a thin film; 1-2 are combined to form a first flexible transparent conductive substrate, and 4-5 are combined to form a second flexible transparent conductive substrate. That is, the first flexible transparent conductive substrate and the second flexible transparent conductive substrate are disposed opposite to each other, with the PDLC functional layer disposed between them.

[0071] Regarding the first flexible transparent conductive substrate :

[0072] According to the present invention, the first flexible transparent conductive substrate includes a thin film and a conductive layer composited on one side surface of the thin film.

[0073] In this invention, the film is a flexible polymer film, preferably a polyethylene terephthalate (PET) film, a polycarbonate film, or a cyclic olefin polymer film, more preferably a PET film. In this invention, the thickness of the film is preferably 100-125 μm.

[0074] In this invention, the conductive layer is a transparent conductive layer. The conductive material in the conductive layer is preferably at least one of metal nanowires, metal mesh, conductive polymer, or graphene, more preferably metal nanowires. The metal nanowires are preferably silver nanowires (Ag NWs), meaning the conductive layer is preferably a silver nanowire layer. Taking silver nanowires as an example, the conductive layer is preferably formed by the following method: dispersing silver nanowires in an organic solvent to form a dispersion; coating the dispersion onto the surface of the film and drying to form the conductive layer. During the preparation of the dispersion, a dispersant is preferably added to assist dispersion; the dispersant is preferably a polymeric dispersant, more preferably at least one of polyvinylpyrrolidone or hydroxypropyl methylcellulose. In this invention, the thickness of the conductive layer is preferably 100-200 nm.

[0075] Regarding the second flexible transparent conductive substrate :

[0076] According to the present invention, the second flexible transparent conductive substrate includes a thin film and a conductive layer composited on one side surface of the thin film.

[0077] The selection range for the thin film and conductive layer is the same as that for the first flexible transparent conductive substrate described above, as follows:

[0078] In this invention, the film is a flexible polymer film, preferably a polyethylene terephthalate (PET) film, a polycarbonate film, or a cyclic olefin polymer film, more preferably a PET film. In this invention, the thickness of the film is preferably 100-125 μm.

[0079] In this invention, the conductive layer is a transparent conductive layer. The conductive material in the conductive layer is preferably at least one of metal nanowires, metal mesh, conductive polymer, or graphene, more preferably metal nanowires. Specifically, the metal nanowires are preferably silver nanowires (Ag NWs), meaning the conductive layer is preferably a silver nanowire layer. In this invention, the thickness of the conductive layer is preferably 100-200 nm, more preferably the same as the thickness of the conductive layer in the first flexible transparent conductive substrate.

[0080] Regarding the PDLC functional layer (i.e., polymer-dispersed liquid crystal functional layer) :

[0081] According to the present invention, the PDLC functional layer comprises a functional material; the functional material is formed by ultraviolet light polymerization-induced phase separation of raw materials; the raw materials comprise the following components (1)-(4):

[0082] (1) Liquid crystal: It accounts for 65.0%~75.0% of the total mass of components (1)-(3);

[0083] (2) Polymerizable monomer mixture: which accounts for 22.0%~30.0% of the total mass of components (1)-(3);

[0084] (3) Surface-functionalized thermal radiation nanomaterials: accounting for 1.0%~5.0% of the total mass of components (1)-(3);

[0085] (4) Photoinitiator: The amount of photoinitiator added is 0.5% to 2.0% of the mass of the polymerizable monomer mixture.

[0086] [About LCD]:

[0087] In this invention, the liquid crystal is preferably a nematic liquid crystal with a birefringence Δn ≥ 0.22 at 589 nm and 20 °C, and a clearing point ≥ 75 °C. The liquid crystal is selected from at least one of E-type nematic liquid crystal, TL-type nematic liquid crystal, HTG-type nematic liquid crystal, or SLC-type nematic liquid crystal, more preferably an E-type nematic liquid crystal, and even more preferably a nematic liquid crystal E8.

[0088] In this invention, the liquid crystal accounts for 68.0% to 72.0% of the total mass of components (1)-(3), specifically 68.0%, 69.0%, 70.0%, 71.0%, and 72.0%.

[0089] [Regarding polymerizable monomer mixtures]:

[0090] In this invention, the polymerizable monomer mixture comprises the following monomers (a)-(b): (a) a basic network-forming monomer; and (b) a fluorinated modified monomer.

[0091] (a) Basic network forms a single unit:

[0092] In this invention, the basic network forming monomer is a combination of multifunctional monomers and monofunctional monomers. The multifunctional monomer is at least one of multifunctional acrylates and multifunctional methacrylates, preferably 1,4-butanediol diacrylate (BDDA). The monofunctional monomer is at least one of monofunctional acrylates and monofunctional methacrylates, preferably lauryl methacrylate (LMA). In this invention, the mass ratio of the multifunctional monomer to the monofunctional monomer is preferably 1:(1.2~2.0), specifically 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9, 1:2.0, and more preferably 1:(1.4±1.6).

[0093] (b) Fluorinated modified monomers:

[0094] In this invention, the fluorinated modified monomer is at least one of fluorinated acrylate and fluorinated methacrylate, preferably 1H,1H-pentafluoropropyl methacrylate (PFPMA).

[0095] In this invention, preferably, the fluorinated modified monomer accounts for 1.0% to 5.0% by mass in the polymerizable monomer mixture, with the remainder being the basic network-forming monomer. Specifically, the content of the fluorinated modified monomer can be 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%, 4.5%, or 5.0%, more preferably 1.5% to 2.5%.

[0096] In this invention, the polymerizable monomer mixture accounts for 27.0% to 30.0% of the total mass of components (1)-(3), specifically 27.0%, 28.0%, 29.0%, and 30.0%.

[0097] [Regarding surface-functionalized thermal radiation nanomaterials]:

[0098] In this invention, the surface-functionalized thermal radiation nanomaterial is a surface-functionalized hexagonal boron nitride nanosheet (f-BNNS); the surface-functionalized hexagonal boron nitride nanosheet is obtained by surface modification of hexagonal boron nitride nanosheet (h-BNNS) with a silane coupling agent. Preferably, the silane coupling agent contains at least one of vinyl, acryloyloxy, or methacryloyloxy, more preferably γ-(methacryloyloxy)propyltrimethoxysilane (KH-570).

[0099] In this invention, the surface-functionalized hexagonal boron nitride nanosheets are preferably prepared by the following method: mixing hexagonal boron nitride nanosheet powder, solvent, and silane coupling agent, heating to react, then separating the solid and liquid to collect the solid, washing, and drying to obtain surface-functionalized hexagonal boron nitride nanosheets. More specifically, dispersing hexagonal boron nitride nanosheet powder in a solvent to obtain a suspension; then mixing the suspension with a silane coupling agent, heating to react, then separating the solid and liquid to collect the solid, washing, and drying to obtain surface-functionalized hexagonal boron nitride nanosheets.

[0100] The average lateral dimension of the hexagonal boron nitride nanosheets (h-BNNS) powder is 100-300 nm, preferably 150-250 nm, and the average thickness is less than 5 nm.

[0101] The solvent is preferably an organic solvent, more preferably at least one selected from toluene, xylene, ethanol, isopropanol, acetone, butanone, or tetrahydrofuran, and most preferably toluene. The organic solvent is preferably an anhydrous solvent.

[0102] The preferred amount of the silane coupling agent is 3% to 5% of the mass of the hexagonal boron nitride nanosheet powder, specifically 3%, 4%, or 5%.

[0103] The heating reaction is preferably carried out in a protective atmosphere. The present invention does not have any particular limitation on the type of gas providing the protective atmosphere; any conventional protective gas in the art is acceptable, such as nitrogen or argon, with nitrogen being more preferred. The heating reaction conditions are heating to reflux; the heating reaction time is preferably 6-8 hours, specifically 6 hours, 7 hours, or 8 hours.

[0104] The preferred method for solid-liquid separation is centrifugation. The preferred method for drying is vacuum drying.

[0105] In this invention, the surface of the obtained surface-functionalized hexagonal boron nitride nanosheets is grafted with organic functional groups containing polymerizable double bonds.

[0106] In this invention, the surface-functionalized thermal radiation nanomaterial accounts for 1.0% to 2.0% of the total mass of components (1)-(3), specifically 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, and 2.0%.

[0107] Taking the silane coupling agent KH-570 as an example, the surface modification process of hexagonal boron nitride nanosheets is as follows: Figure 2 As shown.

[0108] [Regarding photoinitiators]:

[0109] In this invention, the photoinitiator is preferably at least one of benzophenones, α-hydroxy ketones, or acylphosphine oxides as ultraviolet photoinitiators, more preferably at least one of Irgacure 651, Irgacure 184, or Darocur 1173.

[0110] In this invention, the amount of photoinitiator added is 0.5% to 2.0% of the total mass of the polymerizable monomer mixture, specifically 0.5%, 1.0%, 1.5%, or 2.0%.

[0111] In this invention, the functional materials in the PDLC functional layer are formed from the above raw materials through ultraviolet light-induced polymerization and phase separation. The formed functional materials include a polymer network, liquid crystal microdroplets dispersed in the polymer network, and surface-functionalized thermal radiation nanomaterials dispersed in the layer.

[0112] In this invention, in addition to the functional materials mentioned above, the PDLC functional layer also includes spacer microspheres. The liquid crystal spacer microspheres serve as "spacers" in the liquid crystal cell, undertaking the tasks of separating and supporting the liquid crystal layer and controlling the thickness of the liquid crystal cell. In this invention, the microspheres are preferably polymer microspheres, more preferably PMMA microspheres (polymethyl methacrylate microspheres). In this invention, the diameter of the microspheres is preferably 20 ± 1 μm, more preferably 20 μm.

[0113] In this invention, the thickness of the PDLC functional layer is preferably 20±1μm.

[0114] In this invention, preferably, an OCA adhesive is disposed on the other side surface of the thin film in the first flexible transparent conductive substrate, or an OCA adhesive is disposed on the other side surface of the thin film in the second flexible transparent conductive substrate. The OCA adhesive allows the film to be adhered to the surface of the LED module.

[0115] [Second aspect]: This invention provides a method for preparing the PDLC dimming film described in the above technical solution, comprising the following steps:

[0116] S1. Mix surface-functionalized thermal radiation nanomaterials with a portion of liquid crystal to obtain a nanocomposite liquid crystal paste;

[0117] S2. Mix the nanocomposite liquid crystal paste obtained in step S1 with the remaining liquid crystal, polymerizable monomer mixture and photoinitiator to obtain a prepolymer composition.

[0118] S3. The first flexible transparent conductive substrate and the second flexible transparent conductive substrate are arranged opposite each other to form a cavity and assembled into a liquid crystal cell; the prepolymer composition obtained in step S2 is poured into the cavity of the liquid crystal cell, and then ultraviolet light is used for curing to form a PDLC functional layer to obtain a PDLC dimming film.

[0119] The types, amounts, and structural relationships of the surface-functionalized thermal radiation nanomaterials, liquid crystals, polymerizable monomer mixtures, photoinitiators, first flexible transparent conductive substrates, and second flexible transparent conductive substrates are all consistent with those described in the preceding technical solutions, and will not be repeated here.

[0120] In this invention, steps that are sequentially related are performed in that order, while steps that are not sequentially related have no special restrictions on their order. "Steps without sequential relationship" refers to steps that do not necessarily have a sequential order. For example, in steps S1 and S2, step S2 uses the nanocomposite liquid crystal paste obtained in step S1; therefore, step S1 must be performed before step S2, meaning they are sequentially related and must be performed in that order. Similarly, the assembly of the empty liquid crystal cell in steps S2 and S3 is not sequentially related, therefore, their order is not specially restricted; the same applies to other operational procedures, and will not be listed individually.

[0121] Regarding step S1 :

[0122] S1. Surface-functionalized thermal radiation nanomaterials are mixed with a portion of liquid crystal to obtain a nanocomposite liquid crystal paste.

[0123] In this invention, the liquid crystal portion accounts for 10% to 20% of the total mass of the liquid crystal, specifically 10%, 15%, or 20%.

[0124] In this invention, the preferred method for mixing surface-functionalized thermal radiation nanomaterials with a portion of liquid crystal is grinding using a three-roll mill. This method utilizes high shear force to achieve physical dispersion of the nanosheets and leverages the compatibility between the surface organic functional groups and the liquid crystal to achieve stability. In this invention, the preferred operating temperature for the grinding process using the three-roll mill is 15~25℃, i.e., grinding is performed under cooling conditions. Through this grinding process, a uniform, fine slurry without noticeable particle texture is formed, namely, a nanocomposite liquid crystal slurry.

[0125] Regarding step S2 :

[0126] S2. The nanocomposite liquid crystal paste obtained in step S1 is mixed with the remaining liquid crystal, polymerizable monomer mixture and photoinitiator to obtain a prepolymer composition.

[0127] In this invention, the above steps preferably include: mixing the nanocomposite liquid crystal slurry obtained in step S1 with the remaining liquid crystal, the polymerizable monomer mixture, and the photoinitiator; placing the resulting mixture in a shaker for oscillation and mixing to obtain a prepolymer composition. The shaker is preferably a constant-temperature shaker. The temperature of the shaker is preferably 45±2℃. The rotation speed of the shaker is preferably 200±10 rpm, more preferably 200 rpm. The oscillation time is preferably 1~1.5h, specifically 1h or 1.5h. After the above treatment, a uniform and transparent prepolymer composition is obtained.

[0128] Regarding step S3 :

[0129] S3. The first flexible transparent conductive substrate and the second flexible transparent conductive substrate are arranged opposite each other to form a cavity and assembled into a liquid crystal cell; the prepolymer composition obtained in step S2 is poured into the cavity of the liquid crystal cell, and then ultraviolet light is used for curing to form a PDLC functional layer to obtain a PDLC dimming film.

[0130] In this invention, preferably, a cavity is formed by arranging the first flexible transparent conductive substrate and the second flexible transparent conductive substrate opposite to each other, with the conductive layers in the two flexible transparent conductive substrates facing each other (i.e., the two conductive layers are arranged face-to-face, both facing the interior of the cavity), and assembled into a liquid crystal cell. More preferably, a cavity is formed by arranging the first flexible transparent conductive substrate and the second flexible transparent conductive substrate opposite to each other, with the conductive layers in the two flexible transparent conductive substrates facing each other, and microspheres are used as spacers between the two flexible transparent conductive substrates, and assembled into a liquid crystal cell. The liquid crystal spacer microspheres are used as "spacers" in the liquid crystal cell, undertaking the tasks of separating and supporting the liquid crystal layers and controlling the thickness of the liquid crystal cell. In this invention, the microspheres are preferably polymer microspheres, more preferably PMMA microspheres (polymethyl methacrylate microspheres). In this invention, the diameter of the microspheres is preferably 20±1μm, more preferably 20μm.

[0131] In this invention, the prepolymer composition obtained in step S2 is injected into the cavity of the liquid crystal cell. Preferably, the prepolymer composition obtained in step S2 is injected into the cavity of the liquid crystal cell by vacuum-assisted capillary filling.

[0132] In this invention, the filled liquid crystal cell is cured by ultraviolet light. Preferably, the ultraviolet curing is performed in a protective atmosphere. This invention does not have any particular limitation on the type of gas providing the protective atmosphere; any conventional protective gas in the art is acceptable, such as nitrogen or argon, with nitrogen being more preferred. Preferably, the UV light source used for ultraviolet curing is a 365nm light source. The ultraviolet curing conditions are as follows: prepolymerization is performed at a first light intensity, followed by curing at a second light intensity. The first light intensity is preferably 3~8 mW / cm², specifically 3mW / cm², 4mW / cm², 5mW / cm², 6mW / cm², 7mW / cm², or 8mW / cm², with 5mW / cm² being more preferred. The prepolymerization time is preferably 2~5 min, specifically 2 min, 3 min, 4 min, or 5 min, with 3 min being more preferred. The second light intensity is preferably 10~15 mW / cm², specifically 10mW / cm², 11mW / cm², 12mW / cm², 13mW / cm², 14mW / cm², or 15mW / cm², more preferably 12mW / cm². The curing time is preferably 8~12 min, specifically 8 min, 9 min, 10 min, 11 min, or 12 min, more preferably 10 min. Through the above ultraviolet light curing, the ultraviolet light-induced polymerization reaction and phase separation process are completed, ultimately yielding the composite functional dimming film of the present invention.

[0133] [Third aspect]: The present invention also provides a display device, including the PDLC dimming film described in the foregoing technical solution.

[0134] In this invention, preferably, the display device is an LED display. In the LED display, the PDLC dimming film is attached to the light-emitting surface of the LED display screen via an optical adhesive (OCA) layer. In this invention, other components and structures of the LED display are not particularly limited and can be conventional structures in the art, such as… Figure 3 As shown, 1 is the control unit, 2 is the driver IC, 3 is the PCB substrate, 4 is the LED bead, 5 is the encapsulation layer, and 6 is the PDLC dimming film.

[0135] The high-contrast heat-dissipating PDLC dimming film provided by this invention brings multiple significant benefits to LED displays through synergistic innovation in material system and structural process. Firstly, in terms of optical performance, this film utilizes a strong scattering system formed by high birefringence liquid crystal and optimized polymer network, combined with the auxiliary scattering of surface-functionalized boron nitride nanosheets (f-BNNS), to achieve extremely low off-state transmittance. This characteristic enables it to almost completely eliminate specular reflection on the display surface, converting ambient light into uniform, soft, low-brightness diffuse reflection, thereby significantly improving the visual contrast of the display in bright environments without sacrificing image clarity.

[0136] Secondly, regarding thermal management, this invention creatively stabilizes f-BNNS, which has high infrared emissivity, within a polymer network via covalent bonds. This structure not only solves the problems of uneven dispersion and easy aggregation of nanomaterials in organic systems, but also makes the PDLC film itself a highly efficient infrared radiation heat dissipation surface. When attached to the screen surface, the film layer can actively and efficiently radiate the absorbed heat to the external environment in the form of mid- and far-infrared (8-13μm) electromagnetic waves, thereby effectively reducing the internal operating temperature of the LED display, delaying chip light decay, and improving the long-term reliability and service life of the system.

[0137] Furthermore, this invention optimizes the polymer matrix by introducing fluorinated monomers (PFPMA) and synergizes with highly conductive silver nanowires (Ag NWs) flexible electrodes, achieving stable operation at low driving voltages (saturation voltage below 15V) and reducing system power consumption. The entire device is constructed on a flexible substrate, exhibiting excellent bending resistance and perfectly adapting to innovative form factors such as curved and flexible screens. Ultimately, this invention provides a three-in-one solution for LED displays, integrating a high-contrast optical front cover, an active heat dissipation layer, and a flexible protective interface, all in the form of a single thin film, offering significant integration advantages and broad application prospects.

[0138] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims of the present invention.

[0139] Example 1

[0140] 1. Preparation of surface-functionalized boron nitride nanosheets (f-BNNS)

[0141] 1.50 g of h-BNNS powder was dispersed in 150 mL of anhydrous toluene and ultrasonically dispersed for 30 min under ice-water bath assisted to obtain a preliminary dispersion suspension. This suspension was transferred to a three-necked flask equipped with a reflux condenser and a nitrogen inlet tube. Under continuous nitrogen purging, silane coupling agent KH-570 (4% of the mass of the h-BNNS powder) was added. The reaction system was heated to 80 ± 2 °C and stirred under reflux for 7.0 h. After the reaction was complete, the mixture was allowed to cool naturally to room temperature. The reaction solution was transferred to a centrifuge tube and centrifuged at 8000 rpm for 10 min to collect the solid. The solid was washed three times each with anhydrous toluene and anhydrous ethanol to thoroughly remove unreacted silane coupling agent and byproducts. The washed solid was placed in a vacuum drying oven and dried at 60 °C for 12 h to obtain f-BNNS powder with methacryloxy functional groups grafted onto its surface.

[0142] The hexagonal boron nitride nanosheets (h-BNNS) powder used have an average lateral dimension of 150-250 nm and an average thickness of less than 5 nm.

[0143] 2. Raw materials for liquid crystal functional materials in the PDLC functional layer

[0144] (1) Liquid crystal: 70.00g, which accounts for 74.1% of the total mass of components (1)-(3);

[0145] The type is: Nematic liquid crystal E8, with a clearing point of 85℃ and a birefringence (Δn) of 0.23 at a wavelength of 589nm and a temperature of 20℃.

[0146] (2) Polymerizable monomer mixture: 22.95g, which accounts for 24.3% of the total mass of components (1)-(3);

[0147] Specifically, this includes (a)-(b):

[0148] (a) Basic network-forming monomers: 1,4-butanediol diacrylate (BDDA) and lauryl methacrylate (LMA); BDDA:LMA mass ratio = 1:1.5. The basic network-forming monomers constitute 98.0% of the polymerizable monomer mixture by mass.

[0149] (b) Fluorinated modified monomer: 1H,1H-pentafluoropropyl methacrylate (PFPMA). The fluorinated modified monomer accounts for 2.0% by mass of the polymerizable monomer mixture.

[0150] (3) Surface functionalized thermal radiation nanomaterials: 1.5g, which accounts for 1.6% of the total mass of components (1)-(3).

[0151] The type is: surface-functionalized boron nitride nanosheets (f-BNNS) obtained by the preparation method described in item 1 above.

[0152] (4) Photoinitiator: 0.344 g, the amount of which is 1.5% of the mass of the polymerizable monomer mixture. The type is Irgacure 651.

[0153] 3. Substrate and spacers

[0154] Substrate: Two polyethylene terephthalate (PET) films coated with a silver nanowire (Ag NWs) conductive layer, with a sheet resistance of 22±3 Ω / □ and a visible light transmittance of greater than 80% at 550 nm. The PET film thickness is 100 μm, and the silver nanowire conductive layer thickness is 150 nm.

[0155] Spacer: Monodisperse polymethyl methacrylate (PMMA) microspheres with an average diameter of 20.0 ± 0.5 μm.

[0156] 4. Preparation of PDLC dimming film

[0157] S1: The surface-functionalized thermal radiation nanomaterials and a portion of liquid crystal (accounting for 15% of the total mass of the liquid crystal) are placed in a three-roll mill for grinding until a uniform color, fine texture, paste-like consistency, and no visible particles / agglomerates are obtained when spread on a glass plate, i.e., nanocomposite liquid crystal paste.

[0158] S2: Under light-protected conditions, the nanocomposite liquid crystal slurry obtained in step S2, the remaining liquid crystal, the polymerizable monomer mixture, and the photoinitiator are sequentially added to a clean brown glass container. After sealing the container, it is placed in a constant-temperature air shaker at 45±1℃ and continuously shaken and mixed at a speed of 200 rpm for 60 min to obtain a homogeneous and transparent prepolymer composition.

[0159] S3: Using a high-precision coating device, two Ag NWs / PET substrates (conductive side facing inward) are assembled into a standard liquid crystal test cell using PMMA microspheres as spacers. Then, using vacuum-assisted capillary filling technology, the prepolymer composition obtained in step S2 is injected into the above-mentioned empty cell. The fully filled liquid crystal cell is quickly transferred to an ultraviolet curing chamber filled with high-purity nitrogen. Prepolymerization is first performed for 3 minutes using a 365nm light source (5mW / cm²), and then the curing time is increased to 12mW / cm² for 10 minutes to complete the ultraviolet light-induced polymerization reaction and phase separation process, ultimately obtaining a composite functional dimming film, namely a PDLC dimming film.

[0160] Example 2

[0161] 1. Preparation of surface-functionalized boron nitride nanosheets (f-BNNS): Same as step 1 in Example 1.

[0162] 2. Raw materials for liquid crystal functional materials in the PDLC functional layer

[0163] (1) Liquid crystal: 68.00g, which accounts for 70.8% of the total mass of components (1)-(3);

[0164] The type is: Nematic liquid crystal E8, with a clearing point of 85℃ and a birefringence (Δn) of 0.23 at a wavelength of 589nm and a temperature of 20℃.

[0165] (2) Polymerizable monomer mixture: 26.00g, which accounts for 27.1% of the total mass of components (1)-(3);

[0166] Specifically, this includes (a)-(b):

[0167] (a) Basic network-forming monomers: 1,4-butanediol diacrylate (BDDA) and lauryl methacrylate (LMA); BDDA:LMA mass ratio = 1:1.5. The basic network-forming monomers constitute 98.0% of the polymerizable monomer mixture by mass.

[0168] (b) Fluorinated modified monomer: 1H,1H-pentafluoropropyl methacrylate (PFPMA). The fluorinated modified monomer accounts for 2.0% by mass of the polymerizable monomer mixture.

[0169] (3) Surface-functionalized thermal radiation nanomaterials: 2.00g, which accounts for 2.1% of the total mass of components (1)-(3);

[0170] The type is: surface-functionalized boron nitride nanosheets (f-BNNS) obtained by the preparation method described in item 1 above.

[0171] (4) Photoinitiator: 0.39g, the amount of which is 1.5% of the mass of the polymerizable monomer mixture. The type is Irgacure 651.

[0172] 3. Substrate and spacers

[0173] Substrate: Two PET films with a silver nanowire (Ag NWs) conductive layer coated on the surface, with a sheet resistance of 22±3Ω / □, a visible light transmittance of more than 80% at 550nm, a PET film thickness of 100μm, and a silver nanowire conductive layer thickness of 150nm.

[0174] Spacer: Monodisperse polymethyl methacrylate (PMMA) microspheres with an average diameter of 20.0 ± 0.5 μm.

[0175] 4. Preparation of PDLC dimming film

[0176] S1: The surface-functionalized thermal radiation nanomaterials and a portion of liquid crystal (accounting for 15% of the total mass of the liquid crystal) are placed in a three-roll mill for grinding until a uniform color, fine texture, paste-like consistency, and no visible particles / agglomerates are obtained when spread on a glass plate, i.e., nanocomposite liquid crystal paste.

[0177] S2: Under light-protected conditions, the nanocomposite liquid crystal slurry obtained in step S1, the remaining liquid crystal, the polymerizable monomer mixture, and the photoinitiator are sequentially added to a clean brown glass container. After sealing the container, it is placed in a constant temperature air shaker at 45±1℃ and continuously shaken and mixed at a speed of 200 rpm for 60 min to obtain a homogeneous and transparent prepolymer composition.

[0178] S3: Using high-precision coating equipment, two Ag NWs / PET substrates are assembled into a standard liquid crystal test cell using PMMA microspheres as spacers. Then, using vacuum-assisted capillary filling technology, the prepolymer composition obtained in step S2 is injected into the above-mentioned empty cell. The fully filled liquid crystal cell is quickly transferred to a UV curing chamber filled with high-purity nitrogen. Prepolymerization is first performed for 3 minutes using a 365nm light source (5mW / cm²), and then cured for 10 minutes at 12mW / cm² to complete the UV-induced polymerization reaction and phase separation process, ultimately obtaining a composite functional dimming film, namely a PDLC dimming film.

[0179] Comparative Example 1

[0180] The process was carried out according to Example 1, except that surface-functionalized boron nitride nanosheets (f-BNNS) powder was not added during the preparation of the PDLC dimming film. The types and amounts of other raw materials were the same as in Example 1 (for example, the liquid crystal in Example 1 was 70.00g, and the same was true in Comparative Example 1; the polymerizable monomer mixture in Example 1 was 22.95g, and the same was true in Comparative Example 1; and so on).

[0181] The specific process is as follows:

[0182] K1: Under light-protected conditions, add all liquid crystals, the polymerizable monomer mixture, and the photoinitiator sequentially into a clean brown glass container. After sealing the container, place it in a constant-temperature air shaker at 45±1℃ and continuously shake and mix at 200 rpm for 60 minutes to obtain a homogeneous and transparent prepolymer composition.

[0183] K2: Same as step S3 in Example 1.

[0184] Comparative Example 2

[0185] The procedure was carried out in accordance with Example 1, except that in the preparation of the PDLC dimming film, the surface-functionalized boron nitride nanosheets (f-BNNS) powder was replaced with unmodified hexagonal boron nitride nanosheets (h-BNNS) powder, while all other aspects were the same as in Example 1.

[0186] Comparative Example 3

[0187] The implementation was carried out in accordance with Example 1, except that the fluorinated modified monomer was replaced with the basic network forming monomer (i.e., all polymerizable monomers of component (2) were basic network forming monomers), and everything else was the same as in Example 1.

[0188] Performance testing :

[0189] Various performance tests were performed on each embodiment and comparative example, and the results are shown in Table 1.

[0190] Table 1: Test Results of Each Example and Comparative Product

[0191]

[0192] Note: The off-state transmittance refers to the transmittance measured when a 0V voltage is applied between the two electrodes of the PDLC dimming film; the on-state transmittance refers to the transmittance measured when a 15V voltage is applied between the two electrodes of the PDLC dimming film. Contrast Ratio: The ratio of on-state transmittance to off-state transmittance is used to characterize the light modulation capability of the film material itself. When this film is attached to the surface of an LED display screen, its off-state shielding capability and on-state transmittance work synergistically to improve the visual contrast of the display screen under ambient light. Display Screen Surface Temperature: The PDLC dimming film is attached to the surface of the LED module with OCA adhesive. After continuous operation at the same ambient temperature (25±5℃) and the same brightness for 60 minutes, the surface temperature of the film layer is measured using an infrared thermal imager.

[0193] As shown in Table 1, the off-state transmittance of the product in this embodiment is below 0.51%, the contrast ratio is above 153 times, and the surface temperature of the display screen is below 41.5℃, exhibiting both high contrast and high heat dissipation. In contrast, Comparative Examples 1-6 show poorer contrast and heat dissipation. Specifically, the deterioration in Comparative Example 1 demonstrates that the introduction of surface-functionalized boron nitride nanosheets (f-BNNS) powder in this invention effectively improves the contrast and heat dissipation of the PDLC dimming film. The deterioration in Comparative Example 2 demonstrates that the surface modification of hexagonal boron nitride nanosheets (h-BNNS) powder before introduction is more beneficial for improving the contrast and heat dissipation of the PDLC dimming film. The deterioration in Comparative Example 3 demonstrates that the combination of basic network-forming monomers and fluorinated modified monomers in this invention is beneficial for improving the contrast and heat dissipation of the PDLC dimming film.

[0194] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of these embodiments are merely to aid in understanding the method and core ideas of the present invention, including the best mode, and to enable any person skilled in the art to practice the present invention, including manufacturing and using any device or system, and implementing any combined method. It should be noted that those skilled in the art can make various improvements and modifications to the present invention without departing from its principles, and these improvements and modifications also fall within the scope of protection of the claims. The scope of protection of this patent is defined by the claims and may include other embodiments that can be conceived by those skilled in the art. If these other embodiments have structural elements similar to those expressed in the claims, or if they include equivalent structural elements that are not substantially different from those expressed in the claims, then these other embodiments should also be included within the scope of the claims.

Claims

1. A PDLC dimming film, characterized in that, It includes a first flexible transparent conductive substrate, a PDLC functional layer, and a second flexible transparent conductive substrate, which are stacked sequentially. The first flexible transparent conductive substrate includes a thin film and a conductive layer laminated on one side surface of the thin film; wherein the conductive layer is in contact with the PDLC functional layer; The second flexible transparent conductive substrate includes a thin film and a conductive layer laminated to one side surface of the thin film; wherein the conductive layer is in contact with the PDLC functional layer; The PDLC functional layer contains functional materials; the functional materials are formed from raw materials through ultraviolet light polymerization-induced phase separation; the raw materials include the following components (1)-(4): (1) Liquid crystal: It accounts for 65.0%~75.0% of the total mass of components (1)-(3); (2) Polymerizable monomer mixture: which accounts for 22.0%~30.0% of the total mass of components (1)-(3); (3) Surface-functionalized thermal radiation nanomaterials: accounting for 1.0%~5.0% of the total mass of components (1)-(3); (4) Photoinitiator: Its addition amount is 0.5%~2.0% of the mass of the polymerizable monomer mixture; The polymerizable monomer mixture comprises the following monomers (a)-(b): (a) A basic network forming monomer; the basic network forming monomer is a combination of a multifunctional monomer and a monofunctional monomer; the multifunctional monomer is at least one of a multifunctional acrylate and a multifunctional methacrylate; the monofunctional monomer is at least one of a monofunctional acrylate and a monofunctional methacrylate. (b) Fluorinated modified monomer; wherein the fluorinated modified monomer is at least one of fluorinated acrylate and fluorinated methacrylate; The surface-functionalized thermal radiation nanomaterial is a surface-functionalized hexagonal boron nitride nanosheet; the surface-functionalized hexagonal boron nitride nanosheet is obtained by surface modification of hexagonal boron nitride nanosheet with a silane coupling agent.

2. The PDLC dimming film according to claim 1, characterized in that, The surface-functionalized hexagonal boron nitride nanosheets are prepared by the following method: hexagonal boron nitride nanosheet powder, solvent and silane coupling agent are mixed, heated to react, and then the solid is collected by solid-liquid separation, washed and dried to obtain surface-functionalized hexagonal boron nitride nanosheets.

3. The PDLC dimming film according to claim 2, characterized in that, The silane coupling agent is a silane coupling agent containing at least one of vinyl, acryloyloxy, or methacryloxy. The amount of the silane coupling agent is 3% to 5% of the mass of the hexagonal boron nitride nanosheet powder; The heating reaction is performed under the condition of heating to reflux; the heating reaction time is 6-8 hours. The heating reaction is carried out in a protective atmosphere.

4. The PDLC dimming film according to claim 1, characterized in that, The multifunctional monomer is 1,4-butanediol diacrylate; the monofunctional monomer is lauryl methacrylate; the mass ratio of the multifunctional monomer to the monofunctional monomer is 1:(1.2~2.0); The fluorinated modified monomer is 1H,1H-pentafluoropropyl methacrylate; The mass percentage of fluorinated modified monomers in the polymerizable monomer mixture is 1.0% to 5.0%, with the remainder being the basic network forming monomers.

5. The PDLC dimming film according to claim 1, characterized in that, The liquid crystal is a nematic liquid crystal with a birefringence Δn ≥ 0.22 at 589 nm and 20 °C, and a clearing point ≥ 75 °C; The photoinitiator is at least one of benzophenones, α-hydroxy ketones, or acylphosphine oxides as ultraviolet photoinitiators; The film is a flexible polymer film; The conductive material in the conductive layer is at least one of metal nanowires, metal mesh, conductive polymer, or graphene.

6. The PDLC dimming film according to claim 1, characterized in that, The liquid crystal is a nematic liquid crystal E8; The silane coupling agent is γ-(methacryloyloxy)propyltrimethoxysilane; The photoinitiator is at least one of Irgacure 651, Irgacure 184, or Darocur 1173; The film is a polyethylene terephthalate film, a polycarbonate film, or a cyclic olefin polymer film. The conductive material in the conductive layer is silver nanowires; The other side surface of the thin film in the first flexible transparent conductive substrate is provided with OCA adhesive, or the other side surface of the thin film in the second flexible transparent conductive substrate is provided with OCA adhesive.

7. A method for preparing a PDLC dimming film according to any one of claims 1 to 6, characterized in that, Includes the following steps: S1. Mix surface-functionalized thermal radiation nanomaterials with a portion of liquid crystal to obtain a nanocomposite liquid crystal paste; S2. Mix the nanocomposite liquid crystal paste obtained in step S1 with the remaining liquid crystal, polymerizable monomer mixture and photoinitiator to obtain a prepolymer composition. S3. The first flexible transparent conductive substrate and the second flexible transparent conductive substrate are arranged opposite each other to form a cavity and assembled into a liquid crystal cell; the prepolymer composition obtained in step S2 is poured into the cavity of the liquid crystal cell, and then ultraviolet light is used for curing to form a PDLC functional layer to obtain a PDLC dimming film.

8. The preparation method according to claim 7, characterized in that, The liquid crystal portion accounts for 10% to 20% of the total mass of the liquid crystal; In step S1, the mixing method is grinding using a three-roll mill; Step S2 specifically includes: mixing the nanocomposite liquid crystal paste obtained in step S1 with the remaining liquid crystal, polymerizable monomer mixture and photoinitiator, and placing the resulting mixture in a shaker for oscillation and mixing to obtain a prepolymer composition; Step S3 specifically includes: forming a cavity by placing the first flexible transparent conductive substrate and the second flexible transparent conductive substrate opposite to each other, with the conductive layers in the two flexible transparent conductive substrates facing each other, and using microspheres as spacers between the two flexible transparent conductive substrates to assemble a liquid crystal cell; injecting the prepolymer composition obtained in step S2 into the cavity of the liquid crystal cell by vacuum-assisted capillary filling, and then performing ultraviolet light curing to form a PDLC functional layer to obtain a PDLC dimming film.

9. The preparation method according to claim 8, characterized in that, The temperature of the shaker is 45±2℃; the rotation speed of the shaker is 200±10rpm; and the oscillation time is 1~1.5h. The microspheres are PMMA microspheres; the diameter of the microspheres is 20±1μm; The conditions for UV curing are as follows: prepolymerization is performed under a first light intensity, and then curing is performed under a second light intensity; wherein, the first light intensity is 3~8 mW / cm², and the prepolymerization time is 2~5 min; the second light intensity is 10~15 mW / cm², and the curing time is 8~12 min.

10. A display device, characterized in that, The PDLC dimming film includes any one of claims 1 to 6 or any one of claims 7 to 9.

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