Quantum dot composite extrusion type diffusion plate and light emitting device

Abstract

The application discloses a quantum dot compound extrusion type diffusion plate and a light emitting device. The quantum dot compound extrusion type diffusion plate has a light inlet surface and a light outlet surface. From the light inlet surface to the light outlet surface, the quantum dot compound extrusion type diffusion plate comprises first layer structure layer to Nth layer structure layer which are sequentially and combined. The first layer structure layer to the Nth layer structure layer all comprise a high molecular polymer. At least two layers of the first layer structure layer to the Nth layer structure layer comprise quantum dot compounds dispersed in the high molecular polymer. N is not less than 2. The quantum dot compound comprises quantum dots and a coating of the quantum dots. The refractive index of the coating in the structure layer closest to the light inlet surface is the smallest. The light conversion rate of the quantum dot compound extrusion type diffusion plate can be effectively improved, and the light emitting brightness of the light emitting device is improved.

Description

Technical Field

[0001] This application belongs to the field of nanotechnology, and specifically relates to a quantum dot composite extruded diffuser plate and a light-emitting device. Background Technology

[0002] Quantum dots, also known as semiconductor nanocrystals, are a new type of semiconductor nanomaterial with sizes ranging from 1 to 20 nm. Due to quantum size and dielectric confinement effects, they possess unique photoluminescence (PL) and electroluminescence (EL) properties. Compared to traditional organic fluorescent dyes, quantum dots exhibit superior optical properties such as high quantum efficiency, high photochemical stability, resistance to photolysis, broad excitation and narrow emission range, high color purity, and fluorescence emission characteristics that can be adjusted by controlling the quantum dot composition, particle size, and structure. These properties enable televisions to have a high color gamut (NTSC) and have broad application prospects in the field of display technology.

[0003] The backlight module is the backlight source component in LCD displays, typically consisting of a backlight source, multiple layers of backlight material, and a support frame. Backlight quality determines crucial parameters of the LCD screen, such as brightness, emitted light uniformity, and color gradation, and largely influences the screen's luminous effect. Edge-lit backlight modules can be paired with light-emitting diodes (LEDs) and light guide plates, offering the advantage of a thinner profile. Light emitted from the LED packaged light source is coupled into the light guide plate and propagates towards the LCD screen through reflection and scattering by reflectors and dots.

[0004] Currently, the main application of quantum dots in backlight modules is to disperse quantum dots in a medium and place them near the light-incident or light-exit surface of the light guide plate. Placing quantum dots near the light-incident surface makes them susceptible to the temperature of the light source, reducing their lifespan and resulting in low luminous brightness. Placing them near the light-exit surface results in a large quantity of quantum dots, high cost, and a thicker module.

[0005] Therefore, it is necessary to further optimize the application of quantum dots in backlight modules. Summary of the Invention

[0006] To address the aforementioned technical problems, this application provides a quantum dot composite extruded diffuser plate having a light-incident surface and a light-exit surface. From the light-incident surface to the light-exit surface, it comprises a first structural layer to an Nth structural layer stacked sequentially. Each of the first to Nth structural layers contains a polymer. At least two of the first to Nth structural layers contain a quantum dot composite dispersed in the polymer, where N ≥ 2. The quantum dot composite includes quantum dots and a coating material covering the quantum dots.

[0007] Among the structural layers containing the quantum dot composite, the coating in the structural layer closest to the light-incident surface has the lowest refractive index.

[0008] Furthermore, in each structural layer, the quantum dot composite has a weight percentage of 1 to 10 wt%.

[0009] Preferably, in the quantum dot composite, the weight percentage of the quantum dots is 10-30 wt%.

[0010] Furthermore, the particle size of the quantum dot composite is 30–500 nm, preferably 50–300 nm.

[0011] Furthermore, the coating material is inorganic;

[0012] Preferably, the inorganic material includes at least one of aluminum oxide, aluminum nitride, aluminum oxynitride, titanium oxide, titanium nitride, titanium oxynitride, zirconium oxide, zirconium nitride, zirconium oxynitride, silicon oxide, silicon carbide, silicon oxynitride, barium sulfate, zinc sulfide, and graphene.

[0013] Furthermore, in the first to the Nth structural layers, the refractive index of the coating increases layer by layer.

[0014] Furthermore, the thickness of the quantum dot composite diffusion plate is 500 μm to 2 mm.

[0015] Furthermore, the polymer is at least one selected from polystyrene, polyethylene, polypropylene, polythiolene, polyurethane, polymethyl methacrylate, and polymethyl methacrylate-styrene copolymer.

[0016] Furthermore, the refractive index of the coating is 1.4 to 2.8.

[0017] Furthermore, N is 4, and in the first to fourth structural layers, the coatings of the quantum dot composite are silicon dioxide, aluminum oxide, titanium dioxide, and zirconium oxide, respectively.

[0018] This application also provides a light-emitting device, including the above-mentioned quantum dot composite extruded diffuser plate.

[0019] Beneficial Effects: The quantum dot composite extruded diffuser plate of this application comprises N sequentially stacked structural layers, each of which contains a polymer and a quantum dot composite dispersed within the polymer, where N is not less than 2. The quantum dot composite includes quantum dots and a coating material covering the quantum dots. In at least one of the second to Nth structural layers, the refractive index of the coating material is greater than that of the coating material in the first structural layer. This application employs a multi-layer co-extrusion method using a polymer and quantum dot composites with different coatings. Through the protective effect of the coating material and the design of its refractive index, the severe problem of quantum dot light decay during the fabrication process can be reduced, effectively improving the light conversion efficiency of the quantum dot composite extruded diffuser plate, thereby increasing the brightness of the light-emitting device. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of the quantum dot composite extruded diffuser plate in the first specific embodiment of this application;

[0021] Figure 2 This is a schematic diagram of the structure of the quantum dot composite in the first specific embodiment of this application. Detailed Implementation

[0022] The technical solutions in the embodiments of this application will be described in detail below with reference to the implementation methods of this application. It should be noted that the described embodiments are only a part of the embodiments of this application, and not all of the embodiments.

[0023] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. Unless otherwise defined, all terms in this specification (including technical and scientific terms) are as commonly understood by those skilled in the art. Terms defined in common dictionaries should be interpreted as having meanings consistent with their context in the relevant art and in this disclosure, and should not be interpreted ideally or overly broadly unless clearly defined. Furthermore, unless expressly stated to the contrary, the terms “comprising” and “including” when used in this specification indicate the presence of the stated features, regions, integrals, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, regions, integrals, steps, operations, elements, components, and / or sets thereof. Therefore, the above terminology should be understood to mean that the stated elements are included, but not that any other elements are excluded.

[0024] It will be understood that although the terms first, second, etc., may be used herein to describe various elements, components, regions, layers, and / or portions, these elements, components, regions, layers, and / or portions should not be limited by these terms. These terms are used only to distinguish one element, component, region, layer, or portion from another. Therefore, without departing from the teachings of this embodiment, the first element, component, region, layer, or portion discussed below may be referred to as the second element, component, region, layer, or portion.

[0025] definition

[0026] The following definitions apply to some aspects described with respect to certain embodiments of the present invention, and these definitions may also be extended herein.

[0027] Unless the context clearly specifies otherwise, as used herein, the singular forms “a” and “the” include multiple referents. Unless the context clearly specifies otherwise, referring to an object may include multiple objects.

[0028] As used herein, the term "proximity" means close to or adjacent to. Proximity objects may be spaced apart from each other, or may be in actual or direct contact with each other. In some cases, proximity objects may be connected to each other, or may form a whole with each other.

[0029] As used in this article, the term "connection" refers to operational coupling or linking. Linked objects can be directly coupled to each other or indirectly coupled to each other via another set of objects.

[0030] As used herein, relative terms such as “inside,” “inner,” “outside,” “exterior,” “top,” “bottom,” “front,” “back,” “rear,” “upper,” “lower,” “vertical,” “lateral,” “above,” and “below” refer, for example, according to the accompanying drawings, to the orientation of a group of objects relative to each other, but not requiring a particular orientation of these objects during manufacture or use.

[0031] like Figure 1The diagram shown is a schematic of a quantum dot composite extruded diffuser plate according to a first specific embodiment of this application. The quantum dot composite extruded diffuser plate 10 has a light-incident surface and a light-exit surface. From the light-incident surface to the light-exit surface, it includes a first structural layer 11 to an Nth structural layer 1N stacked sequentially. Each of the first structural layer 11 to the Nth structural layer 1N contains a polymer. At least two of the first structural layer 11 to the Nth structural layer 1N contain a quantum dot composite dispersed in the polymer, where N ≥ 2. The quantum dot composite includes quantum dots and a coating material covering the quantum dots. Among the structural layers containing the quantum dot composite, the coating material in the structural layer closest to the light-incident surface has the lowest refractive index. The different refractive indices between the structural layers can effectively enhance the light conversion efficiency of the quantum dot composite extruded diffuser plate. Compared with the existing backlight module structure, the integration of the quantum dot composite into the structural layers of the diffuser plate can effectively reduce the thickness of the backlight module.

[0032] like Figure 2 As shown, the quantum dot composite 101 of this application includes quantum dots 111 and a coating 121 covering the surface of quantum dots 111. The coating 121 can effectively protect quantum dots 111 from water and oxygen attack and improve the stability of quantum dots.

[0033] In a second specific embodiment of this application, the weight percentage of quantum dot composite in each structural layer of the quantum dot composite extruded diffuser is 1 to 10 wt%, so as to increase the transmission path of light in the structural layer.

[0034] In a preferred embodiment, the quantum dot composite contains 10 to 30 wt% quantum dots, thereby further enhancing the luminescence brightness of the extruded diffuser plate of the quantum dot composite.

[0035] In the third specific embodiment of this application, the particle size of the quantum dot composite is 30-500 nm, preferably 50-300 nm, so that the quantum dot composite extruded diffuser plate obtains better light transmittance and light conversion efficiency.

[0036] In the fourth specific embodiment of this application, the coating material in the quantum dot composite is an inorganic material, thereby better protecting the quantum dots and blocking water and oxygen; the inorganic material preferably includes at least one of aluminum oxide, aluminum nitride, aluminum oxynitride, titanium oxide, titanium nitride, titanium oxynitride, zirconium oxide, zirconium nitride, zirconium oxynitride, silicon oxide, silicon carbide, silicon oxynitride, barium sulfate, zinc sulfide, and graphene, and the quantum dot composite can be prepared by existing quantum dot coating processes.

[0037] In the fifth specific embodiment of this application, the quantum dot composite extruded diffusion plate may further include a protective layer, which comprises at least two layers, with a structural layer disposed in the middle of the protective layer. The protective layer and the structural layer are integrally formed, and the protective layer can protect the quantum dots in the structural layer from water and oxygen attack.

[0038] The quantum dot composite extruded diffuser plate of this application is manufactured using an extrusion process, through multi-layer co-extrusion, to integrally form each structural layer. Compared with coating and UV curing methods, the co-extrusion preparation method can be cooled and cured in one step without the need for UV light source curing, and the thickness of each layer in the quantum dot composite extruded diffuser plate is easier to control.

[0039] In a preferred embodiment, both the protective layer and the structural layer are made of light-transmitting materials. The protective layer comprises inorganic materials and / or organic coatings. The inorganic materials include, for example, at least one of alumina, aluminum nitride, aluminum oxynitride, titanium oxide, titanium nitride, titanium oxynitride, zirconium oxide, zirconium nitride, zirconium oxynitride, silicon oxide, silicon carbide, silicon oxynitride, and graphene, formed by magnetron sputtering. The organic coatings include polysilicon resin, epoxy resin, polyurethane, polycarbonate, polyfluoropolymer, polymethyl methacrylate, polyoxymethylene, polyethylene, and polyvinylidene chloride. The resin is selected from at least one of the following: ethylene, ethylene-vinyl alcohol copolymer, polyvinyl acetate, polytetrafluoroethylene, polyvinyl butyral, polypropylene, polyamide, polyethylene terephthalate, polyethylene naphthalate, or polybutylene terephthalate, polyacrylate, polystyrene-acrylonitrile resin, polycopoly resin, polyCR-39 resin, polyOZ series resin, polyTS-26 resin, polyAPO resin, polyMR resin, polyMH resin, polyNAS resin, polyADC resin, polyTOPAS resin, and polyARTON resin.

[0040] In the sixth specific embodiment of this application, the refractive index of the coating increases layer by layer from the first structural layer to the Nth structural layer, thereby enabling the light from the quantum dot composite extruded diffuser plate to be refracted onto the quantum dots as much as possible, thus improving the light conversion efficiency.

[0041] In the seventh specific embodiment of this application, the thickness of the quantum dot composite diffusion plate is 500 μm to 2 mm, thereby ensuring that the quantum dot composite diffusion plate obtains better light transmittance and light conversion efficiency.

[0042] In the sixth specific embodiment of this application, the organic polymer is at least one of polystyrene, polyethylene, polypropylene, polythiolene, polyurethane, polymethyl methacrylate, and polymethyl methacrylate-styrene copolymer, so as to facilitate the preparation of quantum dot composite extruded diffuser plates by extrusion process.

[0043] In the eighth specific embodiment of this application, the refractive index of the coating is 1.4 to 2.8, thereby increasing the optical path length of light in the quantum dot composite extruded diffuser plate, which is beneficial to improving the light conversion efficiency of the diffuser plate.

[0044] In the ninth specific embodiment of this application, the quantum dot composite extruded diffuser plate further includes light-diffusing particles dispersed in the structural layer to further enhance the light extraction efficiency. The light-diffusing particles have a particle size of 100 nm-5 μm. In the quantum dot composite extruded diffuser plate, the weight percentage of light-diffusing particles is 0.1-10 wt%. The light-diffusing particle material is selected from at least one of organosilicon, PMMA, PS, nano-silica, nano-alumina, nano-titanium oxide, and nano-zirconia.

[0045] In the tenth specific embodiment of this application, N is 4. In the first to fourth structural layers, the coating of the quantum dot composite is silicon oxide, aluminum oxide, titanium oxide and zirconium oxide layer by layer from the light-incident surface to the light-exit surface. Zirconium oxide has high hardness and good water and oxygen barrier properties. When used on the side of the quantum dot composite extruded diffuser plate near the light-exit surface, it can effectively block water and oxygen from attacking the quantum dot composite extruded diffuser plate.

[0046] In the eleventh specific embodiment of this application, N is 3, and in the first to the third structural layers, the coating of the quantum dot composite is successively silicon oxide, aluminum oxide, and zirconium oxide from the light-incident surface to the light-exit surface.

[0047] In the twelfth specific embodiment of this application, N is 5, and in the first to the fifth structural layers, the coating of the quantum dot composite is successively silicon oxide, barium sulfate, aluminum oxide, zinc sulfide, and titanium oxide from the light-incident surface to the light-exit surface.

[0048] In the thirteenth specific embodiment of this application, N is 2, and in the first structural layer to the second structural layer, the coating of the quantum dot composite is silicon nitride and zirconium oxide layer by layer from the light-incident surface to the light-exit surface.

[0049] In the fourteenth specific embodiment of this application, N is 6. The first structural layer contains a quantum dot composite with silicon oxide as its coating. The second structural layer contains nano-silicon oxide diffusion particles. The third structural layer contains two quantum dot composites with aluminum oxide and zinc sulfide as their coatings, respectively. The fourth structural layer contains nano-alumina diffusion particles. The fifth structural layer contains a quantum dot composite with zirconium oxide as its coating. The sixth structural layer contains nano-zirconia diffusion particles.

[0050] In the fifteenth specific embodiment of this application, N is 7, and each of the first to seventh structural layers contains a quantum dot composite. The coating of the quantum dot composite, from the light-incident surface to the light-exit surface, consists of silicon oxide, aluminum oxide, barium sulfate, aluminum oxide, zinc sulfide, titanium oxide, and zirconium oxide in sequence.

[0051] In the sixteenth embodiment of this application, N is 8. The first structural layer contains nano-silica light-diffusing particles, the second structural layer contains a quantum dot composite with silicon oxide as the coating, the third structural layer contains nano-silica light-diffusing particles, the fourth structural layer contains a quantum dot composite with aluminum oxide as the coating, the sixth structural layer contains two quantum dot composites with barium sulfate and zinc sulfide as the coatings, respectively, the seventh structural layer contains nano-silica light-diffusing particles, and the eighth structural layer contains a quantum dot composite with zirconium oxide as the coating.

[0052] In the seventeenth embodiment of this application, the quantum dot composite includes red quantum dots or green quantum dots. The two different colored quantum dots can be disposed in the same structural layer to reduce the thickness of the backlight module; or they can be disposed in different structural layers to avoid self-absorption caused by mixing different colored quantum dots.

[0053] The green and red quantum dots of this application comprise one of silicon-based quantum dots, IIB-VIA group compound quantum dots, IIIA-VA group compound quantum dots, VA-VIA group compound quantum dots, perovskite quantum dots, carbon quantum dots, and mixtures of the above-mentioned quantum dots. IIB-VIA group compound quantum dots include one selected from the group consisting of CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, and HgZnSTe. IIIA-VA group compound quantum dots comprise one selected from the group consisting of GaN, GaP, GaAs, AlN, AlP, AlAs, InN, InP, InAs, GaNP, GaNAs, GaPAs, AlNP, AlNAs, AlPAs, InNP, InNAs, InPAs, GaAlNP, GaAlNAs, GaAlPAs, GaInNP, GaInNAs, GaInPAs, InAlNP, InAlNAs, and InAlPAs. In a preferred embodiment, the quantum dots have a core-shell structure. In a preferred embodiment, green and red quantum dots comprise at least one of the following: cadmium selenide, cadmium sulfide, cadmium telluride, zinc selenide, indium phosphide, indium arsenide, and perovskite.

[0054] This application also provides a light-emitting device, including the aforementioned quantum dot composite extruded diffuser plate. The light-emitting device can be a display device or a lighting device. Display devices include, but are not limited to, mobile phones, computers, automotive displays, AR displays, VR displays, smartwatches, flexible displays, flexible display panels, etc. The light-emitting device of this application can be a QLED device, an OLED device, a PLED device, a Micro-LED device, or a Mini-LED device. The light-emitting device of this application can be a top-emitting device, a bottom-emitting device, or a double-sided transparent light-emitting device.

[0055] The structure of a quantum dot composite extruded diffusion plate according to some exemplary embodiments of this application will be described in more detail below; however, the exemplary embodiments of this application are not limited thereto.

[0056] Example 1

[0057] Step 1: Prepare the following green quantum dot composite.

[0058] (1) A quantum dot composite material with SiO2-coated green CdSe / ZnS quantum dots with a particle size of 200 nm was prepared according to conventional methods, wherein the weight percentage of quantum dots was 25 wt% and the refractive index of the SiO2 coating was 1.48.

[0059] (2) A quantum dot composite with Al2O3-coated green CdSe / ZnS quantum dots with a particle size of 200 nm was prepared according to conventional methods, wherein the weight percentage of quantum dots was 20 wt% and the refractive index of Al2O3 coating was 1.76.

[0060] (3) A quantum dot composite material with a particle size of 400 nm and coated with green CdSe / ZnS quantum dots by TiO2 was prepared according to conventional methods. The quantum dot content was 33 wt% and the refractive index of TiO2 coating was 2.66.

[0061] (4) A quantum dot composite with ZrO2-coated green CdSe / ZnS quantum dots with a particle size of 200 nm was prepared according to conventional methods, wherein the weight percentage of quantum dots was 20 wt% and the refractive index of the ZrO2 coating was 2.20.

[0062] Step 2: Prepare the following red quantum dot composite.

[0063] (1) A quantum dot composite material with SiO2-coated red CdSe / ZnS quantum dots with a particle size of 200 nm was prepared according to conventional methods, wherein the weight percentage of quantum dots was 25 wt% and the refractive index of the SiO2 coating was 1.48.

[0064] (2) A quantum dot composite with Al2O3-coated red CdSe / ZnS quantum dots with a particle size of 200 nm was prepared according to conventional methods, wherein the weight percentage of quantum dots was 20 wt% and the refractive index of Al2O3 coating was 1.76.

[0065] (3) A quantum dot composite material with TiO2-coated red CdSe / ZnS quantum dots with a particle size of 400 nm was prepared according to conventional methods, wherein the weight percentage of quantum dots was 33 wt% and the refractive index of TiO2-coated material was 2.66.

[0066] (4) A quantum dot composite with ZrO2-coated red CdSe / ZnS quantum dots with a particle size of 200 nm was prepared according to conventional methods, wherein the weight percentage of quantum dots was 20 wt% and the refractive index of the ZrO2 coating was 2.20.

[0067] Step 3: Preparation of quantum dot composite extruded diffusion plates:

[0068] (1) Based on the mass percentage of each component in the diffuser plate, 1.6 wt% of SiO2-coated CdSe / ZnS quantum dot composite, 0.4 wt% of Al2O3-coated R-CdSe / ZnS quantum dot composite, and 98 wt% of polymethyl methacrylate are blended and added to the first extruder.

[0069] (2) Based on the mass percentage of each component in the diffuser plate, 2 wt% of the quantum dot composite of G-CdSe / ZnS coated with Al2O3, 0.5 wt% of the quantum dot composite of R-CdSe / ZnS coated with Al2O3, and 97.5 wt% of polymethyl methacrylate were blended and added to the second extruder.

[0070] (3) Based on the mass percentage of each component in the diffuser plate, 1.2 wt% of TiO2-coated G-CdSe / ZnS quantum dot composite, 0.3 wt% of Al2O3-coated R-CdSe / ZnS quantum dot composite, and 98.5 wt% of polystyrene were blended and added to the third extruder.

[0071] (4) Based on the mass percentage of each component in the diffuser plate, 2 wt% of the quantum dot composite of G-CdSe / ZnS coated with ZrO2, 0.5 wt% of the quantum dot composite of R-CdSe / ZnS coated with Al2O3, and 97.5 wt% of polystyrene were blended and added to the fourth extruder.

[0072] (5) The first extruder, the second extruder, the third extruder and the fourth extruder are arranged in sequence and co-extruded at 210°C to form a quantum dot composite extruded diffuser plate with a thickness of 1.5 mm. Light enters from the first layer and exits from the fourth layer. The zirconium oxide coating in the quantum dot composite in the fourth layer has high hardness and can significantly block water and oxygen.

[0073] Comparative Example 1

[0074] Preparation of quantum dot diffusion plates:

[0075] Based on the mass percentage of each component in the diffuser plate, 1.6 wt% of green quantum dots, 0.4 wt% of red quantum dots, and 98 wt% of polystyrene were blended and extruded at 210°C to form a quantum dot diffuser plate with a thickness of 2 mm.

[0076] The optical performance of the diffuser plates in Example 1 and Comparative Example 1 was measured using blue light excitation at 450 nm and 1000 nits, respectively. The specific results are shown in Table 1.

[0077] Table 1. Optical performance parameters of the diffuser plates in Example 1 and Comparative Example 1.

[0078] serial number Brightness of light Light conversion efficiency Example 1 4257 nits 425％ Comparative Example 1 2016nits 201％

[0079] As can be seen from the above, the quantum dot composite extruded diffuser plate in Example 1 of this application has higher luminous brightness and better light conversion efficiency compared with the ordinary quantum dot diffuser plate in Comparative Example 1.

[0080] Although the inventors have described and enumerated the technical solutions of this application in detail, it should be understood that for those skilled in the art, it is obvious that modifications and / or alterations to the above embodiments or the adoption of equivalent alternatives can be made without departing from the spirit of this application. The terminology appearing in this application is used to describe and understand the technical solutions of this application and does not constitute a limitation on this application.

Claims

1. A quantum dot composite extruded diffusion plate, characterized in that, It has a light-incident surface and a light-exit surface, and from the light-incident surface to the light-exit surface, it includes a first structural layer to an Nth structural layer stacked sequentially. Each of the first to Nth structural layers contains a polymer, and at least two of the first to Nth structural layers contain a quantum dot composite dispersed in the polymer, where N≥2. The quantum dot composite is composed of quantum dots and a coating material that coats the quantum dots. The quantum dot composite extruded diffuser plate is manufactured using an extrusion process, through multi-layer co-extrusion, so that each structural layer is integrally formed. Among the structural layers containing the quantum dot composite, the refractive index of the coating in the structural layer closest to the light-incident surface is the lowest; from the first structural layer to the Nth structural layer, the refractive index of the coating increases layer by layer; the refractive index of the coating is 1.4~2.

8.

2. The quantum dot composite extruded diffusion plate according to claim 1, characterized in that, In each structural layer, the quantum dot composite has a weight percentage of 1 to 10 wt%.

3. The quantum dot composite extruded diffusion plate according to claim 1, characterized in that, The particle size of the quantum dot composite is 30~500 nm.

4. The quantum dot composite extruded diffusion plate according to claim 1, characterized in that, The coating material is inorganic.

5. The quantum dot composite diffusion plate according to claim 1, characterized in that, The thickness of the quantum dot composite diffusion plate is 500 μm to 2 mm.

6. The quantum dot composite extruded diffusion plate according to claim 1, characterized in that, The polymer is at least one of polystyrene, polyethylene, polypropylene, polythiolene, polyurethane, polymethyl methacrylate, and polymethyl methacrylate-styrene copolymer.

7. The quantum dot composite extruded diffusion plate according to claim 1, characterized in that, When N is 4, the coatings of the quantum dot composite in the first to fourth structural layers are silicon dioxide, aluminum oxide, titanium dioxide, and zirconium oxide, respectively.

8. A light-emitting device, characterized in that, Includes the quantum dot composite extruded diffusion plate according to any one of claims 1-7.

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