A quantum dot thin film and a preparation method thereof

Abstract

The present application discloses a quantum dot thin film and a preparation method thereof. The quantum dot thin film includes a substrate layer, and a plurality of first sawtooth stripes and second sawtooth stripes with isosceles triangle cross-sections and arranged in parallel at equal intervals are respectively formed on both side surfaces of the substrate layer. A protective layer is formed on the surfaces of the first sawtooth stripes and the second sawtooth stripes by vacuum sputtering; the first sawtooth stripes and the second sawtooth stripes on both side surfaces of the substrate layer are arranged perpendicular to each other; different types of first quantum dots and second quantum dots are respectively dispersed in the first sawtooth stripes and the second sawtooth stripes. In the quantum dot thin film of the present application, since different quantum dots are respectively dispersed in different sawtooth stripes, when selecting a coupling agent for surface modification, there is no need to consider problems such as the compatibility of different coupling agents and the matching of process conditions, thus effectively avoiding the agglomeration problem caused by the mixing of multiple types of quantum dots. The process can be simplified and the cost can be reduced.

Description

Technical Field

[0001] This application relates to a quantum display in the field of liquid crystal displays, particularly to a quantum dot light conversion film of a quantum display, and especially to a quantum dot film and a preparation method thereof. Background Art

[0002] A quantum dot liquid crystal display (Quantum Dot LCD) is a new type of display technology that uses tiny quantum dot particles to improve the image quality of the display. The quantum dot liquid crystal display uses a quantum dot film to cover the backlight source. The quantum dot film contains a large number of quantum dot particles, and through these particles, the image quality of the liquid crystal display can be improved. The quantum dot film can improve the color reproducibility, contrast, and viewing angle of the liquid crystal display, making the display effect more vivid and realistic. Currently, quantum dot liquid crystal displays have been widely used in products such as smartphones, TVs, and monitors.

[0003] CN 108089369 A discloses a quantum dot film in which the size of the light scattering agent contained in the light conversion layer is adjusted. The quantum dot film of this prior art is as Figure 1 shown. The quantum dot film 100 includes a light conversion layer 120 and barrier layers 110 on both sides of the light conversion layer 120. The light conversion layer 120 includes a plurality of quantum dots 121 and a plurality of light scattering agents 122. The thickness of the light conversion layer 120 is substantially the same as the size of the light scattering agent 122. According to the quantum dot film 100 of this prior art, a quantum dot film containing a light scattering agent 122 with a size substantially the same as the thickness of the light conversion layer 120 is formed, thereby ensuring the uniform thickness of the light conversion layer 120, improving the aggregation phenomenon of the quantum dots 121 contained in the light conversion layer 120, and improving the color reproducibility and brightness of the light emitted through the quantum dot film, so as to be able to emit high-quality light.

[0004] Different types of quantum dots have different materials and surface properties, and it is easy for them to agglomerate with each other. Moreover, different types of quantum dots and light scattering agents are also prone to agglomeration. Although this prior art has enlarged the size of the light scattering agent, the agglomeration problem of different types of quantum dots still cannot be effectively solved. In addition, the scattering effect of large-sized light scattering agents is not good, but instead, it will cause a large block to the incident light and also weaken the light utilization rate of the quantum dot film. Summary of the Invention

[0005] The technical problem to be solved by this application is to provide a quantum dot film and a preparation method thereof to reduce or avoid the problems mentioned above.

[0006] To solve the above technical problems, the present application proposes a quantum dot film, which is used to be disposed in front of a light guide plate of a backlight module. The quantum dot film includes a substrate layer. Wherein, a plurality of first sawtooth stripes and second sawtooth stripes with isosceles triangle cross-sections arranged in parallel at equal intervals are respectively formed on both side surfaces of the substrate layer. A protective layer is formed on the surfaces of the first sawtooth stripes and the second sawtooth stripes by vacuum sputtering; the first sawtooth stripes and the second sawtooth stripes on both side surfaces of the substrate layer are arranged perpendicular to each other; different types of first quantum dots and second quantum dots are respectively dispersed in the first sawtooth stripes and the second sawtooth stripes.

[0007] Preferably, the length of the base of the isosceles triangle of the first sawtooth stripes and the second sawtooth stripes is 5 - 10 μm, the apex angle is 45 - 135 degrees, the height is 5 - 10 μm, and the minimum gap between adjacent stripes is 0 - 5 μm.

[0008] Preferably, the protective layer is composed of silicon dioxide.

[0009] Preferably, the included angle between the length directions of the first sawtooth stripes and the second sawtooth stripes and the four rectangular sides of the substrate layer is 45 degrees.

[0010] Preferably, online coating layers are formed on both side surfaces of the substrate layer, and the first sawtooth stripes and the second sawtooth stripes are formed outside the online coating layers.

[0011] The present invention also proposes a preparation method of the foregoing quantum dot film, including the following steps: providing a layer of PET film as the substrate layer, and respectively forming first sawtooth stripes and second sawtooth stripes with first quantum dots and second quantum dots on both sides of the substrate layer; forming a protective layer on the outside of the first sawtooth stripes and the second sawtooth stripes of the quantum dot film by vacuum sputtering.

[0012] Preferably, the preparation method further includes the following steps: using two rollers arranged opposite to each other up and down, the upper roller has a pattern matching the shape of the first sawtooth stripes, the lower roller has a pattern matching the shape of the second sawtooth stripes, clamping the PET film between the two rollers for extrusion, and respectively coating ultraviolet curable resins with first quantum dots and second quantum dots between the rollers and the PET film, and then irradiating the PET film with ultraviolet light, so as to obtain the cured first sawtooth stripes and second sawtooth stripes on the PET film.

[0013] Preferably, the preparation method further comprises the following steps: using PET chips as raw materials for preparing PET films, obtaining a single-layer thick sheet through melt extrusion, longitudinally stretching it into a film after preheating, and then passing through a coater to simultaneously coat a mixture of components constituting the online coating layer on both sides of the film, followed by transverse stretching, shaping, cooling, and winding, so as to form an online coating layer on the surface of the PET film; then, using two rollers arranged oppositely up and down, the upper roller has a pattern matching the shape of the first serrated stripe, and the lower roller has a pattern matching the shape of the second serrated stripe, clamping the PET film with the online coating layer between the two rollers for extrusion, and respectively coating an ultraviolet curable resin with the first quantum dots and the second quantum dots between the rollers and the PET film, and then irradiating the PET film with ultraviolet light, so as to obtain the cured first serrated stripe and the second serrated stripe on the outside of the online coating layer of the PET film.

[0014] Preferably, 5wt%-10wt% of a light scattering agent is added to the PET chips.

[0015] Preferably, the surface of the roller is sandblasted to form a concave-convex structure on the pattern matching the first serrated stripe and the second serrated stripe.

[0016] In the quantum dot film of the present application, since different quantum dots are separately dispersed in different serrated stripes, when selecting a coupling agent for surface modification, there is no need to consider issues such as the compatibility of different coupling agents and the matching of process conditions, thus effectively avoiding the agglomeration problem caused by the mixing of various types of quantum dots. The process can be simplified and the cost can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The following drawings are only intended to illustrate and explain the present application schematically and do not limit the scope of the present application.

[0018] Figure 1 It shows a cross-sectional schematic view of a quantum dot film of the prior art.

[0019] Figure 2 It shows a three-dimensional structural schematic view of a quantum dot film according to a specific embodiment of the present application.

[0020] Figure 3 It shows a cross-sectional schematic view of a quantum dot film according to another specific embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] In order to have a clearer understanding of the technical features, objectives, and effects of the present application, the specific embodiments of the present application are now described with reference to the drawings. Among them, the same components are denoted by the same reference numerals.

[0022] AsFigure 2-3 As shown, the present application proposes a quantum dot thin film 100 that can be used in a quantum dot liquid crystal display, which is used to be disposed in front of a light guide plate 30 ( Figure 3 ) of the quantum dot liquid crystal display. For the light conversion principle of the quantum dot thin film 100, reference can be made to the prior art cited in the background art, which is hereby incorporated by reference in its entirety and will not be repeated here.

[0023] The light conversion layer of the prior art quantum dot thin film contains various different types of particles. For example, it can include green quantum dots that emit green light with a wavelength range of about 520 nm to about 560 nm after absorbing blue light. When the light incident on the light conversion layer is blue light with a wavelength range of about 430 nm to about 470 nm, green light is emitted. Additionally, the light conversion layer can also include red quantum dots that release red light with a wavelength range of about 630 nm to about 660 nm after absorbing blue light, thus releasing red light. Additionally, a light scattering agent can also be included in the light conversion layer. These different types of particles need to be uniformly dispersed inside the polymer resin that constitutes the light conversion layer. Since the light conversion efficiency and response speed of blue light LEDs are higher, and green quantum dots and red quantum dots are cheaper, using blue light LEDs as the backlight and combining them with green quantum dots and red quantum dots to obtain white light has a lower cost and better display effect. However, it is very easy for various different types of particles to agglomerate when dispersed separately in the polymer resin, and surface modification for different types of particles may require coupling agents with significantly different properties. Different coupling agents also need to consider issues such as compatibility and process condition matching, resulting in complex processes and high costs, and it is sometimes difficult to ensure the uniformity of the product quality.

[0024] In view of this, the present application proposes an improved quantum dot thin film 100. As shown in the figure, the quantum dot thin film 100 includes a substrate layer 11. On both side surfaces of the substrate layer 11, a plurality of first sawtooth stripes 12 and second sawtooth stripes 13 with an isosceles triangle cross-section are formed in parallel at equal intervals. The sizes of the first sawtooth stripes 12 and the second sawtooth stripes 13 can be exactly the same to reduce the mold cost, or stripes with different sizes and intervals can be selected according to needs. The size ratio of the quantum dot thin film 100 shown in the figure is enlarged for easy observation and understanding. The actual size of the sawtooth stripes is relatively small, and there are only very small textures that are not easily noticeable on the surface, which does not affect the overall light transmittance of the quantum dot thin film 100. Different types of first quantum dots 121 and second quantum dots 131 are respectively dispersed in the first sawtooth stripes 12 and the second sawtooth stripes 13. As mentioned above, the first quantum dots 121 can be green quantum dots, and the second quantum dots 131 can be red quantum dots, or vice versa.

[0025] In this application, since the first quantum dots 121 and the second quantum dots 131 are respectively dispersed in the first serrated stripes 12 and the second serrated stripes 13, when selecting a coupling agent for surface modification, there is no need to consider issues such as the compatibility of different coupling agents and the matching of process conditions, thus effectively avoiding the agglomeration problem caused by the mixing of various types of quantum dots. The process can be simplified and the cost can be reduced. The first quantum dots 121 and the second quantum dots 131 can be of suitable types of quantum dots known in the prior art. The first serrated stripes 12 and the second serrated stripes 13 can be formed on the substrate layer 11 by curing an existing ultraviolet curable resin through a mold. Of course, the selected quantum dots and an appropriate coupling agent for surface modification are also added to the ultraviolet curable resin to avoid agglomeration and improve dispersibility.

[0026] In a specific embodiment, the maximum thickness of the quantum dot film 100 is 100 - 500 μm. In another specific embodiment, it is preferred that the sizes of the first serrated stripes 12 and the second serrated stripes 13 are exactly the same, and the length of the base of the isosceles triangle of the first serrated stripes 12 and the second serrated stripes 13 is 5 - 10 μm, the apex angle is 45 - 135 degrees, the height is 5 - 10 μm, and the minimum gap between adjacent stripes is 0 - 5 μm.

[0027] The substrate layer 11 can be made of a PET film, which has excellent strength, insulation performance, and thermal stability, and can provide support for the quantum dot film 100. Further, in an embodiment not shown, a light scattering agent, such as PMMA particles, can also be dispersedly provided in the PET film of the substrate layer 11 to enable the substrate layer 11 to obtain a light diffusion effect. Since the substrate layer 11 does not contain quantum dots, when dispersing a light scattering agent therein, there is no need to consider issues such as the compatibility of different coupling agents and the matching of process conditions, and the agglomeration problem caused by the mixing of different types of particles is also effectively avoided.

[0028] The first serrated stripes 12 and the second serrated stripes 13 on both side surfaces of the substrate layer 11 can converge the light incident from the light guide plate 30 towards the top of the serrated stripes, thereby adjusting the light incident obliquely from the light guide plate 30 to exit in the vertical direction, so as to increase the light intensity in the vertical direction, thereby improving the light conversion efficiency of the incident light irradiating the quantum dots, and at the same time increasing the forward exit light brightness, which is especially suitable for use as a direct - type backlight. In addition, in order to avoid the formation of Moiré interference fringes due to the concentration of the light converged by the serrated stripes in the same direction, it is preferred that the first serrated stripes 12 and the second serrated stripes 13 are arranged perpendicular to each other, so that the Moiré interference fringes generated by the second serrated stripes 13 on the incident - light side ( Figure 3 middle and below) can be covered by the first serrated stripes 12 on the exit - light side ( Figure 3 middle and above).

[0029] Figure 2-3 Although the quantum dot thin film 100 in [description] is shown as an independent structure, those skilled in the art should understand that it can also be adhesively bonded and compounded with other optical films through an adhesive above it. For example, it can be compounded with other brightness enhancement films or diffusion films, etc., such as to increase the bonding area and avoid delamination. Therefore, adopting a surface structure with the first serrated stripe 12 and the second serrated stripe 13 is beneficial to the bonding combination with other optical films. For example, the contact area with the adhesive can be increased through the serrated stripes. For example, when the apex angle of the isosceles triangle of the serrated stripe is 60 degrees, the serrated stripe can double the surface area relative to planar bonding, thereby increasing the overall adhesion of the quantum dot thin film 100 and avoiding the delamination problem after the quantum dot thin film 100 is compounded.

[0030] In addition, when the first serrated stripe 12 and the second serrated stripe 13 are cured and formed, due to the different surface tensions of the ultraviolet curable resin and the substrate layer, the shrinkage amount is likely to accumulate in the length direction during the curing process, resulting in warping deformation in the length direction of the serrated stripe, which affects the flatness of the quantum dot film. To avoid this situation, it is preferred that the included angle between the length directions of the first serrated stripe 12 and the second serrated stripe 13 and the four rectangular sides of the quantum dot thin film 100 is 45 degrees, as Figure 2 shown. Generally, the quantum dot thin film 100 is usually designed as a rectangle with four mutually perpendicular sides. If the length direction of the serrated stripe is perpendicular to a pair of rectangular sides of the quantum dot thin film 100, the other pair of rectangular sides will be parallel to the length direction of the serrated stripe. In this application, the direction of the serrated stripe is turned to form a 45-degree included angle with the four rectangular sides. Then, the proportion of the shrinkage amount difference in different directions caused by the serrated stripe spreading to the four rectangular sides will tend to be average. Therefore, the warping deformation problem of the quantum dot thin film 100 caused by the setting of the serrated stripe can be avoided, and the delamination problem during subsequent adhesive bonding and compounding can also be avoided, further improving the structural performance of the quantum dot thin film 100.

[0031] Since the quantum dot structure needs to be isolated from oxygen and water vapor, in another specific embodiment of the present application, a protective layer 14 is formed on the surfaces of the first serrated stripe 12 and the second serrated stripe 13 by vacuum sputtering; preferably, the protective layer 14 is composed of silicon dioxide with a thickness of 1 - 3 μm.

[0032] In order to improve the adhesion of the sawtooth stripes, before forming the first sawtooth stripe 12 and the second sawtooth stripe 13, an on-line coating treatment can be carried out on both side surfaces of the substrate layer 11 to form an on-line coating layer (not shown in the figure) with a preferred thickness of 0.1-0.3 μm. The on-line coating can directly coat chemicals on the substrate layer through an on-line coater during the production process of the substrate layer. The on-line coating can be directly formed in the later stage of the production process of the substrate layer without the need to re-unroll the coil. The coating is evenly formed, fast, efficient, and low-cost. In a specific embodiment, the primer solution constituting the on-line coating layer can be coated onto the thick sheet before or during the stretching of the PET film constituting the substrate layer, and then as the thick sheet is stretched into a film with the required thickness, the primer solution coated on its surface becomes thinner during stretching and is cured together with the high temperature during the stretching process to form the on-line coating layer. In a specific embodiment, the on-line coating layer is formed by uniformly mixing acrylic resin, silica nanoparticles with a particle size of 5-10 nm, 1,4-dioxane, polyethylene oxide, and ethylene-vinyl acetate copolymer into a primer solution, and then curing through on-line coating. Specifically, the mass ratios of the components of the on-line coating layer are as follows: acrylic resin: silica nanoparticles: 1,4-dioxane: polyethylene oxide: ethylene-vinyl acetate copolymer is 100:(10-15):(20-30):(10-15):(5-10). Among them, the ethylene-vinyl acetate copolymer can be the ethylene-vinyl acetate copolymer with the trade name Evaflex 550 produced by Mitsui & Co., Ltd. of Japan, and the mass percentage of the vinyl acetate polymer contained therein is 14%.

[0033] According to the raw material weight part ratios in the following table, an on-line coating layer is prepared and obtained on one side surface of a single-layer 188-μm biaxially stretched PET film, and then sawtooth stripes are formed on the outside of the on-line coating layer.

[0034] Example 1 Example 2 Example 3 Example 4 Example 5 Acrylic resin 100 100 100 100 100 Silica nanoparticles 10 11.5 12.5 13.5 15 1,4-Dioxane 20 22 25 28 30 Polyethylene oxide 10 12 13 14 15 Ethylene-vinyl acetate copolymer 5 6 7.5 8 10 Online coating layer thickness (nm) 100 150 200 250 300 Barrier layer thickness (nm) 200 200 200 200 200

[0035] As a comparison, sawtooth stripes are directly formed on one side surface of a single-layer 188-μm biaxially stretched PET film as a comparative example. After measurement, the 180-degree peel force (N / 25 mm) of the sawtooth stripes in Examples 1-5 has increased by 15.3%, 16.5%, 16.3%, 15.8%, and 16.1% respectively compared with the comparative example.

[0036] In an embodiment (not shown), a pair of rollers with patterns matching the shapes of the first serrated stripe 12 and the second serrated stripe 13 can be used to clamp the PET film constituting the substrate layer 11 between the pair of rollers, and an ultraviolet-curable resin containing quantum dots is coated between the rollers and the PET film to form the first serrated stripe 12 and the second serrated stripe 13. At this time, the surface of the roller can be formed with an irregular uneven microstructure by sandblasting, and irregular bumps can be formed on its surface when forming the serrated stripes, so that a light diffusion effect can be obtained to improve the viewing angle of the backlight.

[0037] The preparation method of the quantum dot film of the present application will be further described in detail below with reference to the accompanying drawings. Specifically, the preparation method of the present application includes the following steps:

[0038] First, a layer of PET film is provided as the substrate layer 11, and the first serrated stripe 12 and the second serrated stripe 13 with the first quantum dots 121 and the second quantum dots 131 are respectively formed on both sides of the substrate layer 11.

[0039] As described above, the first serrated stripe 12 and the second serrated stripe 13 can be directly formed on the substrate layer 11. For example, the first serrated stripe 12 and the second serrated stripe 13 can be formed on the substrate layer 11 by using a conventional light-curable resin in the prior art through a mold. For example, two rollers arranged oppositely up and down can be used. The upper roller has a pattern matching the shape of the first serrated stripe 12, and the lower roller has a pattern matching the shape of the second serrated stripe 13. The PET film is clamped between the two rollers and extruded, and at the same time, an ultraviolet-curable resin with the first quantum dots 121 and the second quantum dots 131 is respectively coated between the rollers and the PET film, and then the PET film is irradiated with ultraviolet light, so as to obtain the cured first serrated stripe 12 and the second serrated stripe 13 on the PET film. Among them, the length directions of the patterns on the surfaces of the two rollers arranged oppositely up and down and matching the shapes of the serrated stripes are arranged perpendicular to each other, so that serrated stripes perpendicular to each other can be formed on both side surfaces of the PET film. For example, when the pattern directions on the surfaces of the two rollers form an angle of 45 degrees with the advancing direction of the PET film, serrated stripes forming an angle of 45 degrees with the four rectangular sides of the quantum dot film can be formed.

[0040] Among them, the thickness of the substrate layer 11 is about 100 - 500 μm, and the visible light transmittance is 85% - 95%.

[0041] In this embodiment, since the first serrated stripe 12 and the second serrated stripe 13 are formed by extruding and then curing a resin containing quantum dots, under the action of the extrusion pressure, the quantum dots in the resin can be better dispersed during the extrusion process. Therefore, the thickness of the resin containing quantum dots can be reduced. A better dispersion degree can also reduce the dosage of quantum dots, avoiding excessive blocking of light and affecting the light transmittance. In addition, since only one type of quantum dot is contained in the serrated stripe, different types of particles will not agglomerate during the extrusion operation. In the light conversion layer of the prior art, since it contains multiple types of particles, different types of particles will agglomerate during extrusion. Therefore, the prior art uses a light conversion layer with the same thickness as the dispersant, and the particles in it cannot be extruded during molding, and the extrusion dispersion is insufficient. It can only be compensated by a greater thickness and more quantum dots. Therefore, under the same conditions, compared with the serrated stripe structure containing quantum dots of the present application, the light conversion rate and light transmittance of the prior art are both reduced to a certain extent. For example, the height of the serrated stripe of the present application is only 5-10 μm, which is much lower than the thickness of the 50-150 μm light conversion layer of the prior art. According to the quantum dot content of 3 wt%, the dosage of quantum dots in the present application is greatly reduced, and a light conversion efficiency better than that of the prior art can be obtained, and the forward light brightness is better.

[0042] In another specific embodiment of the present application, online coating layers are formed on both side surfaces of the substrate layer 11, and the first serrated stripe 12 and the second serrated stripe 13 are formed outside the online coating layers of the substrate layer 11. For example, PET chips can be used as the raw material for preparing PET films. After melting and extrusion, a single-layer thick sheet is obtained, preheated and then longitudinally stretched into a film. After longitudinal stretching, through a coater, a mixture of the components constituting the online coating layer of the present application is simultaneously coated on both sides of the film, and then transversely stretched, shaped, cooled, and wound up, so as to form an online coating layer on the surface of the PET film. Then, the same as the previous embodiment, the first serrated stripe 12 and the second serrated stripe 13 are formed outside the online coating layer. For example, two rollers arranged opposite to each other can be used. The upper roller has a pattern matching the shape of the first serrated stripe 12, and the lower roller has a pattern matching the shape of the second serrated stripe 13. The PET film with the online coating layer is clamped between the two rollers for extrusion, and at the same time, an ultraviolet-curable resin containing the first quantum dot 121 and the second quantum dot 131 is respectively coated between the rollers and the PET film, and then the PET film is irradiated with ultraviolet light, so as to obtain the cured first serrated stripe 12 and the second serrated stripe 13 outside the online coating layer of the PET film.

[0043] Furthermore, in the above embodiments, since the process of preparing the PET film from PET chips is included, during the preparation of the PET film, 5 wt%-10 wt% of a light scattering agent can also be added to the PET chips. For example, nano PMMA particles are added, so that while obtaining the PET film with an online coating layer, it has the light scattering function.

[0044] In addition, the surface of the rollers for preparing the first serrated stripe 12 and the second serrated stripe 13 can also be sandblasted to form a concave-convex structure on the pattern matching the first and second serrated stripes, so that light scattering microstructures can be formed on the prepared first serrated stripe 12 and second serrated stripe 13, enabling the prepared first serrated stripe 12 and second serrated stripe 13 to have the light scattering function.

[0045] Then, through vacuum sputtering, a protective layer 14 is formed on the outer sides of the first serrated stripe 12 and the second serrated stripe 13 of the quantum dot film 100. For example, a silica protective layer 14 with a thickness of 1-3 μm can be formed through vacuum sputtering. Since the thickness of the formed protective layer 14 is relatively very thin, Figure 2 the protective layer 14 is not shown in, and at the same time, Figure 3 the size of the protective layer 14 and the quantum dots therein in is also magnified for easy understanding.

[0046] In summary, in the present application, since different quantum dots are separately dispersed in different serrated stripes, when selecting a coupling agent for surface modification, there is no need to consider issues such as the compatibility of different coupling agents and the matching of process conditions, thus effectively avoiding the agglomeration problem caused by the mixing of multiple types of quantum dots. The process can be simplified and the cost can be reduced.

[0047] Those skilled in the art should understand that although the present application is described in the manner of multiple embodiments, not every embodiment only contains an independent technical solution. Such narration in the specification is only for clarity. Those skilled in the art should understand the specification as a whole and consider the technical solutions involved in each embodiment as ways that can be combined with each other to form different embodiments to understand the protection scope of the present application.

[0048] The above are only illustrative specific embodiments of the present application and are not used to limit the scope of the present application. Any equivalent changes, modifications, and combinations made by those skilled in the art without departing from the concept and principles of the present application shall fall within the protection scope of the present application.

Claims

1. A quantum dot film for being disposed in front of a light guide plate (30) of a backlight module, the quantum dot film (100) comprising a substrate layer (11), characterized in that, On both side surfaces of the base material layer (11), a plurality of first serrated stripes (12) and second serrated stripes (13) with isosceles triangle cross-sections arranged in parallel at equal intervals are respectively formed. A protective layer (14) is formed on the surfaces of the first serrated stripes (12) and the second serrated stripes (13) by vacuum sputtering; the first serrated stripes (12) and the second serrated stripes (13) on both side surfaces of the base material layer (11) are arranged perpendicular to each other; different types of first quantum dots (121) and second quantum dots (131) are respectively dispersed in the first serrated stripes (12) and the second serrated stripes (13); the protective layer (14) is composed of silicon dioxide; the included angles between the length directions of the first serrated stripes (12) and the second serrated stripes (13) and the four rectangular sides of the base material layer (11) are 45 degrees.

2. The quantum dot thin film according to claim 1, wherein The length of the base of the isosceles triangle of the first serrated stripes (12) and the second serrated stripes (13) is 5 - 10 μm, the apex angle is 45 - 135 degrees, the height is 5 - 10 μm, and the minimum gap between adjacent stripes is 0 - 5 μm.

3. The quantum dot thin film according to claim 1, wherein Online coating layers are formed on both side surfaces of the base material layer (11), and the first serrated stripes (12) and the second serrated stripes (13) are formed outside the online coating layers.

4. A method for preparing a quantum dot thin film (100) as claimed in claim 1 or 2, comprising the following steps: providing a PET thin film as the base material layer (11), and respectively forming first serrated stripes (12) and second serrated stripes (13) with first quantum dots (121) and second quantum dots (131) on both sides of the base material layer (11); forming a protective layer (14) outside the first serrated stripes (12) and the second serrated stripes (13) of the quantum dot thin film (100) by vacuum sputtering.

5. A method for preparing a quantum dot thin film (100) as claimed in claim 3, comprising the following steps: providing a PET thin film as the base material layer (11), and respectively forming first serrated stripes (12) and second serrated stripes (13) with first quantum dots (121) and second quantum dots (131) on both sides of the base material layer (11); forming a protective layer (14) outside the first serrated stripes (12) and the second serrated stripes (13) of the quantum dot thin film (100) by vacuum sputtering.

6. The preparation method as claimed in claim 4 or 5 further comprises the following steps: using two rollers arranged oppositely up and down, the upper roller has a pattern matching the shape of the first serrated stripes (12), the lower roller has a pattern matching the shape of the second serrated stripes (13), clamping the PET thin film between the two rollers for extrusion, and respectively coating ultraviolet curable resins with first quantum dots (121) and second quantum dots (131) between the rollers and the PET thin film, and then irradiating the PET thin film with ultraviolet light, so as to obtain the cured first serrated stripes (12) and second serrated stripes (13) on the PET thin film.

7. The preparation method according to claim 5 further comprises the following steps: using PET chips as raw materials for preparing PET films, obtaining a single-layer thick sheet through melt extrusion, preheating and then longitudinally stretching it into a film. After longitudinal stretching, pass it through a coater to simultaneously and online coat a mixture of each component constituting the online coating layer on both sides of the film, and then transversely stretch, shape, cool and wind up, so as to form an online coating layer on the surface of the PET film; then, use two rollers arranged oppositely up and down, the upper roller has a pattern matching the shape of the first serrated stripe (12), and the lower roller has a pattern matching the shape of the second serrated stripe (13), clamp the PET film with the online coating layer between the two rollers for extrusion, and respectively coat an ultraviolet-curable resin with the first quantum dots (121) and the second quantum dots (131) between the rollers and the PET film, and then irradiate the PET film with ultraviolet light, so as to obtain the cured first serrated stripe (12) and the second serrated stripe (13) on the outer side of the online coating layer of the PET film.

8. The preparation method according to claim 7, characterized in that, 5 wt%-10 wt% of a light scattering agent is added to the PET chips.

9. The preparation method according to claim 6, wherein, The surface of the roller is treated by sandblasting to form a concave-convex structure on the pattern matching the first serrated stripe and the second serrated stripe.

10. The preparation method according to claim 7 or 8, characterized in that, The surface of the roller is treated by sandblasting to form a concave-convex structure on the pattern matching the first serrated stripe and the second serrated stripe.

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