CN218767722U - Quantum dot film - Google Patents

Abstract

The utility model discloses a quantum dot film, the quantum dot film includes the substrate layer, and the both sides surface of substrate layer is formed with a plurality of equidistant parallel arrangement's the cross-section is isosceles triangle's first sawtooth stripe and second sawtooth stripe respectively, the surface of first sawtooth stripe and second sawtooth stripe is formed with a layer protective layer through vacuum sputtering; the first sawtooth stripes and the second sawtooth stripes on the two side surfaces of the substrate layer are arranged vertically to each other; the first sawtooth stripes and the second sawtooth stripes are respectively dispersed with first quantum dots and second quantum dots with different types, and the substrate layer is dispersedly provided with light scattering particles. The utility model discloses an among the quantum dot film, because different quantum dot disperses respectively and is arranged in different sawtooth stripes, therefore when chooseing for use the coupling agent to carry out surface modification, need not to consider compatibility, the technological condition matching scheduling problem of different coupling agents to multiple type quantum dot has effectively been avoided and has mixed the reunion problem that causes.

Description

Quantum dot film

Technical Field

The utility model relates to a quantum dot film in LCD field.

Background

CN 108089369A discloses a quantum dot thin film in which the size of a light scattering agent contained in a light conversion layer is adjusted. As shown in fig. 1, the quantum dot thin film 100 of the prior art 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, and the thickness of the light conversion layer 120 is substantially the same as the size of the light scattering agents 122. According to the quantum dot thin film 100 of the related art, the quantum dot thin film including the light scattering agent 122 having 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 included in the light conversion layer 120, and improving the color reproducibility and brightness of light emitted through the quantum dot thin film, thereby enabling the emission of light having excellent quality.

Different types of quantum dots are different in material and surface property, and are easy to agglomerate with each other, and different types of quantum dots and light scattering agents are easy to agglomerate with each other. Although the size of the light scattering agent is enlarged in the prior art, the agglomeration problem of different types of quantum dots is still not effectively solved. In addition, the large-size light scattering agent has poor scattering effect, but can generate large blocking to incident light and weaken the light utilization rate of the quantum dot film.

Disclosure of Invention

The to-be-solved technical problem of the present invention is to provide a quantum dot film to reduce or avoid the aforementioned problems.

In order to solve the technical problem, the utility model provides a quantum dot film for set up in the place ahead of backlight unit's light guide plate, the quantum dot film includes the substrate layer, wherein, a plurality of equidistant parallel arrangement's the first sawtooth stripe and the second sawtooth stripe that the cross-section is isosceles triangle are formed respectively on the both sides surface of substrate layer, the surface of first sawtooth stripe and second sawtooth stripe forms a layer protective layer through vacuum sputtering; the first sawtooth stripes and the second sawtooth stripes on the two side surfaces of the substrate layer are arranged vertically to each other; the first sawtooth stripes and the second sawtooth stripes are respectively dispersed with first quantum dots and second quantum dots with different types, and the substrate layer is dispersedly provided with light scattering particles.

Preferably, the length of the base of the isosceles triangle of the first sawtooth stripe and the second sawtooth stripe is 5-10 μm, the vertex angle is 45-135 degrees, and the height is 5-10 μm.

Preferably, the included angles between the length directions of the first sawtooth stripes and the second sawtooth stripes and the four rectangular sides of the base material layer are 45 degrees.

Preferably, the two side surfaces of the substrate layer are formed with an on-line coating layer, and the first sawtooth stripes and the second sawtooth stripes are formed outside the on-line coating layer.

Preferably, the thickness of the in-line coating layer is 0.1 to 0.3 μm.

In the quantum dot film, different quantum dots are respectively dispersed in different sawtooth stripes, so that the problems of compatibility, process condition matching and the like of different coupling agents are not required to be considered when the coupling agents are selected for surface modification, and the problem of agglomeration caused by the mixing of various types of quantum dots is effectively avoided.

Drawings

The drawings are only for purposes of illustrating and explaining the present application and are not to be construed as limiting the scope of the present application.

Fig. 1 shows a schematic cross-sectional view of a quantum dot thin film of the prior art.

Fig. 2 is a schematic perspective view of a quantum dot film according to an embodiment of the present application.

Fig. 3 shows a schematic cross-sectional view of a quantum dot film according to another embodiment of the present application.

Detailed Description

In order to more clearly understand the technical features, objects, and effects of the present application, embodiments of the present application will now be described with reference to the accompanying drawings. Wherein like parts are given like reference numerals.

As shown in fig. 2-3, the present invention provides a quantum dot thin film 100 for a quantum dot liquid crystal display, which is disposed in front of a light guide plate 30 (fig. 3) of the quantum dot liquid crystal display. For the light conversion principle of the quantum dot thin film 100, reference is made to the prior art cited in the background, and the entire contents are incorporated by reference and not repeated.

The light conversion layer of the prior art quantum dot film contains many different types of particles, and for example, may include green quantum dots that emit green light having a wavelength ranging from about 520nm to about 560nm after absorbing blue light, and emit green light when the light incident on the light conversion layer is blue light having a wavelength ranging from about 430nm to about 470 nm. In addition, the light conversion layer may further include red quantum dots that absorb blue light and emit red light having a wavelength ranging from about 630nm to about 660nm, thereby emitting red light. In addition, the light conversion layer may further include a light scattering agent. These different types of particles need to be uniformly dispersed inside the polymer resin constituting the light conversion layer. Because the light conversion efficiency and the response speed of the blue light LED are higher, and the green quantum dots and the red quantum dots are cheaper, the cost for obtaining white light by matching the green quantum dots and the red quantum dots is lower by adopting the blue light LED as backlight, and the display effect is better. However, it is easy to agglomerate various different types of particles dispersed in the polymer resin, and surface modification of different types of particles may require coupling agents with greatly different properties, and different coupling agents need to consider the problems of compatibility, matching process conditions, and the like, resulting in complex process and high cost, and sometimes it is difficult to ensure uniform product quality.

In view of this, the present application provides an improved quantum dot film 100, as shown in the figure, the quantum dot film 100 includes a substrate layer 11, a plurality of first sawtooth stripes 12 and second sawtooth stripes 13 which are equally spaced and arranged in parallel and have isosceles triangle-shaped cross sections are respectively formed on two side surfaces of the substrate layer 11, the first sawtooth stripes 12 and the second sawtooth stripes 13 may have the same size, so as to reduce the cost of the mold, and the stripes with different sizes and intervals may also be selected as required. The scale of the quantum dot film 100 is enlarged for easy observation and understanding, the actual sawtooth stripes are relatively small in size, and the surface has only small texture which is not easy to be perceived, and the overall light transmittance of the quantum dot film 100 is not affected. The first sawtooth stripe 12 and the second sawtooth stripe 13 respectively contain different types of first quantum dots 121 and second quantum dots 131 dispersed therein. As mentioned above, the first quantum dot is a green or red quantum dot, and the second quantum dot is a red or green quantum dot.

In the application, the first quantum dots 121 and the second quantum dots 131 are respectively dispersed in the first sawtooth stripes 12 and the second sawtooth stripes 13, so that when the coupling agent is selected for surface modification, the problems of compatibility, process condition matching and the like of different coupling agents do not need to be considered, and the agglomeration problem caused by the mixing of various types of quantum dots is effectively avoided. The process can be simplified and the cost can be reduced. The first quantum dot 121 and the second quantum dot 131 may employ a suitable type of quantum dot known in the art. The first sawtooth stripes 12 and the second sawtooth stripes 13 can be formed on the substrate layer 11 by curing the existing ultraviolet curing resin through a mold, and of course, selected quantum dots, a proper coupling agent for surface modification and the like are added into the ultraviolet curing resin to avoid agglomeration and improve the dispersibility.

In a specific embodiment, the maximum thickness of the quantum dot film 100 is 100-500 μm. In another embodiment, it is preferable that the first sawtooth stripe 12 and the second sawtooth stripe 13 have the same size, and the isosceles triangles of the first sawtooth stripe 12 and the second sawtooth stripe 13 have a length of 5 to 10 μm, a vertex angle of 45 to 135 degrees, a height of 5 to 10 μm, and a minimum gap between adjacent stripes of 0 to 5 μm.

The substrate layer 11 can be made of a PET film, has excellent strength, insulation performance and thermal stability, and can provide support for the quantum dot film 100. Further, in an embodiment not shown in the figure, light scattering particles, such as PMMA particles, may be dispersed in the substrate layer 11 to obtain a light diffusion effect on the substrate layer 11. Because the substrate layer 11 does not contain quantum dots, the problems of compatibility, matching process conditions and the like of different coupling agents do not need to be considered when the light scattering agent is dispersed in the substrate layer, and the agglomeration problem caused by mixing of different types of particles is effectively avoided.

The first sawtooth stripes 12 and the second sawtooth stripes 13 on the surfaces of the two sides of the substrate layer 11 can assemble the light incident on the light guide plate 30 to the tops of the sawtooth stripes, so that the light obliquely incident on the light guide plate 30 is adjusted to be emergent in the vertical direction, the light intensity in the vertical direction is improved, the light conversion efficiency of the incident light irradiating quantum dots can be improved, the forward emergent light brightness is improved, and the substrate layer is particularly suitable for being used as a direct type backlight source. In order to avoid the concentrated moire fringes at the positions where the light beams converge in the same direction, the first and second saw-tooth fringes 12 and 13 are preferably arranged in a perpendicular state to each other so that the moire fringes generated by the second saw-tooth fringes 13 on the incident light side (lower side in fig. 3) can be masked by the first saw-tooth fringes 12 on the outgoing light side (upper side in fig. 3).

Although the quantum dot film 100 in fig. 2-3 is shown as a separate structure, it will be understood by those skilled in the art that the above layer can be bonded and compounded with other optical film sheets by adhesive, for example, can be compounded with other brightness enhancement films or diffusion films, etc., for example, to increase the bonding area and avoid delamination. The surface structure with the first sawtooth stripes 12 and the second sawtooth stripes 13 is adopted, so that the bonding combination with other optical films is facilitated. For example, the contact area with the adhesive can be increased by the saw-toothed stripe, for example, when the vertex angle of the isosceles triangle of the saw-toothed stripe is 60 degrees, the saw-toothed stripe can double the surface area relative to the plane adhesion, thereby increasing the overall adhesion of the quantum dot film 100 and avoiding the problem of delamination after the quantum dot film 100 is composited.

In addition, when the first sawtooth stripes 12 and the second sawtooth stripes 13 are formed by curing, because the surface tension of the ultraviolet curing resin is different from that of the substrate layer, shrinkage is easily accumulated in the length direction in the curing process, so that buckling deformation occurs in the length direction of the sawtooth stripes, and the flatness of the quantum dot membrane is affected. To avoid this, the longitudinal direction of the first sawtooth stripe 12 and the second sawtooth stripe 13 preferably forms an angle of 45 degrees with four rectangular sides of the quantum dot film 100, as shown in fig. 2. In general, the quantum dot film 100 is generally designed to be rectangular, four sides are perpendicular to each other, and if the length direction of the sawtooth stripes is perpendicular to one pair of rectangular sides of the quantum dot film 100, the other pair of rectangular sides will be parallel to the length direction of the sawtooth stripes. The direction of the sawtooth stripes is turned to form 45-degree included angles with the four rectangular sides, the proportion of the shrinkage difference in different directions caused by the sawtooth stripes to diffuse to the four rectangular sides tends to be average, the problem of warping deformation of the quantum dot film 100 caused by the arrangement of the sawtooth stripes can be avoided, the problem of delamination in subsequent bonding compounding can be avoided, and the structural performance of the quantum dot film 100 is further improved.

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

In order to improve the adhesion of the saw-tooth stripes, before the first saw-tooth stripes 12 and the second saw-tooth stripes 13 are formed, an in-line coating process may be performed on both surfaces of the substrate layer 11 to form an in-line coating layer (not shown) having a thickness of preferably 0.1 to 0.3 μm. The online coating can be directly through online coating machine with the coating of chemical article on the substrate layer in the production process of substrate layer, and online coating can be directly formed in the later stage of the production process of substrate layer, need not launch the operation again with the coiled material, and the coating forms evenly, fast, efficient, and is with low costs. In one embodiment, the primer solution constituting the in-line coating layer may be applied to the slab before or during stretching of the PET film constituting the substrate layer, and then as the slab is stretched into a film of a desired thickness, the primer solution applied to the surface thereof is cured together with the thinning of the slab through a high temperature during stretching to form the in-line coating layer. In one embodiment, the on-line coating layer is formed by uniformly mixing acrylic resin, silica nanoparticles with the particle size of 5-10nm, 1, 4-dioxane, polyethylene oxide and ethylene-vinyl acetate copolymer into a primer solution, and then curing the primer solution through on-line coating. Specifically, the mass ratio of each component of the online coating layer is respectively that acrylic resin: silica nanoparticles: 1, 4-dioxane: polyethylene oxide: the ethylene-vinyl acetate copolymer is 100: (10-15): (20 to 30): (10-15): (5-10). Wherein the ethylene-vinyl acetate copolymer can be ethylene-vinyl acetate copolymer which is sold by the Japan three-well company and has the trademark of Evaflex 550, and the mass percentage of the contained vinyl acetate polymer is 14 percent.

On one side surface of a single-layer 188 μm biaxially oriented PET film, an in-line coating layer was prepared according to the following raw material weight ratio, and then a saw-tooth stripe was formed on the outer side of the in-line coating layer.

	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
On-line coating layer thickness (nm)	100	150	200	250	300
						Thickness of barrier layer (nm)	200	200	200	200	200

For comparison, a saw-toothed stripe was formed directly on one side surface of a single layer of 188 μm biaxially oriented PET film as a comparative example. The 180 degree peel force (N/25 mm) of the sawtooth striations of examples 1-5 were measured to be 15.3%, 16.5%, 16.3%, 15.8% and 16.1% respectively higher than the comparative examples.

In an embodiment not shown in the drawings, a pair of rolls having a pattern matching the shape of the first saw-tooth stripes 12 and the second saw-tooth stripes 13 may be used, the PET film constituting the substrate layer 11 is sandwiched between the pair of rolls, and an ultraviolet curable resin containing quantum dots is applied between the rolls and the PET film to form the first saw-tooth stripes 12 and the second saw-tooth stripes 13. At this time, the surface of the roller can be formed into irregular rugged microstructures by adopting a sand blasting process, and irregular salient points can be formed on the surface of the roller when the sawtooth stripes are formed, so that a light diffusion effect can be obtained, and the visual angle of backlight is improved.

The method for preparing the quantum dot thin film of the present application is described in further detail below with reference to the accompanying drawings. Specifically, the preparation method comprises the following steps:

first, a PET film is provided as the substrate layer 11, and the first sawtooth stripes 12 and the second sawtooth stripes 13 with the first quantum dots 121 and the second quantum dots 131 are respectively formed on both sides of the substrate layer 11.

As described above, the first saw-tooth stripes 12 and the second saw-tooth stripes 13 may be directly formed on the substrate layer 11. For example, the first sawtooth pattern 12 and the second sawtooth pattern 13 may be formed on the substrate layer 11 by a mold using a photo-curable resin which is conventional in the art. For example, two rollers may be used which are opposed to each other, the upper roller having a pattern corresponding to the shape of the first saw-tooth stripes 12 and the lower roller having a pattern corresponding to the shape of the second saw-tooth stripes 13, the PET film may be sandwiched between the two rollers to be pressed, and the uv-curable resin having the first quantum dots 121 and the second quantum dots 131 may be coated between the two rollers and the PET film, respectively, and then the PET film may be irradiated with uv light, thereby obtaining the cured first saw-tooth stripes 12 and the second saw-tooth stripes 13 on the PET film. The length directions of the patterns matched with the shape of the sawtooth stripes on the surfaces of the two rollers which are opposite up and down are arranged perpendicular to each other, so that the sawtooth stripes which are perpendicular to each other can be formed on the surfaces of the two sides of the PET film. For example, the pattern direction of the two roller surfaces forms an included angle of 45 degrees with the advancing direction of the PET film, so that sawtooth stripes forming an included angle of 45 degrees with four rectangular sides of the quantum dot film can be formed.

The thickness of the substrate layer 11 is about 100-500 μm, and the visible light transmittance is 85% -95%.

In this embodiment, because first sawtooth stripe 12 and second sawtooth stripe 13 are formed through carrying out the solidification after the extrusion to the resin that contains the quantum dot, under the effect of extrusion force, the quantum dot in the resin can obtain better dispersion in extrusion process, therefore can reduce the thickness of the resin that contains the quantum dot, and better dispersion can also reduce the quantity of quantum dot, avoids forming too much the blockking to the ray, influences the luminousness. In addition, because the sawtooth stripes only contain one type of quantum dots, the phenomenon that different types of particles are agglomerated during extrusion operation can not occur. Since the light conversion layer in the prior art contains various types of particles, different types of particle agglomeration phenomena can occur during extrusion. Therefore, the light conversion layer with the same thickness as the dispersing agent is adopted in the prior art, the particles in the light conversion layer cannot be extruded during molding, the extrusion dispersion is insufficient, and the particles can only be compensated by the quantum dots with larger thickness, so that the light conversion rate and the light transmittance of the prior art are reduced to a certain extent compared with the sawtooth stripe structure containing the quantum dots in the application under the same condition. For example, the height of the zigzag stripes of the present application is only 5 to 10 μm, which is much reduced compared to the thickness of the light conversion layer of the prior art of 50 to 150 μm, and the amount of the quantum dots of the present application is greatly reduced according to the quantum dot content of 3wt%, and light conversion efficiency superior to that of the prior art can be obtained with better forward luminance.

In another embodiment of the present application, the substrate layer 11 has an in-line coating layer formed on both surfaces thereof, and the first sawtooth stripes 12 and the second sawtooth stripes 13 are formed on the outside of the in-line coating layer of the substrate layer 11. For example, a PET chip is used as a raw material for preparing a PET film, a single-layer thick sheet is obtained by melt extrusion, the sheet is longitudinally stretched into a film after preheating, a mixture of components constituting the on-line coating layer of the present application is simultaneously coated on both sides of the film on line by a coater after longitudinally stretching, and then the film is transversely stretched, shaped, cooled and wound, thereby forming the on-line coating layer on the surface of the PET film. Then, as in the previous embodiment, the first sawtooth stripes 12 and the second sawtooth stripes 13 are formed on the outer side of the on-line coating layer. For example, two rolls may be used which are opposed to each other, the upper roll having a pattern corresponding to the shape of the first saw-tooth stripes 12 and the lower roll having a pattern corresponding to the shape of the second saw-tooth stripes 13, the PET film having the on-line coating layer is sandwiched between the two rolls and pressed, and simultaneously the uv curable resin having the first quantum dots 121 and the second quantum dots 131 is coated between the rolls and the PET film, respectively, and then the PET film is irradiated with uv light, thereby obtaining the cured first saw-tooth stripes 12 and the second saw-tooth stripes 13 on the outer side of the on-line coating layer of the PET film.

Further, in the above embodiment, since the process of preparing the PET film from the PET chip is included, in the process of preparing the PET film, 5wt% to 10wt% of light scattering particles, for example, nano PMMA particles, may be further added to the PET chip, so that the PET film with the on-line coating layer is prepared and simultaneously has a light scattering function.

In addition, the surface of the roll on which the first and second saw- tooth stripes 12 and 13 are prepared may be further subjected to sand blasting to form a convex-concave structure on a pattern matching the first and second saw-tooth stripes, so that a light scattering microstructure may be formed on the prepared first and second saw- tooth stripes 12 and 13 to provide the prepared first and second saw- tooth stripes 12 and 13 with a light scattering function.

Then, the protective layer 14 is formed on the outer sides of the first sawtooth pattern 12 and the second sawtooth pattern 13 of the quantum dot thin film 100 by vacuum sputtering, and for example, a silicon dioxide protective layer 14 having a thickness of 1 to 3 μm may be formed by vacuum sputtering. Since the thickness of the formed protective layer 14 is relatively very thin, the protective layer 14 is not shown in fig. 2, and the size of the protective layer 14 and the quantum dots therein in fig. 3 is enlarged for easy understanding.

In summary, according to the method, different quantum dots are respectively dispersed in different sawtooth stripes, so that the problems of compatibility, process condition matching and the like of different coupling agents are not required to be considered when the coupling agents are selected for surface modification, and the problem of agglomeration caused by the mixing of various types of quantum dots is effectively avoided. The process can be simplified and the cost can be reduced.

It should be appreciated by those skilled in the art that while the present application is described in terms of several embodiments, not every embodiment includes only a single embodiment. The description is thus given for clearness of understanding only, and it is to be understood that all matters in the embodiments are to be interpreted as including all technical equivalents which are encompassed by the claims and are to be interpreted as combined with each other in a different embodiment so as to cover the scope of the present application.

The above description is only illustrative of the present invention and is not intended to limit the scope of the present invention. Any equivalent changes, modifications and combinations that may be made by those skilled in the art without departing from the spirit and principles of the present application shall fall within the scope of the present application.

Claims (5)

1. A quantum dot film is used for being arranged in front of a light guide plate of a backlight module and comprises a substrate layer, and is characterized in that a plurality of first sawtooth stripes and a plurality of second sawtooth stripes which are arranged in parallel at equal intervals and have isosceles triangle-shaped sections are formed on the surfaces of two sides of the substrate layer respectively, and a protective layer is formed on the surfaces of the first sawtooth stripes and the second sawtooth stripes through vacuum sputtering; the first sawtooth stripes and the second sawtooth stripes on the two side surfaces of the substrate layer are arranged vertically to each other; the first sawtooth stripes and the second sawtooth stripes are respectively dispersed with first quantum dots and second quantum dots with different types, and the substrate layer is dispersedly provided with light scattering particles.

2. The quantum dot film of claim 1, wherein the isosceles triangles of the first sawtooth stripe and the second sawtooth stripe have a length of a base side of 5 to 10 μm, an apex angle of 45 to 135 degrees, and a height of 5 to 10 μm.

3. The quantum dot film of claim 2, wherein the first sawtooth stripe and the second sawtooth stripe have a length direction that makes an angle of 45 degrees with four rectangular sides of the substrate layer.

4. The quantum dot film of claim 3, wherein the substrate layer has on-line coating layers formed on both surfaces thereof, and the first sawtooth stripes and the second sawtooth stripes are formed outside the on-line coating layers.

5. The quantum dot film of claim 4, wherein the in-line coating layer has a thickness of 0.1 to 0.3 μm.

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