A light uniformity film, a composite light uniformity film and a preparation method thereof

Abstract

The present application relates to a kind of composite homogenizing films, especially to a kind of heat-resistant composite homogenizing film for weakening LED light shadow and improving uniformity and its preparation method.In order to improve the problem of LED light shadow under high brightness, large pitch and short mixing light distance, and improve the uniformity of light emission, the present application provides a kind of heat-resistant composite homogenizing film and its preparation method.The heat-resistant composite homogenizing film includes a hardening layer, a filter substrate layer, a composite adhesive layer, a light splitting layer and a substrate layer.The light splitting layer is located on the lower surface of the substrate layer, the hardening layer is located on the lower surface of the filter substrate layer, the composite adhesive layer is located on the upper surface of the filter substrate layer, the sharp part of the light splitting layer is embedded in the composite adhesive layer to combine the filter substrate layer with it, the surface finish of the light splitting layer is high, and the abnormal deflection of light is less.The homogenizing film can reasonably distribute the energy concentrated within a certain range of the beam center of point light source to other directions, reduce the energy of the center bright spot on the projection screen, and expand the overall light emitting area, thereby improving the uniformity of energy distribution, while having good scratch resistance and low risk of thermal deformation.

Description

Technical Field

[0001] This invention relates to an optical film, and more particularly to a light-diffusing film that reduces LED light shadows and improves uniformity, a composite light-diffusing film, and a method for preparing the same. Background Technology

[0002] Light-emitting diodes (LEDs) are the most commonly used light source in the field of optoelectronic displays. How to efficiently and uniformly transform this light source into the line light source or even the surface light source we want has always been a topic worthy of continuous research.

[0003] In the traditional field of liquid crystal displays (LCDs), LCD panels require backlight modules to provide a light source, especially direct-lit backlight modules. LED arrays emit light with a certain beam angle vertically upward from the lamp board, and the point light source is converted into a uniform surface light source through diffuser plates and various traditional optical films (such as diffuser films, brightness enhancement films, etc.).

[0004] Since most of the light emitted by an LED is concentrated in the beam center and within a small range of beam angles away from the center, this highly concentrated light will produce high light intensity (the peak light intensity of a cosine light emitter is at the beam center, and the light intensity at other angles gradually decreases, and the ratio of the light intensity to the peak light intensity is equal to the cosine value of that angle). When projected onto the panel, a small and bright spot—a hotspot—will be formed directly above the location of the light. The energy (illuminance) distribution at the center of the hotspot and between two hotspots has a large difference, which will produce the problem of light shadow or uneven light emission.

[0005] Especially in some new display technology applications, when the brightness of a single LED lamp is high, the spacing between lamps is large, or the mixing distance is short, the difference in energy distribution is further amplified, and the lamp shadow phenomenon becomes more and more obvious. For example, in order to pursue the ultimate visual effect, MiniLED models not only design the brightness of a single lamp to be very high, thereby improving contrast and peak brightness, but also design the mixing distance (OD) to be very short in order to reduce the halo phenomenon in dark fields and reduce crosstalk between pixels, making it difficult to resolve lamp shadows. Similarly, large-size conventional direct-lit models need to shorten the OD in order to reduce thickness, or increase the lamp spacing in order to reduce lamps and reduce power consumption, making it equally difficult to resolve lamp shadows.

[0006] The key to solving the problem of light shadows lies in how to reasonably distribute the energy concentrated in a certain range of the beam center of a point light source to other directions under a relatively short mixing distance, so as to reduce the energy of the central bright spot on the projection screen (the panel position in LCD) and expand the overall light-emitting area, thereby improving the uniformity of energy distribution (reducing the standard deviation).

[0007] Traditional diffuser plates and films, due to their inherent optical principles, only utilize particle refraction, scattering, and reflection (whether from air bubbles, organic particles, inorganic particles, or particle-free imprints) to achieve disordered light diffusion (non-directional). This results in a very limited increase in the light-emitting area, and the energy remains concentrated at the center. Therefore, they cannot meet the light homogenization requirements of the aforementioned application scenarios (such as...). Figure 1 (as shown in a and 1b).

[0008] Therefore, it is necessary to develop a light-diffusing film that can directionally adjust the direction of light, effectively separate the centrally concentrated light (spectral splitting), and expand the light-emitting area (light amplification). Figure 1 (as shown in a, 1c). Summary of the Invention

[0009] To improve the light shadow problem of high-brightness, short-dose point light source arrays, this invention provides a light-diffusing film and its preparation method.

[0010] The uniform light distribution film provided by this invention can rationally distribute the energy concentrated within a certain range of the beam center of a point light source to other directions, thereby reducing the energy of the central bright spot on the projection screen and expanding the overall light-emitting area, thus improving the uniformity of energy distribution. The uniform light distribution film provided by this invention can make the emitted light more uniform and the brightness more uniform, improving the lamp shadow problem of high-brightness, short-OD point light source arrays.

[0011] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0012] The present invention provides a light-diffusing film, which comprises a light-splitting layer and a substrate layer.

[0013] The present invention provides a light-uniforming film, which includes a light-splitting layer, a substrate layer and a light-amplifying layer, wherein the light-amplifying layer is located on the upper surface of the substrate layer and the light-splitting layer is located on the lower surface of the substrate layer.

[0014] The linear roughness Ra of the surface of the beam-splitting layer is less than 250 nm. The surface of the beam-splitting layer has a high degree of smoothness.

[0015] The uniform light film can rationally distribute the energy concentrated within 30 degrees of the center beam angle of the point light source beam to other directions, thereby reducing the energy of the central bright spot on the projection screen and expanding the overall light-emitting area, thus improving the uniformity of energy distribution by at least 30%.

[0016] Furthermore, when the light from the light source passes through the homogenizing film within a beam angle of 30 degrees, a single bright spot can be observed on the projection screen to transform into multiple bright spots or a superposition of multiple bright spots. The size of the bright spots becomes smaller and the intensity becomes weaker. The uniformity of the energy distribution is measured by the standard deviation of the illuminance distribution on the projection screen, and the standard deviation of the illuminance distribution can be improved by at least 30%.

[0017] The beam splitting layer is composed of N long ribs stacked in N directions, where N is the topological coefficient. The long ribs are laid flat on the lower surface of the substrate layer and extend infinitely to both ends. The long ribs in the same direction are closely arranged. The N directions divide the 360-degree azimuth angle equally, that is, the angular interval between adjacent directions is 180 / N degrees. N is selected from 1, 2 or 3.

[0018] The cross-sections of the long ribs in the beam-splitting layer are identical, all being isosceles triangles. The left and right sides are either straight lines, convex arcs, or concave arcs with finite ends. The base is a straight line with a length W1 of 10–100 μm and a vertex angle θ of 60–120°. o The curvature of a convex or concave arc (referred to as a concave-convex arc) is expressed by a central angle, α, which ranges from 1 to 30 degrees. o .

[0019] The beam splitting layer is one of a standard surface beam splitting layer, a convex arc surface beam splitting layer, and a concave arc surface beam splitting layer. The left and right sides of the isosceles triangle of the corresponding long rib cross section are respectively a straight line, an outward convex arc (referred to as a convex arc), and an inward concave arc (referred to as a concave arc).

[0020] The substrate layer is a transparent polymer, and the material is selected from one of polyethylene terephthalate (PET), methyl methacrylate (PMMA), polycarbonate (PC), cellulose triacetate (TAC), and cyclic olefin polymer (COP).

[0021] The thickness M of the substrate layer is 25–500 μm.

[0022] The light-diffusing film is one of the following: planar light-diffusing film, prism light-diffusing film, cylindrical lens light-diffusing film, pyramidal light-diffusing film, or microlens light-diffusing film.

[0023] The light-diffusing film is a planar light-diffusing film, which comprises a beam-splitting layer and a substrate layer. The beam-splitting layer is one of a standard surface beam-splitting layer, a convex arc surface beam-splitting layer, or a concave arc surface beam-splitting layer. A beam-splitting layer with straight legs of an isosceles triangle in the cross-section of a long rib is called a standard surface beam-splitting layer; a beam-splitting layer with outwardly convex arc legs is called a convex arc surface beam-splitting layer; and a beam-splitting layer with inwardly concave arc legs is called a concave arc surface beam-splitting layer.

[0024] The light-diffusing film is a prism light-diffusing film, which comprises a beam-splitting layer, a substrate layer, and a light-amplifying layer. The beam-splitting layer is one of a standard surface beam-splitting layer, a convex arc surface beam-splitting layer, or a concave arc surface beam-splitting layer. The light-amplifying layer is a prism layer, formed by laying down triangular prism ribs. The cross-section of each triangular prism rib is an isosceles triangle, with a base V of 10–100 μm and a vertex angle β of 60–120 degrees. o Furthermore, the vertex angle β is 75–105 degrees. o .

[0025] The light-diffusing film is a cylindrical lens light-diffusing film, which comprises a beam-splitting layer, a substrate layer, and a light-amplifying layer. The beam-splitting layer is one of a standard surface beam-splitting layer, a convex arc surface beam-splitting layer, or a concave arc surface beam-splitting layer. The light-amplifying layer is a cylindrical lens layer, which is formed by laying cylindrical lenses flat. The cross-section of the cylindrical lenses is an arc, the width (chord length) F of the arc is 20-1000 μm, the height of the arc is K, and the aspect ratio K / F is 0.05-0.5.

[0026] The light-diffusing film is a pyramidal light-diffusing film, comprising a beam-splitting layer, a substrate layer, and a light-amplifying layer. The beam-splitting layer is one of a standard surface beam-splitting layer, a convex arc surface beam-splitting layer, or a concave arc surface beam-splitting layer. The light-amplifying layer is a pyramidal layer, composed of flatly laid triangular or square pyramids. The vertices of the triangular pyramids form an equilateral triangle arrangement, and the vertices of the square pyramids form a square arrangement. The height T of the pyramids is 10–100 μm, and the angle γ between the lateral surface and the height is 30–60 degrees. o ;

[0027] The light-diffusing film is a microlens light-diffusing film, comprising a beam-splitting layer, a substrate layer, and a light-amplifying layer. The beam-splitting layer is one of a standard surface beam-splitting layer, a convex arc surface beam-splitting layer, or a concave arc surface beam-splitting layer. The light-amplifying layer is a microlens layer, in which the principal optical axes of three adjacent microlenses are connected to form an equilateral triangle array, and the microlenses in the microlens array are closely arranged. The width G of each microlens is 10–100 μm, the height H is H, the aspect ratio H / G is 0.05–0.5, and the distance D between the principal optical axes of adjacent microlenses is equal to G.

[0028] The beam splitter and beam amplifier layers are made of transparent polymer resin.

[0029] The transparent polymer resin is selected from AR (acrylic resin, acrylic resin or modified acrylic resin), PMMA, or PC. AR is preferably processed by photocuring, while PMMA and PC are preferably processed by thermoforming.

[0030] The transparent polymer resin of the spectral splitting layer is selected from AR, PC or PMMA, and the refractive index n1 is selected from 1.4 to 1.65.

[0031] When the light-expanding layer is a prism layer, cylindrical lens layer, pyramidal layer, or microlens layer, the transparent polymer resin is selected from AR, PC, or PMMA, and the refractive index n2 is selected from 1.4 to 1.65.

[0032] This invention provides a light-diffusing film comprising a substrate layer 20 and a beam-splitting layer 21, wherein a light-amplifying layer 22 is absent, as shown below. Figure 10As shown, the homogenizing film is a planar homogenizing film. The thickness M of the substrate layer 20 is 25-500μm, for example 25μm, 75μm, 100μm, 125μm, 250μm, 500μm. The material of the substrate layer is selected from PET, PMMA, or PC. The beam-splitting layer is composed of a transparent polymer resin, the material of which is a photocurable acrylic resin (AR), PMMA, or PC, and the refractive index n1 is 1.4-1.65, for example 1.4, 1.5, 1.58, 1.65. The beam-splitting layer has a uniaxial standard surface design: it is composed of long ribs stacked in N directions. The long ribs are laid flat on the lower surface of the substrate layer, and the long ribs extend infinitely to both ends. The long ribs in the same direction are closely arranged, and the topological coefficient N is 1, that is, uniaxial beam splitting (e.g., Figure 6 (As shown); the beam-splitting layer is selected from the standard surface beam-splitting layer, and the corresponding long rib cross-section is an isosceles triangle with the left and right legs being straight lines finitely intercepted at both ends, that is, the cross-section of the long rib is an isosceles triangle with a vertex angle θ of 60°. o -120 o For example, 60 o 75 o 80 o 90 o 105 o 120 o When the beam splitter is a convex or concave arc surface beam splitter, the left and right sides of the corresponding long rib cross-section are an isosceles triangle, with the outer convex arc (referred to as the convex arc) and the inner concave arc (referred to as the concave arc) respectively finitely cut at both ends, and the vertex angle θ is 60°. o -120 o For example, 60°, 80° o 87 o 90 o 100 o 120 o The central angle α is 1-30°. o For example, 1 o 3 o 10 o 30 o The light-uniforming film exhibits good light-uniformity performance, with a uniformity improvement of U = 30-120%. The aforementioned technical solutions include Examples 1-31.

[0033] This invention provides a light-diffusing film comprising a substrate layer 20, a beam-splitting layer 21, and a light-diffusing layer 22, such as... Figure 11As shown, the light-diffusing film is a prism light-diffusing film. The thickness M of the substrate layer 20 is 25-500μm, for example, 25μm, 75μm, 250μm, 500μm. The material of the substrate layer is selected from PET, PMMA, or PC. The beam-splitting layer is made of transparent polymer resin, specifically photocurable acrylic resin (AR), with a refractive index n1 of 1.5. The light-diffusing layer is also made of transparent polymer resin, specifically photocurable acrylic resin (AR), with a refractive index n2 of 1.4-1.65, for example, 1.4, 1.5, 1.65. The beam-splitting layer has a biaxial standard surface design: it is composed of stacked long ribs in N directions. The long ribs are laid flat on the lower surface of the substrate layer, extending infinitely at both ends. Long ribs in the same direction are closely arranged, and the topological coefficient N is selected from 2, i.e., biaxial beam splitting (e.g., ...). Figure 7 (As shown); the beam-splitting layer is selected from the standard surface beam-splitting layer, and the corresponding long rib cross-section is an isosceles triangle with the left and right legs being straight lines finitely cut at both ends, that is, the cross-section of the long rib is a right-side triangle with a vertex angle θ of 90°. o The light-amplifying layer is prism layer 221, which is composed of prismatic ribs laid flat. The cross-section of each prism rib is an isosceles triangle with a base V of 10-100 μm, for example, 10 μm, 25 μm, 50 μm, 75 μm, 100 μm, and a vertex angle β of 60°. o -120 o For example, 60 o 75 o 90 o 105 o 120 o The light-uniforming film exhibits excellent light-uniformity performance, with a uniformity improvement of U = 91-302%. The aforementioned technical solutions include Examples 37-48.

[0034] This invention provides a light-diffusing film comprising a substrate layer 20, a beam-splitting layer 21, and a light-diffusing layer 22, such as... Figure 12As shown, the light-diffusing film is a cylindrical lens light-diffusing film. The thickness M of the substrate layer 20 is 25-500 μm, for example, 25 μm, 75 μm, 125 μm, 250 μm, 500 μm. The material of the substrate layer is selected from PET, PMMA, or PC. The beam-splitting layer is composed of a transparent polymer resin, which is a photocurable acrylic resin (AR) with a refractive index n1 of 1.5. The light-diffusing layer is composed of a transparent polymer resin, which is a photocurable acrylic resin (AR) with a refractive index n2 of 1.4-1.65, for example, 1.4, 1.5, 1.65. The beam-splitter layer features a biaxial standard plane design: it is composed of stacked long ribs in N directions, which lie flat on the lower surface of the substrate layer and extend infinitely towards both ends. Ribs in the same direction are closely arranged, and the topological coefficient N is selected from 2, hence biaxial beam splitting. The beam-splitter layer is selected as a standard plane beam-splitter layer, and the cross-section of its corresponding long rib is an isosceles triangle with its left and right sides being straight lines finitely intercepted at both ends; that is, the cross-section of the long rib is a right-side triangle with a vertex angle θ of 90°. o The light-diffusing layer is a columnar lens layer 222, formed by laying down columnar lens ribs. The cross-section of the columnar lens is an arc, and the width (chord length) F of the arc is 20-1000 μm, for example, 20 μm, 50 μm, 100 μm, 250 μm, 500 μm, 1000 μm. The height of the arc is K, and the aspect ratio K / F is 0.05-0.5, for example, 0.05, 0.1, 0.3, 0.5. This light-diffusing film has good light-diffusing performance, with a uniformity improvement of U = 97-125%. The aforementioned technical solutions include Examples 49-60.

[0035] This invention provides a light-diffusing film comprising a substrate layer 20, a beam-splitting layer 21, and a light-diffusing layer 22, such as... Figure 13 As shown, the light-diffusing film is a pyramidal light-diffusing film. The thickness M of the substrate layer 20 is 25-500 μm, for example, 25 μm, 75 μm, 250 μm, 500 μm. The material of the substrate layer is selected from PET, PMMA, or PC. The beam-splitting layer is composed of a transparent polymer resin, which is a photocurable acrylic resin (AR) with a refractive index n1 of 1.5. The light-diffusing layer is composed of a transparent polymer resin, which is a photocurable acrylic resin (AR) with a refractive index n2 of 1.4-1.65, for example, 1.4, 1.5, 1.65. The beam-splitter layer features a biaxial standard plane design: it is composed of stacked long ribs in N directions, which lie flat on the lower surface of the substrate layer and extend infinitely towards both ends. Ribs in the same direction are closely arranged, and the topological coefficient N is selected from 2, hence biaxial beam splitting. The beam-splitter layer is selected as a standard plane beam-splitter layer, and the cross-section of its corresponding long rib is an isosceles triangle with its left and right sides being straight lines finitely intercepted at both ends; that is, the cross-section of the long rib is a right-side triangle with a vertex angle θ of 90°. oThe light-diffusing layer is a square pyramid layer 224, composed of paved square pyramids with their vertices arranged in a square pattern. The height T of the pyramids is 10-50 μm, for example, 10 μm, 20 μm, 30 μm, 40 μm, or 50 μm, and the angle γ between the side surface and the height is 30°. o -60 o For example, 30 o 45 o 60 o The light-uniforming film exhibits good light-uniformity performance, with a uniformity improvement of U = 41-270%. The aforementioned technical solutions include Examples 61-70.

[0036] This invention provides a light-diffusing film comprising a substrate layer 20, a beam-splitting layer 21, and a light-diffusing layer 22, such as... Figure 14 As shown, the light-diffusing film is a microlens light-diffusing film. The thickness M of the substrate layer 20 is 25-500 μm, for example, 25 μm, 75 μm, 250 μm, 500 μm. The material of the substrate layer is selected from PET, PMMA, or PC. The beam-splitting layer is composed of a transparent polymer resin, which is a photocurable acrylic resin (AR) with a refractive index n1 of 1.5. The light-diffusing layer is composed of a transparent polymer resin, which is a photocurable acrylic resin (AR) with a refractive index n2 of 1.4-1.65, for example, 1.4, 1.5, 1.65. The beam-splitter layer features a biaxial standard plane design: it is composed of stacked long ribs in N directions, which lie flat on the lower surface of the substrate layer and extend infinitely towards both ends. Ribs in the same direction are closely arranged, and the topological coefficient N is selected from 2, hence biaxial beam splitting. The beam-splitter layer is selected as a standard plane beam-splitter layer, and the cross-section of its corresponding long rib is an isosceles triangle with its left and right sides being straight lines finitely intercepted at both ends; that is, the cross-section of the long rib is a right-side triangle with a vertex angle θ of 90°. o The light-diffusing layer is a microlens layer 225. The principal optical axes of three adjacent microlenses are connected to form an equilateral triangle array, with the microlenses arranged closely together. The width G of each microlens is 10-100 μm, for example, 10 μm, 25 μm, 50 μm, 75 μm, or 100 μm. The height H of each microlens has an aspect ratio H / G of 0.05-0.5, for example, 0.05, 0.1, 0.3, or 0.5. The spacing D between the principal optical axes of adjacent microlenses is equal to G. This light-diffusing film exhibits good light-diffusing performance, with a uniformity improvement of U = 97-114%. The aforementioned technical solutions include embodiments 71-80.

[0037] This invention provides a method for preparing a light-dispersing film, characterized in that a light-dispersing layer is prepared on the back side of the substrate layer using a micro-replication or hot-pressing process, and a light-amplifying layer is prepared on the front side of the substrate layer using a photocuring micro-replication or hot-pressing process, based on a transparent polymer resin formulation.

[0038] Furthermore, the method for preparing the homogenizing film includes the following steps:

[0039] (1) Using the substrate layer as a support layer, a beam splitting layer is prepared on the back side to obtain a planar homogenizing film containing only the beam splitting layer and the substrate layer;

[0040] Furthermore, the method for preparing the homogenizing film includes the following steps:

[0041] (1) Mold 1 for preparing the spectral splitter;

[0042] (2) Using the substrate layer as a support layer, the beam splitting layer is micro-replicated or hot-pressed on the back side using mold 1 to obtain a light-diffusing film containing only the beam splitting layer and the substrate layer (i.e., a planar light-diffusing film, which can also be used as a light-diffusing film semi-finished product with other light-diffusing layer structures).

[0043] Furthermore, the method for preparing the homogenizing film includes the following steps:

[0044] (1) Using the substrate layer as a support layer, a beam-splitting layer is prepared on the back side to obtain a semi-finished product containing a beam-splitting layer;

[0045] (2) Prepare a light-diffusing layer on the front side of the semi-finished product obtained in step (1) to obtain a uniform light film containing both a light-splitting layer and a light-diffusing layer.

[0046] Furthermore, the method for preparing the homogenizing film includes the following steps:

[0047] (1) The mold 1 (concave long rib superimposed texture) for preparing the beam splitting layer is generally made by polishing metal rollers or metal plates through diamond engraving process, wherein the shape of the diamond engraving knife is the same as the cross-section of the long rib.

[0048] (2) Using mold 1, a beam splitting layer (superimposed texture of convex long ribs) is micro-replicated or hot-pressed on the back of the substrate layer to obtain a semi-finished product containing a beam splitting layer.

[0049] (3) The mold 2 (complementary structure of light-expanding layer) for preparing the light-expanding layer is generally made by polishing metal rollers or metal plates through processes such as microbead sandblasting and diamond engraving.

[0050] (4) Using mold 2, a light-diffusing layer is micro-replicated or hot-pressed on the front side of the substrate layer to obtain a uniform light film containing both a light-splitting layer and a light-diffusing layer.

[0051] Furthermore, the method for preparing the homogenizing film includes the following steps:

[0052] (1) The mold 1 (concave long rib superimposed texture) for preparing the beam splitting layer is generally made by polishing metal rollers or metal plates through diamond engraving process, wherein the shape of the diamond engraving knife is the same as the cross-section of the long rib.

[0053] (2) Using mold 1, a beam splitting layer (superimposed texture of convex long ribs) is micro-replicated or hot-pressed on the back of the substrate layer to obtain a semi-finished product containing a beam splitting layer.

[0054] (3) The mold 2 for preparing the light-expanding layer (the light-expanding layer has the same structure) is generally made by polishing metal rollers or metal plates through processes such as microbead sandblasting and diamond engraving.

[0055] (4) The mold 3 (complementary structure of the light-expanding layer) for preparing the light-expanding layer can be obtained by pressing the mold 2 (by pressing a low-hardness metal with a high-hardness metal), or by using an optical film with the same structure as the light-expanding layer as a template to electroform a metal mold with a complementary structure, or by pressing the mold 2 to obtain an optical film with a complementary structure and using it directly as a soft mold 3.

[0056] (5) Using mold 3, a light-diffusing layer is micro-replicated or hot-pressed on the front side of the substrate layer to obtain a uniform light film containing both a light-splitting layer and a light-diffusing layer.

[0057] It should be noted that the processing methods of the light-splitting layer and the light-amplifying layer should be selected according to the type of structure and material, and this invention does not make a preferred method.

[0058] It should be noted that the method for preparing uniform light film provided by the present invention is applicable to the production of sheets and also to the production of rolls.

[0059] This light-diffusing film can be used as an optical functional material in the backlight system of direct-lit LED arrays. It is particularly suitable for Mini LED backlights to improve the shadow problem of high-brightness point light source arrays with short OD (exposure distance). OD represents the distance from the point light source to the optical film closest to the point light source in the backlight architecture. Short OD can refer to OD less than 1mm, or even zero.

[0060] Compared with the prior art, the uniform light film provided by the present invention can rationally distribute the energy concentrated in the beam center of the point light source, especially within the beam angle of 30 degrees, to other directions, thereby reducing the energy of the central bright spot on the projection screen and expanding the overall light-emitting area, thus improving the uniformity of energy distribution by at least 30%.

[0061] In some larger-sized (e.g., TV, monitor) Mini LED backlight applications, due to the larger lamp spacing (generally greater than 5mm), in order to pursue an ultra-thin design with short OD or even zero OD under such large lamp spacing, a light uniformity film product with better light uniformity is needed, even if it means sacrificing some brightness to further improve the light uniformity effect.

[0062] By using a base film with filtering function (filter substrate layer), blue light can be selectively reflected, thus causing the blue light to mix multiple times between the lamp and the filter substrate layer, i.e., to be reflected back and forth multiple times (e.g., ...). Figure 15 As shown), thereby indirectly increasing the propagation path of light (as shown). Figure 16 As shown in the figure, this effectively increases the OD (dispersion distance), which can effectively improve the light uniformity effect.

[0063] At smaller incident angles, the filter substrate reflects blue light; at larger incident angles, the reflectance decreases, and blue light begins to transmit (this is generally the case for multilayer filters; the spectrum is related to the incident angle, such as...). Figure 17a (as shown in / b). Therefore, the main principle of multiple light mixing is as follows: Figure 15 As shown, specular reflection occurs on the lower surface of the filter substrate layer without changing its direction, while diffuse reflection occurs at the reflective surface of the lamp panel, changing its direction and causing the incident angle to gradually increase, ultimately resulting in a higher and higher transmission ratio.

[0064] The present invention provides a composite light-diffusing film, which includes a filter substrate layer, a composite adhesive layer, a beam-splitting layer, and a substrate layer. The beam-splitting layer is located on the lower surface of the substrate layer, and the composite adhesive layer is located on the upper surface of the filter substrate layer. The tip of the beam-splitting layer is bonded to the composite adhesive layer.

[0065] The beam-splitting layer is one of a standard surface beam-splitting layer, a convex arc surface beam-splitting layer, and a concave arc surface beam-splitting layer.

[0066] The surface of the beam-splitting layer has a high degree of smoothness, resulting in minimal abnormal deflection of light.

[0067] Furthermore, the filter substrate layer is a multilayer co-extruded polymer film, and its filtering effect is that it reflects blue light at a small incident angle (less than the critical angle), and the reflection ratio decreases at a large incident angle (greater than the critical angle), and gradually begins to transmit blue light.

[0068] Furthermore, the multilayer co-extruded polymer film is composed of alternating layers of polymers with high and low refractive indices. The refractive index and thickness of each layer are not limited, but the above-mentioned light filtering effect must be met.

[0069] Furthermore, the spectral characteristics of the filter substrate layer, such as the reflection band, reflectivity, and critical angle, are not limited. As long as the reflection band can cover the wavelength range of the blue light source, the uniform light effect of the present invention can be achieved.

[0070] Furthermore, the thickness of the filter substrate layer is not limited; the final design of the number of layers and the thickness of each layer are determined by the spectral characteristics, thereby determining the total thickness.

[0071] Furthermore, the thickness of the composite adhesive layer is selected from 0.5 to 5 μm.

[0072] Furthermore, the composite adhesive layer is composed of a transparent polymer resin, specifically a light-cured acrylic resin (AR), with a refractive index n3 selected from 1.45 to 1.55.

[0073] This invention provides a composite light-diffusing film, comprising, from top to bottom, a substrate layer, a beam-splitting layer, a composite adhesive layer, and a filter substrate layer. The substrate layer and the beam-splitting layer together form a planar light-diffusing film; that is, the composite light-diffusing film can also be understood as being composed of a planar light-diffusing film, a composite adhesive layer, and a filter substrate layer. The thickness M of the substrate layer is 25-500 μm, for example, 25 μm, 75 μm, 100 μm, 125 μm, 250 μm, or 500 μm, and the material of the substrate layer is selected from PET, PMMA, or PC. The beam-splitting layer is composed of a transparent polymer resin, specifically a photocurable acrylic resin (AR), PMMA, or PC, with a refractive index n1 of 1.4-1.65, for example, 1.4, 1.5, 1.58, or 1.65. The composite adhesive layer is composed of a transparent polymer resin, specifically a photocurable acrylic resin (AR), with a refractive index of 1.45-1.55 (e.g., 1.45, 1.5, or 1.55) and a thickness of 0.5-5 μm (e.g., 0.5 μm, 1 μm, or 5 μm). The filter substrate layer is a multilayer co-extruded polymer film. Its filtering effect is to reflect blue light at smaller incident angles (less than the critical angle), and the reflection ratio decreases at larger incident angles (greater than the critical angle), gradually beginning to transmit blue light. The beam-splitting layer is composed of N long ribs stacked in different directions. These long ribs are laid flat on the lower surface of the substrate layer, extending infinitely towards both ends. Long ribs in the same direction are closely arranged, and the topological coefficient N is 1, 2, or 3. The beam-splitting layer is selected from one of a standard surface beam-splitting layer, a convex arc surface beam-splitting layer, or a concave arc surface beam-splitting layer. The cross-section of the long rib corresponding to the standard surface beam-splitting layer is an isosceles triangle with the left and right sides being straight lines finitely intercepted at both ends, i.e., the cross-section of the long rib is a right-side triangle with a vertex angle θ of 60°. o -120 o For example, 60 o 75 o 90 o 105 o , or 120 o When the beam splitter is a convex arc beam splitter, the apex angle θ is 91°. o -120 o For example, 91 o 93 o 100 o or 120 o The central angle α is 1-30°. o For example, 1 o 3 o 10 o , or 30 o When the beam splitter is a concave arc surface beam splitter, the apex angle θ is 60°. o -89 o For example, 60 o 80 o 87 o， , or 89o The central angle α is 1-30°. o For example, 1 o 3 o 10 o , or 30 o The light-uniforming film exhibits good light-uniformity performance, with a uniformity improvement rate U of 160-397%. The aforementioned technical solutions include Examples 81-120.

[0074] This invention provides a method for preparing a composite light-dispersing film. On the back side of the substrate layer, a micro-replication or hot-press molding process is used to prepare multiple light-dispersing layers using transparent polymer resin. On the front side of the filter substrate layer, a coating process is used to prepare a composite adhesive layer using transparent polymer resin, which is then combined with the light-dispersing layers. After the tip of the light-dispersing layer is embedded in the composite adhesive layer, ultraviolet curing is performed to ensure a firm bond between the filter substrate layer and the adhesive layer.

[0075] Furthermore, the preparation method of the composite homogenizing film includes the following steps:

[0076] (1) The mold 1 (concave long rib superimposed texture) for preparing the beam splitting layer is generally made by polishing metal rollers or metal plates through diamond engraving process, wherein the shape of the diamond engraving knife is the same as the cross-section of the long rib.

[0077] (2) Using mold 1, a beam splitting layer (superimposed texture of convex long ribs) is micro-replicated or hot-pressed on the back of the substrate layer to obtain a semi-finished product containing a beam splitting layer.

[0078] (3) Unwind the filter substrate layer at the first unwinding station and coat the front side with a composite adhesive layer (uncured) to obtain a semi-finished product containing the composite adhesive layer. Unwind the splitting layer semi-finished product at the second unwinding station.

[0079] (4) The two rolls of semi-finished products are stacked and composited by tension or pressure, so that the tip of the beam splitter is embedded in the composite adhesive layer, and the composite adhesive layer is quickly cured by ultraviolet curing equipment so that it is firmly bonded to the tip of the beam splitter.

[0080] (5) The composite uniform light film is wound up at the first winding station to obtain the finished product.

[0081] This composite light-diffusing film can be used as an optical functional material in the backlight system of direct-lit LED arrays. It is particularly suitable for larger-sized (e.g., TV, monitor) Mini LED backlight applications to improve the lamp shadow problem of point light source arrays with large pitch, high brightness, and short OD.

[0082] Compared with the prior art, the composite light-diffusing film provided by the present invention can rationally distribute the energy concentrated in the beam center of the point light source, especially within the beam angle of 30 degrees, to other directions, thereby reducing the energy of the central bright spot on the projection screen and expanding the overall light-emitting area, thus improving the uniformity of energy distribution by at least 160%.

[0083] During the cutting and assembly process of the composite light-diffusing film, we found that the bottom filter substrate layer, due to its multi-layer film structure, has a relatively thin single layer and is easily scratched. If the scratch area is large, it will also damage the light-diffusing performance. Therefore, its lower surface needs to be protected with a coating. In addition, considering that the coating is close to the LED light panel, the heat from the LED poses a risk of thermal deformation to the thin filter substrate layer. Therefore, the heat resistance of the coating also has certain requirements.

[0084] The present invention provides a composite light-diffusing film, which includes a hardening layer, a filter substrate layer, a composite adhesive layer, a beam-splitting layer, and a substrate layer. The beam-splitting layer is located on the lower surface of the substrate layer, the hardening layer is located on the lower surface of the filter substrate layer, and the composite adhesive layer is located on the upper surface of the filter substrate layer. The tip of the beam-splitting layer is embedded in the composite adhesive layer to bond with the filter substrate layer.

[0085] The beam splitting layer is composed of N long ribs stacked in N directions, where N is the topological coefficient. The long ribs are laid flat on the lower surface of the substrate layer and extend infinitely to both ends. The long ribs in the same direction are closely arranged. The N directions divide the 360-degree azimuth angle equally, that is, the angular interval between adjacent directions is 180 / N degrees. N is selected from 1, 2 or 3.

[0086] The cross-sections of the long ribs in the beam-splitting layer are identical, all being isosceles triangles. The left and right sides are either straight lines, convex arcs, or concave arcs with finite ends. The base is a straight line with a length W1 of 10–100 μm and a vertex angle θ of 60–120°. o The curvature of a convex or concave arc (referred to as a concave-convex arc) is expressed by a central angle, α, which ranges from 1 to 30 degrees. o .

[0087] The beam-splitting layer is one of a standard surface beam-splitting layer, a convex arc surface beam-splitting layer, and a concave arc surface beam-splitting layer.

[0088] The surface of the beam-splitting layer has a high degree of smoothness, resulting in minimal abnormal deflection of light. Furthermore, the linear roughness Ra of the beam-splitting layer surface is less than 250 nm.

[0089] Furthermore, the filter substrate layer is capable of reflecting blue light.

[0090] Furthermore, the filter substrate layer is a multilayer co-extruded polymer film, and its filtering effect is that it reflects blue light at a small incident angle (less than the critical angle), and the reflection ratio decreases at a large incident angle (greater than the critical angle), and gradually begins to transmit blue light.

[0091] Furthermore, the multilayer co-extruded polymer film is composed of alternating layers of polymers with high and low refractive indices. The refractive index and thickness of each layer are not limited, but the above-mentioned light filtering effect must be met.

[0092] Furthermore, the spectral characteristics of the filter substrate layer, such as the reflection band, reflectivity, and critical angle, are not limited. As long as the reflection band can cover the wavelength range of the blue light source, the uniform light effect of the present invention can be achieved.

[0093] Furthermore, the thickness of the filter substrate layer is not limited; the final design of the number of layers and the thickness of each layer are determined by the spectral characteristics, thereby determining the total thickness.

[0094] Furthermore, the thickness of the composite adhesive layer is selected from 0.5 to 5 μm.

[0095] Furthermore, the composite adhesive layer is composed of a transparent polymer resin, specifically a light-cured acrylic resin (AR), with a refractive index selected from 1.45 to 1.55.

[0096] Furthermore, the hardened layer is a heat-resistant hardened layer or a scratch-resistant hardened layer.

[0097] When the hardening layer is a heat-resistant hardening layer, the composite light-diffusing film is also called a heat-resistant composite light-diffusing film. When the hardening layer is a scratch-resistant hardening layer, the composite light-diffusing film is also called a scratch-resistant composite light-diffusing film.

[0098] Furthermore, the thickness M3 of the scratch-resistant hardened layer is selected from 3 to 10 μm.

[0099] Furthermore, the scratch-resistant hardening layer is composed of a high-hardness transparent polymer resin, which is a light-cured acrylic resin (AR) with a pencil hardness (hereinafter referred to as hardness, using a Mitsubishi pencil, 750g load test) of 1H to 6H.

[0100] Furthermore, the hardened layer is a scratch-resistant hardened layer, and the formulation of the photocurable acrylic resin for the scratch-resistant hardened layer is as follows: a mixture of 20-60 parts monofunctional monomer diluent (functionality = 1), 20-50 parts polyfunctional monomer (functionality = 2-3), 5-15 parts high-functionality oligomer (functionality > 3), 1-50 parts hyperbranched resin, and 2-4 parts photoinitiator. The parts are by weight.

[0101] Furthermore, the thickness M4 of the heat-resistant hardening layer is selected from 3 to 10 μm.

[0102] Furthermore, the heat-resistant curing layer is composed of a high-hardness, heat-resistant, transparent polymer resin, and the material is light-cured acrylic resin (AR). The pencil hardness (hereinafter referred to as hardness, using a Mitsubishi pencil, 750g load test) is 1H to 4H.

[0103] Furthermore, the hardened layer is a heat-resistant hardened layer, and the formulation of the photocurable acrylic resin for the heat-resistant hardened layer is as follows: a mixture of 20-60 parts monofunctional monomer diluent (functionality = 1), 20-50 parts polyfunctional monomer (functionality = 2-3), 5-15 parts heat-resistant oligomer (functionality > 1), 1-50 parts hyperbranched resin, and 2-4 parts photoinitiator. The parts are by weight.

[0104] The monofunctional monomer diluent is selected from one of isoborneol acrylate (IBOA), isoborneol methacrylate (IBOMA), and trimethylolpropane methyl acetal acrylate (CTFA), and has excellent dilution properties, high hardness, and good wear resistance.

[0105] The polyfunctional monomer is selected from one of diethylene glycol dimethacrylate (DEGDMA), neopentyl glycol diacrylate (NPGDA), trimethylolpropane triacrylate (TMPTA), pentaerythritol triacrylate (PET3A), and trimethylolpropane trimethacrylate (TMPTMA), and has high hardness, high crosslinking density, and good scratch resistance.

[0106] The heat-resistant oligomer is selected from one of phenolic epoxy acrylate (NEA, such as 625C-45 provided by Changxing Chemical) and organic-inorganic hybrid oligomer (OIHO, such as 601C-35 provided by Changxing Chemical), and has good heat resistance and high hardness.

[0107] The high-functionality oligomer is selected from one of pentaerythritol tetraacrylate (PETTA), dipentaerythritol hexaacrylate (DPHA), and modified hexaacrylate (modified DPHA, such as polyurethane acrylate oligomers 6144-100, 6145-100, 6149-100, and 6161-100 provided by Changxing Chemical). It has good wear resistance, high crosslinking density, and high hardness.

[0108] This invention does not limit the type of hyperbranched resin; any commonly available brand can be selected, such as 6361-100, 6362-100, and 6363-100 provided by Changxing Chemical, or 2423 and M058 from DSM.

[0109] The photoinitiator can be selected from α-hydroxyalkyl ketone initiators or acyl oxide initiators. Since the selection of photoinitiator is related to the UV lamp group, curing conditions and coating thickness, the present invention does not limit the initiator and can select common brands on the market, such as ethyl 2,4,6-trimethylbenzoylphenylphosphonate (TPO-L), 2,4,6-trimethylbenzoyl chloride diphenylphosphine oxide (TPO), 1-hydroxycyclohexylphenyl methyl ketone (184), 2-hydroxy-2-methyl-phenylacetone-1 (1173) provided by BASF.

[0110] This invention provides a heat-resistant composite light-diffusing film, comprising a substrate layer 20, a beam-splitting layer 21, a composite adhesive layer 24, a light-filtering substrate layer 23, and a heat-resistant curing layer 29, as shown below. Figure 19 As shown, the substrate layer 20 and the beam-splitting layer 21 form a planar light-diffusing film. That is, the heat-resistant composite light-diffusing film can also be understood as consisting of a planar light-diffusing film, a composite adhesive layer, a filter substrate layer, and a heat-resistant curing layer. The thickness M of the substrate layer is 25-500 μm, for example, 25 μm, 75 μm, 100 μm, 125 μm, 250 μm, or 500 μm. The material of the substrate layer is selected from PET, PMMA, or PC. The beam-splitting layer is composed of a transparent polymer resin, specifically a photocurable acrylic resin (AR), PMMA, or PC, with a refractive index n1 of 1.4-1.65, for example, 1.4, 1.5, 1.58, or 1.65. The composite adhesive layer is also composed of a transparent polymer resin, specifically a photocurable acrylic resin (AR), with a refractive index of 1.45-1.55, for example, 1.45, 1.5, or 1.55, and a thickness of 0.5-5 μm, for example, 0.5 μm. μm, 1μm or 5μm; the filter substrate layer is a multilayer co-extruded polymer film, and the filtering effect is that it reflects blue light at a small incident angle (less than the critical angle), and the reflection ratio decreases at a large incident angle (greater than the critical angle), and gradually begins to transmit blue light; the thickness M4 of the heat-resistant curing layer is 3-10μm, for example, 3μm, 5μm or 10μm, and the hardness is 1H-6H, for example, hardness is 1H, 2H, 3H, 4H, 5H, 6H. The heat-resistant curing layer is composed of a high-hardness heat-resistant transparent polymer resin, the material is light-curing acrylic resin (AR), and the formulation uses HC-1, HC-2, HC-3, HC-4, HC-5, HC-6, HC-7. The formulation composition is shown in Table 8. The beam-splitting layer is composed of N long ribs stacked in different directions. These ribs lie flat on the lower surface of the substrate layer, extending infinitely towards both ends. Ribs in the same direction are closely arranged, and the topological coefficient N is 1, 2, or 3. The beam-splitting layer is selected from one of a standard surface beam-splitting layer, a convex arc surface beam-splitting layer, or a concave arc surface beam-splitting layer. For the standard surface beam-splitting layer, the cross-section of the long rib is an isosceles triangle with its left and right legs being straight lines finitely intercepted at both ends; that is, the cross-section of the long rib is a right-side triangle with a vertex angle θ of 60°. o -120o For example, 60 o 75 o 90 o 105 o , or 120 o When the beam splitter is a convex arc beam splitter, the apex angle θ is 91°. o -120 o For example, 91 o 93 o 100 o or 120 o The central angle α is 1-30°. o For example, 1 o 3 o 10 o , or 30 o When the beam splitter is a concave arc surface beam splitter, the apex angle θ is 60°. o -89 o For example, 60 o 80 o 87 o， , or 89 o The central angle α is 1-30°. o For example, 1 o 3 o 10 o , or 30 o The light-uniforming film exhibits good light-uniformity performance, with a uniformity improvement of U = 160-397%, while also demonstrating good heat resistance and a low risk of thermal deformation. The aforementioned technical solutions include Examples 121-168.

[0111] Furthermore, the formulation of the photocurable acrylic resin for the heat-resistant curing layer is as follows: a mixture of 20-45 parts of monofunctional monomer diluent IBOA or CTFA, 20-50 parts of polyfunctional monomer NPGDA or TMPTA, 9-15 parts of heat-resistant oligomer (functionality >1), 3-50 parts of hyperbranched resin, and 2-3 parts of photoinitiator. The aforementioned formulations include Examples 163-164 and 166-168.

[0112] This invention provides a scratch-resistant composite light-diffusing film, comprising a substrate layer 20, a beam-splitting layer 21, a composite adhesive layer 24, a light-filtering substrate layer 23, and a scratch-resistant hardening layer 29, as shown below. Figure 19As shown, the substrate layer 20 and the beam splitting layer 21 form a planar light-diffusing film. That is, the scratch-resistant composite light-diffusing film can also be understood as being composed of a planar light-diffusing film, a composite adhesive layer, a filter substrate layer and a scratch-resistant hardening layer. The thickness M of the substrate layer is 25-500 μm, for example, 25 μm, 75 μm, 100 μm, 125 μm, 250 μm, or 500 μm, and the material of the substrate layer is selected from PET, PMMA, or PC; the beam-splitting layer is composed of a transparent polymer resin, which is a photocurable acrylic resin (AR), PMMA, or PC, and the refractive index n1 is 1.4-1.65, for example, 1.4, 1.5, 1.58, or 1.65; the composite adhesive layer is composed of a transparent polymer resin, which is also a photocurable acrylic resin (AR), with a refractive index of 1.45-1.55, for example, 1.45, 1.5, or 1.55, and a thickness of 0.5-5 μm, for example, 0.5 μm. The thickness M3 of the filter substrate layer is 3-10 μm, for example, 3 μm, 5 μm, or 10 μm, and the hardness is 1H-6H, for example, 1H, 2H, 3H, 4H, 5H, 6H. The hardness of the scratch-resistant hardening layer is 1H, 1μm, or 5μm; the filter substrate layer is a multilayer co-extruded polymer film, and the filter effect is that it reflects blue light at a small incident angle (less than the critical angle), and the reflection ratio decreases at a large incident angle (greater than the critical angle), and gradually begins to transmit blue light. The thickness M3 of the scratch-resistant hardening layer is 3-10 μm, for example, 3μm, 5μm, or 10μm, and the hardness is 1H-6H, for example, 1H, 2H, 3H, 4H, 5H, 6H. The scratch-resistant hardening layer is composed of a high-hardness transparent polymer resin, and the material is light-cured acrylic resin (AR). The formulation uses HC-8, HC-9, HC-10, HC-11, HC-12, HC-13, and HC-14. The formulation composition is shown in Table 10. The beam-splitting layer is composed of N long ribs stacked in different directions. These ribs lie flat on the lower surface of the substrate layer, extending infinitely towards both ends. Ribs in the same direction are closely arranged, and the topological coefficient N is 1, 2, or 3. The beam-splitting layer is selected from one of a standard surface beam-splitting layer, a convex arc surface beam-splitting layer, or a concave arc surface beam-splitting layer. For the standard surface beam-splitting layer, the cross-section of the long rib is an isosceles triangle with its left and right legs being straight lines finitely intercepted at both ends; that is, the cross-section of the long rib is a right-side triangle with a vertex angle θ of 60°. o -120 o For example, 60 o 75 o 90 o 105 o or 120 o When the beam splitter is a convex arc beam splitter, the apex angle θ is 91°. o -120 o For example, 91 o 93 o 100 o or 120 o The central angle α is 1-30°. o For example, 1o, 3 o 10 o, or 30 o When the beam splitter is a concave arc surface beam splitter, the apex angle θ is 60°. o -89 o For example, 60 o 80 o 87 o， , or 89 o The central angle α is 1-30°. o For example, 1 o 3 o 10 o , or 30 o The light-uniforming film exhibits good light-uniformity performance, with a uniformity improvement of U = 160-397%, while also demonstrating good heat resistance and a low risk of thermal deformation. The aforementioned technical solutions include Examples 169-216.

[0113] Furthermore, the formulation of the photocurable acrylic resin for the scratch-resistant hardening layer is as follows: a mixture of 20-45 parts of monofunctional monomer diluent IBOA or CFTA, 20-50 parts of polyfunctional monomer NPGDA or TMPTA, 9-15 parts of high-functionality oligomer (functionality > 3), 3-50 parts of hyperbranched resin, and 2-3 parts of photoinitiator. The parts are by weight. The aforementioned technical solutions include Examples 211-212 and Examples 214-216.

[0114] This invention provides a method for preparing a composite light-dispersing film. A beam-splitting layer is prepared on the back side of a substrate layer using a micro-replication or hot-pressing process with transparent polymer resin. A hardening layer is prepared on the back side of a filter substrate layer using a coating process. A composite adhesive layer is prepared on the front side of the filter substrate layer using a coating process with transparent polymer resin and then composited with the beam-splitting layer. After the tip of the beam-splitting layer is embedded in the composite adhesive layer, ultraviolet curing is performed to ensure a firm bond between the filter substrate layer and the adhesive layer.

[0115] Furthermore, the preparation method of the composite homogenizing film includes the following steps:

[0116] (1) The mold 1 (concave long rib superimposed texture) for preparing the beam splitting layer is generally made by polishing metal rollers or metal plates through diamond engraving process, wherein the shape of the diamond engraving knife is the same as the cross-section of the long rib.

[0117] (2) Using mold 1, a beam splitting layer (superimposed texture of convex long ribs) is micro-replicated or hot-pressed on the back of the substrate layer to obtain a semi-finished product containing a beam splitting layer.

[0118] (3) A hardened layer is prepared by coating and curing on the back of the filter substrate layer to obtain the filter substrate layer semi-finished product-1.

[0119] (4) Unwind the filter substrate layer semi-finished product-1 at the first unwinding station and coat the front side with a composite adhesive layer (uncured) to obtain the semi-finished product-2 containing the composite adhesive layer. Unwind the beam splitting layer semi-finished product at the second unwinding station.

[0120] (5) The two rolls of semi-finished products are stacked and composited by tension or pressure, so that the tip of the beam splitter is embedded in the composite adhesive layer, and the composite adhesive layer is quickly cured by ultraviolet curing equipment so that it is firmly bonded to the tip of the beam splitter.

[0121] (6) The composite uniform film is wound up at the first winding station to obtain the finished product.

[0122] When the hardened layer is a scratch-resistant hardened layer, this composite light-diffusing film can be used as an optical functional material in the backlight system of a direct-lit LED array. It is particularly suitable for larger-sized (e.g., TV, monitor) Mini LED backlight applications to improve the lamp shadow problem of point light source arrays with large pitch, high brightness, and short OD, while also having good scratch resistance.

[0123] When the curing layer is a heat-resistant curing layer, this composite light-diffusing film can be used as an optical functional material in the backlight system of a direct-lit LED array. It is particularly suitable for larger-sized (e.g., TV, monitor) Mini LED backlight applications to improve the lamp shadow problem of large-pitch, high-brightness, short-dish-out point light source arrays and reduce the risk of thermal deformation.

[0124] Compared with the prior art, the composite light-diffusing film provided by the present invention can rationally distribute the energy concentrated in the beam center of the point light source, especially within the beam angle of 30 degrees, to other directions, thereby reducing the energy of the central bright spot on the projection screen and expanding the overall light-emitting area, thus improving the uniformity of energy distribution by at least 160%. Attached Figure Description

[0125] Figure 1 A comparison of typical light-diffusing films / light-diffusing films (light source a, light source b + light-diffusing film, light source c + light-diffusing film);

[0126] Figure 2 This is a schematic diagram of the architecture for evaluating the light homogenization performance of a light homogenizing film.

[0127] Figure 3 shows the evaluation method of the beam-splitting effect of the homogenizing film (a. spherical coordinate system, b. Lambertian light source, c. Lambertian light source + homogenizing film);

[0128] Figure 4 This is a schematic diagram of the composition and cross-section of the light-diffusing film (a) substrate layer + beam-splitting layer, b) substrate layer + beam-splitting layer + light-diffusing layer;

[0129] Figure 5 The diagram shows the principle of light dispersion (a) and the principle of light amplification (b).

[0130] Figure 6 Design principle for long rib stacking (N=1) of beam splitter layer (a. long rib stacking method b. beam splitting structure details c. beam splitting effect d. magnified details of beam splitting effect);

[0131] Figure 7 Design principle for long rib stacking (N=2) of beam splitter layer (a. long rib stacking method b. beam splitting structure details c. beam splitting effect d. magnified details of beam splitting effect);

[0132] Figure 8 Design principle for long rib stacking (N=3) of beam splitter layer (a. long rib stacking method b. beam splitting structure details c. beam splitting effect d. magnified details of beam splitting effect);

[0133] Figure 9 Schematic diagrams of long ribs of different shapes and their cross-sections (a) three three-dimensional diagrams; b) triangles with convex arc edges in cross-section; c) triangles with straight edges in cross-section; d) triangles with concave arc edges in cross-section.

[0134] Figure 10 This is a schematic diagram of the three-dimensional structure of a planar homogenizing film;

[0135] Figure 11 A schematic diagram of the three-dimensional structure of the prism homogenizing film and the cross-section of the prism rib;

[0136] Figure 12 This is a schematic diagram of the three-dimensional structure of the cylindrical lens homogenizing film and the cross-section of the cylindrical lens.

[0137] Figure 13 Schematic diagrams of the three-dimensional structure of the pyramidal uniform light film and the square pyramidal structure;

[0138] Figure 14 This is a schematic diagram of the three-dimensional structure of the microlens homogenizing film and the microlens structure.

[0139] Figure 15 This is a schematic diagram illustrating the principle of a filter substrate layer reflecting light at small angles and transmitting light at large angles.

[0140] Figure 16 A schematic diagram illustrating the equivalent increase in OD value for multiple reflected light (specular reflection from the filter substrate layer and diffuse reflection from the lamp panel);

[0141] Figure 17a Visible light transmittance spectra of the filter substrate layer at different incident angles (AOI);

[0142] Figure 17b Blue light reflectance spectra of the filter substrate layer at different incident angles (AOI) (b);

[0143] Figure 18 This is a schematic diagram of the cross-section of the composite homogenizing film;

[0144] Figure 19 This is a schematic diagram of the cross-section of the composite homogenizing film.

[0145] in:

[0146] 0: LED light board; 1: LED; 00: LED light board; 01: LED; 2: Light-diffusing film; 3: Absorption screen;

[0147] 20: Substrate layer; 21: Beam splitter layer; 22: Beam amplification layer; 23: Filter substrate layer; 24: Composite adhesive layer; 29: Hardening layer;

[0148] 40: Input light; 411: Transmitted light; 412: Retrieved light; 42: Output light; 43: Secondary input light

[0149] 50: Ridge of the long / short rib; 51: Valley between the long / short rib;

[0150] 221: Prism structure; 222: Cylindrical lens structure; 224: Square pyramid structure; 225: Microlens structure. Detailed Implementation

[0151] To better understand the structure of the present invention and the functional features and advantages it can achieve, the preferred embodiments of the present invention will be described in detail below with reference to the drawings.

[0152] This invention provides a light-diffusing film, wherein the beam-splitting layer of the film performs beam splitting, the light-amplifying layer performs the main light-amplifying function, and if there is no light-amplifying layer, the substrate layer can play a certain role in light amplification. Its main principle is as follows: Figure 5 As shown.

[0153] Taking a planar homogenizing film as an example, since the main rays of the light source are concentrated in the normal direction, Figure 5 A illustrates the beam splitting process that occurs after the normal input light 40 is incident on the beam splitter layer 21. The light enters through the inclined outer surfaces on both sides of the beam splitter layer, resulting in deflection in at least two directions (the number varies depending on the beam splitter structure; if it's a square pyramid, it actually has four directions). The resulting incident light 411 is transmitted within the homogenizing film and exits from the upper surface of the substrate layer 20, undergoing another deflection (from denser to sparser), producing further separated output light 42. This is the basic principle of the beam splitting process. A beam of light from a point source is dispersed by the beam splitter layer; beams from several point sources are also dispersed by the beam splitter layer. The dispersed light beams superimpose, making the output light more uniform.

[0154] Taking a planar homogenizing film as an example, a small amount of light rays at a large angle are incident obliquely towards the beam-splitting layer. Figure 5b illustrates the light amplification process that occurs after light 40, input at a 45-degree angle, is incident on the beam splitter layer 21. Taking the light on the right as an example, the light is incident to the right through the inclined outer surface of the beam splitter layer, propagates through to the upper surface of the substrate layer, and undergoes total internal reflection due to the angle satisfying the critical angle for total internal reflection, generating recovered light 412. This portion of the light passes through the beam splitter layer and undergoes diffuse reflection at the bottom lamp panel, generating upward secondary input light 43. When this portion of the light reaches the beam splitter layer again, it is at a considerable horizontal distance from the position of the initial input light 40. Alternatively, this repeated up-and-down light circulation can be understood as indirectly expanding the vertical mixing distance. In short, this process ultimately allows light energy to be distributed over a larger area, which is the basic principle of the light amplification process.

[0155] Although a single planar homogenizing film mainly performs a beam splitting function with a relatively small proportion of a beam amplification function, when multiple homogenizing films are stacked, the input light to the top homogenizing film is already tilted, which can increase the proportion of a beam amplification function.

[0156] In general, in order for the actual optical path to conform to the design principle, especially when multiple layers are stacked together, to ensure the ratio of transmitted light to total internal reflection in each layer, the surface smoothness of the beam splitter and beam amplifier should be as high as possible, and the line roughness should be as low as possible, so as to reduce abnormal deflection of light.

[0157] The optimal fabrication method for the beam-splicing layer is imprinting using a precision-engraved mold; other methods such as laser engraving and photolithography cannot guarantee high-precision surface finish. The beam-splicing layer's structural design employs a long-rib stacking principle, such as... Figure 6 , Figure 7 , Figure 8 As shown, long ribs can also be understood as grooves left by diamond carving tools. The shape of long ribs can vary (e.g., Figure 9 As shown in a), its cross-section can be as follows: Figure 9 b、 Figure 9 c. Figure 9 The three types of triangles shown in d.

[0158] The performance of the light-diffusing film provided by the present invention shall be evaluated in the following manner.

[0159] (A) Illuminance distribution and relative standard deviation

[0160] like Figure 2As shown, the uniform light component 2 is placed above the LED light panel and LED 0, and below the projection screen or absorption screen 3. The LED light panel has a reflective function, integrating a reflective sheet or coating. The luminous area of ​​a single LED is S1 = 60 × 60 μm. The size of the absorption screen is infinitely large, and the vertical distance between the absorption screen and the LED is Z = 500 μm. Using optical simulation methods such as Light Tools, the illuminance distribution over an area of ​​S2 = 1200 μm × 1200 μm on the absorption screen is analyzed, and the relative standard deviation (RSD) is calculated.

[0161] Note 1: This setting is scaled down to approximately 1 / 5 of the actual scale, which does not affect the equivalence evaluation;

[0162] Note 2: Since the addition of the homogenizing component will change the luminous flux and the total amount of radiation received within the observation range, and the degree of change varies among different optical components, using the relative standard deviation instead of the standard deviation directly can eliminate the influence of changes in the base value. (Relative standard deviation = standard deviation / mean)

[0163] Note 3: The light source is set to a cosine light emitter with a beam angle of 30 degrees.

[0164] (B) Light uniformity performance

[0165] Obviously, the lower the RSD, the smaller the difference between the illuminance value at each point and the average value, and the more uniform the illuminance distribution. Taking RSD0 without the light-diffusing component as the baseline value of 100%, and RSD1 with the light-diffusing component as the measured value, the improvement in uniformity U = (RSD0 / RSD1-1) × 100%, U can be used as an evaluation index of the light-diffusing performance of the light-diffusing component.

[0166] Note: In the standard architecture described in (A), RSD0 = 5.47

[0167] (C) Beamform

[0168] like Figure 3a The diagram shows a typical spherical coordinate system, with the center of the sphere as the origin of the light source and the Z-axis as the direction of emission. This spherical coordinate system can be used to describe the beam shape of the initial light source or after passing through a homogenizing component. Figure 3b It is the beamform of a Lambertian point light source (the original LED light). Figure 3c It is the beam shape after passing through the planar homogenizing film.

[0169] Note 3: Since the homogenizing film is not used in isolation, and there are other films in the backlight structure (such as quantum dot film / fluorescent film, ordinary diffusion film, brightness enhancement film or composite film), the beam shape is only used as a qualitative consideration of the beam splitting effect of a single homogenizing film. The final beam shape of the backlight depends on the complete optical film stack. When designing the homogenizing film, there is no need to worry that large-angle light will not be corrected to the normal direction.

[0170] like Figure 4 As shown in Figure a, the present invention provides a light-diffusing film, which includes a substrate layer 20 and a beam-splitting layer 21, with the beam-splitting layer located on the lower surface of the substrate layer 20.

[0171] like Figure 4 As shown in b, the present invention provides a light-diffusing film, which includes a substrate layer 20, a beam-splitting layer 21, and a light-diffusing layer 22. The beam-splitting layer is located on the lower surface of the substrate layer 20, and the light-diffusing layer is located on the upper surface of the substrate layer 20.

[0172] Example 1

[0173] This invention provides a light-diffusing film comprising a substrate layer 20 and a beam-splitting layer 21, wherein a light-amplifying layer 22 is absent, as shown below. Figure 10 As shown, the light-diffusing film is a planar light-diffusing film. The thickness M of the substrate layer 20 is 75 μm, and the material of the substrate layer is selected from PET. The beam-splitting layer is composed of a transparent polymer resin, specifically a photocurable acrylic resin (AR), with a refractive index n1 of 1.5. The beam-splitting layer has a uniaxial standard surface design: it is composed of stacked long ribs in N directions. The long ribs are laid flat on the lower surface of the substrate layer, extending infinitely at both ends. The long ribs in the same direction are closely arranged, and the topological coefficient N is 1, i.e., uniaxial beam splitting (e.g., ...). Figure 6 (As shown); the beam-splitting layer is selected from the standard surface beam-splitting layer, and the corresponding long rib cross-section is an isosceles triangle with the left and right legs being straight lines finitely cut at both ends, that is, the cross-section of the long rib is a right-side triangle with a vertex angle θ of 90°. o The light-homogenizing film exhibits good light-homogenizing performance, with a uniformity improvement of U = 46%.

[0174] Examples 2-36

[0175] As in the planar uniform light film provided in Example 1, the other parameters are listed in Table 1.

[0176] Table 1 shows the design parameters and homogenization performance of the planar homogenizing films provided in Examples 1-36.

[0177]

[0178]

[0179] As shown in Table 1, by comparing Examples 1-12, it can be seen that the thickness and material of the substrate layer have little effect on the light homogenization performance U of the homogenizing film, but the material or refractive index of the beam-splitting layer does affect U. For uniaxial beam-splitting layers, the higher the refractive index, the more obvious the beam splitting, the better the light homogenization performance, and the larger U. By comparing Examples 13-22, it can be seen that the larger the apex angle θ of the cross-sectional triangle, the closer the structure is to a plane, the less obvious the beam splitting, the worse the light homogenization performance, and the smaller U, and vice versa. By comparing Examples 1, 8, 9 and 31-36, it can be seen that for biaxial and triaxial beam-splitting layer designs, similar to uniaxial, the higher the refractive index, the more obvious the beam splitting, the better the light homogenization performance, and the larger U. Under the same refractive index, triaxial is better than biaxial, which is better than uniaxial. By comparing Examples 23-30, it can be seen that when the waist of the cross-sectional triangle is bent at different degrees of curvature, it still plays a beam splitting role, and the larger α (the greater the curvature), the better the light homogenization performance U. Note that in Examples 23 to 30, in order to compare with Example 1, the average tilt angle δ of the side is set to 45 degrees (consistent with Example 1). For example, if the cross-section of Example 23 is a convex arc-sided triangle, then δ = (0.5θ + (0.5θ - α)) / 2 = (θ - α) / 2 = (120 - 30) / 2 = 45 degrees. If the cross-section of Example 24 is a concave arc-sided triangle, then δ = (0.5θ + (0.5θ + α)) / 2 = (θ + α) / 2 = (60 + 30) / 2 = 45 degrees. From this result, it can be seen that the arc-sided design improves the uniform light performance compared with the straight-sided design.

[0180] Example 37

[0181] This invention provides a light-diffusing film comprising a substrate layer 20, a beam-splitting layer 21, and a light-diffusing layer 22, such as... Figure 11 As shown, the light-diffusing film is a prism light-diffusing film. The thickness M of the substrate layer 20 is 75 μm, and the material of the substrate layer is selected from PET. The beam-splitting layer is composed of a transparent polymer resin, which is a photocurable acrylic resin (AR) with a refractive index n1 of 1.5. The light-diffusing layer is composed of a transparent polymer resin, which is a photocurable acrylic resin (AR) with a refractive index n2 of 1.5. The beam-splitting layer has a biaxial standard surface design: it is composed of long ribs stacked in N directions. The long ribs are laid flat on the lower surface of the substrate layer and extend infinitely to both ends. The long ribs in the same direction are closely arranged. The topological coefficient N is selected from 2, that is, biaxial beam splitting (e.g., Figure 7 (As shown); the beam-splitting layer is selected from the standard surface beam-splitting layer, and the corresponding long rib cross-section is an isosceles triangle with the left and right legs being straight lines finitely cut at both ends, that is, the cross-section of the long rib is a right-side triangle with a vertex angle θ of 90°. o The light-diffusing layer is prism layer 221, which is composed of prismatic ribs laid flat. The cross-section of each prism rib is an isosceles triangle with a base V of 50 μm and a vertex β of 90°. o The light homogenizing film exhibits excellent light homogenization performance, with a uniformity improvement of U = 91%.

[0182] Examples 38-48

[0183] The other parameters of the prism homogenizing film provided in Example 37 are listed in Table 2.

[0184] Table 2 shows the design parameters and homogenization performance of the prism homogenizing films provided in Examples 37-48.

[0185]

[0186] Note: The materials used for the beam-splitting and beam-amplifying layers in Examples 37-48 are all AR.

[0187] As shown in Table 2, comparative examples 37-42 show that the thickness and material of the substrate layer, as well as the size of the prism in the light-diffusing layer (i.e., the width V of the bottom edge), have little impact on the light-diffusing performance U of the homogenizing film. Comparative examples 37 and 43-45 show that the apex angle β of the prism structure affects U; a smaller or larger apex angle than 90 degrees results in better light amplification, better light-diffusing performance, and a larger U. Comparative examples 46-48 show that the refractive index n2 of the prism structure also affects the light-diffusing performance.

[0188] Example 49

[0189] This invention provides a light-diffusing film comprising a substrate layer 20, a beam-splitting layer 21, and a light-diffusing layer 22, such as... Figure 12 As shown, the homogenizing film is a cylindrical lens homogenizing film. The thickness M of the substrate layer 20 is 75 μm, and the material of the substrate layer is selected from PET. The beam-splitting layer is composed of transparent polymer resin, which is photocurable acrylic resin (AR) with a refractive index n1 of 1.5. The beam-diffusing layer is composed of transparent polymer resin, which is photocurable acrylic resin (AR) with a refractive index n2 of 1.5. The beam-splitting layer has a biaxial standard surface design: it is composed of long ribs stacked in N directions. The long ribs are laid flat on the lower surface of the substrate layer and extend infinitely to both ends. The long ribs in the same direction are closely arranged. The topological coefficient N is selected from 2, i.e., biaxial beam splitting. The beam-splitting layer is selected as a standard surface beam-splitting layer. The cross-section of the corresponding long rib is an isosceles triangle with the left and right sides being straight lines finitely intercepted at both ends. That is, the cross-section of the long rib is a right-side triangle with a vertex angle θ of 90°. o The light-diffusing layer is a cylindrical lens layer 222, which is formed by laying cylindrical lens ribs. The cross-section of the cylindrical lens is an arc, the width (chord length) F of the arc is 50 μm, the height of the arc is K, and the aspect ratio K / F is 0.5. This light-diffusing film has good light-diffusing performance, with a uniformity improvement of U = 115%.

[0190] Examples 50-60

[0191] The cylindrical lens homogenizing film provided in Example 49 has other parameters listed in Table 3.

[0192] Table 3 shows the design parameters and homogenization performance of the cylindrical lens homogenizing films provided in Examples 49-60.

[0193]

[0194] Note: The materials used for the beam-splitting and beam-amplifying layers in Examples 49-60 are all AR.

[0195] As shown in Table 3, comparative examples 49-55 show that the thickness and material of the substrate layer, as well as the size (i.e., the arc width F) of the cylindrical lens in the light-diffusing layer, have little effect on the light-diffusing performance U of the homogenizing film. Comparative examples 49 and 56-58 show that the aspect ratio K / F of the cylindrical lens structure has a slight effect on U; a larger K / F results in a more convex cylindrical lens shape, better light-diffusing effect, better light-diffusing performance of the homogenizing film, and a larger U. Comparative examples 49, 59, and 60 show that the refractive index n2 of the cylindrical lens structure also affects the light-diffusing performance; a higher refractive index results in a larger U.

[0196] Example 61

[0197] This invention provides a light-diffusing film comprising a substrate layer 20, a beam-splitting layer 21, and a light-diffusing layer 22, such as... Figure 13 As shown, the light-diffusing film is a pyramidal light-diffusing film. The thickness M of the substrate layer 20 is 75 μm, and the material of the substrate layer is selected from PET. The beam-splitting layer is composed of transparent polymer resin, which is photocurable acrylic resin (AR) with a refractive index n1 of 1.5. The light-diffusing layer is composed of transparent polymer resin, which is photocurable acrylic resin (AR) with a refractive index n2 of 1.5. The beam-splitting layer has a biaxial standard surface design: it is composed of long ribs stacked in N directions. The long ribs are laid flat on the lower surface of the substrate layer and extend infinitely to both ends. The long ribs in the same direction are closely arranged. The topological coefficient N is selected from 2, i.e., biaxial beam splitting. The beam-splitting layer is selected as a standard surface beam-splitting layer. The cross-section of the corresponding long rib is an isosceles triangle with the left and right sides being straight lines finitely intercepted at both ends. That is, the cross-section of the long rib is a right-side triangle with a vertex angle θ of 90°. o The light-diffusing layer is a square pyramid layer 224, which is composed of flat square pyramids. The vertices of the pyramids are arranged in a square. The height T of the pyramids is 30 μm, and the angle γ between the side surface and the height is 45°. o The light-homogenizing film exhibits good light-homogenizing performance, with a uniformity improvement of U = 41%.

[0198] Examples 62-70

[0199] The other parameters of the pyramidal light-diffusing film provided in Example 61 are listed in Table 4.

[0200] Table 4 shows the design parameters and homogenization performance of the pyramidal homogenizing films provided in Examples 61-70.

[0201]

[0202] Note: The materials of the beam-splitting layer and the beam-amplifying layer in Examples 61-70 are all AR.

[0203] As shown in Table 4, comparative examples 61-66 show that the thickness and material of the substrate layer, as well as the size of the pyramidal structure in the light-diffusing layer (i.e., the height T of the pyramid), have little impact on the light-diffusing performance U of the homogenizing film. Comparative examples 61, 67, and 68 show that the angle γ between the side surface and the height has a significant impact on U; a smaller γ results in a more convex pyramidal shape, better light-diffusing effect, better light-diffusing performance of the homogenizing film, and a larger U. Comparative examples 61, 69, and 70 show that the refractive index n2 of the pyramidal structure also affects the light-diffusing performance; a higher refractive index results in a larger U.

[0204] Example 71

[0205] This invention provides a light-diffusing film comprising a substrate layer 20, a beam-splitting layer 21, and a light-diffusing layer 22, such as... Figure 14 As shown, the light-diffusing film is a microlens light-diffusing film. The thickness M of the substrate layer 20 is 75 μm, and the material of the substrate layer is selected from PET. The beam-splitting layer is composed of transparent polymer resin, which is photocurable acrylic resin (AR) with a refractive index n1 of 1.5. The light-diffusing layer is composed of transparent polymer resin, which is photocurable acrylic resin (AR) with a refractive index n2 of 1.5. The beam-splitting layer has a biaxial standard surface design: it is composed of long ribs stacked in N directions. The long ribs are laid flat on the lower surface of the substrate layer and extend infinitely to both ends. The long ribs in the same direction are closely arranged. The topological coefficient N is selected from 2, i.e., biaxial beam splitting. The beam-splitting layer is selected as a standard surface beam-splitting layer. The cross-section of the corresponding long rib is an isosceles triangle with the left and right sides being straight lines finitely intercepted at both ends. That is, the cross-section of the long rib is a right-side triangle with a vertex angle θ of 90°. o The light-diffusing layer is a microlens layer 225. The principal optical axes of three adjacent microlenses are connected to form an equilateral triangle array, with the microlenses closely packed together. The width G of each microlens is 50 μm, the height H is 0.5, and the distance D between the principal optical axes of adjacent microlenses is equal to G. This light-diffusing film exhibits good light-diffusing performance, with a uniformity improvement of U = 103%.

[0206] The other parameters of the microlens homogenizing film provided in Example 71 are listed in Table 5.

[0207] Table 5 shows the design parameters and homogenization performance of the microlens homogenizing films provided in Examples 71-80.

[0208]

[0209]

[0210] Note: The materials of the beam-splitting layer and the beam-amplifying layer in Examples 71-80 are all AR.

[0211] As shown in Table 5, comparative examples 71-75 show that the thickness and material of the substrate layer, as well as the size of the microlens in the light-diffusing layer (i.e., the width G of the pyramid), have little effect on the light-diffusing performance U of the uniform light film. Comparative examples 71 and 76-78 show that the aspect ratio H / G has a certain influence on U; when the aspect ratio = 0.1, the light-diffusing effect is slightly better, the light-diffusing performance of the uniform light film is slightly better, and U is slightly larger. Comparative examples 71, 79, and 80 show that the refractive index n2 of the microlens structure also affects the light-diffusing performance; the higher the refractive index, the larger U.

[0212] Example 81

[0213] This invention provides a composite light-diffusing film, comprising a substrate layer 20, a beam-splitting layer 21, a composite adhesive layer 24, and a filter substrate layer 23, as shown below. Figure 18 As shown, the substrate layer 20 and the beam-splitting layer 21 form a planar light-diffusing film. That is, the composite light-diffusing film can also be understood as being composed of a planar light-diffusing film, a composite adhesive layer, and a filter substrate layer. The thickness M of the substrate layer 20 is 75 μm, and the material of the substrate layer is selected from PET. The beam-splitting layer is composed of a transparent polymer resin, specifically a photocurable acrylic resin (AR), with a refractive index n1 of 1.5. The composite adhesive layer is also composed of a transparent polymer resin, also a photocurable acrylic resin (AR), with a refractive index of 1.5 and a thickness of 1 μm. The filter substrate layer is a multilayer co-extruded polymer film. Its filtering effect is that it reflects blue light at smaller incident angles (less than the critical angle), and the reflection ratio decreases at larger incident angles (greater than the critical angle), gradually beginning to transmit blue light. The beam-splitting layer features a uniaxial standard plane design: it is composed of stacked long ribs in N directions, which lie flat on the lower surface of the substrate layer and extend infinitely at both ends. Ribs in the same direction are closely arranged, with a topology coefficient N of 1, i.e., uniaxial beam splitting (e.g., ...). Figure 6 (As shown); the beam-splitting layer is selected from the standard surface beam-splitting layer, and the corresponding long rib cross-section is an isosceles triangle with the left and right legs being straight lines finitely cut at both ends, that is, the cross-section of the long rib is a right-side triangle with a vertex angle θ of 90°. o The light-homogenizing film exhibits good light-homogenizing performance, with a uniformity improvement of U = 193%.

[0214] Examples 82-120

[0215] The composite light-diffusing film provided in Example 81 has other parameters listed in Table 6.

[0216] Table 6 shows the design parameters and uniformity performance of the composite light-diffusing films provided in Examples 81-120.

[0217]

[0218]

[0219] Note: The composite adhesive layer in Examples 81-120 is made of AR material with a refractive index of 1.5; the filter substrate layer is selected from the small-angle blue-reflective DC series of Toray Picasus dimming film products (such as 47QPD5, 49QPD5, 51QPD5, etc.); as shown in Table 6, by comparing Examples 1 and 81, it can be seen that after adding the filter substrate layer, the light uniformity performance U of the composite light uniform film is significantly improved compared to when the filter substrate layer is not added. By comparing Examples 81-82, it can be seen that the thickness and material of the substrate layer have little effect on the light uniformity performance U of the light uniform film, but the material or refractive index of the beam splitter layer does affect U. For a uniaxial beam splitter layer, the higher the refractive index, the more obvious the beam splitting, the better the light uniformity performance, and the larger U. By comparing Examples 93-102, it can be seen that the larger the apex angle θ of the cross-sectional triangle, the closer the structure is to a plane, the less obvious the beam splitting, the worse the light uniformity performance, and the smaller U, and vice versa. Comparing Examples 81, 88, 89 with 111-116, it can be seen that for biaxial and triaxial beam-splitting layer designs, similar to uniaxial designs, a higher refractive index results in more pronounced beam splitting, better homogenization performance, and a larger U. Furthermore, at the same refractive index, triaxial is superior to biaxial, which is superior to uniaxial. Comparing Examples 103-110, it can be seen that when the legs of the cross-sectional triangle are bent at different degrees of curvature, they still function as beam splitters, and a larger α (greater bending) further improves the homogenization performance U. Comparing Examples 81 with 117-120, it can be seen that the thickness and refractive index of the composite adhesive layer have little impact on the homogenization performance.

[0220] Example 121

[0221] This invention provides a heat-resistant composite light-diffusing film, comprising a substrate layer 20, a beam-splitting layer 21, a composite adhesive layer 24, a light-filtering substrate layer 23, and a heat-resistant curing layer 29, as shown below. Figure 19As shown, the substrate layer 20 and the beam splitting layer 21 form a planar light-diffusing film. That is, the heat-resistant composite light-diffusing film can also be understood as being composed of a planar light-diffusing film, a composite adhesive layer, a filter substrate layer and a heat-resistant curing layer. The thickness M of the substrate layer 20 is 75 μm, and the material of the substrate layer is selected from PET. The beam-splitting layer is composed of a transparent polymer resin, which is a photocurable acrylic resin (AR) with a refractive index n1 of 1.5. The composite adhesive layer is composed of a transparent polymer resin, which is also a photocurable acrylic resin (AR) with a refractive index of 1.5 and a thickness of 1 μm. The filter substrate layer is a multilayer co-extruded polymer film. The filter effect is that it reflects blue light at a small incident angle (less than the critical angle), and the reflection ratio decreases at a large incident angle (greater than the critical angle), and gradually begins to transmit blue light. The thickness M4 of the heat-resistant curing layer is 5 μm, and the hardness is 2H. The heat-resistant curing layer is composed of a high-hardness heat-resistant transparent polymer resin, which is a photocurable acrylic resin (AR) with a formulation of HC-1. The formulation composition is shown in Table 8. The beam-splitting layer features a uniaxial standard plane design: it is composed of stacked long ribs in N directions, which lie flat on the lower surface of the substrate layer and extend infinitely at both ends. Ribs in the same direction are closely arranged, with a topology coefficient N of 1, i.e., uniaxial beam splitting (e.g., ...). Figure 6 (As shown); the beam-splitting layer is selected from the standard surface beam-splitting layer, and the corresponding long rib cross-section is an isosceles triangle with the left and right legs being straight lines finitely cut at both ends, that is, the cross-section of the long rib is a right-side triangle with a vertex angle θ of 90°. o The light-uniforming film exhibits good light-uniformity performance, with a uniformity improvement of U=193%, while also demonstrating good heat resistance and a low risk of thermal deformation.

[0222] Examples 122-168

[0223] As shown in Example 121, the other parameters of the heat-resistant composite uniform light film are listed in Table 7, and the formulation of the heat-resistant curing layer is shown in Table 8. Examples 122-163 have good heat resistance and low risk of thermal deformation, while Examples 164-168 have excellent heat resistance and low risk of thermal deformation.

[0224] Table 7 shows the design parameters and light-uniforming performance of the heat-resistant composite light-uniforming films provided in Examples 121-168.

[0225]

[0226]

[0227] Note: The composite adhesive layer in Examples 121-168 is made of AR material; the thickness of the composite adhesive layer in Examples 121-156 and 161-168 is 1 μm with a refractive index of 1.5; the thickness of Example 157 is 0.5 μm with a refractive index of 1.5; the thickness of Example 158 is 5 μm with a refractive index of 1.5; the thickness of Example 159 is 1 μm with a refractive index of 1.45; and the thickness of Example 160 is 1 μm with a refractive index of 1.55. The filter substrate layer is selected from the small-angle blue-reflective DC series of Toray Picasus dimming film products (such as 47QPD5, 49QPD5, 51QPD5, etc.).

[0228] Table 8 shows the design parameters and light-uniforming performance of the heat-resistant composite light-uniforming films provided in Examples 121-168.

[0229]

[0230] As shown in Table 7, comparing Examples 81 and 121, it can be seen that adding a heat-resistant curing layer does not affect the light uniformity performance U of the heat-resistant composite light-uniforming film compared to when there is no heat-resistant curing layer, but the hardness is significantly improved (the original pencil hardness of the lower surface is F), and the heat resistance is better with a low risk of thermal deformation. Comparing Examples 121-132, it can be seen that the thickness and material of the substrate layer have little effect on the light uniformity performance U of the light-uniforming film, but the material or refractive index of the beam-splitting layer does affect U. For a uniaxial beam-splitting layer, the higher the refractive index, the more obvious the beam splitting, the better the light uniformity performance, and the larger U. Comparing Examples 133-142, it can be seen that the larger the apex angle θ of the cross-sectional triangle, the closer the structure is to a plane, the less obvious the beam splitting, the worse the light uniformity performance, and the smaller U, and vice versa. Comparing Examples 121, 128, 129 with Examples 151-156, it can be seen that for biaxial and triaxial beam-splitting layer designs, similar to uniaxial designs, a higher refractive index results in more pronounced beam splitting, better homogenization performance, and a larger U. Furthermore, at the same refractive index, triaxial is superior to biaxial, which is superior to uniaxial. Comparing Examples 143-150, it can be seen that when the legs of the triangular cross-section are bent at different degrees of curvature, they still function as beam splitters, and a larger α (greater bending) further improves the homogenization performance U. Comparing Examples 121 with Examples 161-168, it can be seen that the thickness of the heat-resistant curing layer affects the hardness; when the resin formulation is the same, a greater thickness results in higher hardness. Furthermore, by comparing Table 8 with Examples 162-168 in Table 7, it can be seen that when the amount of polyfunctional monomers and hyperbranched resins added to the formulation is greater, the crosslinking density of the high-hardness resin is greater, the harder it is after curing, and the better the scratch resistance of the heat-resistant hardened layer. When the amount of heat-resistant oligomers added to the formulation increases, the heat resistance is improved from good to excellent, and the risk of heat deformation is lower.

[0231] Example 169

[0232] This invention provides a scratch-resistant composite light-diffusing film, comprising a substrate layer 20, a beam-splitting layer 21, a composite adhesive layer 24, a light-filtering substrate layer 23, and a scratch-resistant hardening layer 29, as shown below. Figure 19 As shown, the substrate layer 20 and the beam-splitting layer 21 form a planar light-diffusing film. This scratch-resistant composite light-diffusing film can also be understood as consisting of a planar light-diffusing film, a composite adhesive layer, a filter substrate layer, and a hardening layer. The substrate layer 20 has a thickness M of 75 μm and is made of PET. The beam-splitting layer is made of transparent polymer resin, specifically photocurable acrylic resin (AR), with a refractive index n1 of 1.5. The composite adhesive layer is also made of transparent polymer resin, photocurable acrylic resin (AR), with a refractive index of 1.5 and a thickness of 1 μm. The filter substrate layer is a multilayer co-extruded polymer film. Its filtering effect is to reflect blue light at smaller incident angles (less than the critical angle) and to decrease the reflection ratio at larger incident angles (greater than the critical angle), gradually transmitting blue light. The hardening layer has a thickness M3 of 5 μm and a hardness of 2H. It is made of high-hardness transparent polymer resin, specifically photocurable acrylic resin (AR), with a formulation of HC-8. The formulation composition is shown in Table 10. The beam-splitting layer features a uniaxial standard plane design: it is composed of stacked long ribs in N directions, which lie flat on the lower surface of the substrate layer and extend infinitely at both ends. Ribs in the same direction are closely arranged, with a topology coefficient N of 1, i.e., uniaxial beam splitting (e.g., ...). Figure 6 (As shown); the beam-splitting layer is selected from the standard surface beam-splitting layer, and the corresponding long rib cross-section is an isosceles triangle with the left and right legs being straight lines finitely cut at both ends, that is, the cross-section of the long rib is a right-side triangle with a vertex angle θ of 90°. o The light-homogenizing film exhibits good light-homogenizing performance, with a uniformity improvement of U = 193%.

[0233] Examples 170-216

[0234] As provided in Example 169, the other parameters of the anti-scratch composite light-diffusing film are listed in Table 9, and the formulation of the hardened layer is shown in Table 10.

[0235] Table 9 shows the design parameters and light-uniforming performance of the scratch-resistant composite light-uniforming films provided in Examples 169-216.

[0236]

[0237] Note: The composite adhesive layer in Examples 169-216 is made of AR material; the thickness of the composite adhesive layer in Examples 169-204 and 209-216 is 1 μm and the refractive index is 1.5; the thickness of Example 205 is 0.5 μm and the refractive index is 1.5; the thickness of Example 206 is 5 μm and the refractive index is 1.5; the thickness of Example 207 is 1 μm and the refractive index is 1.45; and the thickness of Example 208 is 1 μm and the refractive index is 1.55. The filter substrate layer is selected from the small-angle blue-reflecting DC series of Toray Picasus dimming film products (such as 47QPD5, 49QPD5, 51QPD5, etc.).

[0238] Table 10 shows the design parameters and light homogenization performance of the scratch-resistant composite light-diffusing films provided in Examples 169-216.

[0239]

[0240] As shown in Table 9, comparing Examples 81 and 169, it can be seen that adding a hardening layer does not affect the uniformity performance U of the scratch-resistant composite light-diffusing film compared to when there is no hardening layer, but the hardness is significantly improved (the original pencil hardness of the lower surface is F). Comparing Examples 169-180, it can be seen that the thickness and material of the substrate layer have little effect on the uniformity performance U of the light-diffusing film, but the material or refractive index of the beam-splitting layer does affect U. For uniaxial beam-splitting layers, the higher the refractive index, the more obvious the beam splitting, the better the uniformity performance, and the larger U. Comparing Examples 181-190, it can be seen that the larger the apex angle θ of the cross-sectional triangle, the closer the structure is to a plane, the less obvious the beam splitting, the worse the uniformity performance, and the smaller U, and vice versa. Comparing Examples 169, 176, 177, and 199-204, it can be seen that for biaxial and triaxial beam-splitting layer designs, similar to uniaxial, the higher the refractive index, the more obvious the beam splitting, the better the uniformity performance, and the larger U. Furthermore, at the same refractive index, triaxial is superior to biaxial, which is superior to uniaxial. Comparing Examples 191-198, it can be seen that when the legs of the cross-sectional triangle are bent at different degrees of curvature, they still play a role in beam dispersion, and the larger α (the greater the bending) the beam uniformity performance U is improved. Comparing Examples 169 and 209-216, it can be seen that the thickness of the hardened layer affects the hardness; when the resin formulation is the same, the greater the thickness, the higher the hardness. Furthermore, comparing Examples 210-216 in Table 9 with those in Table 10, it can be seen that the higher the proportions of polyfunctional monomers, highly functional oligomers, and hyperbranched resins in the formulation, the greater the crosslinking density of the high-hardness resin, the harder the cured layer, and the better its scratch resistance.

[0241] It should be noted that this article focuses on protecting the design principle of the heat-resistant composite light-diffusing film, and does not limit the design of the filter substrate layer and the heat-resistant curing resin formulation. The manufacturers and models of the filter substrate layer and the heat-resistant curing resin formulation used are not intended to limit the scope of protection of this invention. All equivalent variations and modifications made to the composite light-diffusing film according to this invention are covered within the patent scope of this invention.

Claims

1. A light-uniforming film, characterized in that, The light-diffusing film consists of a beam-splitting layer, a substrate layer, and a light-amplifying layer. The light-amplifying layer is located on the upper surface of the substrate layer, and the beam-splitting layer is located on the lower surface of the substrate layer. The substrate layer is made of PET. The beam-splitting layer is made of transparent polymer resin, specifically photocurable acrylic resin, with a refractive index n1 of 1.

5. The light-amplifying layer is also made of transparent polymer resin, specifically photocurable acrylic resin, with a refractive index n2 of 1.

5. The beam-splitting layer is composed of stacked long ribs in N directions. These long ribs are laid flat on the lower surface of the substrate layer, extending infinitely towards both ends. Long ribs in the same direction are closely arranged, with N being 2. The cross-section of the long ribs in the beam-splitting layer is an isosceles triangle, with the left and right sides being straight lines finitely intercepted at both ends. The cross-section of the long ribs is a right-side triangle with a vertex angle θ of 90°. The light-amplifying layer is a square pyramid layer, composed of flatly laid square pyramids, with the vertices of the pyramids arranged in a square pattern. The height T of the pyramid is 50 μm, and the angle γ between the side and the height is 30°.

2. A composite light-diffusing film, characterized in that, The composite light-diffusing film is composed of a hardening layer, a filter substrate layer, a composite adhesive layer, a beam-splitting layer, and a substrate layer. The beam-splitting layer is located on the lower surface of the substrate layer, the hardening layer is located on the lower surface of the filter substrate layer, and the composite adhesive layer is located on the upper surface of the filter substrate layer. The tip of the beam-splitting layer is embedded in the composite adhesive layer to bond the filter substrate layer and the beam-splitting layer. The substrate layer is made of PET; the beam-splitting layer is composed of transparent polymer resin, specifically photocurable acrylic resin, with a refractive index n1 of 1.65; the composite adhesive layer is composed of transparent polymer resin, specifically photocurable acrylic resin, with a refractive index of 1.5 and a thickness of 1 μm; the filter substrate layer is a multilayer co-extruded polymer film, whose filtering effect is to reflect blue light when the angle is less than the critical angle, and the reflection ratio decreases when the angle is greater than the critical angle, gradually starting to transmit blue light; the thickness M4 of the hardened layer is 5 μm, and the hardness is 2H; the beam-splitting layer is composed of N long ribs stacked in different directions, which are laid flat on the lower surface of the substrate layer, extending infinitely towards both ends, with long ribs in the same direction closely arranged, and the N directions equally dividing the 360-degree azimuth angle, where N is 3; the cross-sections of the long ribs in the beam-splitting layer are identical, all being isosceles triangles, with the left and right sides being straight lines with finite ends, and the base being a straight line; the cross-section of the long ribs in the beam-splitting layer is a right-sided triangle with a vertex angle θ of 90°.

3. The composite light-diffusing film according to claim 2, characterized in that, The hardened layer is a scratch-resistant hardened layer, and the formula of the photocurable acrylic resin of the scratch-resistant hardened layer is as follows: a mixture of 20-60 parts monofunctional monomer diluent (functionality = 1), 20-50 parts polyfunctional monomer (functionality = 2-3), 5-15 parts high-functionality oligomer (functionality > 3), 1-50 parts hyperbranched resin and 2-4 parts photoinitiator; the parts are by weight.

4. The composite light-diffusing film according to claim 2, characterized in that, The hardened layer is a heat-resistant hardened layer, and the formulation of the photocurable acrylic resin of the heat-resistant hardened layer is as follows: a mixture of 20-60 parts monofunctional monomer diluent (functionality = 1), 20-50 parts polyfunctional monomer (functionality = 2-3), 5-15 parts heat-resistant oligomer (functionality > 1), 1-50 parts hyperbranched resin and 2-4 parts photoinitiator, wherein the parts are parts by weight.

5. The composite light-diffusing film according to claim 4, characterized in that, The monofunctional monomer diluent is selected from one of isoborneol acrylate (IBOA), isoborneol methacrylate (IBOMA), and trimethylolpropane methyl acetal acrylate (CTFA); the polyfunctional monomer is selected from one of diethylene glycol dimethacrylate (DEGDMA), neopentyl glycol diacrylate (NPGDA), trimethylolpropane triacrylate (TMPTA), pentaerythritol triacrylate (PET3A), and trimethylolpropane trimethacrylate (TMPTMA); the heat-resistant oligomer is selected from phenolic epoxy acrylate.

6. A method for preparing a composite homogenizing film according to any one of claims 2-5, characterized in that, A beam-splitting layer is prepared on the back side of the substrate layer using a micro-replication or hot-pressing process with transparent polymer resin. A hardening layer is prepared on the back side of the filter substrate layer using a coating process. A composite adhesive layer is prepared on the front side of the filter substrate layer using transparent polymer resin using a coating process and then bonded to the beam-splitting layer. After the tip of the beam-splitting layer is embedded in the composite adhesive layer, ultraviolet curing is performed to ensure a strong bond between the filter substrate layer and the beam-splitting layer.

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