Composite film, backlight module and display device

Abstract

Disclosed in the present application are a composite film, a backlight module and a display device. A first optical film of the composite film comprises a first substrate, a first optical layer and a microstructure layer, the microstructure layer being connected to a first surface of the first substrate, and the first optical layer being connected to a second surface of the first substrate. The weight percentage content A of diffusion particles of the first optical layer satisfies: 10.5wt.％≤A≤22.0wt.％; the weight percentage content a1 of a first refractive material of the diffusion particles and the weight percentage content a2 of a reflective material thereof satisfy: 0.4≤a1 / a2≤2.0. Thus, the composite film can achieve both light diffusion and brightening functions, simplify the structure of a backlight module and the assembly process, save the amount of material used, and reduce the space occupied by the backlight module.

Description

Composite films, backlight modules and display devices Technical Field

[0001] This application relates to the field of backlight module technology, and in particular to a composite film, a backlight module and a display device. Background Technology

[0002] As people's demands for the optical performance of LCD display devices such as monitors, televisions, and interactive smart panels increase, the ability to achieve higher brightness and more uniform images under low energy consumption and low cost conditions has spurred the development of more new technologies. Display devices generally consist of a backlight module and an LCD screen. The backlight module is composed of a light source, a diffuser plate, and optical films. The light emitted by the light source passes through the diffuser plate and optical films in sequence before being projected onto the LCD screen. The diffuser plate diffuses the light, and the optical films converge and focus the diffused light to achieve the purpose of increasing brightness.

[0003] In related technologies, the assembly of display devices, including light sources, diffuser plates, optical films, and liquid crystal screens, is relatively complex, resulting in heavy display devices and poor display effects; the manufacturing processes of diffuser plates and optical films are complex and the material costs are high.

[0004] Summary of the Invention

[0005] This application provides a composite film, a backlight module, and a display device, which can solve the problem of high cost of backlight modules.

[0006] In a first aspect, embodiments of this application provide a composite film including a first optical film. The first optical film includes a first substrate, a first optical layer, and a microstructure layer. The microstructure layer is connected to a first surface (the surface facing away from the light source) of the first substrate, and the first optical layer is connected to a second surface (the surface facing the light source) of the first substrate.

[0007] The first optical layer comprises a uniformly mixed first optical adhesive and diffusing particles, wherein the diffusing particles comprise a first refractive material and a reflective material; based on the total weight of the first optical adhesive, the weight percentage of the diffusing particles is A, the weight percentage of the first refractive material is a1, and the weight percentage of the reflective material is a2, wherein 10.5 wt.% ≤ A ≤ 22.0 wt.%, and 0.4 ≤ a1 / a2 ≤ 2.0.

[0008] In some embodiments, the first optical layer satisfies at least one of the following conditions:

[0009] (1)18.0wt.%≤A≤22.0wt.%;

[0010] (2)4.0wt.%≤a1≤10.0wt.%;

[0011] (3)4.0wt.%≤a2≤13.0wt.%.

[0012] In some embodiments, the first optical film satisfies at least one of the following conditions:

[0013] (1) The particle size of the first refractive material is r1, 1μm≤r1≤50μm;

[0014] (2) The particle size of the reflective material is r2, 0.1μm≤r2≤20μm;

[0015] (4) The thickness of the first optical layer is m1, 5μm≤m1≤15μm;

[0016] (5) The thickness of the first substrate is m2, 100μm≤m2≤300μm.

[0017] In some embodiments, the microstructure layer includes a plurality of microprisms that deflect light, wherein the angle of the microprisms is α, and 85°≤α≤105°.

[0018] In some embodiments, the microstructure layer satisfies at least one of the following conditions:

[0019] (1) The edge spacing between two adjacent microprisms of the microstructure layer is L1, 110μm≤L1≤300μm;

[0020] (2) The thickness of the microstructure layer is g, where 30μm≤g≤70μm;

[0021] (3) The height of the microprism is h, 5μm≤h≤50μm;

[0022] (3) The microstructure layer covers the surface of the first substrate facing away from the light source.

[0023] In some embodiments, the reflective material includes at least one of TiO2 and SiO2;

[0024] In some embodiments, the first refractive material includes at least one of polymethyl methacrylate, butyl 2-methyl-2-acrylate monomer, polycarbonate, polystyrene, and polypropylene;

[0025] In some embodiments, the material of the first substrate includes at least one selected from polycarbonate, polyethylene terephthalate, polystyrene, polyethylene, and polymethyl methacrylate;

[0026] In some embodiments, the material of the microstructure layer includes a UV adhesive.

[0027] In some embodiments, the composite film further includes a diffusion film disposed on one side of the first surface of the first optical film;

[0028] The diffusion film includes a second substrate and a second optical layer, wherein the second optical layer is connected to the surface of the second substrate facing away from the first optical film;

[0029] The second optical layer includes a second optical adhesive and a second refractive material. Based on the total weight of the second optical adhesive, the weight percentage of the second refractive material is a3, where 3wt.% ≤ a3 ≤ 10wt.%.

[0030] In some embodiments, the diffusion membrane satisfies at least one of the following conditions:

[0031] (1) The particle size of the second refractive material is r3, 1μm≤r3≤50μm

[0032] (2) The thickness of the second optical layer is n1, 13μm≤n1≤19μm;

[0033] (3) The thickness of the second substrate is n2, 100μm≤n2≤300μm.

[0034] In some embodiments, the first optical film and the diffusion film are integrally disposed; or, the composite film further includes a brightness enhancement layer, which is connected between the first optical film and the diffusion film, and the first optical film, the brightness enhancement layer and the diffusion film are integrally disposed.

[0035] In some embodiments, the composite film further includes a brightness enhancement layer, which is connected between the first optical film and the diffusion film;

[0036] The brightness enhancement layer includes a 0° brightness enhancement film; or,

[0037] The brightness enhancement layer includes a 90° brightness enhancement film; or,

[0038] The brightness enhancement layer includes a first brightness enhancement film and a second brightness enhancement film. The first brightness enhancement film has a first prism, and the second brightness enhancement film has a second prism. The angle difference between the first prism and the second prism is 90°.

[0039] Secondly, this application provides a backlight module including a light source and a composite film as described above. The light source is used to generate light, and the composite film is disposed on the light-emitting side of the light source. The light emitted by the light source passes through the first optical layer, the first substrate and the microstructure layer of the composite film in sequence before being emitted.

[0040] Thirdly, embodiments of this application provide a display device, including a liquid crystal display (LCD) screen and a backlight module as described above. The LCD screen is disposed on the side of the composite film facing away from the light source, and the light emitted by the light source passes through the composite film and is projected onto the LCD screen.

[0041] Based on the composite film, backlight module, and display device of this application embodiment, the first optical film of the composite film includes a first substrate, a first optical layer, and a microstructure layer. By selecting the weight percentage A of the diffusing particles in the first optical layer to satisfy 10.5wt.%≤A≤22.0wt.%, and the weight percentage a1 of the first refractive material and the weight percentage a2 of the reflective material of the diffusing particles to satisfy 0.4≤a1 / a2≤2.0, the composite film can both atomize and brighten light, and can replace the diffuser plate and optical film in related technologies in the backlight module, simplifying the structure of the backlight module, simplifying the assembly process, saving material usage, and reducing the space occupied by the backlight module. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 is a cross-sectional view of a composite membrane according to an embodiment of this application;

[0044] Figure 2 is a schematic diagram of the disassembled structure of the first optical film and the diffusion film according to an embodiment of this application;

[0045] Figure 3 is a cross-sectional view of the composite membrane according to another embodiment of this application;

[0046] Figure 4 is a schematic diagram of the disassembled structure of a first optical film, a diffusion film, and a light enhancement layer according to an embodiment of this application;

[0047] Figure 5 is a cross-sectional view of a composite membrane according to another embodiment of this application;

[0048] Figure 6 is a schematic diagram of the disassembled structure of the first optical film, the diffusion film, and the two brightness enhancement layers according to an embodiment of this application.

[0049] Reference numerals: 10, composite film; 100, first optical film; 110, first substrate; 120, first optical layer; 130, microstructure layer; 121, first optical adhesive; 122, diffusing particles; 200, diffusing film; 210, second substrate; 220, second optical layer; 221, second optical adhesive; 222, second refractive material; 300, brightness enhancement layer; 310, first brightness enhancement film; 320, second brightness enhancement film. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of this application clearer, this application will be further described in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit this application.

[0051] In related technologies, the film solution of the backlight module of the display device usually adopts a separate combination of diffuser plate and optical film. Among them, the combination of multiple layers of optical film can be: upper diffuser film + 0° brightness enhancement film, upper diffuser film + 0° brightness enhancement film + 90° brightness enhancement film, upper diffuser film + 90° brightness enhancement film + 0° brightness enhancement film, etc. The upper diffuser film can be prepared by mixing diffuser particles with optical adhesive and then coating it on the surface of the substrate. The 0° brightness enhancement film and 90° brightness enhancement film can be prepared by coating the substrate surface with optical adhesive, rolling it with a mold, and then curing it with ultraviolet light (UV) to form a microprism structure. The diffuser plate can be obtained by rolling a mixture of light-transmitting material and diffuser particles. The diffuser plate atomizes the light emitted by the light source and projects it onto the 0° brightness enhancement film and / or the 90° brightness enhancement film. The 90° brightness enhancement film is used to focus and converge the light parallel to the direction of the LCD screen to achieve the effect of brightening. The 0° brightness enhancement film is used to focus and converge the light perpendicular to the direction of the LCD screen to achieve the effect of brightening. The upper diffuser film is used to further atomize the light passing through the 0° brightness enhancement film / 90° brightness enhancement film and then project it onto the LCD screen.

[0052] However, traditional diffuser plates are typically about 2.0mm thick and weigh over 4KG, which not only increases the overall weight of the device but also requires considerable manpower during assembly. When the diffuser plate collides with the bent edge of the back panel, it is prone to cracking, leading to unstable display effects and impacting the user experience. Furthermore, existing backlight modules include diffuser plates and optical films. During assembly, the light source, diffuser plate, optical films, and LCD screen of the backlight module must be sequentially aligned and their relative positions fixed to complete the assembly process, which is complex and costly.

[0053] Based on this, embodiments of this application provide a composite film, a backlight module, and a display device. This composite film has excellent optical performance and can replace the diffuser plate and optical film in existing backlight module designs, solving the technical problems of heavy weight and poor display effect in existing display devices. This significantly reduces the manufacturing and material costs of the display device.

[0054] The composite film, backlight module, and display device provided in this application are described in detail below.

[0055] As shown in Figures 1 and 2, this is a schematic diagram of the structure of a composite film 10 according to an embodiment of this application. The composite film 10 includes a first optical film 100, which includes a first substrate 110, a first optical layer 120, and a microstructure layer 130. The microstructure layer 130 is connected to the first surface (the surface facing away from the light source) of the first substrate 110, and the first optical layer 120 is connected to the second surface (the surface facing the light source) of the first substrate 110.

[0056] The microstructure layer 130 includes multiple microprisms that enhance light intensity, as shown in Figure 2. Each microprism has an angle α, meaning it has at least two optical surfaces facing away from the first substrate 110. Adjacent optical surfaces are connected at an angle, and the angle between two adjacent surfaces is the angle α of the microprism. The angle α is 85° ≤ α ≤ 105°. For example, α can be 85°, 85°, 90°, 95°, 100°, 105°, or any range thereof. For example, when the microprism is a strip prism with two optical surfaces, the angle is the angle between the two optical surfaces. When the microprism is a cone prism with three optical surfaces, the smallest angle between two adjacent optical surfaces is the angle of the microprism.

[0057] The first optical layer 120 includes a uniformly mixed first optical adhesive 121 and diffusing particles 122. The diffusing particles 122 include a first refractive material and a reflective material. Based on the total weight of the first optical adhesive 121, the weight percentage of the diffusing particles 122 is A, the weight percentage of the first refractive material is a1, and the weight percentage of the reflective material is a2. Among these, 10.5 wt.% ≤ A ≤ 22.0 wt.%, and 0.4 ≤ a1 / a2 ≤ 2.0. For example, A can be 10.5 wt.%, 13.4 wt.%, 15.5 wt.%, 18.0 wt.%, 22.0 wt.%, or any range of the above. a1 / a2 can be 0.6, 0.7, 0.9, 1.2, 1.4, or any range of the above.

[0058] In this embodiment, the first optical film 100 of the composite film 10 includes a first optical layer 120 and a microstructure layer 130. The first optical adhesive 121 of the first optical layer 120 allows light to pass through, the first refractive material of the first optical layer 120 scatters light, and the reflective material of the first optical layer 120 reflects light. By selecting the weight percentage a1 of the first refractive material and the weight percentage a2 of the reflective material to satisfy 0.4 ≤ a1 / a2 ≤ 2.0, the first refractive material and the reflective material can be combined, achieving a light-fogging effect in the first optical adhesive 121. Furthermore, by selecting the diffusing particles 122... The weight percentage A satisfies 10.5 wt.% ≤ A ≤ 22.0 wt.%, and the amount of diffuser particles 122 is appropriate, resulting in more angles of light after the diffuser particles 122 change direction, and a better uniform light atomization effect. Furthermore, the microstructure layer 130 is selected to have multiple microprisms, with the edge angle α of the microprisms satisfying 85° ≤ α ≤ 105°. The microstructure layer 130 can cooperate in receiving light passing through the first optical layer 120, maintaining the atomization effect of the first optical layer 120 while also allowing total internal reflection of light with an angle greater than total internal reflection, allowing only small-angle light to refract and pass through, thereby achieving a brightening effect. Therefore, the composite film 10 of this embodiment can both atomize and brighten light, replacing the diffuser plate and optical film in related technologies and being applied to backlight modules, simplifying the structure of the backlight module, simplifying the assembly process, saving material usage, and reducing the space occupied by the backlight module. When A exceeds the upper limit of 22.0 wt.%, the amount of diffusing particles 122 is excessive, resulting in a high particle density and a multi-layered diffusion structure. Light has already undergone multiple refractions or total internal reflections, and the atomization effect is not further improved. When A is below the lower limit of 10.5 wt.%, the amount of diffusing particles 122 is insufficient, resulting in a low particle density that is difficult to meet the requirements for atomization and brightness enhancement. When a1 / a2 exceeds the upper limit of 1.4, the content of the first refractive material is excessive, resulting in a better atomization effect but potentially leading to insufficient light brightness transmitted through the composite film 10. When a1 / a2 is below the lower limit of 0.6, the content of reflective material is excessive, resulting in poor atomization of light and a tendency to produce shadows.

[0059] In some embodiments, 4.0 wt.% ≤ a1 ≤ 10.0 wt.%, for example, a1 can be 4.0 wt.%, 5.3 wt.%, 6.5 wt.%, 8.5 wt.%, 10.0 wt.%, or any range thereof. Within the above range, the amount of the first refractive material is appropriate and has a good scattering effect on light, so as to cooperate with the reflective material to enhance the atomization effect on light.

[0060] In some embodiments, the first refractive material includes at least one of polymethyl methacrylate (PMMA), butyl 2-methyl-2-acrylate (PBMA), polycarbonate (PC), polystyrene (PS), and polypropylene (PP). The above materials are usually present in the form of spherical particles with uniform particle size. The above materials also have good light refraction effect, enabling the first refractive material to effectively scatter light and appear transparent or translucent without affecting the color of the underlying material. At the same time, they also have good heat resistance and can remain stable in high-temperature environments.

[0061] In some embodiments, 4.0 wt.% ≤ a2 ≤ 13.0 wt.%, for example, a2 can be 4.0 wt.%, 6.5 wt.%, 8.8 wt.%, 10.0 wt.%, 13.0 wt.%, or any range thereof. Within the above range, the amount of reflective material is appropriate, and it has a good reflective effect on light, so that the amount and angle of light emitted from the first optical layer 120 are appropriate, thereby improving the atomization effect.

[0062] In some embodiments, the reflective material includes at least one of TiO2 and SiO2. TiO2 has a high refractive index and typically exists as spherical or near-spherical particles. The uneven surface structure of TiO2 particles can also scatter light, thus TiO2 can effectively scatter light and produce a uniform light scattering effect. Furthermore, TiO2 is white, possessing excellent hiding power and whiteness, and also exhibits good lightfastness, not easily fading from prolonged exposure to sunlight. SiO2 has a low refractive index and typically exists as spherical or near-spherical particles. The uniform size and shape of SiO2 particles enable it to effectively scatter light. SiO2 is transparent or translucent and does not affect the color of the underlying material. SiO2 also has good heat resistance and remains stable at high temperatures.

[0063] In some embodiments, the particle size of the first refractive material is r1, where 1 μm ≤ r1 ≤ 50 μm. For example, r1 can be 1 μm, 4 μm, 8 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, or any range thereof. Within the above range, the first refractive material can effectively scatter light, optimize the atomization effect, and simultaneously allow the first refractive material to be uniformly mixed in the first optical adhesive 121.

[0064] In some embodiments, the particle size of the reflective material is r2, where 0.1 μm ≤ r2 ≤ 20 μm. For example, r2 can be 0.1 μm, 0.6 μm, 1 μm, 2 μm, 6 μm, 10 μm, 14 μm, 20 μm, or any range thereof. Within the above range, the reflective material can effectively reflect light, optimize the fogging effect, and has low light loss, which helps to improve the incremental effect, while also allowing the reflective material to be uniformly mixed in the first optical adhesive 121.

[0065] In some embodiments, the thickness of the first optical layer 120 is m1, where 5μm ≤ m1 ≤ 15μm. For example, m1 can be 5μm, 6μm, 7μm, 8μm, 10μm, 12μm, 15μm, or any range thereof. Within the above range, the first refractive material and the reflective material can be uniformly dispersed in the first optical adhesive 121, ensuring a suitable optical path for the light entering the first optical layer 120, thereby improving the fogging effect and providing a good brightening effect.

[0066] In some embodiments, a first refractive material and a reflective material may be added to a liquid first optical adhesive 121, mixed evenly, and then uniformly coated onto the surface of a first substrate 110. After the first optical adhesive 121 has cured, a first optical layer 120 is formed.

[0067] In some embodiments, the thickness of the first substrate 110 is m2, where 100μm ≤ m2 ≤ 300μm. For example, m2 can be 100μm, 130μm, 160μm, 180μm, 220μm, 250μm, 300μm, or any range thereof. Within the above range, the first substrate 110 can provide good support for the first optical layer 120 and the microstructure layer 130, preventing the first optical layer 120 and the microstructure layer 130 from deforming and breaking due to bending deformation of the first substrate 110, and enabling the first optical layer 120 and the microstructure layer 130 to be stably attached to the surface of the first substrate 110, facilitating processing.

[0068] In some embodiments, the material of the first substrate 110 includes at least one of polycarbonate, polyethylene terephthalate, polystyrene, polyethylene, and polymethyl methacrylate. Using the above materials, the first substrate 110 has good light transmittance and low light deflection.

[0069] In some embodiments, the microstructure layer 130 covers the first surface (the surface facing away from the light source) of the first substrate 110, so that all light passing through the first substrate 110 can reach the microstructure layer 130.

[0070] In some embodiments, the edge spacing between two adjacent microprisms of the microstructure layer 130 is L1, where 110 μm ≤ L1 ≤ 300 μm. For example, L1 can be 110 μm, 150 μm, 180 μm, 200 μm, 240 μm, 300 μm, or any range thereof. Within this range, the optical path and angle of light propagation between the multiple microprisms are appropriate, thereby optimizing the brightening effect.

[0071] In some embodiments, the thickness of the microstructure layer 130 is g, where 30 μm ≤ g ≤ 70 μm. For example, g can be 30 μm, 33 μm, 40 μm, 45 μm, 50 μm, 60 μm, 70 μm, or any range thereof. Within this range, the optical path of light entering the microstructure layer 130 is appropriate, thereby improving the fogging and brightening effects, and the microstructure layer 130 has good structural strength and is not easily broken.

[0072] In some embodiments, the height of the microprism is h, where 5μm ≤ h ≤ 50μm. For example, h can be 5μm, 8μm, 10μm, 15μm, 20μm, 30μm, 50μm, or any range thereof. The microstructure layer 130 in this embodiment can be formed by spraying 5μm to 50μm steel grit or quartz sand onto the surface of a roller mold to create a pitted structure. An optical adhesive layer is then applied to the surface of the first substrate 110, and the optical adhesive is rolled onto the pitted roller mold. After UV curing, the microstructure layer 130 with microprisms is formed. By selecting the height of the microprism within the above range, the microstructure layer 130 can improve the fogging and brightening effects while also ensuring the microprisms have a suitable sharpness for bonding with other structures and preventing easy breakage. In this embodiment, the shape of the steel grit or quartz sand sprayed onto the surface of the roller mold can be used to prepare a microprism with the desired angle α.

[0073] In some embodiments, the material of the microstructure layer 130 includes a UV adhesive.

[0074] In some embodiments, the composite film 10 further includes a diffusion film 200 disposed on one side of the first surface of the first optical film 100. The diffusion film 200 can further atomize the light passing through the microstructure layer 130 and further improve the uniformity of the light passing through the composite film 10.

[0075] As shown in Figure 2, the diffusion film 200 includes a second substrate 210 and a second optical layer 220. The second optical layer 220 is connected to the surface of the second substrate 210 facing away from the first optical film 100. The second optical layer 220 includes a second optical adhesive 221 and a second refractive material 222. Based on the total weight of the second optical adhesive 221, the weight percentage of the second refractive material 222 is a3, where 3wt.%≤a3≤10wt.%. The second refractive material 222 further scatters the light, allowing the first optical film 100 and the diffusion film 200 to work together to achieve better light atomization and brightening effects.

[0076] In some embodiments, the particle size of the second refractive material 222 is r3, where 1 μm ≤ r3 ≤ 50 μm, so that the second refractive material 222 can be uniformly dispersed in the second optical adhesive 221. The second refractive material 222 includes at least one of polymethyl methacrylate (PMMA), butyl 2-methyl-2-acrylate (PBMA), polycarbonate (PC), polystyrene (PS), and polypropylene (PP).

[0077] In some embodiments, the thickness of the second optical layer 220 is n1, where 13μm≤n1≤19μm, so that the optical path of the light entering the second optical layer 220 is appropriate, thereby improving the atomization effect and the brightening effect.

[0078] In some embodiments, the second refractive material 222 can be added to the liquid second optical adhesive 221, mixed evenly, and then uniformly coated onto the surface of the second substrate 210. After the second optical adhesive 221 cures, a second optical layer 220 is formed. The first optical adhesive 121 and the second optical adhesive 221 can be optical adhesives with the same refractive index.

[0079] In some embodiments, the thickness of the second substrate 210 is n2, where 100μm≤n2≤300μm. The material of the second substrate 210 includes at least one of polycarbonate, polyethylene terephthalate, polystyrene, polyethylene, and polymethyl methacrylate. Using the above materials, the first substrate 110 has good light transmittance and minimal light deflection.

[0080] In some embodiments, as shown in FIG1, the first optical film 100 and the diffusion film 200 are integrally disposed. For example, an adhesive material 400 is provided between the layers of the first optical film 100 and the diffusion film 200 to bond the first optical film 100 and the diffusion film 200 together to form a composite film 10. In some embodiments, as shown in FIGS. 3 to 6, the composite film 10 further includes a brightness enhancement layer 300, which is connected between the first optical film 100 and the diffusion film 200, and the first optical film 100, the brightness enhancement layer 300, and the diffusion film 200 are integrally disposed. For example, an adhesive material 400 is provided between the layers of the first optical film 100, the brightness enhancement layer 300, and the diffusion film 200 to bond the first optical film 100, the brightness enhancement layer 300, and the diffusion film 200 together to form a composite film 10. The adhesive material 400 between any two adjacent layers of the first optical film 100, the brightness enhancement layer 300 and the diffusion film 200 of the composite film 10 can be a liquid optical adhesive filled in the gap between the layers. After the liquid optical adhesive is cured, the various layers of the composite film 10 are cured into one piece to form the composite film 10, so that it can be assembled into the backlight module.

[0081] Optionally, as shown in Figures 3 and 4, the brightness enhancement layer 300 includes a 0° brightness enhancement film; or, the brightness enhancement layer 300 includes a 90° brightness enhancement film; or, as shown in Figures 5 and 6, the brightness enhancement layer 300 includes a first brightness enhancement film 310 and a second brightness enhancement film 320, the first brightness enhancement film 310 having a first prism and the second brightness enhancement film 320 having a second prism, the angle difference between the first prism and the second prism being 90°, and the one with the larger angle between the first brightness enhancement film 310 and the second brightness enhancement film 320 being placed on the side of the other facing the diffusion film 200, so as to achieve the purpose of brightening.

[0082] When the brightness enhancement layer 300 includes a first brightness enhancement film 310 and a second brightness enhancement film 320, optionally, as shown in Figures 5 and 6, the first prism of the first brightness enhancement film 310 has an angle of 0°, that is, the first brightness enhancement film 310 is a 0° brightness enhancement film, and the second prism of the second brightness enhancement film 320 has an angle of 90°, that is, the second brightness enhancement film 320 is a 90° brightness enhancement film; or, the first prism of the first brightness enhancement film 310 has an angle of 8°, and the second prism of the second brightness enhancement film 320 has an angle of 98°; or, the first prism of the first brightness enhancement film 310 has an angle of 45°, and the second prism of the second brightness enhancement film 320 has an angle of 135°.

[0083] This application also provides a backlight module, which includes a light source and a composite film 10 as described above. The light source generates light, and the composite film 10 is disposed on the light-emitting side of the light source. The light emitted by the light source passes sequentially through the first optical layer 120, the first substrate 110, and the microstructure layer 130 of the composite film 10 before exiting. The composite film 10 of this application embodiment can both atomize and brighten the light, and can replace the diffuser plate and optical film in related technologies in the backlight module, simplifying the structure of the backlight module.

[0084] The backlight module of this embodiment is identical to the backlight module structure in the related art except that it uses a composite film 10 to replace the diffuser plate and optical film. That is, the backlight module structures in the related art, except for the diffuser layer and optical film, are all applicable to this application. By using the composite film 10, the backlight module of this embodiment can also have all the beneficial effects of the composite film 10. At the same time, it simplifies the structure of the backlight module, simplifies the assembly process, saves material usage, and helps reduce the space occupied by the backlight module.

[0085] This application embodiment also provides a display device, which includes, but is not limited to, monitors, televisions, interactive smart flat panels, and other liquid crystal display devices. The display device includes a liquid crystal screen and a backlight module as described above. The liquid crystal screen is disposed on the side of the composite film 10 away from the light source, and the light emitted by the light source passes through the composite film 10 and is projected onto the liquid crystal screen.

[0086] In some embodiments, the composite film 10 can be bonded to the back of the LCD screen using double-sided adhesive, or OCA adhesive can be applied to the surface of the composite film 10 and fully adhered to the back of the LCD screen, or the composite film 10 can be installed on the back plate of the backlight module by means of drilling, snap-fitting, etc., or the composite film 10 can be installed on the bezel of the display device.

[0087] In some embodiments, the size of the LCD screen is greater than or equal to 43 inches.

[0088] Example

[0089] The following examples and comparative examples illustrate the implementation of the composite membrane 10 of this application in more detail. Those skilled in the art will understand that the preparation methods described in this application are merely examples, and any other suitable preparation methods are within the scope of this application. Various tests and evaluations were performed according to the methods described below. Furthermore, unless otherwise specified, "parts" and "%" are quality bases.

[0090] Example 1

[0091] (1) Preparation of the first optical film 100

[0092] TiO2, SiO2, PMMA, and PBMA are mixed in a mass ratio of 1:0.2:4:1, and then added to a liquid optical adhesive and mixed evenly to form a mixed slurry with a solid content of 20 wt%. The particle size r2 of TiO2 is 2 μm, the particle size r2 of SiO2 is 3 μm, the particle size r1 of PMMA is 10 μm, and the particle size r1 of PBMA is 12 μm. The mixed slurry is coated onto one surface of a first substrate 110 made of polyethylene terephthalate (PET) with a thickness m2 of 100 μm and a coating thickness m1 of 10 ± 5 μm. After the liquid optical adhesive cures, a first optical adhesive 121 is formed, resulting in a first optical layer 120.

[0093] Liquid optical adhesive is applied to the opposite surface of the first substrate 110 with a coating thickness g of 35±1μm. The optical adhesive is rolled using a roller mold with pits on the surface and cured with UV to form a microstructure layer 130 with microprisms. The height h of the microprisms is 35±1μm, the angle α is 90±1°, and the edge spacing L1 between two adjacent microprisms is 210±50μm, thus obtaining the first optical film 100.

[0094] (2) Preparation of diffusion film 200

[0095] PMMA and PBMA are mixed at a mass ratio of 4:1 and added to liquid optical adhesive, then mixed evenly to form a mixed slurry with a solid content of 8±5wt%. The PMMA particle size r3 is 10μm, and the PBMA particle size r3 is 12μm. The mixed slurry is coated onto one surface of a second substrate 210 made of polyethylene terephthalate (PET) with a thickness n2 of 100μm and a coating thickness n1 of 16±5μm. After the liquid optical adhesive cures, a second optical adhesive 221 is formed. PMMA and PBMA are mixed in the second optical adhesive 221 and together form a second optical layer 220, thus obtaining a diffusion film 200.

[0096] (3) Preparation of composite membrane 10

[0097] A liquid optical adhesive is coated on the surface of the second substrate 210 facing away from the second optical layer 220. The microstructure layer 130 of the first optical film 100 is bonded to the optical adhesive coated on the surface of the second substrate 210, and the microstructure layer 130 is brought into contact with the surface of the second substrate 210. After the liquid optical adhesive is cured, the first optical film 100 and the diffusion film 200 are integrated to obtain the composite film 10.

[0098] The refractive index of the liquid optical adhesive used in this application embodiment is 1.55±0.1.

[0099] Examples 2 to 11

[0100] Comparative Examples 1 to 6 were the same as in Example 1, except that in step (1) the contents of TiO2, SiO2, PMMA, and PBMA were adjusted as shown in Table 1 in the preparation of the first optical film 100, and the angle α of the microprism was adjusted.

[0101] Examples 12 to 19

[0102] Except for step (1), in the preparation of the first optical film 100, the first diffused particles include only PMMA, the reflective material includes only TiO2, and the contents of PMMA and TiO2 are adjusted as shown in Table 1, the rest is the same as in Example 1.

[0103] Example 20

[0104] Except for step (3) preparation of composite membrane 10, the rest is the same as in Example 1.

[0105] Step (3) The preparation of the composite film 10 includes: coating the surface of the second substrate 210 away from the second optical layer 220 with liquid optical adhesive, bonding the 0° brightness enhancement film with the optical adhesive coated on the surface of the second substrate 210 and making the 0° brightness enhancement film contact with the surface of the second substrate 210, and coating the surface of the 0° brightness enhancement film away from the diffusion film 200 with liquid optical adhesive, bonding the first optical film 100 with the optical adhesive coated on the surface of the 0° brightness enhancement film and making the microstructure layer 130 of the first optical film 100 contact with the surface of the 0° brightness enhancement film, and obtaining the composite film 10 after the liquid optical adhesive has cured.

[0106] Example 21 is the same as Example 20 except that the preparation of the composite film 10 in step (3) also includes a 90° brightness enhancement film and the 90° brightness enhancement film is used to replace the 0° brightness enhancement film.

[0107] Example 22 is the same as Example 20, except that step (3) of preparing the composite film 10 also includes a 90° brightness enhancement film, which is placed between the 0° brightness enhancement film and the diffusion film 200. The 90° brightness enhancement film is in contact with the surfaces of both the 0° brightness enhancement film and the diffusion film 200, and the 90° brightness enhancement film is connected to the 0° brightness enhancement film and to the diffusion film 200 respectively by cured optical adhesive.

[0108] The composite films 10 prepared in each embodiment and comparative example were subjected to atomization effect and transmittance test using an NDH5000 fully automatic haze meter (from Shanghai Shouli Industrial Co., Ltd.) under the same test conditions. The haze value was judged based on the effect of obscuring the light source. Obscuring effects of less than 45%, 45%–60%, 60%–75%, 75%–85%, and above 85% were respectively represented as "poor," "relatively poor," "good," "fairly good," and "very good" atomization effects. A "poor" atomization effect resulted in a clearly visible light source, while a "very good" atomization effect resulted in no visible light source.

[0109] The preparation parameters and performance parameters of Examples 1 to 22 and Comparative Examples 1 to 6 are shown in Table 1.

[0110] Table 1

[0111] As can be seen from Examples 1 to 8 and Comparative Examples 1 to 4 in Table 1, by adding diffusing particles to the first optical adhesive of the first optical layer, and selecting materials in the diffusing particles that satisfy 10.5 wt.% ≤ A ≤ 22.0 wt.% and 0.4 ≤ a1 / a2 ≤ 2.0, the composite film exhibits good atomization and light transmission effects. Specifically, as shown in Examples 1 to 4, based on the requirement for atomized light, within a certain range, adding a higher content of diffusing particles to the first optical adhesive can yield a composite film with better atomization effect. As shown in Examples 5 to 8, based on the requirement for light transmission, within a certain range, reducing the content of diffusing particles added to the first optical adhesive or reducing the content of reflective material can yield a composite film with better light transmission and good atomization effect.

[0112] As can be seen from Examples 9 to 11 and Comparative Examples 5 to 6 in Table 1, by selecting the angle of the microprism to satisfy 85°≤α≤105°, the microprism and the diffusion particles in the first optical layer can cooperate to obtain a composite film with good atomization effect.

[0113] As can be seen from Examples 12 to 19 in Table 1, the first diffusing particle and the reflective material each consist of only one material, and the resulting composite film also has good atomization and light transmission effects.

[0114] As can be seen from Examples 20 to 22 in Table 1, when the composite film also includes a 0° brightness enhancement film and a 90° brightness enhancement film, the obtained composite film has a good atomization effect, and the light transmission effect of the composite film can be further improved.

[0115] In the accompanying drawings of this embodiment, the same or similar reference numerals correspond to the same or similar components. In the description of this application, it should be understood that if terms such as "second," "first," "left," and "right" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, they are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms describing positional relationships in the accompanying drawings are only for illustrative purposes and should not be construed as limiting this patent. For those skilled in the art, the specific meaning of the second set of terms can be understood according to the specific circumstances.

[0116] The second description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A composite diaphragm, characterized by, It includes a first optical film, which includes a first substrate, a first optical layer and a microstructure layer. The microstructure layer is connected to a first surface of the first substrate, and the first optical layer is connected to a second surface of the first substrate. The first optical layer comprises a uniformly mixed first optical adhesive and diffusing particles, wherein the diffusing particles comprise a first refractive material and a reflective material; based on the total weight of the first optical adhesive, the weight percentage of the diffusing particles is A, the weight percentage of the first refractive material is a1, and the weight percentage of the reflective material is a2, wherein 10.5 wt.% ≤ A ≤ 22.0 wt.%, and 0.4 ≤ a1 / a2 ≤ 2.

0.

2. The composite diaphragm of claim 1, wherein The first optical layer satisfies at least one of the following conditions: (1)18.0wt.%≤A≤22.0wt.%; (2)4.0wt.%≤a1≤10.0wt.%; (3)4.0wt.%≤a2≤13.0wt.%.

3. The composite diaphragm of claim 1, wherein The first optical film satisfies at least one of the following conditions: (1) The particle size of the first refractive material is r1, 1μm≤r1≤50μm; (2) The particle size of the reflective material is r2, 0.1μm≤r2≤20μm; (4) The thickness of the first optical layer is m1, 5μm≤m1≤15μm; (5) The thickness of the first substrate is m2, 100μm≤m2≤300μm.

4. The composite diaphragm of claim 1, wherein The microstructure layer includes multiple microprisms that deflect light, and the angle of the microprisms is α, where 85°≤α≤105°.

5. The composite diaphragm of claim 4, wherein The microstructure layer satisfies at least one of the following conditions: (1) The edge spacing between two adjacent microprisms in the microstructure layer is L1, 110μm≤L1≤ 300μm; (2) The thickness of the microstructure layer is g, where 30μm≤g≤70μm; (3) The height of the microprism is h, 5μm≤h≤50μm; (3) The microstructure layer covers the first surface.

6. The composite membrane according to claim 1, characterized in that, The reflective material includes at least one of TiO2 and SiO2; The first refractive material includes at least one of polymethyl methacrylate, butyl 2-methyl-2-acrylate monomer, polycarbonate, polystyrene, and polypropylene; The material of the first substrate includes at least one of polycarbonate, polyethylene terephthalate, polystyrene, polyethylene, and polymethyl methacrylate; The material of the microstructure layer includes UV adhesive.

7. The composite diaphragm of claim 1, wherein The composite film further includes a diffusion film, which is disposed on one side of the first surface of the first optical film; The diffusion film includes a second substrate and a second optical layer, wherein the second optical layer is connected to the surface of the second substrate facing away from the first optical film; The second optical layer includes a second optical adhesive and a second refractive material. Based on the total weight of the second optical adhesive, the weight percentage of the second refractive material is a3, where 3wt.% ≤ a3 ≤ 10wt.%.

8. The composite diaphragm of claim 7, wherein, The diffusion membrane satisfies at least one of the following conditions: (1) The particle size of the second refractive material is r3, 1μm≤r3≤50μm (2) The thickness of the second optical layer is n1, 13μm≤n1≤19μm; (3) The thickness of the second substrate is n2, 100μm≤n2≤300μm.

9. The composite membrane according to claim 7, characterized in that, The first optical film and the diffusion film are integrally formed; or, The composite film further includes a brightness enhancement layer, which is connected between the first optical film and the diffusion film, and the first optical film, the brightness enhancement layer and the diffusion film are integrally formed.

10. The composite diaphragm of claim 7, wherein, The composite film further includes a brightness enhancement layer, which is connected between the first optical film and the diffusion film; The brightness enhancement layer includes a 0° brightness enhancement film; or, The brightness enhancement layer includes a 90° brightness enhancement film; or, The brightness enhancement layer includes a first brightness enhancement film and a second brightness enhancement film. The first brightness enhancement film has a first prism, and the second brightness enhancement film has a second prism. The angle difference between the first prism and the second prism is 90°.

11. A backlight module, characterized in that, include: A light source, used to produce light; and The composite film as described in any one of claims 1-10, wherein the composite film is disposed on the light-emitting side of the light source, and the light emitted by the light source passes through the first optical layer, the first substrate and the microstructure layer of the composite film in sequence before being emitted.

12. A display device, characterized by comprising: include: LCD screen; and In the backlight module of claim 11, the liquid crystal screen is disposed on the side of the composite film away from the light source, and the light emitted by the light source passes through the composite film and is projected onto the liquid crystal screen.

Images