Composite ar coating structure for light-emitting diode light guide plate

Abstract

The utility model discloses a kind of composite AR coating structures for light high bright light guide plate before hot pressing, from bottom to top include base layer, intermediate layer and top layer in sequence, the base layer is PC light guide plate base material, the intermediate layer is hard coating, and the top layer is AR coating layer.Multiple AR film effectively inhibits reflection, so that more light is utilized, and the light guide plate is significantly improved light efficiency and visual brightness.The composite structure of "hard coating+AR film" provides mechanical strength and friction resistance, chemical resistance far more than single coating.Low-temperature process protects PC base material and hot-pressing dot from deforming and failing throughout the process;Plasma activation and special resin ensure interlayer adhesion, solve the problem of film layer blistering and peeling off.Used coating, UV curing and magnetron sputtering are mature and high-speed continuous industrial technology, which is very suitable for mass production.

Description

Technical Field

[0001] This utility model relates to the field of hot-pressed light guide plate technology, specifically a composite AR coating structure for hot-pressed high-brightness front light guide plates. Background Technology

[0002] Hot-pressed light guide plates (LGPs) are widely used in front lighting systems to achieve high brightness and uniform light output due to their ability to precisely control light direction through microstructured dots on their surface. Currently, mainstream high-end light guide plates are made of PC material through hot pressing, but their surface still faces three major challenges:

[0003] 1. Scratch-prone: PC material itself has low hardness, making it prone to scratches during transportation, assembly, and use, affecting optical performance and product aesthetics; 2. Reflection loss: Light undergoes Fresnel reflection at the interface between the light guide plate and air, resulting in considerable light energy loss and reducing overall luminous efficiency and brightness; 3. Poor heat resistance: Traditional anti-reflective (AR) coating processes require high temperatures, while PC material has a low glass transition temperature (Tg). High temperatures can cause thermal deformation of the light guide plate and damage to the microstructure dots, thus completely losing its light guiding function. Utility Model Content

[0004] In order to overcome the shortcomings of existing technical solutions, this utility model provides a composite AR coating structure for hot-pressed high-brightness light guide plates, which can effectively solve the problems mentioned in the background technology.

[0005] The technical solution adopted by this utility model to solve its technical problem is:

[0006] A composite AR coating structure for hot-pressed high-brightness light guide plates includes, from bottom to top, a base layer, an intermediate layer and a top layer. The base layer is a PC light guide plate substrate, the intermediate layer is a hard coating, and the top layer is an AR coating layer.

[0007] The surface or interior of the PC light guide plate substrate is formed with microstructure dots by hot pressing, and the microstructure dots are used to control total internal reflection and emission of light.

[0008] The hard coating is directly applied to the surface of the PC light guide plate substrate and the surface of the microstructure dots. The hard coating is a UV-curable resin layer, and the UV-curable resin is chemically bonded to the PC light guide plate substrate to form covalent bonds.

[0009] The AR coating layer is deposited on the side of the hard coating away from the PC light guide plate substrate. The AR coating layer is a multilayer interference film system formed by alternating stacking of various metal oxide layers in a specific thickness and order.

[0010] As a further description of the above technical solution, the thickness of the hard coating is 3-10 μm, and after curing, it forms a dense network structure with high cross-linking density.

[0011] As a further description of the above technical solution, the hard coating has a pencil hardness ≥3H and a glass transition temperature Tg >100℃.

[0012] As a further description of the above technical solution, the metal oxide layer includes at least two of SiO2, TiO2, and Nb2O5.

[0013] As a further description of the above technical solution, the average reflectivity of the AR coating layer in the 450-650nm visible light band is ≤1.5%.

[0014] As a further description of the above technical solution, the AR coating layer is formed by low-temperature magnetron sputtering process, and the substrate temperature is always ≤80℃ during the deposition process.

[0015] As a further description of the above technical solution, the microstructure dots are integrally formed on one side surface or inside of the PC light guide plate substrate.

[0016] As a further description of the above technical solution, the hard coating completely covers the surface of the microstructure dots.

[0017] As a further description of the above technical solution, the microstructure dots are at least one of V-grooves and microlenses.

[0018] Compared with the prior art, the beneficial effects of this utility model are:

[0019] The composite AR coating structure of this utility model for hot-pressed high-brightness light guide plates has at least one of the following beneficial effects during use:

[0020] 1. High brightness: The multi-layer AR film effectively suppresses reflection, allowing more light to be utilized and significantly improving the light output efficiency and visual brightness of the light guide plate; 2. High durability: The composite structure of "hard coating + AR film" provides mechanical strength and abrasion and chemical resistance far exceeding that of a single coating; 3. High reliability: The low-temperature process protects the PC substrate and hot-pressed dots from deformation and failure throughout the process; plasma activation and special resin ensure interlayer adhesion and solve the problems of film blistering and peeling; 4. Mass production feasibility: The coating, UV curing and magnetron sputtering technologies used are all mature and can be carried out at high speed and continuously, making them very suitable for large-scale production. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the first part of a composite AR coating structure for a hot-pressed high-brightness light guide plate according to the present invention.

[0022] Figure 2 This is a schematic diagram of the second part of the composite AR coating structure for a hot-pressed high-brightness light guide plate according to the present invention.

[0023] Numbering on the map:

[0024] 1. Base layer; 101. PC light guide plate substrate; 102. Microstructure dots; 2. Intermediate layer; 201. Hard coating; 3. Top layer; 301. AR coating layer. Detailed Implementation

[0025] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0026] like Figure 1-2 As shown, this utility model provides a composite AR coating structure for a hot-pressed high-brightness light guide plate, which includes a base layer 1, an intermediate layer 2 and a top layer 3 from bottom to top. The base layer 1 is a PC light guide plate substrate 101, the intermediate layer 2 is a hard coating 201, and the top layer 3 is an AR coating layer 301.

[0027] This embodiment is based on a composite structure of a "hard coating 201-AR film layer". This structure is directly constructed on the functional dots of the hot-pressed PC light guide plate, giving it high gloss and high durability surface properties without damaging the dots.

[0028] The PC light guide plate substrate 101 has microstructure dots 102 formed on its surface or inside by hot pressing. The microstructure dots 102 are used to control total internal reflection and emission of light.

[0029] The PC light guide plate substrate 101 serves as the main structural element, and a precise microstructure dot 102 is formed on one side or inside it through a hot pressing process to control the total internal reflection and emission of light.

[0030] The hard coating 201 is directly coated on the surface of the PC light guide plate substrate 101 and the surface of the microstructure dots 102. The hard coating 201 is a UV-curable resin layer. The UV-curable resin and the PC light guide plate substrate 101 are connected by chemical bonding to form covalent bonds.

[0031] The hard coating 201 is directly applied to the PC substrate and its microstructure dots 102. It is composed of a specialized UV-curable resin, whose chemical composition ensures strong covalent bonding with the PC surface, achieving excellent adhesion. After curing, it forms a dense network with high cross-linking density, providing a surface hardness far exceeding that of the PC substrate (up to >3H pencil hardness), serving as the primary scratch-resistant functional layer. Simultaneously, its high glass transition temperature (Tg>100℃) provides thermal protection for subsequent processes.

[0032] The AR coating layer 301 is deposited on the side of the hard coating 201 away from the PC light guide plate substrate 101. The AR coating layer 301 is a multilayer interference film system formed by alternating stacking of various metal oxide layers in a specific thickness and order.

[0033] The AR coating layer 301 is deposited on the hard coating layer 201 by low-temperature magnetron sputtering. It is composed of various metal oxides (such as SiO2, TiO2, Nb2O5, etc.) stacked alternately in a specific thickness and order, forming a multilayer interference film system that can effectively eliminate reflected light in specific wavelengths (such as visible light). The hard coating layer 201 provides an ideal substrate that is hard, smooth, chemically inert, and has good adhesion.

[0034] Specifically, using a lint-free cloth and high-purity isopropanol, grease, fingerprints, and dust are thoroughly removed from the surface of the hot-pressed light guide plate in a dust-free environment, ensuring that no particulate matter remains in the microstructure dots 102. The cleaned light guide plate is then treated with atmospheric pressure or vacuum plasma. The highly active particles in the plasma effectively bombard and clean the PC surface, while simultaneously introducing polar groups (such as hydroxyl and carboxyl groups) into its molecular chains, significantly increasing the surface energy. This allows the subsequent hard coating 201 resin to fully wet and penetrate every corner of the microstructure dots 102, achieving an "anchored" mechanical interlocking and chemical bonding, which is key to obtaining ultra-high adhesion.

[0035] Depending on the dot structure, slot coating or precision spraying can be selected to ensure that the resin liquid can uniformly cover all microstructures without producing liquid accumulation or defects, forming a uniform wet film with a thickness of 3-10 μm. Under nitrogen protection, UV light of a specific wavelength is used for irradiation, causing the photoinitiator in the resin to generate free radicals, initiating a polymerization reaction, and forming a highly cross-linked three-dimensional network structure within seconds, resulting in a hard and transparent protective layer.

[0036] The light guide plate with the hard coating 201 cured is sent into the magnetron sputtering vacuum chamber. By precisely controlling the process parameters (such as working gas pressure, sputtering power, and gas flow rate), and under the condition that the substrate temperature is always below 80°C, oxide targets with different refractive indices are sputtered and deposited sequentially. The thickness of each film is monitored in real time by an optical monitoring system, so as to accurately construct a multilayer AR film system that can achieve an average reflectivity of less than 1.5% in the target wavelength band (such as 450-650nm).

[0037] Furthermore, the thickness of the hard coating 201 is 3-10 μm, and after curing, it forms a dense network structure with high cross-linking density.

[0038] The UV-curable resin and the PC substrate form covalent bonds through chemical bonding. The active groups in the resin (such as hydroxyl and epoxy groups) react chemically with the ester groups on the PC molecular chain. At the same time, the coating "completely covers the surface of the microstructure dots 102", including complex areas such as the bottom of the V-groove and the curved surface of the microlens, forming a dual adhesion of "mechanical anchoring + chemical bonding", which solves the problem of traditional coatings "easily falling off due to only physical adhesion".

[0039] Furthermore, the hard coating 201 has a pencil hardness ≥3H and a glass transition temperature Tg >100℃.

[0040] After the coating is cured, the glass transition temperature Tg is greater than 100℃ and the pencil hardness is greater than 3H. On the one hand, the subsequent AR coating adopts a low-temperature process of ≤80℃. The coating Tg is higher than the coating temperature, which can block the heat transfer to the PC substrate and prevent the PC from collapsing due to high temperature softening. On the other hand, the high hardness and dense structure can resist friction / scratching during transportation and assembly, and prevent the PC substrate from being directly damaged.

[0041] Furthermore, the metal oxide layer includes at least two of SiO2, TiO2, and Nb2O5.

[0042] AR coating layer 301 is a multilayer interference film system in which "multiple metal oxides are stacked alternately in a specific thickness and order". The metal oxides include at least two of SiO2 and TiO2 / Nb2O5. An optical interference system is constructed by alternating stacking of "low refractive index layer-high refractive index layer" (such as SiO2-TiO2-SiO2).

[0043] Furthermore, the AR coating layer 301 has an average reflectivity of ≤1.5% in the 450-650nm visible light band.

[0044] The dense network structure makes the coating surface flat, smooth, and chemically inert (without easily reactive groups), providing a "uniform-stable-inert" deposition substrate for the top 3AR coating - avoiding the influence of microscopic defects (such as pores and impurities) on the PC substrate surface on the uniformity of the AR film layer, and ensuring the stability of the optical interference effect of the AR layer.

[0045] By utilizing the "light interference cancellation" effect—when visible light (450-650nm band) is incident on the AR film, the upper and lower surfaces of different films will generate reflected light respectively; by precisely controlling the thickness of each film, the reflected light of adjacent films will have a 180° phase difference and the amplitude of the reflected light will be similar, eventually canceling each other out, thereby greatly reducing the surface reflectivity.

[0046] Furthermore, the AR coating layer 301 is formed by low-temperature magnetron sputtering, and the substrate temperature is always ≤80℃ during the deposition process.

[0047] During the deposition process, the substrate temperature remains ≤80℃—this temperature is lower than the glass transition temperature of the PC light guide plate (approximately 150℃). Combined with the thermal barrier effect of the hard coating 201, thermal deformation of the PC substrate and damage to the microstructure dots 102 can be completely avoided. In addition, magnetron sputtering can achieve uniform deposition of metal oxides, and even on the surface of the microstructure dots 102 covered by the hard coating 201, an AR film layer of uniform thickness can be formed, ensuring uniform anti-reflection effect on complex surfaces.

[0048] Furthermore, the microstructure dots 102 are integrally formed on one side surface or inside the PC light guide plate substrate 101.

[0049] The PC light guide plate substrate 101 is integrally formed with microstructure dots 102 (at least one such as V-groove or microlens) on one side surface or inside through a hot pressing process. The dots are "customized optical structures" - their groove depth, spacing, curvature and other parameters are designed according to the uniformity of light output from the target, and the hot pressing integral forming ensures the accuracy of the dot structure.

[0050] Furthermore, the hard coating 201 completely covers the surface of the microstructure dots 102.

[0051] Furthermore, the microstructure dots 102 are at least one of V-grooves and microlenses.

[0052] In summary, the multi-layer AR film effectively suppresses reflection, allowing more light to be utilized and significantly improving the light extraction efficiency and visual brightness of the light guide plate. The composite structure of the "hard coating 201 + AR film" provides mechanical strength and resistance to abrasion and chemicals far exceeding that of a single coating. The low-temperature process protects the PC substrate and hot-pressed dots from deformation and failure throughout the process; plasma activation and a special resin ensure interlayer adhesion, solving the problems of film blistering and peeling. The coating, UV curing, and magnetron sputtering techniques used are all mature and high-speed continuous industrial technologies, making them very suitable for large-scale production.

[0053] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A composite AR coating structure for a hot-pressed high-brightness light guide plate, characterized in that: From bottom to top, it includes a base layer, an intermediate layer and a top layer. The base layer is a PC light guide plate substrate, the intermediate layer is a hard coating, and the top layer is an AR coating layer. The surface or interior of the PC light guide plate substrate is formed with microstructure dots by hot pressing, and the microstructure dots are used to control total internal reflection and emission of light. The hard coating is directly applied to the surface of the PC light guide plate substrate and the surface of the microstructure dots. The hard coating is a UV-curable resin layer, and the UV-curable resin is chemically bonded to the PC light guide plate substrate to form covalent bonds. The AR coating layer is deposited on the side of the hard coating away from the PC light guide plate substrate. The AR coating layer is a multilayer interference film system formed by alternating stacking of various metal oxide layers in a specific thickness and order.

2. The composite AR coating structure for a hot-pressed high-brightness light guide plate according to claim 1, characterized in that: The thickness of the hard coating is 3-10 μm, and after curing, it forms a dense network structure with high cross-linking density.

3. A composite AR coating structure for a hot-pressed high-brightness light guide plate according to claim 1 or 2, characterized in that: The hard coating has a pencil hardness ≥3H and a glass transition temperature Tg >100℃.

4. The composite AR coating structure for a hot-pressed high-brightness light guide plate according to claim 1, characterized in that: The metal oxide layer includes at least two of SiO2, TiO2, and Nb2O5.

5. The composite AR coating structure for a hot-pressed high-brightness light guide plate according to claim 1, characterized in that: The AR coating layer has an average reflectivity of ≤1.5% in the 450-650nm visible light band.

6. The composite AR coating structure for a hot-pressed high-brightness light guide plate according to claim 1, characterized in that: The AR coating layer is formed by low-temperature magnetron sputtering, and the substrate temperature is always ≤80℃ during the deposition process.

7. The composite AR coating structure for a hot-pressed high-brightness light guide plate according to claim 1, characterized in that: The microstructure dots are integrally formed on one side surface or inside the PC light guide plate substrate.

8. The composite AR coating structure for a hot-pressed high-brightness light guide plate according to claim 1, characterized in that: The hard coating completely covers the surface of the microstructure dots.

9. The composite AR coating structure for a hot-pressed high-brightness light guide plate according to claim 1, characterized in that: The microstructure dots are at least one of V-grooves and microlenses.

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